import os
import sys
from argparse import ArgumentParser, Action
from datetime import datetime
import logging
logging.basicConfig(stream=sys.stdout)
logger = logging.getLogger('cli')


CWD = os.getcwd()

from . import forge
from . import maint
from .config_manager import get_config
from . import server


def pre_check_permissions():

    def is_writable(d):
        return os.access(d, os.W_OK)

    if is_writable(get_config()['AUDIO_INPUT']):
        yield "Audio input '%s' writable" % get_config()['AUDIO_INPUT']
    if not os.access(get_config()['AUDIO_INPUT'], os.R_OK):
        yield "Audio input '%s' unreadable" % get_config()['AUDIO_INPUT']
        sys.exit(10)
    if is_writable(os.getcwd()):
        yield "Code writable"
    if not is_writable(get_config()['AUDIO_OUTPUT']):
        yield "Audio output '%s' not writable" % get_config()['AUDIO_OUTPUT']
        logger.critical("Aborting")
        sys.exit(10)


def pre_check_user():
    if os.geteuid() == 0:
        yield "You're running as root; this is dangerous"

def pre_check_ffmpeg():
    path = get_config()['FFMPEG_PATH']
    if not path.startswith('/'):
        yield "FFMPEG_PATH is not absolute: %s" % path
        from subprocess import check_output
        try:
            check_output([path, '-version'])
        except OSError:
            yield "FFMPEG not found as " + path
    else:
        if not os.path.exists(path):
            yield "FFMPEG not found in " + path


class DateTimeAction(Action):
    def __call__(self, parser, namespace, values, option_string=None):
        if len(values) == 15 or len(values) == 13:
            parsed_val = datetime.strptime(values, '%Y%m%d-%H%M%S')
        else:
            raise ValueError("'%s' is not a valid datetime" % values)
        setattr(namespace, self.dest, parsed_val)


def common_pre():
    prechecks = [pre_check_user, pre_check_permissions, pre_check_ffmpeg]
    configs = ['default_config.py']
    if 'TECHREC_CONFIG' in os.environ:
        for conf in os.environ['TECHREC_CONFIG'].split(':'):
            if not conf:
                continue
            path = os.path.realpath(conf)
            if not os.path.exists(path):
                logger.warn("Configuration file '%s' does not exist; skipping"
                            % path)
                continue
            configs.append(path)
    os.chdir(os.path.dirname(os.path.realpath(__file__)))
    for conf in configs:
        get_config().from_pyfile(conf)

    for check in prechecks:
        for warn in check():
            logger.warn(warn)

def main():
    parser = ArgumentParser(description='creates mp3 from live recordings')
    parser.add_argument('--verbose', '-v', action='count',
                        default=0,
                        help='Increase verbosity; can be used multiple times')
    parser.add_argument('--pretend', '-p', action='store_true', default=False,
                        help='Only pretend; no real action will be done')
    sub = parser.add_subparsers(title='main subcommands',
                                description='valid subcommands')
    serve_p = sub.add_parser('serve', help="Start an HTTP server")
    serve_p.set_defaults(func=server.main_cmd)
    forge_p = sub.add_parser('forge', help="Create an audio file")
    forge_p.add_argument('starttime', metavar='START',
            help='Start time, espressed as 19450425_1200 (%%Y%%m%%d-%%H%%M%%S)',
            action=DateTimeAction)
    forge_p.add_argument('endtime', metavar='END',
            help='End time, espressed as 19450425_1200 (%%Y%%m%%d-%%H%%M%%S)',
            action=DateTimeAction)
    forge_p.add_argument('-o', metavar='OUTFILE', dest='outfile',
                         default='out.mp3', help='Path of the output mp3')
    forge_p.set_defaults(func=forge.main_cmd)

    cleanold_p = sub.add_parser('cleanold', help="Remove old files from DB",
            description="Will remove oldfiles with no filename from DB")
    cleanold_p.add_argument('-t', metavar='MINAGE', dest='minage',
                         default='14', type=int,
                         help='Minimum age (in days) for removal')
    cleanold_p.set_defaults(func=maint.cleanold_cmd)


    options = parser.parse_args()
    options.cwd = CWD
    if options.verbose < 1:
        logging.basicConfig(level=logging.WARNING)
    elif options.verbose == 1:
        logging.basicConfig(level=logging.INFO)
    elif options.verbose >= 2:
        logging.basicConfig(level=logging.DEBUG)
        if options.verbose > 2:
            logging.info("giving verbose flag >2 times is useless")
    common_pre()
    options.func(options)
if __name__ == "__main__":
    main()