import appdirs

import argparse
import mimetypes
import os
import sys
import shutil

from spotdl.command_line.exceptions import ArgumentError
import spotdl.util
import spotdl.config

from collections.abc import Sequence
import logging
logger = logging.getLogger(__name__)


_LOG_LEVELS = {
    "INFO": logging.INFO,
    "WARNING": logging.WARNING,
    "ERROR": logging.ERROR,
    "DEBUG": logging.DEBUG,
}

if os.path.isfile(spotdl.config.DEFAULT_CONFIG_FILE):
    saved_config = spotdl.config.read_config(spotdl.config.DEFAULT_CONFIG_FILE)
else:
    saved_config = {}

_CONFIG_BASE = spotdl.util.merge(
    spotdl.config.DEFAULT_CONFIGURATION,
    saved_config,
)


def get_arguments(config_base=_CONFIG_BASE):
    defaults = config_base["spotify-downloader"]
    parser = argparse.ArgumentParser(
        description="Download and convert tracks from Spotify, Youtube etc.",
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
    )

    # `--remove-config` does not require the any of the group arguments to be passed.
    require_group_args = not "--remove-config" in sys.argv[1:]
    group = parser.add_mutually_exclusive_group(required=require_group_args)

    group.add_argument(
        "-s",
        "--song",
        nargs="+",
        help="download track(s) by spotify link or name"
    )
    group.add_argument(
        "-l",
        "--list",
        help="download tracks from a file (WARNING: this file will be modified!)"
    )
    group.add_argument(
        "-p",
        "--playlist",
        help="load tracks from playlist URL into <playlist_name>.txt or "
             "if `--write-to=<path/to/file.txt>` has been passed",
    )
    group.add_argument(
        "-a",
        "--album",
        help="load tracks from album URL into <album_name>.txt or if "
             "`--write-to=<path/to/file.txt>` has been passed"
    )
    group.add_argument(
        "-aa",
        "--all-albums",
        help="load all tracks from artist URL into <artist_name>.txt "
             "or if `--write-to=<path/to/file.txt>` has been passed"
    )
    group.add_argument(
        "-u",
        "--username",
        help="load tracks from user's playlist into <playlist_name>.txt "
             "or if `--write-to=<path/to/file.txt>` has been passed"
    )

    parser.add_argument(
        "--write-m3u",
        help="generate an .m3u playlist file with youtube links given "
             "a text file containing tracks",
        action="store_true",
    )
    parser.add_argument(
        "-m",
        "--manual",
        default=defaults["manual"],
        help="choose the track to download manually from a list of matching tracks",
        action="store_true",
    )
    parser.add_argument(
        "-nm",
        "--no-metadata",
        default=defaults["no_metadata"],
        help="do not embed metadata in tracks",
        action="store_true",
    )
    parser.add_argument(
        "-ne",
        "--no-encode",
        default=defaults["no_encode"],
        action="store_true",
        help="do not encode media using FFmpeg",
    )
    parser.add_argument(
        "--overwrite",
        default=defaults["overwrite"],
        choices={"prompt", "force", "skip"},
        help="change the overwrite policy",
    )
    parser.add_argument(
        "-q",
        "--quality",
        default=defaults["quality"],
        choices={"best", "worst"},
        help="preferred audio quality",
    )
    parser.add_argument(
        "-i",
        "--input-ext",
        default=defaults["input_ext"],
        choices={"automatic", "m4a", "opus"},
        help="preferred input format",
    )
    parser.add_argument(
        "-o",
        "--output-ext",
        default=defaults["output_ext"],
        choices={"mp3", "m4a", "flac"},
        help="preferred output format",
    )
    parser.add_argument(
        "--write-to",
        default=defaults["write_to"],
        help="write tracks from Spotify playlist, album, etc. to this file",
    )
    parser.add_argument(
        "-f",
        "--output-file",
        default=defaults["output_file"],
        help="path where to write the downloaded track to, special tags "
        "are to be surrounded by curly braces. Possible tags: "
        # TODO: Add possible tags
        # "{}".format([spotdl.util.formats[x] for x in spotdl.util.formats]),
    )
    parser.add_argument(
        "--trim-silence",
        default=defaults["trim_silence"],
        help="remove silence from the start of the audio",
        action="store_true",
    )
    parser.add_argument(
        "-sf",
        "--search-format",
        default=defaults["search_format"],
        help="search format to search for on YouTube, special tags "
        "are to be surrounded by curly braces. Possible tags: "
        # TODO: Add possible tags
        # "{}".format([spotdl.util.formats[x] for x in spotdl.util.formats]),
    )
    parser.add_argument(
        "-d",
        "--dry-run",
        default=defaults["dry_run"],
        help="show only track title and YouTube URL, and then skip "
        "to the next track (if any)",
        action="store_true",
    )
    # parser.add_argument(
    #     "--processor",
    #     default=defaults["processor"],
    #     choices={"synchronous", "threaded"},
    #     help='list downloading strategy: - "synchronous" downloads '
    #     'tracks one-by-one. - "threaded" (highly experimental at the '
    #     'moment! expect it to slash & burn) pre-fetches the next '
    #     'track\'s metadata for more efficient downloading'
    # )
    parser.add_argument(
        "-ns",
        "--no-spaces",
        default=defaults["no_spaces"],
        help="replace spaces in metadata values with underscores when "
        "generating filenames",
        action="store_true",
    )
    parser.add_argument(
        "-ll",
        "--log-level",
        default=defaults["log_level"],
        choices=_LOG_LEVELS.keys(),
        type=str.upper,
        help="set log verbosity",
    )
    parser.add_argument(
        "-sk",
        "--skip",
        default=defaults["skip"],
        help="path to file containing tracks to skip",
    )
    parser.add_argument(
        "-w",
        "--write-successful",
        default=defaults["write_successful"],
        help="path to file to write successful tracks to",
    )
    parser.add_argument(
        "--spotify-client-id",
        default=defaults["spotify_client_id"],
        help=argparse.SUPPRESS,
    )
    parser.add_argument(
        "--spotify-client-secret",
        default=defaults["spotify_client_secret"],
        help=argparse.SUPPRESS,
    )
    parser.add_argument(
        "-c",
        "--config",
        default=spotdl.config.DEFAULT_CONFIG_FILE,
        help="path to custom config.yml file"
    )
    parser.add_argument(
        "--remove-config",
        default=False,
        action="store_true",
        help="remove previously saved config"
    )
    parser.add_argument(
        "-V",
        "--version",
        action="version",
        version="%(prog)s {}".format(spotdl.__version__),
    )

