-----------------------------------------------------------------------------
-- POP3 support for the Lua language.
-- 
-- Module: Messages
-- Author: Guilherme Martins
-- Bug fixes: Brett England
-- Conforming to: RFC 1939
-----------------------------------------------------------------------------
module("pop3.message", package.seeall)

local Private,Public = {}, {}

--Debug option
Private.DEBUG = false

local function debug(...)
   if Private.DEBUG then print("LUAPOP3 DEBUG : ",unpack(arg)) end
end

-----------
-- function : getParsedMessage(msg,resp)
--
-- Parses the message and returns a mesage object
--
------------------------------------------------------
function Public.getParsedMessage(body)
   local msg = {}
   Private.fillProperties(msg,body)
   return msg
end

-------------
-- function : fillProperties(msg,body)
--
-- Gets the message attributes from resp and add to 
-- the message as properties
--
-- Returns the message
--------------------------
function Private.fillProperties(msg,body)
   
   -- Creates the message string from the body
   local bodyStr = table.concat(body,"\n");
   msg.all = bodyStr
   local message_s = string.gsub(bodyStr, "^.-\n", "")

   
   local _, _, header, bodyPart = string.find(message_s, "^(.-\n)\n(.*)")	
   
   -- Code history
   --local _,_,header, bodyPart = string.find(bodyStr.."\n","(.-\n)\n(.*)")
   
   msg.header = Private.headers(header)
   msg.body = Private.fillMessageParts(msg,bodyPart)
   
   -- Code history
   --msg.attchment = Private.fillMessageAttchments(msg,bodyPart)	
   --Private.fillHeaderProperties(msg,header)

end

-------------------
-- function: headers(header)
-- Parse the headers attributes to a table
--
-- Returns a table with the header like properties
--
-- Coded by Diego Nehab
--
-- Modified by Guilherme Martins
--------------------------------------------------------------
function Private.headers(headers_s)
   local headers = {}
   headers_s = "\n" .. headers_s .. "$$$:\n"
   local i, j = 1, 1
   local name, value, _
   while 1 do
      j = string.find(headers_s, "\n%S-:", i+1)
      if not j then break end
      _, _, name, value = string.find(string.sub(headers_s, i+1, j-1), "(%S-):%s?(.*)")
      value = string.gsub(value or "", "\r\n", "\n")
      value = string.gsub(value, "\n%s*", " ")
      name = string.lower(name)
      if headers[name] then headers[name] = headers[name] .. ", " ..  value
      else headers[name] = value end
      i, j = j, i
   end
   headers["$$$"] = nil
   return headers
end

-------------------------
-- function : fillMessageParts(msg,body)
--
-- Create a message body depending from the content-type
-- if the message is multipart, returns a table with the parts 
-- else returns a table with a single text part
--
-----------------------------------------------------------------------
function Private.fillMessageParts(msg,body)
   local result = {}
   local content = msg.header["content-type"] or ""
   
   --find the content type from the header property
   local _,_,content,atts = string.find(content,"([%w/]*)%s*;%s*(.*)")

   -- if donīt have this attribute, uses text/plain
   content = content or "text/plain"
   atts = atts or "" 
   
   debug(content)
   debug(atts)
   
   -- Checks for multpart main type or text
   local slashIndex = string.find(content,"/")
   
   if string.lower(content) == "text/plain" then
      --pure text case
      return {body}
      
   elseif string.lower(string.sub(content,1,slashIndex-1)) == "multipart" then
      --Multipart case
      local boundary
      -- get the parts boundary from the header	
      for key,value in string.gfind(atts,"(%w*)=[\"]?([%w-_:%+=.%s]*)") do
	 if string.lower(key) == "boundary" then
	    boundary = value
	    break;
	 end
	 boundary = ""		
      end
      
      debug("BOUNDARY = ",boundary)
      
      -- if the boundary was not founded throws a error
      if boundary == "" then return error("No message part boundary found for multipart mail message!") end
      
      -- get the last boundary index
      local _,endpart = string.find(body,"--"..boundary.."--",1,true)
      
      if endpart then
	 local s,e = string.find(body,"--"..boundary,1,true)
	 
	 -- mount the parts
	 while true do
	    local firstIndex,last2index = string.find(body,"--"..boundary,e,true)
	    if not firstIndex then break; end	 		
	    local part = string.sub(body,e+1,firstIndex-1)
	    part = Private.getParsedPart(part)
	    debug("PART",part)
	    table.insert(result,part)
	    s,e = firstIndex , last2index
	 end
	 return result
      end
   else
      return {body}
   end
   
end

---------------------
--function : getParsedPart
--
-- Gets the message Part parsed as a table with a pheader
-- property thats represent the part headers and a pcontent
-- that represent the body part
--
-- Returns the message Part
----------------------------------
function Private.getParsedPart(part) 
   local result = {}
   local part_s = string.gsub(part, "^.-\n", "")
   
   local _, _, header, bodyPart = string.find(part_s, "^(.-\n)\n(.*)")
   result.pheader =  Private.headers(header)
   result.pcontent=string.sub(bodyPart,1,string.len(bodyPart)-1)   
   
   return result
end

return Public