#!/usr/bin/env python3

import os
import sys
import subprocess
import argparse

def main():
    try:
        return main_()
    except SystemExit as e:
        try:
            return int(e.code)
        except:
            print(e.code)
            return 1

def kvpair(x):
    if x == "YES":
        return True
    elif x == "NO":
        return False
    elif x == "\\YES":
        return "YES"
    elif x == "\\NO":
        return "NO"
    else:
        return x

def main_():
    argp = argparse.ArgumentParser()
    argp.add_argument("source", nargs="+")
    argp.add_argument("destination")
    argp.add_argument("-p", "--profile", choices=["aac", "m4a", "ogg", "wav", "wma"])
    argp.add_argument("-u", "--update", help="Only process new files", action="store_true")
    argp.add_argument("--avconv", default="avconv")
    argp.add_argument("-m", nargs=2, action="append", type=kvpair, default=[])
    argp.add_argument("-i", nargs=2, action="append", type=kvpair, default=[])
    argp.add_argument("-o", nargs=2, action="append", type=kvpair, default=[])

    args = argp.parse_args()

    i_flags = dict()
    o_flags = dict()
    m_flags = dict()

    # no video
    o_flags["vn"] = True
    m_flags["update"] = args.update

    # capability checks
    s = subprocess.check_output([args.avconv, "-codecs"], stderr=subprocess.DEVNULL)
    if b"faac" in s:
        aac = {"acodec": "faac"}
    else:
        aac = {"acodec": "aac", "strict": "experimental"}
    if b"libvorbis" in s:
        vorbis = {"acodec": "libvorbis"}
    else:
        vorbis = {"acodec": "vorbis", "strict": "experimental"}

    # profiles
    m_flags["fileext"] = "raw"

    if args.profile == "aac":
        m_flags["fileext"] = "aac"
        o_flags.update(aac)
    elif args.profile == "m4a":
        m_flags["fileext"] = "m4a"
        o_flags.update(aac)
    elif args.profile == "ogg":
        m_flags["fileext"] = "ogg"
        o_flags.update(vorbis)
    elif args.profile == "wav":
        m_flags["fileext"] = "wav"
        o_flags["acodec"] = "pcm_f32le"
    elif args.profile == "wma":
        m_flags["fileext"] = "wma"
        o_flags["acodec"] = "wmav2"
        o_flags["ac"] = 2

    i_flags.update(dict(args.i))
    o_flags.update(dict(args.o))
    m_flags.update(dict(args.m))

    if len(args.source) > 1:
        run_multiple(m_flags, args.avconv, i_flags, args.source, o_flags, args.destination)
    else:
        run_once(m_flags, args.avconv, i_flags, args.source[0], o_flags, args.destination)
    return 0


def make_destfile(source, m, destination):
    if not os.path.isdir(destination):
        return destination
    stem, ext = os.path.splitext(source)
    destfile = ".".join((stem, m["fileext"]))
    return os.path.join(destination, destfile)


def add_args(argv, argdict):
    for k,v in argdict.items():
        argv.append("-%s" % k)
        if v is not True:
            argv.append(str(v))


def make_argv(m, avconv, i, source, o, destination):
    argv = [avconv]
    add_args(argv, i)
    argv.append("-i")
    argv.append(source)
    add_args(argv, o)
    argv.append(make_destfile(source, m, destination))
    return argv


def run_once(m, avconv, i, source, o, destination):
    dest = make_destfile(source, m, destination)
    if m["update"] and os.path.exists(dest) and os.stat(dest).st_mtime >= os.stat(source).st_mtime:
        return
    try:
        subprocess.check_call(make_argv(m, avconv, i, source, o, destination))
    except subprocess.CalledProcessError as e:
        raise SystemExit("Worker avconv process exited with nonzero return code: %i\nCommand was: %s\nAborting." % (e.returncode, e.cmd))


def run_multiple(m, avconv, i, sources, o, destination):
    if not os.path.isdir(destination):
        os.mkdir(destination)
    for source in sources:
        run_once(m, avconv, i, source, o, destination)

if __name__ == "__main__":
    main()