    return ArgumentHandler(parser=parser)


class ArgumentHandler:
    def __init__(self, args=None, parser=argparse.ArgumentParser(""), config_base=_CONFIG_BASE):
        args_were_passed = args is not None
        if not args_were_passed:
            args = parser.parse_args().__dict__

        config_file = args.get("config")
        configured_args = args.copy()
        if config_file and os.path.isfile(config_file):
            config = spotdl.config.read_config(config_file)
            parser.set_defaults(**config["spotify-downloader"])
            configured_args = parser.parse_args().__dict__

        if args_were_passed:
            parser.set_defaults(**args)
            configured_args = parser.parse_args().__dict__

        defaults = config_base["spotify-downloader"]
        args = spotdl.util.merge(defaults, args)

        self.parser = parser
        self.args = args
        self.configured_args = configured_args

    def get_configured_args(self):
        return self.configured_args

    def get_logging_level(self):
        return _LOG_LEVELS[self.args["log_level"]]

    def run_errands(self):
        args = self.get_configured_args()

        if (args.get("list")
            and not mimetypes.MimeTypes().guess_type(args["list"])[0] == "text/plain"
        ):
            raise ArgumentError(
                "{0} is not of a valid argument to --list, argument must be plain text file.".format(
                    args["list"]
                )
            )

        if args.get("write_m3u") and not args.get("list"):
            raise ArgumentError("--write-m3u can only be used with --list.")

        if args["write_to"] and not (
            args.get("playlist") or args.get("album") or args.get("all_albums") or args.get("username") or args.get("write_m3u")
        ):
            raise ArgumentError(
                "--write-to can only be used with --playlist, --album, --all-albums, --username, or --write-m3u."
            )

        ffmpeg_exists = shutil.which("ffmpeg")
        if not ffmpeg_exists:
            logger.warn("FFmpeg was not found in PATH. Will not re-encode media to specified output format.")
            args["no_encode"] = True

        if args["no_encode"] and args["trim_silence"]:
            logger.warn("--trim-silence can only be used when an encoder is set.")

        if args["output_file"] == "-" and args["no_metadata"] is False:
            logger.warn(
                "Cannot write metadata when target is STDOUT. Pass "
                "--no-metadata explicitly to hide this warning."
            )
            args["no_metadata"] = True
        elif os.path.isdir(args["output_file"]):
            adjusted_output_file = os.path.join(
                args["output_file"],
                self.parser.get_default("output_file")
            )
            logger.warn(
                "Given output file is a directory. Will download tracks "
                "in this directory with their filename as per the default "
                "file format. Pass --output-file=\"{}\" to hide this "
                "warning.".format(
                    adjusted_output_file
                )
            )
            args["output_file"] = adjusted_output_file

        return args