diff --git a/.github/workflows/luacheck.yml b/.github/workflows/luacheck.yml
index a03fe92..d00f53a 100644
--- a/.github/workflows/luacheck.yml
+++ b/.github/workflows/luacheck.yml
@@ -1,6 +1,6 @@
 name: luacheck
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   build:
diff --git a/README.md b/README.md
index bd40e4d..31a15c6 100644
--- a/README.md
+++ b/README.md
@@ -29,6 +29,13 @@ To provide a web-based interface to receive/send mails you can use the [mtui](ht
 To access your mail click on the inventory mail button or use the "/mail" command
 Mails can be deleted, marked as read or unread, replied to and forwarded to another player
 
+# Compatibility / Migration
+
+Overview:
+* `v1` all the data is in the `<worldfolder>/mails.db` file
+* `v2` every player has its own (in-) mailbox in the `<worldfolder>/mails/<playername>.json` file
+* `v3` every player has an entry in the `<playername>` modstorage (inbox, outbox, contacts)
+
 # Dependencies
 * None
 
@@ -43,6 +50,12 @@ See the "LICENSE" file
 
 * Cheapie (initial idea/project)
 * Rubenwardy (lua/ui improvements)
+* BuckarooBanzay (cleanups, refactoring)
+* Athozus (outbox, maillists, ui fixes)
+* fluxionary (minor fixups)
+* SX (various fixes)
+* Toby1710 (ux fixes)
+* Peter Nerlich (cc, bcc)
 
 # Old/Historic stuff
 * Old forum topic: https://forum.minetest.net/viewtopic.php?t=14464
diff --git a/api.lua b/api.lua
index 1559954..24d1a47 100644
--- a/api.lua
+++ b/api.lua
@@ -10,36 +10,15 @@ end
 mail.receive_mail_message = "You have a new message from %s! Subject: %s\nTo view it, type /mail"
 mail.read_later_message = "You can read your messages later by using the /mail command"
 
---[[
-mail sending function, can be invoked with one object argument (new api) or
-all 4 parameters (old compat version)
-see: "Mail format" api.md
+function mail.send(m)
+	if type(m.from) ~= "string" then return false, "'from' is not a string" end
+	if type(m.to) ~= "string" then return false, "'to' is not a string" end
+	if type(m.body) ~= "string" then return false, "'body' is not a string" end
 
-TODO: refactor this garbage code!
---]]
-function mail.send(...)
-	-- figure out format
-	local m
-	if #{...} == 1 then
-		-- new format (one table param)
-		m = ...
-		-- populate "to" field
-		m.to = m.to or m.dst
-		-- populate "from" field
-		m.from = m.from or m.src
-	else
-		-- old format
-		m = {}
-		m.from, m.to, m.subject, m.body = ...
-	end
+	-- defaults
+	m.subject = m.subject or "(No subject)"
 
-	-- sane default values
-	m.subject = m.subject or ""
-	m.body = m.body or ""
-
-	if m.subject == "" then
-		m.subject = "(No subject)"
-	end
+	-- limit subject line
 	if string.len(m.subject) > 30 then
 		m.subject = string.sub(m.subject,1,27) .. "..."
 	end
@@ -47,11 +26,14 @@ function mail.send(...)
 	-- normalize to, cc and bcc while compiling a list of all recipients
 	local recipients = {}
 	local undeliverable = {}
+	m.to = mail.concat_player_list(mail.extractMaillists(m.to, m.from))
 	m.to = mail.normalize_players_and_add_recipients(m.to, recipients, undeliverable)
 	if m.cc then
+		m.cc = mail.concat_player_list(mail.extractMaillists(m.cc, m.from))
 		m.cc = mail.normalize_players_and_add_recipients(m.cc, recipients, undeliverable)
 	end
 	if m.bcc then
+		m.bcc = mail.concat_player_list(mail.extractMaillists(m.bcc, m.from))
 		m.bcc = mail.normalize_players_and_add_recipients(m.bcc, recipients, undeliverable)
 	end
 
@@ -60,9 +42,7 @@ function mail.send(...)
 		for name in pairs(undeliverable) do
 			undeliverable_names[#undeliverable_names + 1] = '"' .. name .. '"'
 		end
-		return f("recipients %s don't exist; cannot send mail.",
-			table.concat(undeliverable_names, ", ")
-		)
+		return false, f("recipients %s don't exist; cannot send mail.", table.concat(undeliverable_names, ", "))
 	end
 
 	local extra = {}
@@ -85,20 +65,26 @@ function mail.send(...)
 
 	-- form the actual mail
 	local msg = {
-		unread  = true,
-		sender  = m.from,
-		to      = m.to,
-		cc      = m.cc,
+		id = mail.new_uuid(),
+		from = m.from,
+		to = m.to,
+		cc = m.cc,
+		bcc = m.bcc,
 		subject = m.subject,
-		body    = m.body,
-		time    = os.time(),
+		body = m.body,
+		time = os.time(),
 	}
 
-	-- send the mail to all recipients
+	-- add in senders outbox
+	local entry = mail.get_storage_entry(m.from)
+	table.insert(entry.outbox, 1, msg)
+	mail.set_storage_entry(m.from, entry)
+
+	-- add in every receivers inbox
 	for recipient in pairs(recipients) do
-		local messages = mail.getMessages(recipient)
-		table.insert(messages, 1, msg)
-		mail.setMessages(recipient, messages)
+		entry = mail.get_storage_entry(recipient)
+		table.insert(entry.inbox, msg)
+		mail.set_storage_entry(recipient, entry)
 	end
 
 	-- notify recipients that happen to be online
@@ -115,4 +101,6 @@ function mail.send(...)
 			break
 		end
 	end
+
+	return true
 end
diff --git a/api.md b/api.md
index b0800e2..7ef2ea9 100644
--- a/api.md
+++ b/api.md
@@ -9,47 +9,28 @@ mail = {
 	cc = "carbon copy",
 	bcc = "players, which, get, a, copy, but, are, not, visible, to, others",
 	subject = "subject line",
-	body = "mail body",
-	-- 8 attachments max
-	attachments = {"default:stone 99", "default:gold_ingot 99"}
+	body = "mail body"
 }
 ```
 
-The fields `to`, `cc` and `bcc` can contain a player, multiple player names separated by commas, or be empty. Players in `to` are the recipiants, who are addressed directly. `cc` specifies players that get the mail to get notified, but are not immediate part of the conversation. There is no technical difference between `to` and `cc`, it just implies meaning for the players. Players can see all fields making up the mail except `bcc`, which is the only difference to `cc`.
-
-Attachments need to be provided for each player getting the mail. Until this is implemented, trying to send a mail to multiple players will fail.
-
-The `from` and `to` fields were renamed from the previous format:
-
-```lua
-mail = {
-	src = "source name",
-	dst = "destination name",
-	subject = "subject line",
-	body = "mail body",
-	-- 8 attachments max
-	attachments = {"default:stone 99", "default:gold_ingot 99"}
-}
-```
+The fields `to`, `cc` and `bcc` can contain a player, multiple player names separated by commas, or be empty.
+Players in `to` are the recipiants, who are addressed directly. `cc` specifies players that get the mail to get notified, but are not immediate part of the conversation.
+There is no technical difference between `to` and `cc`, it just implies meaning for the players.
+Players can see all fields making up the mail except `bcc`, which is the only difference to `cc`.
 
 ## Sending mail
-Old variant (pre-1.1)
-```lua
-local error = mail.send("source name", "destination name", "subject line", "mail body")
--- error will contain an error message if mail couldn't be delivered, otherwise nil
-```
 
-New variant (1.1+)
 ```lua
-local error = mail.send({
-	from = "sender name",
-	to = "destination name",
-	cc = "carbon copy",
-	bcc = "blind carbon copy",
+local success, error = mail.send({
+	from = "singleplayer",
+	to = "playername",
+	cc = "carbon, copy",
+	bcc = "blind, carbon, copy",
 	subject = "subject line",
 	body = "mail body"
 })
--- error will contain an error message if mail couldn't be delivered, otherwise nil
+
+-- if "success" is false the error parameter will contain a message
 ```
 
 # Hooks
@@ -61,22 +42,56 @@ mail.register_on_receive(function(m)
 end)
 ```
 
