local serial = require "serialization"
local w, lzss = pcall(require,"lzss")
if not w then lzss = nil end
local tArgs = {...}
local fsnames = {"lfs","luafilesystem","filesystem"}
local w, fs
for k,v in pairs(fsnames) do
 w,fs = pcall(require,v)
 if w then break end
end
if not w then error("luafilesystem not detected") end

local function cint(n,l)
 local t={}
 for i = 0, 7 do
  t[i+1] = (n >> (i * 8)) & 0xFF
 end
 return string.reverse(string.char(table.unpack(t)):sub(1,l))
end

local function genHeader(fname,len)
 return string.format("%s%s%s",cint(fname:len(),2),fname,cint(len,2))
end

local function fnormalize(path)
 local rt = {}
 for segment in path:gmatch("[^/]+") do
  if segment ~= "." and segment ~= ".." then
   rt[#rt+1] = segment
  end
 end
 return table.concat(rt,"/")
end

local dirs, files = {tArgs[1]},{}
for _,dir in ipairs(dirs) do
 for file in fs.dir(dir) do
  if file == "." or file == ".." then
  elseif fs.attributes(dir.."/"..file).mode == "directory" then
   dirs[#dirs+1] = dir.."/"..file
  elseif file ~= "package.cfg" then
   files[#files+1] = dir.."/"..file
  end
 end
end

local f = io.open(tArgs[1].."/package.cfg","rb")
if not f then error("no package.cfg in source") end
local pkginfo = serial.unserialize(f:read("*a"))
f:close()

local outpath = tArgs[2].."/"..tArgs[1]..".mtar"

local of = io.open(outpath,"wb")
for k,v in ipairs(files) do
 local f = io.open(v,"rb")
 if f then
  local content = f:read("*a")
  f:close()
  of:write(genHeader(fnormalize(v:sub(tArgs[1]:len()+1)),content:len()))
  of:write(content)
 end
end
of:write(string.char(0):rep(2))
of:close()

if lzss then
 print("Compressing "..outpath.." to "..outpath..".lss")
 local f = io.open(outpath,"rb")
 local of = io.open(outpath..".lss","wb")
 while true do
  local b = f:read(4096)
  if not b or b:len() < 1 then break end
  b = lzss.compress(b)
  of:write(b)
 end
 f:close()
 of:close()
 outpath = outpath .. ".lss"
 pkginfo.compressed = true
end
pkginfo.filename = fnormalize(outpath:sub(tArgs[2]:len()+1))
pkginfo.version = tArgs[3]

local repo = {}
local f = io.open(tArgs[2].."/packages.cfg","rb")
if f then
 repo = serial.unserialize(f:read("*a")) or {}
 f:close()
end
repo[tArgs[1]] = pkginfo

local f = io.open(tArgs[2].."/packages.cfg","wb")
if f then
 f:write(serial.serialize(repo))
 f:close()
end