# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
"""Loading pretrained models.
"""

import logging
from pathlib import Path
import typing as tp
from log import log_step

from dora.log import fatal, bold

from .hdemucs import HDemucs
from .repo import RemoteRepo, LocalRepo, ModelOnlyRepo, BagOnlyRepo, AnyModelRepo, ModelLoadingError  # noqa
from .states import _check_diffq

logger = logging.getLogger(__name__)
ROOT_URL = "https://dl.fbaipublicfiles.com/demucs/"
REMOTE_ROOT = Path(__file__).parent / 'remote'

SOURCES = ["drums", "bass", "other", "vocals"]
DEFAULT_MODEL = 'htdemucs'


def demucs_unittest():
    model = HDemucs(channels=4, sources=SOURCES)
    return model


def add_model_flags(parser):
    group = parser.add_mutually_exclusive_group(required=False)
    group.add_argument("-s", "--sig", help="Locally trained XP signature.")
    group.add_argument("-n", "--name", default=None,
                       help="Pretrained model name or signature. Default is htdemucs.")
    parser.add_argument("--repo", type=Path,
                        help="Folder containing all pre-trained models for use with -n.")


def _parse_remote_files(remote_file_list) -> tp.Dict[str, str]:
    root: str = ''
    models: tp.Dict[str, str] = {}
    for line in remote_file_list.read_text().split('\n'):
        line = line.strip()
        if line.startswith('#'):
            continue
        elif line.startswith('root:'):
            root = line.split(':', 1)[1].strip()
        else:
            sig = line.split('-', 1)[0]
            assert sig not in models
            models[sig] = ROOT_URL + root + line
    return models


def get_model(name: str,
              repo: tp.Optional[Path] = None):
    """`name` must be a bag of models name or a pretrained signature
    from the remote AWS model repo or the specified local repo if `repo` is not None.
    """
    if name == 'demucs_unittest':
        return demucs_unittest()
    model_repo: ModelOnlyRepo
    if repo is None:
        models = _parse_remote_files(REMOTE_ROOT / 'files.txt')
        model_repo = RemoteRepo(models)
        bag_repo = BagOnlyRepo(REMOTE_ROOT, model_repo)
    else:
        if not repo.is_dir():
            fatal(f"{repo} must exist and be a directory.")
        model_repo = LocalRepo(repo)
        bag_repo = BagOnlyRepo(repo, model_repo)
    any_repo = AnyModelRepo(model_repo, bag_repo)
    try:
        model = any_repo.get_model(name)
    except ImportError as exc:
        if 'diffq' in exc.args[0]:
            _check_diffq()
        raise

    model.eval()
    return model


def get_model_from_args(args):
    """
    Load local model package or pre-trained model.
    """
    if args.name is None:
        args.name = DEFAULT_MODEL
        log_step("warning", 100, "Important: the default model was recently changed to `htdemucs`."
                "the latest Hybrid Transformer Demucs model. In some cases, this model can "
              "actually perform worse than previous models. To get back the old default model "
              "use `-n mdx_extra_q`.")
    return get_model(name=args.name, repo=args.repo)