#!/usr/bin/python
# Copyright (C) 2012, Jeff Epler <jepler@unpy.net>
# See license information at bottom

import mmap
import optparse
import os
import struct

MODE_UNKNOWN, MODE_PACK, MODE_UNPACK = range(3)
mode = MODE_UNKNOWN

parser = optparse.OptionParser()
parser.add_option('-p', '--pack', action="store_const", const=MODE_PACK)
parser.add_option('-u', '--unpack', action="store_const", const=MODE_UNPACK)
opts, args = parser.parse_args()

if len(args) == 1 or len(args) == 2:
    if mode == MODE_UNKNOWN:
        if os.path.isdir(args[0]):
            indir = args[0]
            if len(args) == 1:
                outfile = args[0] + '.dat'
            else:
                outfile = args[1]
            mode = MODE_PACK
        else:
            infile = args[0]
            if len(args) == 1:
                outdir = os.path.basename(os.path.splitext(args[0])[0])
            else:
                outdir = args[1]
            mode = MODE_UNPACK
    elif mode == MODE_PACK:
        indir = args[0]
        if len(args) == 1:
            outfile = args[0] + '.dat'
        else:
            outfile = args[1]
    else:
        infile = args[0]
        if len(args) == 1:
            outfile = os.path.basename(args[0])
        else:
            outfile = args[1]
else:
    raise SystemExit, """\
Usage: %(p)s [--pack]   data      # pack files in data/ to data.dat
       %(p)s [--unpack] data.dat  # unpack data.dat to data/""" % {
            'p': os.path.basename(sys.argv[0])}

def splitall(p):
    h, t = os.path.split(p)
    if h: return splitall(h) + (t,)
    else: return t,

def dropfirst(path):
    return os.path.join(*splitall(path)[1:]) # Remove first compo.

def gather(dir):
    for dirpath, dirnames, filenames in os.walk(dir):
        for f in filenames:
            j = os.path.join(dirpath, f)
            yield (j, dropfirst(j), os.stat(j).st_size)

made = set()
def makedirs(d):
    if d in made: return
    made.add(d)
    try:
        os.makedirs(d)
    except os.error:
        pass

def parse_ftl_dat(buf, st):
    data_size, name_size = struct.unpack("<LL", buf[st:st+8])
    name_start = st + 8
    data_start = name_start + name_size
    data_end = data_start + data_size
    name = buf[name_start : data_start]
    data = buf[data_start : data_end]
    return data_end, name, data

if mode == MODE_PACK:
    print "# pack", repr(indir), "->", repr(outfile)
    files = list(gather(indir))
    out = open(outfile, "wb")
    out.write(struct.pack("<L", len(files)))
    off = 4 * (len(files) + 1)
    for f in files:
        out.write(struct.pack("<L", off))
        off += len(f[1]) + f[2] + 8

    for f in files:
        out.write(struct.pack("<LL", f[2], len(f[1])))
        out.write(f[1])
        fin = open(f[0], "rb")
        m = mmap.mmap(fin.fileno(), 0, access=mmap.PROT_READ)
        out.write(m)
        m.close()
        del m
        fin.close()
elif mode == MODE_UNPACK:
    print "# unpack", repr(infile), "->", repr(outdir)
    inf = open(infile, "rb")
    buf = mmap.mmap(inf.fileno(), 0, access=mmap.PROT_READ)
    st = 4
    st, = struct.unpack("<L", buf[st:st+4])
    while st < len(buf):
        st, name, data = parse_ftl_dat(buf, st)
        print "#", repr(name), len(data)
        split = splitall(name)
        if os.curdir in split or os.pardir in split:
            print "unsanitary name", repr(split)
            continue
        ofn = os.path.join(outdir, *split)
        makedirs(os.path.dirname(ofn))
        open(ofn, "wb").write(data)
else:
    raise SystemExit, "what mode??"

#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA