-- -----------------------------------------------------------------------------
-- -- SMTP client support for the Lua language.
-- -- LuaSocket toolkit.
-- -- Author: Diego Nehab
-- -----------------------------------------------------------------------------

-- -----------------------------------------------------------------------------
-- -- Declare module and import dependencies
-- -----------------------------------------------------------------------------
-- local base = _G
-- local coroutine = require("coroutine")
-- local string = require("string")
-- local math = require("math")
-- local os = require("os")
-- local socket = require("socket")
-- local tp = require("socket.tp")
-- local ltn12 = require("ltn12")
-- local headers = require("socket.headers")
-- local mime = require("mime")

-- socket.smtp = {}
-- local _M = socket.smtp

-- -----------------------------------------------------------------------------
-- -- Program constants
-- -----------------------------------------------------------------------------
-- -- timeout for connection
-- _M.TIMEOUT = 60
-- -- default server used to send e-mails
-- _M.SERVER = "localhost"
-- -- default port
-- _M.PORT = 25
-- -- domain used in HELO command and default sendmail
-- -- If we are under a CGI, try to get from environment
-- _M.DOMAIN = os.getenv("SERVER_NAME") or "localhost"
-- -- default time zone (means we don't know)
-- _M.ZONE = "-0000"

-- ---------------------------------------------------------------------------
-- -- Low level SMTP API
-- -----------------------------------------------------------------------------
-- local metat = { __index = {} }

-- function metat.__index:greet(domain)
--     self.try(self.tp:check("2.."))
--     self.try(self.tp:command("EHLO", domain or _M.DOMAIN))
--     return socket.skip(1, self.try(self.tp:check("2..")))
-- end

-- function metat.__index:mail(from)
--     self.try(self.tp:command("MAIL", "FROM:" .. from))
--     return self.try(self.tp:check("2.."))
-- end

-- function metat.__index:rcpt(to)
--     self.try(self.tp:command("RCPT", "TO:" .. to))
--     return self.try(self.tp:check("2.."))
-- end

-- function metat.__index:data(src, step)
--     self.try(self.tp:command("DATA"))
--     self.try(self.tp:check("3.."))
--     self.try(self.tp:source(src, step))
--     self.try(self.tp:send("\r\n.\r\n"))
--     return self.try(self.tp:check("2.."))
-- end

-- function metat.__index:quit()
--     self.try(self.tp:command("QUIT"))
--     return self.try(self.tp:check("2.."))
-- end

-- function metat.__index:close()
--     return self.tp:close()
-- end

-- function metat.__index:login(user, password)
--     self.try(self.tp:command("AUTH", "LOGIN"))
--     self.try(self.tp:check("3.."))
--     self.try(self.tp:send(mime.b64(user) .. "\r\n"))
--     self.try(self.tp:check("3.."))
--     self.try(self.tp:send(mime.b64(password) .. "\r\n"))
--     return self.try(self.tp:check("2.."))
-- end

-- function metat.__index:plain(user, password)
--     local auth = "PLAIN " .. mime.b64("\0" .. user .. "\0" .. password)
--     self.try(self.tp:command("AUTH", auth))
--     return self.try(self.tp:check("2.."))
-- end

-- function metat.__index:auth(user, password, ext)
--     if not user or not password then return 1 end
--     if string.find(ext, "AUTH[^\n]+LOGIN") then
--         return self:login(user, password)
--     elseif string.find(ext, "AUTH[^\n]+PLAIN") then
--         return self:plain(user, password)
--     else
--         self.try(nil, "authentication not supported")
--     end
-- end

-- -- send message or throw an exception
-- function metat.__index:send(mailt)
--     self:mail(mailt.from)
--     if base.type(mailt.rcpt) == "table" then
--         for i,v in base.ipairs(mailt.rcpt) do
--             self:rcpt(v)
--         end
--     else
--         self:rcpt(mailt.rcpt)
--     end
--     self:data(ltn12.source.chain(mailt.source, mime.stuff()), mailt.step)
-- end

-- function _M.open(server, port, create)
--     local tp = socket.try(tp.connect(server or _M.SERVER, port or _M.PORT,
--         _M.TIMEOUT, create))
--     local s = base.setmetatable({tp = tp}, metat)
--     -- make sure tp is closed if we get an exception
--     s.try = socket.newtry(function()
--         s:close()
--     end)
--     return s
-- end

