--- A Lua implementation of .zip file archiving (used for creating .rock files),

-- using only lzlib.

--module("luarocks.tools.zip", package.seeall)

local zip = {}



local zlib = require("zlib")

local fs = require("luarocks.fs")

local dir = require("luarocks.dir")



local function number_to_bytestring(number, nbytes)

   local out = {}

   for _ = 1, nbytes do

      local byte = number % 256

      table.insert(out, string.char(byte))

      number = (number - byte) / 256

   end

   return table.concat(out)

end



--- Begin a new file to be stored inside the zipfile.

-- @param self handle of the zipfile being written.

-- @param filename filenome of the file to be added to the zipfile.

-- @return true if succeeded, nil in case of failure.

local function zipwriter_open_new_file_in_zip(self, filename)

   if self.in_open_file then

      self:close_file_in_zip()

      return nil

   end

   local lfh = {}

   self.local_file_header = lfh

   lfh.last_mod_file_time = 0 -- TODO

   lfh.last_mod_file_date = 0 -- TODO

   lfh.crc32 = 0 -- initial value

   lfh.compressed_size = 0 -- unknown yet

   lfh.uncompressed_size = 0 -- unknown yet

   lfh.file_name_length = #filename

   lfh.extra_field_length = 0

   lfh.file_name = filename:gsub("\\", "/")

   lfh.external_attr = 0 -- TODO properly store permissions

   self.in_open_file = true

   self.data = {}

   return true

end



--- Write data to the file currently being stored in the zipfile.

-- @param self handle of the zipfile being written.

-- @param buf string containing data to be written.

-- @return true if succeeded, nil in case of failure.

local function zipwriter_write_file_in_zip(self, buf)

   if not self.in_open_file then

      return nil

   end

   local lfh = self.local_file_header

   local cbuf = zlib.compress(buf):sub(3, -5)

   lfh.crc32 = zlib.crc32(lfh.crc32, buf)

   lfh.compressed_size = lfh.compressed_size + #cbuf

   lfh.uncompressed_size = lfh.uncompressed_size + #buf

   table.insert(self.data, cbuf)

   return true

end



--- Complete the writing of a file stored in the zipfile.

-- @param self handle of the zipfile being written.

-- @return true if succeeded, nil in case of failure.

local function zipwriter_close_file_in_zip(self)

   local zh = self.ziphandle

   

   if not self.in_open_file then

      return nil

   end



   -- Local file header

   local lfh = self.local_file_header

   lfh.offset = zh:seek()

   zh:write(number_to_bytestring(0x04034b50, 4)) -- signature

   zh:write(number_to_bytestring(20, 2)) -- version needed to extract: 2.0

   zh:write(number_to_bytestring(0, 2)) -- general purpose bit flag

   zh:write(number_to_bytestring(8, 2)) -- compression method: deflate

   zh:write(number_to_bytestring(lfh.last_mod_file_time, 2))

   zh:write(number_to_bytestring(lfh.last_mod_file_date, 2))

   zh:write(number_to_bytestring(lfh.crc32, 4))

   zh:write(number_to_bytestring(lfh.compressed_size, 4))

   zh:write(number_to_bytestring(lfh.uncompressed_size, 4))

   zh:write(number_to_bytestring(lfh.file_name_length, 2))

   zh:write(number_to_bytestring(lfh.extra_field_length, 2))

   zh:write(lfh.file_name)



   -- File data   

   for _, cbuf in ipairs(self.data) do

      zh:write(cbuf)

   end

   

   -- Data descriptor

   zh:write(number_to_bytestring(lfh.crc32, 4))

   zh:write(number_to_bytestring(lfh.compressed_size, 4))

   zh:write(number_to_bytestring(lfh.uncompressed_size, 4))

   

   table.insert(self.files, lfh)

   self.in_open_file = false

   

   return true

end



-- @return boolean or (boolean, string): true on success,

-- false and an error message on failure.

local function zipwriter_add(self, file)

   local fin

   local ok, err = self:open_new_file_in_zip(file)

   if not ok then

      err = "error in opening "..file.." in zipfile"

   else

      fin = io.open(fs.absolute_name(file), "rb")

      if not fin then

         ok = false

         err = "error opening "..file.." for reading"

      end

   end

   if ok then

      local buf = fin:read("*a")

      if not buf then

         err = "error reading "..file

         ok = false

      else

         ok = self:write_file_in_zip(buf)

         if not ok then

            err = "error in writing "..file.." in the zipfile"

         end

      end

   end

   if fin then

      fin:close()

   end

   if ok then

      ok = self:close_file_in_zip()

      if not ok then

         err = "error in writing "..file.." in the zipfile"

      end

   end

   return ok == true, err

end



--- Complete the writing of the zipfile.

