#!/usr/bin/env python
"""A program to show using iso9660 to extract a file from an ISO-9660
image.

If a single argument is given, it is used as the ISO 9660 image to use
in the extraction. Otherwise a compiled in default ISO 9660 image name
(that comes with the libcdio distribution) will be used.  A program to
show using iso9660 to extract a file from an ISO-9660 image."""
#
#  Copyright (C) 2006, 2008, 2013, 2021 Rocky Bernstein <rocky@gnu.org>
#
#  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 3 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, see <http://www.gnu.org/licenses/>.

import os, sys

libdir = os.path.join(os.path.dirname(__file__), "..")
if libdir[-1] != os.path.sep:
    libdir += os.path.sep
sys.path.insert(0, libdir)
import pycdio
import iso9660

PY3 = sys.version_info[0] == 3

# Python has rounding (round) and trucation (int), but what about an integer
# ceiling function? Until I learn what it is...
def ceil(x):
    return int(round(x + 0.5))


# The default CD image if none given
iso_image_path = "../data"
iso_image_fname = os.path.join(iso_image_path, "isofs-m1.cue")

# File to extract if none given.
iso9660_path = "/"
local_filename = "COPYING"

if len(sys.argv) > 1:
    iso_image_fname = sys.argv[1]
    if len(sys.argv) > 2:
        local_filename = sys.argv[1]
        if len(sys.argv) > 3:
            print(
                """
usage: %s [CD-ROM-or-image [filename]]
Extracts filename from CD-ROM-or-image.
"""
                % sys.argv[0]
            )
            sys.exit(1)

try:
    iso = iso9660.ISO9660.FS(source=iso_image_fname)
except:
    print("Sorry, couldn't open %s as a ISO9660 CD image." % iso_image_fname)
    sys.exit(1)

statbuf = iso.stat(local_filename, False)

if statbuf is None:
    print(
        'Could not get ISO-9660 file information for file "%s" in "%s"'
        % (local_filename, iso_image_fname)
    )
    file_stats = iso.readdir("/")
    print("Top-level names:")
    for stat in file_stats:
        filename = stat[0]
        print("%s" % filename)
    iso.close()
    sys.exit(2)

try:
    OUTPUT = os.open(local_filename, os.O_CREAT | os.O_WRONLY, 0o664)
except:
    print("Can't open %s for writing" % local_filename)

# Copy the blocks from the ISO-9660 filesystem to the local filesystem.
blocks = ceil(statbuf["size"] / pycdio.ISO_BLOCKSIZE)
for i in range(blocks):
    lsn = statbuf["LSN"] + i
    size, buf = iso.read_data_blocks(lsn)

    if size < 0:
        print("Error reading ISO 9660 file %s at LSN %d" % (local_filename, lsn))
        sys.exit(4)
        pass

    if PY3:
        os.write(OUTPUT, bytes(buf, "UTF-8"))
    else:
        os.write(OUTPUT, buf)
        pass

# Make sure the file size has the exact same byte size. Without the
# truncate below, the file will a multiple of ISO_BLOCKSIZE.

os.ftruncate(OUTPUT, statbuf["size"])

print("Extraction of file '%s' from %s successful." % (local_filename, iso_image_fname))

os.close(OUTPUT)
iso.close()
sys.exit(0)