-- -- convert headers to lowercase
-- local function lower_headers(headers)
--     local lower = {}
--     for i,v in base.pairs(headers or lower) do
--         lower[string.lower(i)] = v
--     end
--     return lower
-- end

-- ---------------------------------------------------------------------------
-- -- Multipart message source
-- -----------------------------------------------------------------------------
-- -- returns a hopefully unique mime boundary
-- local seqno = 0
-- local function newboundary()
--     seqno = seqno + 1
--     return string.format('%s%05d==%05u', os.date('%d%m%Y%H%M%S'),
--         math.random(0, 99999), seqno)
-- end

-- -- send_message forward declaration
-- local send_message

-- -- yield the headers all at once, it's faster
-- local function send_headers(tosend)
--     local canonic = headers.canonic
--     local h = "\r\n"
--     for f,v in base.pairs(tosend) do
--         h = (canonic[f] or f) .. ': ' .. v .. "\r\n" .. h
--     end
--     coroutine.yield(h)
-- end

-- -- yield multipart message body from a multipart message table
-- local function send_multipart(mesgt)
--     -- make sure we have our boundary and send headers
--     local bd = newboundary()
--     local headers = lower_headers(mesgt.headers or {})
--     headers['content-type'] = headers['content-type'] or 'multipart/mixed'
--     headers['content-type'] = headers['content-type'] ..
--         '; boundary="' ..  bd .. '"'
--     send_headers(headers)
--     -- send preamble
--     if mesgt.body.preamble then
--         coroutine.yield(mesgt.body.preamble)
--         coroutine.yield("\r\n")
--     end
--     -- send each part separated by a boundary
--     for i, m in base.ipairs(mesgt.body) do
--         coroutine.yield("\r\n--" .. bd .. "\r\n")
--         send_message(m)
--     end
--     -- send last boundary
--     coroutine.yield("\r\n--" .. bd .. "--\r\n\r\n")
--     -- send epilogue
--     if mesgt.body.epilogue then
--         coroutine.yield(mesgt.body.epilogue)
--         coroutine.yield("\r\n")
--     end
-- end

-- -- yield message body from a source
-- local function send_source(mesgt)
--     -- make sure we have a content-type
--     local headers = lower_headers(mesgt.headers or {})
--     headers['content-type'] = headers['content-type'] or
--         'text/plain; charset="iso-8859-1"'
--     send_headers(headers)
--     -- send body from source
--     while true do
--         local chunk, err = mesgt.body()
--         if err then coroutine.yield(nil, err)
--         elseif chunk then coroutine.yield(chunk)
--         else break end
--     end
-- end

-- -- yield message body from a string
-- local function send_string(mesgt)
--     -- make sure we have a content-type
--     local headers = lower_headers(mesgt.headers or {})
--     headers['content-type'] = headers['content-type'] or
--         'text/plain; charset="iso-8859-1"'
--     send_headers(headers)
--     -- send body from string
--     coroutine.yield(mesgt.body)
-- end

-- -- message source
-- function send_message(mesgt)
--     if base.type(mesgt.body) == "table" then send_multipart(mesgt)
--     elseif base.type(mesgt.body) == "function" then send_source(mesgt)
--     else send_string(mesgt) end
-- end

-- -- set defaul headers
-- local function adjust_headers(mesgt)
--     local lower = lower_headers(mesgt.headers)
--     lower["date"] = lower["date"] or
--         os.date("!%a, %d %b %Y %H:%M:%S ") .. (mesgt.zone or _M.ZONE)
--     lower["x-mailer"] = lower["x-mailer"] or socket._VERSION
--     -- this can't be overriden
--     lower["mime-version"] = "1.0"
--     return lower
-- end

-- function _M.message(mesgt)
--     mesgt.headers = adjust_headers(mesgt)
--     -- create and return message source
--     local co = coroutine.create(function() send_message(mesgt) end)
--     return function()
--         local ret, a, b = coroutine.resume(co)
--         if ret then return a, b
--         else return nil, a end
--     end
-- end

-- ---------------------------------------------------------------------------
-- -- High level SMTP API
-- -----------------------------------------------------------------------------
-- _M.send = socket.protect(function(mailt)
--     local s = _M.open(mailt.server, mailt.port, mailt.create)
--     local ext = s:greet(mailt.domain)
--     s:auth(mailt.user, mailt.password, ext)
--     s:send(mailt)
--     s:quit()
--     return s:close()
-- end)

-- return _M