-# internal mail format (on-disk)
-The mail format on-disk
+# Internals
 
-> (worldfolder)/mails/(playername).json
-
-```json
-[{
-	"unread": true,
-	"sender": "sender name",
-	"subject": "subject name",
-	"body": "main\nmultiline\nbody",
-	"time": 1551258349,
-	"attachments": [
-		"default:stone 99",
-		"default:gold_ingot 99"
-	]
-}]
-
-```
+mod-storage entry for a player (indexed by playername and serialized with json):
+```lua
+{
+	contacts = {
+		{
+			-- name of the player (unique key in the list)
+			name = "",
+			-- note
+			note = ""
+		},{
+			...
+		}
+	},
+	inbox = {
+		{
+			-- globally unique mail id
+			id = "d6cce35c-487a-458f-bab2-9032c2621f38",
+			-- sending player name
+			from = "",
+			-- receiving player name
+			to = "",
+			-- carbon copy (optional)
+			cc = "playername, playername2",
+			-- blind carbon copy (optional)
+			bcc = "",
+			-- mail subject
+			subject = "",
+			-- mail body
+			body = "",
+			-- timestamp (os.time())
+			time = 1234,
+			-- read-flag (true: player has read the mail, inbox only)
+			read = true
+		},{
+			...
+		}
+	},
+	outbox = {
+		-- same format as "inbox"
+	},
+	lists = {
+		{
+			-- name of the maillist (unique key in the list)
+			name = "",
+			-- description
+			description = "",
+			-- playername list
+			players = {"playername", "playername2"}
+		}
+	}
+}
diff --git a/api.spec.lua b/api.spec.lua
new file mode 100644
index 0000000..a9f9d2f
--- /dev/null
+++ b/api.spec.lua
@@ -0,0 +1,12 @@
+mtt.register("send mail", function(callback)
+    -- send a mail
+    local success, err = mail.send({from = "player1", to = "player2", subject = "something", body = "blah"})
+    assert(success)
+    assert(not err)
+
+    -- check the receivers inbox
+    local entry = mail.get_storage_entry("player2")
+    assert(entry)
+    assert(#entry.inbox > 0)
+    callback()
+end)
diff --git a/gui.lua b/gui.lua
index 07f0a2f..9607771 100644
--- a/gui.lua
+++ b/gui.lua
@@ -1,189 +1,8 @@
--- refactor these to some proper management thing
-mail.selected_idxs = {
-	messages = {},
-	contacts = {},
-	to = {},
-	cc = {},
-	bcc = {},
-}
-
-mail.message_drafts = {}
-
-local selected_idxs = mail.selected_idxs
-local message_drafts = mail.message_drafts
-
-local theme
-if minetest.get_modpath("default") then
-	theme = default.gui_bg .. default.gui_bg_img
-else
-	theme = ""
-end
-
-mail.inbox_formspec = "size[8,9;]" .. theme .. [[
-		button[6,0.10;2,0.5;new;New]
-		button[6,0.95;2,0.5;read;Read]
-		button[6,1.70;2,0.5;reply;Reply]
-		button[6,2.45;2,0.5;replyall;Reply All]
-		button[6,3.20;2,0.5;forward;Forward]
-		button[6,3.95;2,0.5;delete;Delete]
-		button[6,4.82;2,0.5;markread;Mark Read]
-		button[6,5.55;2,0.5;markunread;Mark Unread]
-		button[6,6.55;2,0.5;contacts;Contacts]
-		button[6,7.40;2,0.5;about;About]
-		button_exit[6,8.45;2,0.5;quit;Close]
-
-		tablecolumns[color;text;text]
-		table[0,0;5.75,9;messages;#999,From,Subject]]
-
-mail.contacts_formspec = "size[8,9;]" .. theme .. [[
-		button[6,0.10;2,0.5;new;New]
-		button[6,0.85;2,0.5;edit;Edit]
-		button[6,1.60;2,0.5;delete;Delete]
-		button[6,8.25;2,0.5;back;Back]
-		tablecolumns[color;text;text]
-		table[0,0;5.75,9;contacts;#999,Name,Note]]
-
-mail.select_contact_formspec = "size[8,9;]" .. theme .. [[
-		tablecolumns[color;text;text]
-		table[0,0;3.5,9;contacts;#999,Name,Note%s]
-		button[3.55,2.00;1.75,0.5;toadd;→ Add]
-		button[3.55,2.75;1.75,0.5;toremove;← Remove]
-		button[3.55,6.00;1.75,0.5;ccadd;→ Add]
-		button[3.55,6.75;1.75,0.5;ccremove;← Remove]
-		tablecolumns[color;text;text]
-		table[5.15,0.0;2.75,4.5;to;#999,TO:,Note%s]
-		tablecolumns[color;text;text]
-		table[5.15,4.6;2.75,4.5;cc;#999,CC:,Note%s]
-		button[3.55,8.25;1.75,0.5;back;Back]
-	]]
-
-
-function mail.show_about(name)
-	local formspec = [[
-			size[8,5;]
-			button[7.25,0;0.75,0.5;back;X]
-			label[0,0;Mail]
-			label[0,0.5;By cheapie]
-			label[0,1;http://github.com/cheapie/mail]
-			label[0,1.5;See LICENSE file for license information]
-			label[0,2.5;NOTE: Communication using this system]
-			label[0,3;is NOT guaranteed to be private!]
-			label[0,3.5;Admins are able to view the messages]
-			label[0,4;of any player.]
-		]] .. theme
-
-	minetest.show_formspec(name, "mail:about", formspec)
-end
-
-function mail.show_inbox(name)
-	local formspec = { mail.inbox_formspec }
-	local messages = mail.getMessages(name)
-
-	message_drafts[name] = nil
-
-	if messages[1] then
-		for _, message in ipairs(messages) do
-			mail.ensure_new_format(message, name)
-			if message.unread then
-				if not mail.player_in_list(name, message.to) then
-					formspec[#formspec + 1] = ",#FFD788"
-				else
-					formspec[#formspec + 1] = ",#FFD700"
-				end
-			else
-				if not mail.player_in_list(name, message.to) then
-					formspec[#formspec + 1] = ",#CCCCDD"
-				else
-					formspec[#formspec + 1] = ","
-				end
-			end
-			formspec[#formspec + 1] = ","
-			formspec[#formspec + 1] = minetest.formspec_escape(message.sender)
-			formspec[#formspec + 1] = ","
-			if message.subject ~= "" then
-				if string.len(message.subject) > 30 then
-					formspec[#formspec + 1] =
-							minetest.formspec_escape(string.sub(message.subject, 1, 27))
-					formspec[#formspec + 1] = "..."
-				else
-					formspec[#formspec + 1] = minetest.formspec_escape(message.subject)
-				end
-			else
-				formspec[#formspec + 1] = "(No subject)"
-			end
-		end
-		if selected_idxs.messages[name] then
-			formspec[#formspec + 1] = ";"
-			formspec[#formspec + 1] = tostring(selected_idxs.messages[name] + 1)
-		end
-		formspec[#formspec + 1] = "]"
-	else
-		formspec[#formspec + 1] = "]label[2.25,4.5;No mail]"
-	end
-	minetest.show_formspec(name, "mail:inbox", table.concat(formspec, ""))
-end
-
-function mail.show_contacts(name)
-	local formspec = mail.contacts_formspec .. mail.compile_contact_list(name, selected_idxs.contacts[name])
-	minetest.show_formspec(name, "mail:contacts", formspec)
-end
-
-function mail.show_edit_contact(name, contact_name, note, illegal_name_hint)
-	local formspec = [[
-			size[6,7]
-			button[4,6.25;2,0.5;back;Back]
-			field[0.25,0.5;4,1;name;Player name:;%s]
-			textarea[0.25,1.6;4,6.25;note;Note:;%s]
-			button[4,0.10;2,1;save;Save]
-		]]
-	if illegal_name_hint == "collision" then
-		formspec = formspec .. [[
-				label[4,1;That name]
-				label[4,1.5;is already in]
-				label[4,2;your contacts.]
-			]]
-	elseif illegal_name_hint == "empty" then
-		formspec = formspec .. [[
-				label[4,1;The contact]
-				label[4,1.5;name cannot]
-				label[4,2;be empty.]
-			]]
-	end
-	formspec = formspec .. theme
-	formspec = string.format(formspec,
-		minetest.formspec_escape(contact_name or ""),
-		minetest.formspec_escape(note or ""))
-	minetest.show_formspec(name, "mail:editcontact", formspec)
-end
-
-function mail.show_select_contact(name, to, cc)
-	local formspec = mail.select_contact_formspec
-	local contacts = mail.compile_contact_list(name, selected_idxs.contacts[name])
-
-	-- compile lists
-	if to then
-		to = mail.compile_contact_list(name, selected_idxs.to[name], to)
-	else
-		to = ""
-	end
-	if cc then
-		cc = mail.compile_contact_list(name, selected_idxs.cc[name], cc)
-	else
-		cc = ""
-	end
-	--[[if bcc then
-		bcc = table.concat(mail.compile_contact_list(name, selected_idxs.bcc[name], bcc)
-	else
-		bcc = ""
-	end]]--
-	formspec = string.format(formspec, contacts, to, cc)--, bcc()
-	minetest.show_formspec(name, "mail:selectcontact", formspec)
-end
 
 function mail.compile_contact_list(name, selected, playernames)
 	-- TODO: refactor this - not just compiles *a* list, but *the* list for the contacts screen (too inflexible)
 	local formspec = {}
-	local contacts = mail.getContacts(name)
+	local contacts = mail.get_contacts(name)
 
 	if playernames == nil then
 		local length = 0
@@ -250,465 +69,9 @@ function mail.compile_contact_list(name, selected, playernames)
 		formspec[#formspec + 1] = "]"
 	end
 	return table.concat(formspec, "")
+
 end
 
