mail/ui/message.lua

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)