#!/usr/bin/env python3

"""

Mapfile format:
## More than meets the eye

@ -a2 -q19

1  1x09 - Fire on the Mountain
^  ^
|  +- Output file name (sans .mp4)
+---- Title number

Argument lines starting with `@` contain extra
arguments passed to HandBrakeCLI. Each one
affects all the output lines until a new
such line is seen.

Actual comments starting with `#` and empty
lines are ignored.

Greetz and thankz to Con Kolivas for
the HandBrake options!
"""

import multiprocessing
import os
import subprocess
import sys

DVDW_DEVICE = os.environ.get('DVDW_DEVICE', '/dev/sr0')
DVDW_CPUCOUNT = os.environ.get('DVDW_CPUCOUNT', multiprocessing.cpu_count())
DVDW_MODE = os.environ.get('DVDW_MODE', 'pal_4_3')

OPT_720P = 'nombtree:keyint=1000:scenecut=10:ref=9:ip_factor=1:pb_factor=1:' \
           'direct_pred=auto:weight_b:analyse=all:me=umh:mixed_refs:' \
           'trellis=0:nofast_pskip:level_idc=41:threads={}:' \
           'aq_mode=0:nodeterministic:psy-rd=0|0:b-adapt=2:level=4.1:' \
           'direct=auto:fast-pskip=0:ipratio=1.00:pbratio=1.00:aq-mode=0' \
           ':mbtree=0:cabac=0:no-dct-decimate=1:aq-strength=0:bframes=16'.format(DVDW_CPUCOUNT)

BASE_MODES = {
    'pal_4_3': {
        'width': 720,
        'height': 576,
        'fps': 25,
    },
    'ntsc_4_3': {
        'width': 720,
        'height': 480,
        'fps': 30,
    }
}

BASE_ARGS = '-i {DVDW_DEVICE} -e x264 -x {OPT} ' \
            '-w {width} -l {height} -r {fps} ' \
            '--no-loose-crop --crop 0:0:0:0 ' \
            '--comb-detect ' \
            '-t {tracknum} ' \
            '{extra_args}'


def find_handbrake():
    """Do a simple search in $PATH for HandBrakeCLI
    """

    for path in os.environ['PATH'].split(':'):
        candidate = os.path.join(path, 'HandBrakeCLI')
        if os.path.exists(candidate):
            return candidate


def get_arguments(mapfile, mode):
    """Parse `mapfile` and combine its arguments
    with the ones in `mode`.
    """

    fmt = mode.copy()
    fmt['DVDW_DEVICE'] = DVDW_DEVICE
    fmt['extra_args'] = ''

    args = []
    for line in open(mapfile, 'r'):
        split_line = line.strip().split()

        if not split_line:
            continue

        if line.startswith('#'):
            continue
        elif split_line[0] == '@':
            fmt['extra_args'] = ' '.join(split_line[1:])
            continue

        fmt['tracknum'] = split_line[0]
        trackname = ' '.join(split_line[1:])

        args_list = BASE_ARGS.format(**fmt)

        args.append((args_list, trackname))

    return args


def main(mapfile):
    """Parse and rip
    """

    hb = find_handbrake()
    if not hb:
        print('HandBrakeCLI not found')
        return 1

    mode = BASE_MODES.get(DVDW_MODE)
    if mode['width'] <= 720:
        mode['OPT'] = OPT_720P
    else:
        raise NotImplementedError('Not here yet')

    args = get_arguments(mapfile, mode)
    for arg, trackname in args:
        cmd = '{} {}'.format(hb, arg)
        cmd = cmd.split()
        cmd.extend(('-o', '{}.mp4'.format(trackname)))

        ret = subprocess.run(cmd)

    return ret.returncode


if __name__ == '__main__':
    if len(sys.argv) == 1:
        print('USAGE: {} MAPFILE'.format(sys.argv[0]))
        sys.exit(1)

    sys.exit(main(sys.argv[1]))