-function mail.show_message(name, msgnumber)
-	local messages = mail.getMessages(name)
-	local message = messages[msgnumber]
-	local formspec = [[
-			size[8,9]
-
-			box[0,0;7,1.9;#466432]
-
-			button[7.25,0.15;0.75,0.5;back;X]
-
-			label[0.2,0.1;From: %s]
-			label[0.2,0.5;To: %s]
-			label[0.2,0.9;CC: %s]
-			label[0.2,1.3;Date: %s]
-
-			label[0,2.1;Subject: %s]
-			textarea[0.25,2.6;8,7.0;;;%s]
-
-			button[0,8.5;2,1;reply;Reply]
-			button[2,8.5;2,1;replyall;Reply All]
-			button[4,8.5;2,1;forward;Forward]
-			button[6,8.5;2,1;delete;Delete]
-		]] .. theme
-
-	local from = minetest.formspec_escape(message.sender) or ""
-	local to = minetest.formspec_escape(message.to) or ""
-	local cc = minetest.formspec_escape(message.cc) or ""
-	local date = type(message.time) == "number"
-		and minetest.formspec_escape(os.date("%Y-%m-%d %X", message.time)) or ""
-	local subject = minetest.formspec_escape(message.subject) or ""
-	local body = minetest.formspec_escape(message.body) or ""
-	formspec = string.format(formspec, from, to, cc, date, subject, body)
-
-	if message.unread then
-		message.unread = false
-		mail.setMessages(name, messages)
-	end
-
-	minetest.show_formspec(name,"mail:message",formspec)
-end
-
-function mail.show_compose(name, defaultto, defaultsubj, defaultbody, defaultcc, defaultbcc)
-	local formspec = [[
-			size[8,9]
-			button[0,0;1,1;tocontacts;To:]
-			field[1.1,0.3;3.2,1;to;;%s]
-			button[4,0;1,1;cccontacts;CC:]
-			field[5.1,0.3;3.1,1;cc;;%s]
-			button[4,0.75;1,1;bcccontacts;BCC:]
-			field[5.1,1.05;3.1,1;bcc;;%s]
-			field[0.25,2;8,1;subject;Subject:;%s]
-			textarea[0.25,2.5;8,6;body;;%s]
-			button[0.5,8.5;3,1;cancel;Cancel]
-			button[4.5,8.5;3,1;send;Send]
-		]] .. theme
-
-	defaultto = defaultto or ""
-	defaultsubj = defaultsubj or ""
-	defaultbody = defaultbody or ""
-	defaultcc = defaultcc or ""
-	defaultbcc = defaultbcc or ""
-
-	formspec = string.format(formspec,
-		minetest.formspec_escape(defaultto),
-		minetest.formspec_escape(defaultcc),
-		minetest.formspec_escape(defaultbcc),
-		minetest.formspec_escape(defaultsubj),
-		minetest.formspec_escape(defaultbody))
-
-	minetest.show_formspec(name, "mail:compose", formspec)
-end
-
-function mail.reply(name, message)
-	mail.ensure_new_format(message)
-	local replyfooter = "Type your reply here.\n\n--Original message follows--\n" ..message.body
-	mail.show_compose(name, message.sender, "Re: "..message.subject, replyfooter)
-end
-
-function mail.replyall(name, message)
-	mail.ensure_new_format(message)
-	local replyfooter = "Type your reply here.\n\n--Original message follows--\n" ..message.body
-
-	-- new recipients are the sender plus the original recipients, minus ourselves
-	local recipients = message.to or ""
-	if message.sender ~= nil then
-		recipients = message.sender .. ", " .. recipients
-	end
-	recipients = mail.parse_player_list(recipients)
-	for k,v in pairs(recipients) do
-		if v == name then
-			table.remove(recipients, k)
-			break
-		end
-	end
-	recipients = mail.concat_player_list(recipients)
-
-	-- new CC is old CC minus ourselves
-	local cc = mail.parse_player_list(message.cc)
-	for k,v in pairs(cc) do
-		if v == name then
-			table.remove(cc, k)
-			break
-		end
-	end
-	cc = mail.concat_player_list(cc)
-
-	mail.show_compose(name, recipients, "Re: "..message.subject, replyfooter, cc)
-end
-
-function mail.forward(name, message)
-	local fwfooter = "Type your message here.\n\n--Original message follows--\n" .. (message.body or "")
-	mail.show_compose(name, "", "Fw: " .. (message.subject or ""), fwfooter)
-end
-
-function mail.handle_receivefields(player, formname, fields)
-	if formname == "mail:about" then
-		minetest.after(0.5, function()
-			mail.show_inbox(player:get_player_name())
-		end)
-		return true
-
-	elseif formname == "mail:inbox" then
-		local name = player:get_player_name()
-		local messages = mail.getMessages(name)
-
-		if fields.messages then
-			local evt = minetest.explode_table_event(fields.messages)
-			selected_idxs.messages[name] = evt.row - 1
-			if evt.type == "DCL" and messages[selected_idxs.messages[name]] then
-				mail.show_message(name, selected_idxs.messages[name])
-			end
-			return true
-		end
-
-		if fields.read then
-			if messages[selected_idxs.messages[name]] then
-				mail.show_message(name, selected_idxs.messages[name])
-			end
-
-		elseif fields.delete then
-			if messages[selected_idxs.messages[name]] then
-				table.remove(messages, selected_idxs.messages[name])
-				mail.setMessages(name, messages)
-			end
-
-			mail.show_inbox(name)
-
-		elseif fields.reply and messages[selected_idxs.messages[name]] then
-			local message = messages[selected_idxs.messages[name]]
-			mail.reply(name, message)
-
-		elseif fields.replyall and messages[selected_idxs.messages[name]] then
-			local message = messages[selected_idxs.messages[name]]
-			mail.replyall(name, message)
-
-		elseif fields.forward and messages[selected_idxs.messages[name]] then
-			local message = messages[selected_idxs.messages[name]]
-			mail.forward(name, message)
-
-		elseif fields.markread then
-			if messages[selected_idxs.messages[name]] then
-				messages[selected_idxs.messages[name]].unread = false
-				-- set messages immediately, so it shows up already when updating the inbox
-				mail.setMessages(name, messages)
-			end
-			mail.show_inbox(name)
-
-		elseif fields.markunread then
-			if messages[selected_idxs.messages[name]] then
-				messages[selected_idxs.messages[name]].unread = true
-				-- set messages immediately, so it shows up already when updating the inbox
-				mail.setMessages(name, messages)
-			end
-			mail.show_inbox(name)
-
-		elseif fields.new then
-			mail.show_compose(name)
-
-		elseif fields.contacts then
-			mail.show_contacts(name)
-
-		elseif fields.about then
-			mail.show_about(name)
-
-		end
-
-		return true
-
-	elseif formname == "mail:message" then
-		local name = player:get_player_name()
-		local messages = mail.getMessages(name)
-
-		if fields.back then
-			mail.show_inbox(name)
-			return true	-- don't uselessly set messages
-
-		elseif fields.reply then
-			local message = messages[selected_idxs.messages[name]]
-			mail.reply(name, message)
-
-		elseif fields.replyall then
-			local message = messages[selected_idxs.messages[name]]
-			mail.replyall(name, message)
-
-		elseif fields.forward then
-			local message = messages[selected_idxs.messages[name]]
-			mail.forward(name, message)
-
-		elseif fields.delete then
-			if messages[selected_idxs.messages[name]] then
-				table.remove(messages,selected_idxs.messages[name])
-				mail.setMessages(name, messages)
-			end
-			mail.show_inbox(name)
-		end
-
-		return true
-
-	elseif formname == "mail:compose" then
-		local name = player:get_player_name()
-		if fields.send then
-			local error = mail.send({
-				from = name,
-				to = fields.to,
-				cc = fields.cc,
-				bcc = fields.bcc,
-				subject = fields.subject,
-				body = fields.body,
-			})
-			if error then
-				minetest.chat_send_player(name, error)
-				return
-			end
-
-			local contacts = mail.getContacts(name)
-			local recipients = mail.parse_player_list(fields.to)
-			local changed = false
-			for _,v in pairs(recipients) do
-				if contacts[string.lower(v)] == nil then
-					contacts[string.lower(v)] = {
-						name = v,
-						note = "",
-					}
-					changed = true
-				end
-			end
-			if changed then
-				mail.setContacts(name, contacts)
-			end
-
-			minetest.after(0.5, function()
-				mail.show_inbox(name)
-			end)
-
-		elseif fields.tocontacts or fields.cccontacts or fields.bcccontacts then
-			message_drafts[name] = {
-				to = fields.to,
-				cc = fields.cc,
-				bcc = fields.bcc,
-				subject = fields.subject,
-				body = fields.body,
-			}
-			mail.show_select_contact(name, fields.to, fields.cc, fields.bcc)
-
-		elseif fields.cancel then
-			message_drafts[name] = nil
-			mail.show_inbox(name)
-		end
-
-		return true
-
-	elseif formname == "mail:selectcontact" then
-		local name = player:get_player_name()
-		local contacts = mail.getContacts(name)
-		local draft = message_drafts[name]
-
-		-- get indexes for fields with selected rows
-		-- execute their default button's actions if double clicked
-		for k,action in pairs({
-			contacts = "toadd",
-			to = "toremove",
-			cc = "ccremove",
-			bcc = "bccremove"
-		}) do
-			if fields[k] then
-				local evt = minetest.explode_table_event(fields[k])
-				selected_idxs[k][name] = evt.row - 1
-				if evt.type == "DCL" and selected_idxs[k][name] then
-					fields[action] = true
-				end
-				return true
-			end
-		end
-
-		local update = false
-		-- add
-		for _,v in pairs({"to","cc","bcc"}) do
-			if fields[v.."add"] then
-				update = true
-				if selected_idxs.contacts[name] then
-					for k, contact, i in mail.pairsByKeys(contacts) do
-						if k == selected_idxs.contacts[name] or i == selected_idxs.contacts[name] then
-							local list = mail.parse_player_list(draft[v])
-							list[#list+1] = contact.name
-							selected_idxs[v][name] = #list
-							draft[v] = mail.concat_player_list(list)
-							break
-						end
-					end
-				end
-			end
-		end
-		-- remove
-		for _,v in pairs({"to","cc","bcc"}) do
-			if fields[v.."remove"] then
-				update = true
-				if selected_idxs[v][name] then
-					local list = mail.parse_player_list(draft[v])
-					table.remove(list, selected_idxs[v][name])
-					if #list < selected_idxs[v][name] then
-						selected_idxs[v][name] = #list
-					end
-					draft[v] = mail.concat_player_list(list)
-				end
-			end
-		end
-
-		if update then
-			mail.show_select_contact(name, draft.to, draft.cc, draft.bcc)
-			return true
-		end
-
-		-- delete old idxs
-		for _,v in ipairs({"contacts","to","cc","bcc"}) do
-			selected_idxs[v][name] = nil
-		end
-
-		mail.show_compose(name, draft.to, draft.subject, draft.body, draft.cc, draft.bcc)
-
-		return true
-
-	elseif formname == "mail:contacts" then
-		local name = player:get_player_name()
-		local contacts = mail.getContacts(name)
-
-		if fields.contacts then
-			local evt = minetest.explode_table_event(fields.contacts)
-			for k, _, i in mail.pairsByKeys(contacts) do
-				if i == evt.row - 1 then
-					selected_idxs.contacts[name] = k
-					break
-				end
-			end
-			if evt.type == "DCL" and contacts[selected_idxs.contacts[name]] then
-				mail.show_edit_contact(
-					name,
-					contacts[selected_idxs.contacts[name]].name,
-					contacts[selected_idxs.contacts[name]].note
-				)
-			end
-
-		elseif fields.new then
-			selected_idxs.contacts[name] = "#NEW#"
-			mail.show_edit_contact(name, "", "")
-
-		elseif fields.edit and selected_idxs.contacts[name] and contacts[selected_idxs.contacts[name]] then
-			mail.show_edit_contact(
-				name,
-				contacts[selected_idxs.contacts[name]].name,
-				contacts[selected_idxs.contacts[name]].note
-			)
-
-		elseif fields.delete then
-			if contacts[selected_idxs.contacts[name]] then
-				-- delete the contact and set the selected to the next in the list,
-				-- except if it was the last. Then determine the new last
-				local found = false
-				local last = nil
-				for k in mail.pairsByKeys(contacts) do
-					if found then
-						selected_idxs.contacts[name] = k
-						break
-					elseif k == selected_idxs.contacts[name] then
-						contacts[selected_idxs.contacts[name]] = nil
-						selected_idxs.contacts[name] = nil
-						found = true
-					else
-						last = k
-					end
-				end
-				if found and not selected_idxs.contacts[name] then
-					-- was the last in the list, so take the previous (new last)
-					selected_idxs.contacts[name] = last
-				end
-
-				mail.setContacts(name, contacts)
-			end
-
-			mail.show_contacts(name)
-
-		elseif fields.back then
-			mail.show_inbox(name)
-		end
-
-		return true
-
-	elseif formname == "mail:editcontact" then
-		local name = player:get_player_name()
-		local contacts = mail.getContacts(name)
-
-		if fields.save then
-			if selected_idxs.contacts[name] and selected_idxs.contacts[name] ~= "#NEW#" then
-				local contact = contacts[selected_idxs.contacts[name]]
-				if selected_idxs.contacts[name] ~= string.lower(fields.name) then
-					-- name changed!
-					if #fields.name == 0 then
-						mail.show_edit_contact(name, contact.name, fields.note, "empty")
-						return true
-
-					elseif contacts[string.lower(fields.name)] ~= nil then
-						mail.show_edit_contact(name, contact.name, fields.note, "collision")
-						return true
-
-					else
-						contacts[string.lower(fields.name)] = contact
-						contacts[selected_idxs.contacts[name]] = nil
-					end
-				end
-				contact.name = fields.name
-				contact.note = fields.note
-
-			else
-				local contact = {
-					name = fields.name,
-					note = fields.note,
-				}
-				contacts[string.lower(contact.name)] = contact
-			end
-
-			mail.setContacts(name, contacts)
-			mail.show_contacts(name)
-
-		elseif fields.back then
-			mail.show_contacts(name)
-		end
-
-		return true
-
-	elseif fields.mail then
-		mail.show_inbox(player:get_player_name())
-		return true
-	end
-end
-
-minetest.register_on_player_receive_fields(mail.handle_receivefields)
-
-
 if minetest.get_modpath("unified_inventory") then
 	mail.receive_mail_message = mail.receive_mail_message ..
 		" or use the mail button in the inventory"
@@ -718,6 +81,9 @@ if minetest.get_modpath("unified_inventory") then
 	unified_inventory.register_button("mail", {
 			type = "image",
 			image = "mail_button.png",
-			tooltip = "Mail"
+			tooltip = "Mail",
+			action = function(player)
+				mail.show_mail_menu(player:get_player_name())
+			end
 		})
 end
diff --git a/init.lua b/init.lua
index c607b1b..43ffd1b 100644
--- a/init.lua
+++ b/init.lua
@@ -1,15 +1,38 @@
 mail = {
-	-- api version
-	apiversion = 1.1,
+	-- version
+	version = 3,
 
-	-- mail directory
-	maildir = minetest.get_worldpath().."/mails",
-	contactsdir = minetest.get_worldpath().."/mails/contacts"
+	-- mod storage
+	storage = minetest.get_mod_storage(),
+
+	-- ui theme prepend
+	theme = "",
+
+	-- ui forms
+	ui = {},
+
+	-- per-user ephemeral data
+	selected_idxs = {
+		inbox = {},
+		sent = {},
+		contacts = {},
+		maillists = {},
+		to = {},
+		cc = {},
+		bcc = {},
+		boxtab = {}
+	},
+
+	message_drafts = {}
 }
 
+if minetest.get_modpath("default") then
+	mail.theme = default.gui_bg .. default.gui_bg_img
+end
 
 local MP = minetest.get_modpath(minetest.get_current_modname())
 dofile(MP .. "/util/normalize.lua")
+dofile(MP .. "/util/uuid.lua")
 dofile(MP .. "/chatcommands.lua")
 dofile(MP .. "/migrate.lua")
 dofile(MP .. "/hud.lua")
@@ -17,10 +40,26 @@ dofile(MP .. "/storage.lua")
 dofile(MP .. "/api.lua")
 dofile(MP .. "/gui.lua")
 dofile(MP .. "/onjoin.lua")
+dofile(MP .. "/ui/mail.lua")
+dofile(MP .. "/ui/inbox.lua")
+dofile(MP .. "/ui/outbox.lua")
+dofile(MP .. "/ui/message.lua")
+dofile(MP .. "/ui/events.lua")
+dofile(MP .. "/ui/contacts.lua")
+dofile(MP .. "/ui/edit_contact.lua")
+dofile(MP .. "/ui/select_contact.lua")
+dofile(MP .. "/ui/maillists.lua")
+dofile(MP .. "/ui/edit_maillists.lua")
+dofile(MP .. "/ui/compose.lua")
+dofile(MP .. "/ui/about.lua")
 
 -- migrate storage
 mail.migrate()
 
 if minetest.get_modpath("mtt") then
 	dofile(MP .. "/mtt.lua")
-end
\ No newline at end of file
+	dofile(MP .. "/api.spec.lua")
+	dofile(MP .. "/migrate.spec.lua")
+	dofile(MP .. "/util/uuid.spec.lua")
+	dofile(MP .. "/util/normalize.spec.lua")
+end
diff --git a/migrate.lua b/migrate.lua
index 1cefbd7..5378686 100644
--- a/migrate.lua
+++ b/migrate.lua
@@ -1,50 +1,98 @@
 
