Message filters/sorters (#56)

* Add sorters for inbox/outbox

* Add ascending/descending, fix selection issue

* Add filters

* Update translations

* Fix UI

* Fix luacheck

* Fix fields disappearing after clicking on tabs/buttons

* Fix luacheck (2)

* Fix first message not sorted correctly

storage.lua

@@ -43,6 +43,77 @@ function mail.get_message(playername, msg_id)
 	end
 end
 
+function mail.sort_messages(unsorted_messages, sortfield, sortdirection)
+    local messages = {}
+    if not sortfield or sortfield == "" then
+        sortfield = "3"
+    end
+    if not sortdirection or sortdirection == "" then
+		sortdirection = "1"
+	end
+
+	if unsorted_messages[1] then
+		-- add first message
+		table.insert(messages, unsorted_messages[1])
+		table.remove(unsorted_messages, 1)
+		-- sort messages
+		for _, unsorted_msg in ipairs(unsorted_messages) do
+			local is_message_sorted = false
+			for j, sorted_msg in ipairs(messages) do
+				if sortfield == "1" and unsorted_msg.from >= sorted_msg.from then -- for inbox
+					table.insert(messages, j, unsorted_msg)
+					is_message_sorted = true
+					break
+				elseif sortfield == "1" and unsorted_msg.to >= sorted_msg.to then -- for outbox
+					table.insert(messages, j, unsorted_msg)
+					is_message_sorted = true
+					break
+				elseif sortfield == "2" and unsorted_msg.subject >= sorted_msg.subject then
+					table.insert(messages, j, unsorted_msg)
+					is_message_sorted = true
+					break
+				elseif sortfield == "3" and unsorted_msg.time >= sorted_msg.time then
+					table.insert(messages, j, unsorted_msg)
+					is_message_sorted = true
+					break
+				end
+			end
+			if not is_message_sorted then
+				table.insert(messages, 1, unsorted_msg)
+			end
+		end
+	end
+
+	-- reverse for descending
+
+	local sorted_messages = messages
+
+	if sortdirection == "2" then
+		sorted_messages = {}
+		for i=#messages, 1, -1 do
+			sorted_messages[#sorted_messages+1] = messages[i]
+		end
+	end
+
+	return sorted_messages
+end
+
+function mail.filter_messages(unfiltered_messages, filter)
+	if not filter or filter == "" then
+		return unfiltered_messages
+	end
+
+	local filtered_messages = {}
+
+	for _, msg in ipairs(unfiltered_messages) do
+		if string.find(msg.from, filter) or string.find(msg.to, filter) or string.find(msg.subject, filter) then
+			table.insert(filtered_messages, msg)
+		end
+	end
+
+	return filtered_messages
+end
+
 -- marks a mail read by its id
 function mail.mark_read(playername, msg_id)
 	local entry = mail.get_storage_entry(playername)