mail/ui/events.lua

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)