--- migrate from mail.db to player-file-based mailbox
+local STORAGE_VERSION_KEY = "@@version"
+
+local function migrate_v1_to_v3()
+	local file = io.open(minetest.get_worldpath().."/mail.db", "r")
+	assert(file)
+	print("[mail] Migration from v1 to v3 database")
+
+	local data = file:read("*a")
+	local oldmails = minetest.deserialize(data)
+	file:close()
+
+	for name, oldmessages in pairs(oldmails) do
+		print("[mail,v1] + migrating player '" .. name .. "'")
+		local entry = mail.get_storage_entry(name)
+		for _, msg in ipairs(oldmessages) do
+			table.insert(entry.inbox, {
+				id = mail.new_uuid(),
+				from  = msg.sender or msg.from,
+				to      = msg.to or name,
+				subject = msg.subject,
+				body    = msg.body,
+				time    = msg.time or os.time(),
+			})
+		end
+		mail.set_storage_entry(name, entry)
+	end
+
+	-- rename file
+	print("[mail,v1] migration done, renaming old mail.db")
+	os.rename(minetest.get_worldpath().."/mail.db", minetest.get_worldpath().."/mail.db.old")
+end
+
+local function read_json_file(path)
+	local file = io.open(path, "r")
+	local content = {}
+	if file then
+		local json = file:read("*a")
+		content = minetest.parse_json(json or "[]") or {}
+		file:close()
+	end
+	return content
+end
+
+-- migrate from v2 to v3 database
+local function migrate_v2_to_v3()
+	local maildir = minetest.get_worldpath().."/mails"
+	minetest.mkdir(maildir) -- if necessary (eg. first login)
+	print("[mail] Migration from v2 to v3 database")
+
+	-- defer execution until auth-handler ready (first server-step)
+	minetest.after(0, function()
+		for playername, _ in minetest.get_auth_handler().iterate() do
+			local entry = mail.get_storage_entry(playername)
+
+			local player_contacts = read_json_file(maildir .. "/contacts/" .. playername .. ".json")
+			for _, c in pairs(player_contacts) do
+				table.insert(entry.contacts, { name = c.name, note = c.note })
+			end
+
+			local saneplayername = string.gsub(playername, "[.|/]", "")
+			local player_inbox = read_json_file(maildir .. "/" .. saneplayername .. ".json")
+			print("[mail,v2] + migrating player '" .. playername .. "'")
+			for _, msg in ipairs(player_inbox) do
+				table.insert(entry.inbox, {
+					id = mail.new_uuid(),
+					from  = msg.sender or msg.from,
+					to      = msg.to or playername,
+					cc      = msg.cc,
+					subject = msg.subject,
+					body    = msg.body,
+					time    = msg.time or os.time(),
+				})
+			end
+
+			mail.set_storage_entry(playername, entry)
+		end
+		print("[mail,v2] migration done")
+	end)
+end
 
 function mail.migrate()
-	-- create directory, just in case
-	minetest.mkdir(mail.maildir)
-	minetest.mkdir(mail.contactsdir)
-
-	local file = io.open(minetest.get_worldpath().."/mail.db", "r")
-	if file then
-		print("[mail] migrating to new per-player storage")
-
-		local data = file:read("*a")
-		local oldmails = minetest.deserialize(data)
-		file:close()
-
-		for name, oldmessages in pairs(oldmails) do
-			mail.setMessages(name, oldmessages)
-		end
-
-		-- rename file
-		print("[mail] migration done, renaming old mail.db")
-		os.rename(minetest.get_worldpath().."/mail.db", minetest.get_worldpath().."/mail.db.old")
+	-- check for v2 storage first, v1-migration might have set the v3-flag already
+	local version = mail.storage:get_int(STORAGE_VERSION_KEY)
+	if version < 3 then
+		-- v2 to v3
+		migrate_v2_to_v3()
+		mail.storage:set_int(STORAGE_VERSION_KEY, 3)
 	end
 
-end
-
-
-function mail.migrate_contacts(playername)
-	local file = io.open(mail.getContactsFile(playername), 'r')
-	if not file then
-		-- file doesn't exist! This is a case for Migrate Man!
-		local messages = mail.getMessages(playername)
-		local contacts = {}
-
-		if messages and not contacts then
-			for _, message in pairs(messages) do
-				mail.ensure_new_format(message)
-				if contacts[string.lower(message.from)] == nil then
-					contacts[string.lower(message.from)] = {
-						name = message.from,
-						note = "",
-					}
-				end
-			end
-		end
-	else
-		file:close()	-- uh, um, nope, let's leave those alone, shall we?
+	-- check for v1 storage
+	local v1_file = io.open(minetest.get_worldpath().."/mail.db", "r")
+	if v1_file then
+		-- v1 to v3
+		migrate_v1_to_v3()
+		mail.storage:set_int(STORAGE_VERSION_KEY, 3)
 	end
-end
+end
\ No newline at end of file
diff --git a/migrate.spec.lua b/migrate.spec.lua
new file mode 100644
index 0000000..b98341b
--- /dev/null
+++ b/migrate.spec.lua
@@ -0,0 +1,28 @@
+
+mtt.register("migrate v1", function(callback)
+    local entry = mail.get_storage_entry("old_v1_player")
+    assert(entry)
+    assert(#entry.inbox == 1)
+    assert(entry.inbox[1].from == "singleplayer")
+    assert(entry.inbox[1].to == "old_v1_player")
+    assert(entry.inbox[1].subject == "test1")
+    assert(entry.inbox[1].body == "test2")
+    assert(entry.inbox[1].id)
+    assert(entry.inbox[1].time > 0)
+
+    callback()
+end)
+
+mtt.register("migrate v2", function(callback)
+    local entry = mail.get_storage_entry("old_v2_player")
+    assert(entry)
+    assert(#entry.inbox == 1)
+    assert(entry.inbox[1].from == "someone-else")
+    assert(entry.inbox[1].to == "old_v2_player")
+    assert(entry.inbox[1].subject == "test1")
+    assert(entry.inbox[1].body == "test2")
+    assert(entry.inbox[1].id)
+    assert(entry.inbox[1].time == 1678467148)
+
+    callback()
+end)
\ No newline at end of file
diff --git a/mtt.lua b/mtt.lua
index 9b12fb7..7c8cf0b 100644
--- a/mtt.lua
+++ b/mtt.lua
@@ -1,14 +1,10 @@
 
-mtt.register("send mail", function(callback)
-    -- create "player2"
+mtt.register("setup", function(callback)
+    -- create test players
     local auth_handler = minetest.get_auth_handler()
+    auth_handler.set_password("player1", "")
     auth_handler.set_password("player2", "")
+    auth_handler.set_password("player3", "")
 
-    -- send a mail
-    mail.send("player1", "player2", "something", "blah")
-
-    -- check the receivers inbox
-    local list2 = mail.getMessages("player2")
-    assert(list2 ~= nil and #list2 > 0)
     callback()
 end)
\ No newline at end of file
diff --git a/onjoin.lua b/onjoin.lua
index c8e1877..0bf36d2 100644
--- a/onjoin.lua
+++ b/onjoin.lua
@@ -1,6 +1,7 @@
 minetest.register_on_joinplayer(function(player)
 	minetest.after(2, function(name)
-		local messages = mail.getMessages(name)
+		local entry = mail.get_storage_entry(name)
+		local messages = entry.inbox
 
 		local unreadcount = 0
 
@@ -16,6 +17,4 @@ minetest.register_on_joinplayer(function(player)
 
 		end
 	end, player:get_player_name())
-
-	mail.migrate_contacts(player:get_player_name())
 end)
diff --git a/storage.lua b/storage.lua
index 8e028eb..89a1eab 100644
--- a/storage.lua
+++ b/storage.lua
@@ -1,47 +1,195 @@
+-- storage getter/setter
+local STORAGE_PREFIX = "mail/"
 
-function mail.getMailFile(playername)
-	local saneplayername = string.gsub(playername, "[.|/]", "")
-	return mail.maildir .. "/" .. saneplayername .. ".json"
+-- create or populate empty fields on an entry
+local function populate_entry(e)
+	e = e or {}
+	e.contacts = e.contacts or {}
+	e.inbox = e.inbox or {}
+	e.outbox = e.outbox or {}
+	e.lists = e.lists or {}
+	return e
 end
 
-function mail.getContactsFile(playername)
-	local saneplayername = string.gsub(playername, "[.|/]", "")
-	return mail.maildir .. "/contacts/" .. saneplayername .. ".json"
-end
-
-
-function mail.getMessages(playername)
-	local messages = mail.read_json_file(mail.getMailFile(playername))
-	if messages then
-		for _, msg in ipairs(messages) do
-			if not msg.time then
-				-- add missing time field if not available (happens with old data)
-				msg.time = 0
-			end
-		end
-
-		-- sort by received date descending
-		table.sort(messages, function(a,b) return a.time > b.time end)
-		-- show hud notification
-		mail.hud_update(playername, messages)
-	end
-
-	return messages
-end
-
-function mail.setMessages(playername, messages)
-	if mail.write_json_file(mail.getMailFile(playername), messages) then
-		mail.hud_update(playername, messages)
-		return true
+function mail.get_storage_entry(playername)
+	local str = mail.storage:get_string(STORAGE_PREFIX .. playername)
+	if str == "" then
+		-- new entry
+		return populate_entry()
 	else
-		minetest.log("error","[mail] Save failed - messages may be lost! ("..playername..")")
-		return false
+		-- deserialize existing entry
+		local e = minetest.parse_json(str)
+		return populate_entry(e)
 	end
 end
 
+function mail.set_storage_entry(playername, entry)
+	mail.storage:set_string(STORAGE_PREFIX .. playername, minetest.write_json(entry))
+end
 
-function mail.getContacts(playername)
-	return mail.read_json_file(mail.getContactsFile(playername))
+-- get a mail by id from the players in- or outbox
+function mail.get_message(playername, msg_id)
+	local entry = mail.get_storage_entry(playername)
+	for _, msg in ipairs(entry.inbox) do
+		if msg.id == msg_id then
+			return msg
+		end
+	end
+	for _, msg in ipairs(entry.outbox) do
+		if msg.id == msg_id then
+			return msg
+		end
+	end
+end
+
+-- marks a mail read by its id
+function mail.mark_read(playername, msg_id)
+	local entry = mail.get_storage_entry(playername)
+	for _, msg in ipairs(entry.inbox) do
+		if msg.id == msg_id then
+			msg.read = true
+			mail.set_storage_entry(playername, entry)
+			return
+		end
+	end
+end
+
+-- marks a mail unread by its id
+function mail.mark_unread(playername, msg_id)
+	local entry = mail.get_storage_entry(playername)
+	for _, msg in ipairs(entry.inbox) do
+		if msg.id == msg_id then
+			msg.read = false
+			mail.set_storage_entry(playername, entry)
+			return
+		end
+	end
+end
+
+-- deletes a mail by its id
+function mail.delete_mail(playername, msg_id)
+	local entry = mail.get_storage_entry(playername)
+	for i, msg in ipairs(entry.inbox) do
+		if msg.id == msg_id then
+			table.remove(entry.outbox, i)
+			mail.set_storage_entry(playername, entry)
+			return
+		end
+	end
+	for i, msg in ipairs(entry.outbox) do
+		if msg.id == msg_id then
+			table.remove(entry.outbox, i)
+			mail.set_storage_entry(playername, entry)
+			return
+		end
+	end
+end
+
+-- add or update a contact
+function mail.update_contact(playername, contact)
+	local entry = mail.get_storage_entry(playername)
+	local existing_updated = false
+	for i, existing_contact in ipairs(entry.contacts) do
+		if existing_contact.name == contact.name then
+			-- update
+			entry.contacts[i] = contact
+			existing_updated = true
+			break
+		end
+	end
+	if not existing_updated then
+		-- insert
+		table.insert(entry.contacts, contact)
+	end
+	mail.set_storage_entry(playername, entry)
+end
+
+-- deletes a contact
+function mail.delete_contact(playername, contactname)
+	local entry = mail.get_storage_entry(playername)
+	for i, existing_contact in ipairs(entry.contacts) do
+		if existing_contact.name == contactname then
+			-- delete
+			table.remove(entry.contacts, i)
+			mail.set_storage_entry(playername, entry)
+			return
+		end
+	end
+end
+
+-- get all contacts
+function mail.get_contacts(playername)
+	local entry = mail.get_storage_entry(playername)
+	return entry.contacts
+end
+
+-- returns the maillists of a player
+function mail.get_maillists(playername)
+	local entry = mail.get_storage_entry(playername)
+	return entry.lists
+end
+
+-- returns the maillists of a player
+function mail.get_maillist_by_name(playername, listname)
+	local entry = mail.get_storage_entry(playername)
+	for _, list in ipairs(entry.lists) do
+		if list.name == listname then
+			return list
+		end
+	end
+end
+
+-- updates or creates a maillist
+function mail.update_maillist(playername, list)
+	local entry = mail.get_storage_entry(playername)
+	local existing_updated = false
+	for i, existing_list in ipairs(entry.lists) do
+		if existing_list.name == list.name then
+			-- update
+			entry.lists[i] = list
+			existing_updated = true
+			break
+		end
+	end
+	if not existing_updated then
+		-- insert
+		table.insert(entry.lists, list)
+	end
+	mail.set_storage_entry(playername, entry)
+end
+
+function mail.delete_maillist(playername, listname)
+	local entry = mail.get_storage_entry(playername)
+	for i, list in ipairs(entry.lists) do
+		if list.name == listname then
+			-- delete
+			table.remove(entry.lists, i)
+			mail.set_storage_entry(playername, entry)
+			return
+		end
+	end
+end
+
+function mail.extractMaillists(receivers_string, maillists_owner)
+	local globalReceivers = mail.parse_player_list(receivers_string) -- receivers including maillists
+	local receivers = {} -- extracted receivers
+
+	-- extract players from mailing lists
+	for _, receiver in ipairs(globalReceivers) do
+		local receiverInfo = receiver:split("@") -- @maillist
+		if receiverInfo[1] and receiver == "@" .. receiverInfo[1] then
+			local maillist = mail.get_maillist_by_name(maillists_owner, receiverInfo[1])
+			if maillist then
+				for _, playername in ipairs(maillist.players) do
+					table.insert(receivers, playername)
+				end
+			end
+		else -- in case of player
+			table.insert(receivers, receiver)
+		end
+	end
+
+	return receivers
 end
 