-- @param self handle of the zipfile being written.

-- @return true if succeeded, nil in case of failure.

local function zipwriter_close(self)

   local zh = self.ziphandle

   

   local central_directory_offset = zh:seek()

   

   local size_of_central_directory = 0

   -- Central directory structure

   for _, lfh in ipairs(self.files) do

      zh:write(number_to_bytestring(0x02014b50, 4)) -- signature

      zh:write(number_to_bytestring(3, 2)) -- version made by: UNIX

      zh:write(number_to_bytestring(20, 2)) -- version needed to extract: 2.0

      zh:write(number_to_bytestring(0, 2)) -- general purpose bit flag

      zh:write(number_to_bytestring(8, 2)) -- compression method: deflate

      zh:write(number_to_bytestring(lfh.last_mod_file_time, 2))

      zh:write(number_to_bytestring(lfh.last_mod_file_date, 2))

      zh:write(number_to_bytestring(lfh.crc32, 4))

      zh:write(number_to_bytestring(lfh.compressed_size, 4))

      zh:write(number_to_bytestring(lfh.uncompressed_size, 4))

      zh:write(number_to_bytestring(lfh.file_name_length, 2))

      zh:write(number_to_bytestring(lfh.extra_field_length, 2))

      zh:write(number_to_bytestring(0, 2)) -- file comment length

      zh:write(number_to_bytestring(0, 2)) -- disk number start

      zh:write(number_to_bytestring(0, 2)) -- internal file attributes

      zh:write(number_to_bytestring(lfh.external_attr, 4)) -- external file attributes

      zh:write(number_to_bytestring(lfh.offset, 4)) -- relative offset of local header

      zh:write(lfh.file_name)

      size_of_central_directory = size_of_central_directory + 46 + lfh.file_name_length

   end

   

   -- End of central directory record

   zh:write(number_to_bytestring(0x06054b50, 4)) -- signature

   zh:write(number_to_bytestring(0, 2)) -- number of this disk

   zh:write(number_to_bytestring(0, 2)) -- number of disk with start of central directory

   zh:write(number_to_bytestring(#self.files, 2)) -- total number of entries in the central dir on this disk

   zh:write(number_to_bytestring(#self.files, 2)) -- total number of entries in the central dir

   zh:write(number_to_bytestring(size_of_central_directory, 4))

   zh:write(number_to_bytestring(central_directory_offset, 4))

   zh:write(number_to_bytestring(0, 2)) -- zip file comment length

   zh:close()



   return true

end



--- Return a zip handle open for writing.

-- @param name filename of the zipfile to be created.

-- @return a zip handle, or nil in case of error.

function zip.new_zipwriter(name)

   

   local zw = {}

  

   zw.ziphandle = io.open(fs.absolute_name(name), "wb")

   if not zw.ziphandle then

      return nil

   end

   zw.files = {}

   zw.in_open_file = false

   

   zw.add = zipwriter_add

   zw.close = zipwriter_close

   zw.open_new_file_in_zip = zipwriter_open_new_file_in_zip

   zw.write_file_in_zip = zipwriter_write_file_in_zip

   zw.close_file_in_zip = zipwriter_close_file_in_zip



   return zw

end



--- Compress files in a .zip archive.

-- @param zipfile string: pathname of .zip archive to be created.

-- @param ... Filenames to be stored in the archive are given as

-- additional arguments.

-- @return boolean or (boolean, string): true on success,

-- false and an error message on failure.

function zip.zip(zipfile, ...)

   local zw = zip.new_zipwriter(zipfile)

   if not zw then

      return nil, "error opening "..zipfile

   end



   local ok, err

   for _, file in pairs({...}) do

      if fs.is_dir(file) then

         for _, entry in pairs(fs.find(file)) do

            local fullname = dir.path(file, entry)

            if fs.is_file(fullname) then

               ok, err = zw:add(fullname)

               if not ok then break end

            end

         end

      else

         ok, err = zw:add(file)

         if not ok then break end

      end

   end



   ok = zw:close()

   if not ok then

      return false, "error closing "..zipfile

   end

   return ok, err

end





return zip