-- mail.lua

--[[--
	Data structure for mail files:
	{
		["sender"] = (string),
		["receivers"] = (table) {
			[1] = (string),
			[2] = (string),
			etc.
		},
		["subject"] = (string),
		["message"] = (string),
	}

	Printer page size: 25x21
--]]--

--(( Settings ))--

local filename = "mail.dat"
local drivePath = "back"

--(( Variables ))--

err = {
	missing_item = "No item inside the disk drive!",
	invalid_item = "The item in the disk drive is not a valid disk!",
}

local drive = peripheral.wrap(drivePath)
or error("Unable to wrap disk drive!")

--(( Functions ))--

-- write a letter
function writeMail(mail)
	if drive.hasData() then
		local path = fs.combine(drive.getMountPath(),filename)

		local file = fs.open(path,"w")
		file.write(textutils.serialize(mail))
		file.close()

		rs.setOutput("top",true)
		sleep(1)
		rs.setOutput("top",false)
	else
		error("No disk available!")
	end
end

-- get a formatted title for the mail
function getTitle(mail, page, pages)
	local title = '"'
	util.wordwrap(mail.subject, function(row) title=title..row end, 32, 0)
	title = title .. '" from '
	util.wordwrap(mail.sender, function(row) title=title..row end, 32, 0)

	if pages > 1 then
		title = title .. " (page " .. page .. " of " .. pages .. ")"
	end

	return title
end

-- prepare the mail for writing
function prepareMessage(data)
	local w,h = 25,21 -- size of page
	local rows = {}
	local message = data.message
	local offset = 0

	repeat
		util.wordwrap("From: "..data.sender, rows, w, 0)
		util.wordwrap("Subject: "..data.subject, rows, w, 1)
		table.insert(rows, string.rep("-",w))
		message = util.wordwrap(message, rows, w, h - #rows - 2 + offset)
		for i=1,h-#rows-1+offset do table.insert(rows, "") end
		table.insert(rows,666)

		offset = #rows
	until message == nil

	-- Go through 2nd time
	local pages = math.ceil(#rows/h)

	for i,row in ipairs(rows) do
		if row == 666 then
			local page = math.ceil(i/h)

			row = "[ Page " .. page .. " / " .. pages .. " ]--"
			row = string.rep("-",25-#row)..row

			-- apply change
			rows[i] = row
		end
	end

	return rows
end

function splitPages(rows)
	local h = 21 -- height of page
	local pages = {}

	for i,sRow in ipairs(rows) do
		local page = math.ceil(i/h)
		local nRow = i-(page-1)*h

		pages[page] = pages[page] or {}
		pages[page][nRow] = sRow
	end

	return pages
end

function getDrive()
	return drive
end

-- eof