 function mail.pairsByKeys(t, f)
@@ -63,33 +211,3 @@ function mail.pairsByKeys(t, f)
 	return iter
 end
 
-function mail.setContacts(playername, contacts)
-	if mail.write_json_file(mail.getContactsFile(playername), contacts) then
-		return true
-	else
-		minetest.log("error","[mail] Save failed - contacts may be lost! ("..playername..")")
-		return false
-	end
-end
-
-
-function mail.read_json_file(path)
-	local file = io.open(path, "r")
-	local content = {}
-	if file then
-		local json = file:read("*a")
-		content = minetest.parse_json(json or "[]") or {}
-		file:close()
-	end
-	return content
-end
-
-function mail.write_json_file(path, content)
-	local file = io.open(path,"w")
-	local json = minetest.write_json(content)
-	if file and file:write(json) and file:close() then
-		return true
-	else
-		return false
-	end
-end
diff --git a/storage.spec.lua b/storage.spec.lua
new file mode 100644
index 0000000..1be9ea4
--- /dev/null
+++ b/storage.spec.lua
@@ -0,0 +1,45 @@
+
+mtt.register("storage", function(callback)
+    -- sanity checks
+    local playername = "player1"
+    local entry = mail.get_storage_entry(playername)
+    assert(entry)
+
+    -- create
+    local contact = {
+        name = "other-player",
+        note = "my-note"
+    }
+    mail.update_contact(playername, contact)
+
+    -- read
+    local contacts = mail.get_contacts(playername)
+    assert(#contacts == 1)
+    assert(contacts[1].note == contact.note)
+    assert(contacts[1].name == contact.name)
+
+    -- read through api
+    local contacts2 = mail.get_contacts(playername)
+    assert(#contacts2 == 1)
+    assert(contacts2[1].note == contact.note)
+    assert(contacts2[1].name == contact.name)
+
+    -- update
+    mail.update_contact(playername, {
+        name = contact.name,
+        note = "xy"
+    })
+
+    -- read updated
+    contacts = mail.get_contacts(playername)
+    assert(#contacts == 1)
+    assert(contacts[1].note == "xy")
+    assert(contacts[1].name == contact.name)
+
+    -- delete
+    mail.delete_contact(playername, contact.name)
+    contacts = mail.get_contacts(playername)
+    assert(#contacts == 0)
+
+    callback()
+end)
\ No newline at end of file
diff --git a/test/Dockerfile b/test/Dockerfile
index 6324d80..9c1bd1b 100644
--- a/test/Dockerfile
+++ b/test/Dockerfile
@@ -1,6 +1,13 @@
 ARG ENGINE_VERSION=5.5.0
 FROM registry.gitlab.com/minetest/minetest/server:${ENGINE_VERSION}
 
