# Copyright (c) OpenMMLab. All rights reserved.
import argparse
import os
import os.path as osp
from copy import deepcopy

import mmengine
from mmengine.config import Config, ConfigDict, DictAction
from mmengine.hooks import Hook
from mmengine.runner import Runner

from mmcls.utils import register_all_modules


def parse_args():
    parser = argparse.ArgumentParser(
        description='MMCLS test (and eval) a model')
    parser.add_argument('config', help='test config file path')
    parser.add_argument('checkpoint', help='checkpoint file')
    parser.add_argument(
        '--work-dir',
        help='the directory to save the file containing evaluation metrics')
    parser.add_argument('--out', help='the file to save metric results.')
    parser.add_argument(
        '--dump',
        type=str,
        help='dump predictions to a pickle file for offline evaluation')
    parser.add_argument(
        '--cfg-options',
        nargs='+',
        action=DictAction,
        help='override some settings in the used config, the key-value pair '
        'in xxx=yyy format will be merged into config file. If the value to '
        'be overwritten is a list, it should be like key="[a,b]" or key=a,b '
        'It also allows nested list/tuple values, e.g. key="[(a,b),(c,d)]" '
        'Note that the quotation marks are necessary and that no white space '
        'is allowed.')
    parser.add_argument(
        '--show-dir',
        help='directory where the visualization images will be saved.')
    parser.add_argument(
        '--show',
        action='store_true',
        help='whether to display the prediction results in a window.')
    parser.add_argument(
        '--interval',
        type=int,
        default=1,
        help='visualize per interval samples.')
    parser.add_argument(
        '--wait-time',
        type=float,
        default=2,
        help='display time of every window. (second)')
    parser.add_argument(
        '--no-pin-memory',
        action='store_true',
        help='whether to disable the pin_memory option in dataloaders.')
    parser.add_argument(
        '--launcher',
        choices=['none', 'pytorch', 'slurm', 'mpi'],
        default='none',
        help='job launcher')
    parser.add_argument('--local_rank', type=int, default=0)
    args = parser.parse_args()
    if 'LOCAL_RANK' not in os.environ:
        os.environ['LOCAL_RANK'] = str(args.local_rank)
    return args


def merge_args(cfg, args):
    """Merge CLI arguments to config."""
    cfg.launcher = args.launcher

    # work_dir is determined in this priority: CLI > segment in file > filename
    if args.work_dir is not None:
        # update configs according to CLI args if args.work_dir is not None
        cfg.work_dir = args.work_dir
    elif cfg.get('work_dir', None) is None:
        # use config filename as default work_dir if cfg.work_dir is None
        cfg.work_dir = osp.join('./work_dirs',
                                osp.splitext(osp.basename(args.config))[0])

    cfg.load_from = args.checkpoint

    # -------------------- visualization --------------------
    if args.show or (args.show_dir is not None):
        assert 'visualization' in cfg.default_hooks, \
            'VisualizationHook is not set in the `default_hooks` field of ' \
            'config. Please set `visualization=dict(type="VisualizationHook")`'

        cfg.default_hooks.visualization.enable = True
        cfg.default_hooks.visualization.show = args.show
        cfg.default_hooks.visualization.wait_time = args.wait_time
        cfg.default_hooks.visualization.out_dir = args.show_dir
        cfg.default_hooks.visualization.interval = args.interval

    # -------------------- Dump predictions --------------------
    if args.dump is not None:
        assert args.dump.endswith(('.pkl', '.pickle')), \
            'The dump file must be a pkl file.'
        dump_metric = dict(type='DumpResults', out_file_path=args.dump)
        if isinstance(cfg.test_evaluator, (list, tuple)):
            cfg.test_evaluator = list(cfg.test_evaluator).append(dump_metric)
        else:
            cfg.test_evaluator = [cfg.test_evaluator, dump_metric]

    # set dataloader args
    default_dataloader_cfg = ConfigDict(
        pin_memory=True,
        collate_fn=dict(type='default_collate'),
    )

    def set_default_dataloader_cfg(cfg, field):
        if cfg.get(field, None) is None:
            return
        dataloader_cfg = deepcopy(default_dataloader_cfg)
        dataloader_cfg.update(cfg[field])
        cfg[field] = dataloader_cfg
        if args.no_pin_memory:
            cfg[field]['pin_memory'] = False

    set_default_dataloader_cfg(cfg, 'test_dataloader')

    if args.cfg_options is not None:
        cfg.merge_from_dict(args.cfg_options)

    return cfg


def main():
    args = parse_args()

    # register all modules in mmcls into the registries
    # do not init the default scope here because it will be init in the runner
    register_all_modules(init_default_scope=False)

    # load config
    cfg = Config.fromfile(args.config)
    cfg = merge_args(cfg, args)

    # build the runner from config
    runner = Runner.from_cfg(cfg)

    if args.out:

        class SaveMetricHook(Hook):

            def after_test_epoch(self, _, metrics=None):
                if metrics is not None:
                    mmengine.dump(metrics, args.out)

        runner.register_hook(SaveMetricHook(), 'LOWEST')

    # start testing
    runner.test()


if __name__ == '__main__':
    main()