+# copy old v1 maildb for migration testing
+COPY ./mail.db /root/.minetest/worlds/world/mail.db
+# copy old v2 mail-dir and auth.sqlite for migration testing
+COPY ./old_v2_player.json /root/.minetest/worlds/world/mails/
+COPY ./auth.sqlite /root/.minetest/worlds/world/auth.sqlite
+
+
 USER root
 RUN apk add git &&\
     mkdir -p /root/.minetest/worlds/world/worldmods/ &&\
diff --git a/test/auth.sqlite b/test/auth.sqlite
new file mode 100644
index 0000000..e6bac67
Binary files /dev/null and b/test/auth.sqlite differ
diff --git a/test/mail.db b/test/mail.db
new file mode 100644
index 0000000..3104acb
--- /dev/null
+++ b/test/mail.db
@@ -0,0 +1 @@
+local _={};_[1]="singleplayer";return {old_v1_player={{unread=true,subject="test1",sender=_[1],body="test2"}},[_[1]]={}}
\ No newline at end of file
diff --git a/test/minetest.conf b/test/minetest.conf
index 992f787..afea5f2 100644
--- a/test/minetest.conf
+++ b/test/minetest.conf
@@ -1,3 +1,4 @@
 default_game = minetest_game
 mg_name = v7
-mtt_enable = true
\ No newline at end of file
+mtt_enable = true
+mtt_filter = mail
\ No newline at end of file
diff --git a/test/old_v2_player.json b/test/old_v2_player.json
new file mode 100644
index 0000000..2bb859a
--- /dev/null
+++ b/test/old_v2_player.json
@@ -0,0 +1 @@
+[{"body":"test2","sender":"someone-else","subject":"test1","time":1678467148,"unread":false}]
\ No newline at end of file
diff --git a/ui/about.lua b/ui/about.lua
new file mode 100644
index 0000000..36226fb
--- /dev/null
+++ b/ui/about.lua
@@ -0,0 +1,27 @@
+local FORMNAME = "mail:about"
+
+function mail.show_about(name)
+	local formspec = [[
+			size[8,5;]
+			button[7.25,0;0.75,0.5;back;X]
+			label[0,0;Mail]
+			label[0,0.5;By cheapie]
+			label[0,1;http://github.com/cheapie/mail]
+			label[0,1.5;See LICENSE file for license information]
+			label[0,2.5;NOTE: Communication using this system]
+			label[0,3;is NOT guaranteed to be private!]
+			label[0,3.5;Admins are able to view the messages]
+			label[0,4;of any player.]
+		]] .. mail.theme
+
+	minetest.show_formspec(name, FORMNAME, formspec)
+end
+
+minetest.register_on_player_receive_fields(function(player, formname)
+	if formname ~= FORMNAME then
+		return
+	end
+
+	local playername = player:get_player_name()
+	mail.show_mail_menu(playername)
+end)
\ No newline at end of file
diff --git a/ui/compose.lua b/ui/compose.lua
new file mode 100644
index 0000000..ad7f653
--- /dev/null
+++ b/ui/compose.lua
@@ -0,0 +1,89 @@
+local FORMNAME = "mail:compose"
+
+function mail.show_compose(name, to, subject, body, cc, bcc)
+	local formspec = [[
+			size[8,9]
+			button[0,0;1,1;tocontacts;To:]
+			field[1.1,0.3;3.2,1;to;;%s]
+			button[4,0;1,1;cccontacts;CC:]
+			field[5.1,0.3;3.1,1;cc;;%s]
+			button[4,0.75;1,1;bcccontacts;BCC:]
+			field[5.1,1.05;3.1,1;bcc;;%s]
+			field[0.25,2;8,1;subject;Subject:;%s]
+			textarea[0.25,2.5;8,6;body;;%s]
+			button[0.5,8.5;3,1;cancel;Cancel]
+			button[4.5,8.5;3,1;send;Send]
+		]] .. mail.theme
+
+	formspec = string.format(formspec,
+		minetest.formspec_escape(to or ""),
+		minetest.formspec_escape(cc or ""),
+		minetest.formspec_escape(bcc or ""),
+		minetest.formspec_escape(subject or ""),
+		minetest.formspec_escape(body or ""))
+
+	minetest.show_formspec(name, FORMNAME, formspec)
+end
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+	if formname ~= FORMNAME then
+		return
+	end
+
+	local name = player:get_player_name()
+    if fields.send then
+        local success, err = mail.send({
+            from = name,
+            to = fields.to,
+            cc = fields.cc,
+            bcc = fields.bcc,
+            subject = fields.subject,
+            body = fields.body,
+        })
+        if not success then
+            minetest.chat_send_player(name, err)
+            return
+        end
+
+        -- add new contacts if some receivers aren't registered
+        local contacts = mail.get_contacts(name)
+        local recipients = mail.parse_player_list(fields.to)
+        local isNew = true
+        for _,recipient in ipairs(recipients) do
+            if recipient:sub(1,1) == "@" then -- in case of maillist -- check if first char is @
+                isNew = false
+            else
+                for _,contact in ipairs(contacts) do
+                    if contact.name == recipient then
+                        isNew = false
+                        break
+                    end
+                end
+            end
+            if isNew then
+                mail.update_contact(name, {name = recipient, note = ""})
+            end
+        end
+
+        minetest.after(0.5, function()
+            mail.show_mail_menu(name)
+        end)
+
+    elseif fields.tocontacts or fields.cccontacts or fields.bcccontacts then
+        mail.message_drafts[name] = {
+            to = fields.to,
+            cc = fields.cc,
+            bcc = fields.bcc,
+            subject = fields.subject,
+            body = fields.body,
+        }
+        mail.show_select_contact(name, fields.to, fields.cc, fields.bcc)
+
+    elseif fields.cancel then
+        mail.message_drafts[name] = nil
+
+        mail.show_mail_menu(name)
+    end
+
+    return true
+end)
\ No newline at end of file
diff --git a/ui/contacts.lua b/ui/contacts.lua
new file mode 100644
index 0000000..1ea642a
--- /dev/null
+++ b/ui/contacts.lua
@@ -0,0 +1,83 @@
+local FORMNAME = "mail:contacts"
+
+local contacts_formspec = "size[8,9;]" .. mail.theme .. [[
+		button[6,0.10;2,0.5;new;New]
+		button[6,0.85;2,0.5;edit;Edit]
+		button[6,1.60;2,0.5;delete;Delete]
+		button[6,8.25;2,0.5;back;Back]
+		tablecolumns[color;text;text]
+		table[0,0;5.75,9;contacts;#999,Name,Note]]
+
+
+function mail.show_contacts(name)
+    local formspec = contacts_formspec .. mail.compile_contact_list(name, mail.selected_idxs.contacts[name])
+    minetest.show_formspec(name, FORMNAME, formspec)
+end
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+	if formname ~= FORMNAME then
+		return
+	end
+
+	local name = player:get_player_name()
+	local contacts = mail.get_contacts(name)
+
+	if fields.contacts then
+		local evt = minetest.explode_table_event(fields.contacts)
+		for k, _, i in mail.pairsByKeys(contacts) do
+			if i == evt.row - 1 then
+				mail.selected_idxs.contacts[name] = k
+				break
+			end
+		end
+		if evt.type == "DCL" and contacts[mail.selected_idxs.contacts[name]] then
+			mail.show_edit_contact(
+				name,
+				contacts[mail.selected_idxs.contacts[name]].name,
+				contacts[mail.selected_idxs.contacts[name]].note
+			)
+		end
+
+	elseif fields.new then
+		mail.selected_idxs.contacts[name] = "#NEW#"
+		mail.show_edit_contact(name, "", "")
+
+	elseif fields.edit and mail.selected_idxs.contacts[name] and contacts[mail.selected_idxs.contacts[name]] then
+		mail.show_edit_contact(
+			name,
+			contacts[mail.selected_idxs.contacts[name]].name,
+			contacts[mail.selected_idxs.contacts[name]].note
+		)
+
+	elseif fields.delete then
+		if contacts[mail.selected_idxs.contacts[name]] then
+			-- delete the contact and set the selected to the next in the list,
+			-- except if it was the last. Then determine the new last
+			local found = false
+			local last = nil
+			for k in mail.pairsByKeys(contacts) do
+				if found then
+					mail.selected_idxs.contacts[name] = k
+					break
+				elseif k == mail.selected_idxs.contacts[name] then
+					mail.delete_contact(name, contacts[mail.selected_idxs.contacts[name]].name)
+					mail.selected_idxs.contacts[name] = nil
+					found = true
+				else
+					last = k
+				end
+			end
+			if found and not mail.selected_idxs.contacts[name] then
+				-- was the last in the list, so take the previous (new last)
+				mail.selected_idxs.contacts[name] = last
+			end
+		end
+
+		mail.show_contacts(name)
+
+	elseif fields.back then
+		mail.show_mail_menu(name)
+	end
+
+	return true
+end)
\ No newline at end of file
diff --git a/ui/edit_contact.lua b/ui/edit_contact.lua
new file mode 100644
index 0000000..15aa50a
--- /dev/null
+++ b/ui/edit_contact.lua
@@ -0,0 +1,74 @@
+local FORMNAME = "mail:editcontact"
+
+function mail.show_edit_contact(name, contact_name, note, illegal_name_hint)
+	local formspec = [[
+			size[6,7]
+			button[4,6.25;2,0.5;back;Back]
+			field[0.25,0.5;4,1;name;Player name:;%s]
+			textarea[0.25,1.6;4,6.25;note;Note:;%s]
+			button[4,0.10;2,1;save;Save]
+		]]
+	if illegal_name_hint == "collision" then
+		formspec = formspec .. [[
+				label[4,1;That name]
+				label[4,1.5;is already in]
+				label[4,2;your contacts.]
+			]]
+	elseif illegal_name_hint == "empty" then
+		formspec = formspec .. [[
+				label[4,1;The contact]
+				label[4,1.5;name cannot]
+				label[4,2;be empty.]
+			]]
+	end
+	formspec = formspec .. mail.theme
+	formspec = string.format(formspec,
+		minetest.formspec_escape(contact_name or ""),
+		minetest.formspec_escape(note or ""))
+	minetest.show_formspec(name, FORMNAME, formspec)
+end
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+	if formname ~= FORMNAME then
+		return
+	end
+
+	local name = player:get_player_name()
+	local contacts = mail.get_contacts(name)
+
+	if fields.save then
+		if mail.selected_idxs.contacts[name] and mail.selected_idxs.contacts[name] ~= "#NEW#" then
+			local contact = contacts[mail.selected_idxs.contacts[name]]
+			if mail.selected_idxs.contacts[name] ~= string.lower(fields.name) then
+				-- name changed!
+				if #fields.name == 0 then
+					mail.show_edit_contact(name, contact.name, fields.note, "empty")
+					return true
+
+				elseif contacts[string.lower(fields.name)] ~= nil then
+					mail.show_edit_contact(name, contact.name, fields.note, "collision")
+					return true
+
+				else
+					mail.update_contact(name, contact)
+					contacts[mail.selected_idxs.contacts[name]] = nil
+				end
+			end
+			contact.name = fields.name
+			contact.note = fields.note
+			mail.update_contact(name, contact)
+
+		else
+			mail.update_contact(name, {
+				name = fields.name,
+				note = fields.note,
+			})
+		end
+		mail.show_contacts(name)
+
+	elseif fields.back then
+		mail.show_contacts(name)
+	end
+
+	return true
+end)
\ No newline at end of file
diff --git a/ui/edit_maillists.lua b/ui/edit_maillists.lua
new file mode 100644
index 0000000..64f7c9c
--- /dev/null
+++ b/ui/edit_maillists.lua
@@ -0,0 +1,53 @@
+local FORMNAME = "mail:editmaillist"
+
+function mail.show_edit_maillist(playername, maillist_name, desc, players, illegal_name_hint)
+	local formspec = [[
+			size[6,7]
+			button[4,6.25;2,0.5;back;Back]
+			field[0.25,0.5;4,1;name;Maillist name:;%s]
+			textarea[0.25,1.6;4,2;desc;Desc:;%s]
+			textarea[0.25,3.6;4,4.25;players;Players:;%s]
+			button[4,0.10;2,1;save;Save]
+		]]
+	if illegal_name_hint == "collision" then
+		formspec = formspec .. [[
+				label[4,1;That name]
+				label[4,1.5;is already in]
+				label[4,2;your maillists.]
+			]]
+	elseif illegal_name_hint == "empty" then
+		formspec = formspec .. [[
+				label[4,1;The maillist]
+				label[4,1.5;name cannot]
+				label[4,2;be empty.]
+			]]
+	end
+	formspec = formspec .. mail.theme
+	formspec = string.format(formspec,
+		minetest.formspec_escape(maillist_name or ""),
+		minetest.formspec_escape(desc or ""),
+		minetest.formspec_escape(players or ""))
+	minetest.show_formspec(playername, FORMNAME, formspec)
+end
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+	if formname ~= FORMNAME then
+		return
+	end
+
+	local name = player:get_player_name()
+	if fields.save then
+		mail.update_maillist(name, {
+			owner = name,
+			name = fields.name,
+			desc = fields.desc,
+			players = mail.parse_player_list(fields.players)
+		})
+		mail.show_maillists(name)
+
+	elseif fields.back then
+		mail.show_maillists(name)
+	end
+
+	return true
+end)
\ No newline at end of file
diff --git a/ui/events.lua b/ui/events.lua
new file mode 100644
index 0000000..04fc878
--- /dev/null
+++ b/ui/events.lua
@@ -0,0 +1,116 @@
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+    if formname ~= "mail:inbox" and formname ~= "mail:sent" then
+        return
+    end
+
+    local name = player:get_player_name()
+
+    -- split inbox and sent msgs for different tests
+    local entry = mail.get_storage_entry(name)
+
+    local messagesInbox = entry.inbox
+    local messagesSent = entry.outbox
+
+    if fields.inbox then -- inbox table
+        local evt = minetest.explode_table_event(fields.inbox)
+        mail.selected_idxs.inbox[name] = evt.row - 1
+        if evt.type == "DCL" and messagesInbox[mail.selected_idxs.inbox[name]] then
+            mail.show_message(name, messagesInbox[mail.selected_idxs.inbox[name]].id)
+        end
+        return true
+    end
+
+    if fields.sent then -- sent table
+        local evt = minetest.explode_table_event(fields.sent)
+        mail.selected_idxs.sent[name] = evt.row - 1
+        if evt.type == "DCL" and messagesSent[mail.selected_idxs.sent[name]] then
+            mail.show_message(name, messagesSent[mail.selected_idxs.sent[name]].id)
+        end
+        return true
+    end
+
+    if fields.boxtab == "1" then
+        mail.selected_idxs.boxtab[name] = 1
+        mail.show_inbox(name)
+
+    elseif fields.boxtab == "2" then
+        mail.selected_idxs.boxtab[name] = 2
+        mail.show_sent(name)
+
+    elseif fields.read then
+        if formname == "mail:inbox" and messagesInbox[mail.selected_idxs.inbox[name]] then -- inbox table
+            mail.show_message(name, messagesInbox[mail.selected_idxs.inbox[name]].id)
+        elseif formname == "mail:sent" and messagesSent[mail.selected_idxs.sent[name]] then -- sent table
+            mail.show_message(name, messagesSent[mail.selected_idxs.sent[name]].id)
+        end
+
+    elseif fields.delete then
+        if formname == "mail:inbox" and messagesInbox[mail.selected_idxs.inbox[name]] then -- inbox table
+            mail.delete_mail(name, messagesInbox[mail.selected_idxs.inbox[name]].id)
+        elseif formname == "mail:sent" and messagesSent[mail.selected_idxs.sent[name]] then -- sent table
+            mail.delete_mail(name, messagesSent[mail.selected_idxs.sent[name]].id)
+        end
+
+        mail.show_mail_menu(name)
+
+    elseif fields.reply then
+        if formname == "mail:inbox" and messagesInbox[mail.selected_idxs.inbox[name]] then
+            local message = messagesInbox[mail.selected_idxs.inbox[name]]
+            mail.reply(name, message)
+        elseif formname == "mail:sent" and messagesSent[mail.selected_idxs.sent[name]] then
+            local message = messagesSent[mail.selected_idxs.sent[name]]
+            mail.reply(name, message)
+        end
+
+    elseif fields.replyall then
+        if formname == "mail:inbox" and messagesInbox[mail.selected_idxs.inbox[name]] then
+            local message = messagesInbox[mail.selected_idxs.inbox[name]]
+            mail.replyall(name, message)
+        elseif formname == "mail:sent" and messagesSent[mail.selected_idxs.sent[name]] then
+            local message = messagesSent[mail.selected_idxs.sent[name]]
+            mail.replyall(name, message)
+        end
+
+    elseif fields.forward then
+        if formname == "mail:inbox" and messagesInbox[mail.selected_idxs.inbox[name]] then
+            local message = messagesInbox[mail.selected_idxs.inbox[name]]
+            mail.forward(name, message)
+        elseif formname == "mail:sent" and messagesSent[mail.selected_idxs.sent[name]] then
+            local message = messagesSent[mail.selected_idxs.sent[name]]
+            mail.forward(name, message)
+        end
+
+    elseif fields.markread then
+        if formname == "mail:inbox" and messagesInbox[mail.selected_idxs.inbox[name]] then
+            mail.mark_read(name, messagesInbox[mail.selected_idxs.inbox[name]].id)
+        elseif formname == "mail:sent" and messagesSent[mail.selected_idxs.sent[name]] then
+            mail.mark_read(name, messagesSent[mail.selected_idxs.sent[name]].id)
+        end
+
+        mail.show_mail_menu(name)
+
+    elseif fields.markunread then
+        if formname == "mail:inbox" and messagesInbox[mail.selected_idxs.inbox[name]] then
+            mail.mark_unread(name, messagesInbox[mail.selected_idxs.inbox[name]].id)
+        elseif formname == "mail:sent" and messagesSent[mail.selected_idxs.sent[name]] then
+            mail.mark_unread(name, messagesSent[mail.selected_idxs.sent[name]].id)
+        end
+
+        mail.show_mail_menu(name)
+
+    elseif fields.new then
+        mail.show_compose(name)
+
+    elseif fields.contacts then
+        mail.show_contacts(name)
+
+    elseif fields.maillists then
+        mail.show_maillists(name)
+
+    elseif fields.about then
+        mail.show_about(name)
+
+    end
+
+    return true
+end)
diff --git a/ui/inbox.lua b/ui/inbox.lua
new file mode 100644
index 0000000..5851003
--- /dev/null
+++ b/ui/inbox.lua
@@ -0,0 +1,66 @@
+local inbox_formspec = "size[8,10;]" .. mail.theme .. [[
+    tabheader[0.3,1;boxtab;Inbox,Sent messages;1;false;false]
+
+    button[6,0.10;2,0.5;new;New]
+    button[6,0.95;2,0.5;read;Read]
+    button[6,1.70;2,0.5;reply;Reply]
+    button[6,2.45;2,0.5;replyall;Reply All]
+    button[6,3.20;2,0.5;forward;Forward]
+    button[6,3.95;2,0.5;delete;Delete]
+    button[6,4.82;2,0.5;markread;Mark Read]
+    button[6,5.55;2,0.5;markunread;Mark Unread]
+    button[6,6.8;2,0.5;contacts;Contacts]
+    button[6,7.6;2,0.5;maillists;Mail lists]
+    button[6,8.7;2,0.5;about;About]
+    button_exit[6,9.5;2,0.5;quit;Close]
+
+    tablecolumns[color;text;text]
+    table[0,0.7;5.75,9.35;inbox;#999,From,Subject]]
+
+
+function mail.show_inbox(name)
+    local formspec = { inbox_formspec }
+    local entry = mail.get_storage_entry(name)
+    local messages = entry.inbox
+
+    mail.message_drafts[name] = nil
+
+    if messages[1] then
+        for _, message in ipairs(messages) do
+            if not message.read then
+                if not mail.player_in_list(name, message.to) then
+                    formspec[#formspec + 1] = ",#FFD788"
+                else
+                    formspec[#formspec + 1] = ",#FFD700"
+                end
+            else
+                if not mail.player_in_list(name, message.to) then
+                    formspec[#formspec + 1] = ",#CCCCDD"
+                else
+                    formspec[#formspec + 1] = ","
+                end
+            end
+            formspec[#formspec + 1] = ","
+            formspec[#formspec + 1] = minetest.formspec_escape(message.from)
+            formspec[#formspec + 1] = ","
+            if message.subject ~= "" then
+                if string.len(message.subject) > 30 then
+                    formspec[#formspec + 1] = minetest.formspec_escape(string.sub(message.subject, 1, 27))
+                    formspec[#formspec + 1] = "..."
+                else
+                    formspec[#formspec + 1] = minetest.formspec_escape(message.subject)
+                end
+            else
+                formspec[#formspec + 1] = "(No subject)"
+            end
+        end
+        if mail.selected_idxs.inbox[name] then
+            formspec[#formspec + 1] = ";"
+            formspec[#formspec + 1] = tostring(mail.selected_idxs.inbox[name] + 1)
+        end
+        formspec[#formspec + 1] = "]"
+    else
+        formspec[#formspec + 1] = "]label[2.25,4.5;No mail]"
+    end
+    minetest.show_formspec(name, "mail:inbox", table.concat(formspec, ""))
+end
diff --git a/ui/mail.lua b/ui/mail.lua
new file mode 100644
index 0000000..47b92ad
--- /dev/null
+++ b/ui/mail.lua
@@ -0,0 +1,10 @@
+-- helper function for tabbed overview
+
+function mail.show_mail_menu(playername)
+    local index = mail.selected_idxs.boxtab[playername] or 1
+    if index == 1 then
+        mail.show_inbox(playername)
+    elseif index == 2 then
+        mail.show_sent(playername)
+    end
+end
\ No newline at end of file
diff --git a/ui/maillists.lua b/ui/maillists.lua
new file mode 100644
index 0000000..5a82b86
--- /dev/null
+++ b/ui/maillists.lua
@@ -0,0 +1,110 @@
+local FORMNAME = "mail:maillists"
+
+local maillists_formspec = "size[8,9;]" .. mail.theme .. [[
+		button[6,0.10;2,0.5;new;New]
+		button[6,0.85;2,0.5;edit;Edit]
+		button[6,1.60;2,0.5;delete;Delete]
+		button[6,8.25;2,0.5;back;Back]
+		tablecolumns[color;text;text]
+		table[0,0;5.75,9;maillists;#999,Name,Description]]
+
+function mail.show_maillists(name)
+	local formspec = { maillists_formspec }
+	local maillists = mail.get_maillists(name)
+
+	if maillists[1] then
+		for _, maillist in ipairs(maillists) do
+			formspec[#formspec + 1] = ","
+			formspec[#formspec + 1] = ","
+			formspec[#formspec + 1] = "@" .. minetest.formspec_escape(maillist.name)
+			formspec[#formspec + 1] = ","
+			if maillist.desc ~= "" then
+				if string.len(maillist.desc) > 30 then
+					formspec[#formspec + 1] = minetest.formspec_escape(string.sub(maillist.desc, 1, 27))
+					formspec[#formspec + 1] = "..."
+				else
+					formspec[#formspec + 1] = minetest.formspec_escape(maillist.desc)
+				end
+			else
+				formspec[#formspec + 1] = "(No description)"
+			end
+		end
+		if mail.selected_idxs.maillists[name] then
+			formspec[#formspec + 1] = ";"
+			formspec[#formspec + 1] = mail.selected_idxs.maillists[name]
+		end
+		formspec[#formspec + 1] = "]"
+	else
+		formspec[#formspec + 1] = "]label[2.25,4.5;No maillist]"
+	end
+	minetest.show_formspec(name, FORMNAME, table.concat(formspec, ""))
+end
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+	if formname ~= FORMNAME then
+		return
+	end
+
+	local name = player:get_player_name()
+	local maillists = mail.get_maillists(name)
+
+	if fields.maillists then
+		local evt = minetest.explode_table_event(fields.maillists)
+		mail.selected_idxs.maillists[name] = evt.row - 1
+		if evt.type == "DCL" and maillists[mail.selected_idxs.maillists[name]] then
+			local maillist = mail.get_maillist_by_name(name, maillists[mail.selected_idxs.maillists[name]].name)
+			local players_string = mail.concat_player_list(maillist.players)
+			mail.show_edit_maillist(
+				name,
+				maillists[mail.selected_idxs.maillists[name]].name,
+				maillists[mail.selected_idxs.maillists[name]].desc,
+				players_string
+			)
+		end
+
+	elseif fields.new then
+		mail.selected_idxs.maillists[name] = "#NEW#"
+		mail.show_edit_maillist(name, "", "", "Player1, Player2, Player3")
+
+	elseif fields.edit and maillists[mail.selected_idxs.maillists[name]] then
+		local maillist = mail.get_maillist_by_name(name, maillists[mail.selected_idxs.maillists[name]].name)
+		local players_string = mail.concat_player_list(maillist.players)
+		mail.show_edit_maillist(
+			name,
+			maillists[mail.selected_idxs.maillists[name]].name,
+			maillists[mail.selected_idxs.maillists[name]].desc,
+			players_string
+		)
+
+	elseif fields.delete then
+		if maillists[mail.selected_idxs.maillists[name]] then
+			-- delete the maillist and set the selected to the next in the list,
+			-- except if it was the last. Then determine the new last
+			local found = false
+			local last = nil
+			for k in mail.pairsByKeys(maillists) do
+				if found then
+					mail.selected_idxs.maillists[name] = k
+					break
+				elseif k == mail.selected_idxs.maillists[name] then
+					mail.delete_maillist(maillists[mail.selected_idxs.maillists[name]].name)
+					mail.selected_idxs.maillists[name] = nil
+					found = true
+				else
+					last = k
+				end
+			end
+			if found and not mail.selected_idxs.maillists[name] then
+				-- was the last in the list, so take the previous (new last)
+				mail.selected_idxs.maillists[name] = last
+			end
+		end
+
+		mail.show_maillists(name)
+
+	elseif fields.back then
+		mail.show_mail_menu(name)
+	end
+
+	return true
+end)
\ No newline at end of file
diff --git a/ui/message.lua b/ui/message.lua
new file mode 100644
index 0000000..3fb999f
--- /dev/null
+++ b/ui/message.lua
@@ -0,0 +1,136 @@
+local FORMNAME = "mail:message"
+
+function mail.show_message(name, id)
+	local message = mail.get_message(name, id)
+
+	local formspec = [[
+			size[8,9]
+
+			box[0,0;7,1.9;#466432]
+
+			button[7.25,0.15;0.75,0.5;back;X]
+
+			label[0.2,0.1;From: %s]
+			label[0.2,0.5;To: %s]
+			label[0.2,0.9;CC: %s]
+			label[0.2,1.3;Date: %s]
+
+			label[0,2.1;Subject: %s]
+			textarea[0.25,2.6;8,7.0;;;%s]
+
+			button[0,8.5;2,1;reply;Reply]
+			button[2,8.5;2,1;replyall;Reply All]
+			button[4,8.5;2,1;forward;Forward]
+			button[6,8.5;2,1;delete;Delete]
+		]] .. mail.theme
+
+	local from = minetest.formspec_escape(message.from) or ""
+	local to = minetest.formspec_escape(message.to) or ""
+	local cc = minetest.formspec_escape(message.cc) or ""
+	local date = type(message.time) == "number"
+		and minetest.formspec_escape(os.date("%Y-%m-%d %X", message.time)) or ""
+	local subject = minetest.formspec_escape(message.subject) or ""
+	local body = minetest.formspec_escape(message.body) or ""
+	formspec = string.format(formspec, from, to, cc, date, subject, body)
+
+	if not message.read then
+		-- mark as read
+		mail.mark_read(name, id)
+	end
+
+	minetest.show_formspec(name, FORMNAME, formspec)
+end
+
+function mail.reply(name, message)
+	local replyfooter = "Type your reply here.\n\n--Original message follows--\n" ..message.body
+	mail.show_compose(name, message.from, "Re: "..message.subject, replyfooter)
+end
+
+function mail.replyall(name, message)
+	local replyfooter = "Type your reply here.\n\n--Original message follows--\n" ..message.body
+
+	-- new recipients are the sender plus the original recipients, minus ourselves
+	local recipients = message.to or ""
+	if message.from ~= nil then
+		recipients = message.from .. ", " .. recipients
+	end
+	recipients = mail.parse_player_list(recipients)
+	for k,v in pairs(recipients) do
+		if v == name then
+			table.remove(recipients, k)
+			break
+		end
+	end
+	recipients = mail.concat_player_list(recipients)
+
+	-- new CC is old CC minus ourselves
+	local cc = mail.parse_player_list(message.cc)
+	for k,v in pairs(cc) do
+		if v == name then
+			table.remove(cc, k)
+			break
+		end
+	end
+	cc = mail.concat_player_list(cc)
+
+	mail.show_compose(name, recipients, "Re: "..message.subject, replyfooter, cc)
+end
+
+function mail.forward(name, message)
+	local fwfooter = "Type your message here.\n\n--Original message follows--\n" .. (message.body or "")
+	mail.show_compose(name, "", "Fw: " .. (message.subject or ""), fwfooter)
+end
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+	if formname ~= FORMNAME then
+		return
+	end
+
+	local name = player:get_player_name()
+	local entry = mail.get_storage_entry(name)
+
+	local messagesInbox = entry.inbox
+	local messagesSent = entry.outbox
+
+	if fields.back then
+		mail.show_mail_menu(name)
+		return true	-- don't uselessly set messages
+
+	elseif fields.reply then
+		local message = ""
+		if messagesInbox[mail.selected_idxs.inbox[name]] then
+			message = messagesInbox[mail.selected_idxs.inbox[name]]
+		elseif messagesSent[mail.selected_idxs.sent[name]] then
+			message = messagesSent[mail.selected_idxs.sent[name]]
+		end
+		mail.reply(name, message)
+
+	elseif fields.replyall then
+		local message = ""
+		if messagesInbox[mail.selected_idxs.inbox[name]] then
+			message = messagesInbox[mail.selected_idxs.inbox[name]]
+		elseif messagesSent[mail.selected_idxs.sent[name]] then
+			message = messagesSent[mail.selected_idxs.sent[name]]
+		end
+		mail.replyall(name, message)
+
+	elseif fields.forward then
+		local message = ""
+		if messagesInbox[mail.selected_idxs.inbox[name]] then
+			message = messagesInbox[mail.selected_idxs.inbox[name]]
+		elseif messagesSent[mail.selected_idxs.sent[name]] then
+			message = messagesSent[mail.selected_idxs.sent[name]]
+		end
+		mail.forward(name, message)
+
+	elseif fields.delete then
+		if messagesInbox[mail.selected_idxs.inbox[name]] then
+			mail.delete_mail(name, messagesInbox[mail.selected_idxs.inbox[name]].id)
+		elseif messagesSent[mail.selected_idxs.sent[name]] then
+			mail.delete_mail(name, messagesSent[mail.selected_idxs.sent[name]].id)
+		end
+		mail.show_mail_menu(name)
+	end
+
+	return true
+end)
\ No newline at end of file
diff --git a/ui/outbox.lua b/ui/outbox.lua
new file mode 100644
index 0000000..ae980a7
--- /dev/null
+++ b/ui/outbox.lua
@@ -0,0 +1,53 @@
+
+local sent_formspec = "size[8,10;]" .. mail.theme .. [[
+    tabheader[0.3,1;boxtab;Inbox,Sent messages;2;false;false]
+
+    button[6,0.10;2,0.5;new;New]
+    button[6,0.95;2,0.5;read;Read]
+    button[6,1.70;2,0.5;reply;Reply]
+    button[6,2.45;2,0.5;replyall;Reply All]
+    button[6,3.20;2,0.5;forward;Forward]
+    button[6,3.95;2,0.5;delete;Delete]
+    button[6,6.8;2,0.5;contacts;Contacts]
+    button[6,7.6;2,0.5;maillists;Mail lists]
+    button[6,8.7;2,0.5;about;About]
+    button_exit[6,9.5;2,0.5;quit;Close]
+
+    tablecolumns[color;text;text]
+    table[0,0.7;5.75,9.35;sent;#999,To,Subject]]
+
+
+function mail.show_sent(name)
+	local formspec = { sent_formspec }
+	local entry = mail.get_storage_entry(name)
+	local messages = entry.outbox
+
+	mail.message_drafts[name] = nil
+
+	if messages[1] then
+		for _, message in ipairs(messages) do
+			formspec[#formspec + 1] = ","
+			formspec[#formspec + 1] = ","
+			formspec[#formspec + 1] = minetest.formspec_escape(message.to)
+			formspec[#formspec + 1] = ","
+			if message.subject ~= "" then
+				if string.len(message.subject) > 30 then
+					formspec[#formspec + 1] = minetest.formspec_escape(string.sub(message.subject, 1, 27))
+					formspec[#formspec + 1] = "..."
+				else
+					formspec[#formspec + 1] = minetest.formspec_escape(message.subject)
+				end
+			else
+				formspec[#formspec + 1] = "(No subject)"
+			end
+		end
+		if mail.selected_idxs.sent[name] then
+			formspec[#formspec + 1] = ";"
+			formspec[#formspec + 1] = tostring(mail.selected_idxs.sent[name] + 1)
+		end
+		formspec[#formspec + 1] = "]"
+	else
+		formspec[#formspec + 1] = "]label[2.25,4.5;No mail]"
+	end
+	minetest.show_formspec(name, "mail:sent", table.concat(formspec, ""))
+end
diff --git a/ui/select_contact.lua b/ui/select_contact.lua
new file mode 100644
index 0000000..74494a5
--- /dev/null
+++ b/ui/select_contact.lua
@@ -0,0 +1,115 @@
+local FORMNAME = "mail:selectcontact"
+
+local select_contact_formspec = "size[8,9;]" .. mail.theme .. [[
+    tablecolumns[color;text;text]
+    table[0,0;3.5,9;contacts;#999,Name,Note%s]
+    button[3.55,2.00;1.75,0.5;toadd;→ Add]
+    button[3.55,2.75;1.75,0.5;toremove;← Remove]
+    button[3.55,6.00;1.75,0.5;ccadd;→ Add]
+    button[3.55,6.75;1.75,0.5;ccremove;← Remove]
+    tablecolumns[color;text;text]
+    table[5.15,0.0;2.75,4.5;to;#999,TO:,Note%s]
+    tablecolumns[color;text;text]
+    table[5.15,4.6;2.75,4.5;cc;#999,CC:,Note%s]
+    button[3.55,8.25;1.75,0.5;back;Back]
+]]
+
+
+function mail.show_select_contact(name, to, cc)
+	local formspec = select_contact_formspec
+	local contacts = mail.compile_contact_list(name, mail.selected_idxs.contacts[name])
+
+	-- compile lists
+	if to then
+		to = mail.compile_contact_list(name, mail.selected_idxs.to[name], to)
+	else
+		to = ""
+	end
+	if cc then
+		cc = mail.compile_contact_list(name, mail.selected_idxs.cc[name], cc)
+	else
+		cc = ""
+	end
+	--[[if bcc then
+		bcc = table.concat(mail.compile_contact_list(name, mail.selected_idxs.bcc[name], bcc)
+	else
+		bcc = ""
+	end]]--
+	formspec = string.format(formspec, contacts, to, cc)--, bcc()
+	minetest.show_formspec(name, FORMNAME, formspec)
+end
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+	if formname ~= FORMNAME then
+		return
+	end
+
+	local name = player:get_player_name()
+	local contacts = mail.get_contacts(name)
+	local draft = mail.message_drafts[name]
+
+	-- get indexes for fields with selected rows
+	-- execute their default button's actions if double clicked
+	for k,action in pairs({
+		contacts = "toadd",
+		to = "toremove",
+		cc = "ccremove",
+		bcc = "bccremove"
+	}) do
+		if fields[k] then
+			local evt = minetest.explode_table_event(fields[k])
+			mail.selected_idxs[k][name] = evt.row - 1
+			if evt.type == "DCL" and mail.selected_idxs[k][name] then
+				fields[action] = true
+			end
+			return true
+		end
+	end
+
+	local update = false
+	-- add
+	for _,v in pairs({"to","cc","bcc"}) do
+		if fields[v.."add"] then
+			update = true
+			if mail.selected_idxs.contacts[name] then
+				for k, contact, i in mail.pairsByKeys(contacts) do
+					if k == mail.selected_idxs.contacts[name] or i == mail.selected_idxs.contacts[name] then
+						local list = mail.parse_player_list(draft[v])
+						list[#list+1] = contact.name
+						mail.selected_idxs[v][name] = #list
+						draft[v] = mail.concat_player_list(list)
+						break
+					end
+				end
+			end
+		end
+	end
+	-- remove
+	for _,v in pairs({"to","cc","bcc"}) do
+		if fields[v.."remove"] then
+			update = true
+			if mail.selected_idxs[v][name] then
+				local list = mail.parse_player_list(draft[v])
+				table.remove(list, mail.selected_idxs[v][name])
+				if #list < mail.selected_idxs[v][name] then
+					mail.selected_idxs[v][name] = #list
+				end
+				draft[v] = mail.concat_player_list(list)
+			end
+		end
+	end
+
+	if update then
+		mail.show_select_contact(name, draft.to, draft.cc, draft.bcc)
+		return true
+	end
+
+	-- delete old idxs
+	for _,v in ipairs({"contacts","to","cc","bcc"}) do
+		mail.selected_idxs[v][name] = nil
+	end
+
+	mail.show_compose(name, draft.to, draft.subject, draft.body, draft.cc, draft.bcc)
+
+	return true
+end)
\ No newline at end of file
diff --git a/util/channel.lua b/util/channel.lua
deleted file mode 100644
index e879adf..0000000
--- a/util/channel.lua
+++ /dev/null
@@ -1,91 +0,0 @@
--- bi-directional http-channel
--- with long-poll GET and POST on the same URL
-
-local function Channel(http, url, cfg)
-	cfg = cfg or {}
-	local extra_headers = cfg.extra_headers or {}
-	local timeout = cfg.timeout or 1
-	local long_poll_timeout = cfg.long_poll_timeout or 30
-	local error_retry = cfg.error_retry or 10
-
-	-- assemble post-header with json content
-	local post_headers = { "Content-Type: application/json" }
-	for _,header in pairs(cfg.extra_headers) do
-		table.insert(post_headers, header)
-	end
-
-	local recv_listeners = {}
-	local run = true
-
-	local recv_loop
-
-	recv_loop = function()
-		assert(run)
-
-		-- long-poll GET
-		http.fetch({
-			url = url,
-			extra_headers = extra_headers,
-			timeout = long_poll_timeout
-		}, function(res)
-			if res.succeeded and res.code == 200 then
-				local data = minetest.parse_json(res.data)
-
-				if data then
-					for _,listener in pairs(recv_listeners) do
-						if #data > 0 then
-							-- array received
-							for _, entry in ipairs(data) do
-								listener(entry)
-							end
-						else
-							-- single item received
-							listener(data)
-						end
-					end
-				end
-				-- reschedule immediately
-				minetest.after(0, recv_loop)
-			else
-				-- error, retry after some time
-				minetest.after(error_retry, recv_loop)
-			end
-		end)
-	end
-
-
-	local send = function(data)
-		assert(run)
-		-- POST
-
-		http.fetch({
-			url = url,
-			extra_headers = post_headers,
-			timeout = timeout,
-			post_data = minetest.write_json(data)
-		}, function()
-			-- TODO: error-handling
-		end)
-	end
-
-	local receive = function(listener)
-		table.insert(recv_listeners, listener)
-	end
-
-	local close = function()
-		run = false
-	end
-
-	recv_loop();
-
-	return {
-		send = send,
-		receive = receive,
-		close = close
-	}
-
-end
-
-
-
-return Channel
diff --git a/util/normalize.lua b/util/normalize.lua
index 3064bf3..b817068 100644
--- a/util/normalize.lua
+++ b/util/normalize.lua
@@ -6,11 +6,11 @@ and add individual player names to recipient list
 --]]
 function mail.normalize_players_and_add_recipients(field, recipients, undeliverable)
     local order = mail.parse_player_list(field)
-    for _, player_name in ipairs(order) do
-        if not minetest.player_exists(player_name) then
-            undeliverable[player_name] = true
+    for _, recipient_name in ipairs(order) do
+        if not minetest.player_exists(recipient_name) then
+            undeliverable[recipient_name] = true
         else
-            recipients[player_name] = true
+            recipients[recipient_name] = true
         end
     end
     return mail.concat_player_list(order)
@@ -59,9 +59,3 @@ function mail.player_in_list(name, list)
     end
     return false
 end
-
-function mail.ensure_new_format(message, name)
-    if message.to == nil then
-        message.to = name
-    end
-end
diff --git a/util/normalize.spec.lua b/util/normalize.spec.lua
new file mode 100644
index 0000000..88628ad
--- /dev/null
+++ b/util/normalize.spec.lua
@@ -0,0 +1,12 @@
+
+mtt.register("util/normalize_players_and_add_recipients", function(callback)
+    local recipients = {}
+    local undeliverable = {}
+    local to = mail.normalize_players_and_add_recipients("player1,player2", recipients, undeliverable)
+
+    assert(to == "player1, player2")
+    assert(not next(undeliverable))
+    assert(recipients["player1"])
+    assert(recipients["player2"])
+    callback()
+end)
\ No newline at end of file
diff --git a/util/uuid.lua b/util/uuid.lua
new file mode 100644
index 0000000..571aa4a
--- /dev/null
+++ b/util/uuid.lua
@@ -0,0 +1,9 @@
+-- source: https://gist.github.com/jrus/3197011
+local random = math.random
+function mail.new_uuid()
+    local template ='xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'
+    return string.gsub(template, '[xy]', function (c)
+        local v = (c == 'x') and random(0, 0xf) or random(8, 0xb)
+        return string.format('%x', v)
+    end)
+end
\ No newline at end of file
diff --git a/util/uuid.spec.lua b/util/uuid.spec.lua
new file mode 100644
index 0000000..549399e
--- /dev/null
+++ b/util/uuid.spec.lua
@@ -0,0 +1,7 @@
+
+
+mtt.register("uuid", function(callback)
+    assert(mail.new_uuid())
+    assert(mail.new_uuid() ~= mail.new_uuid())
+    callback()
+end)
\ No newline at end of file