"""Shared configuration parsing for PRIMA commands."""
import argparse
from pathlib import Path


def parse_with_config(parser, argv=None):
    import yaml

    parser.add_argument('--config', type=Path, help='YAML configuration; CLI options override it.')
    probe = argparse.ArgumentParser(add_help=False)
    probe.add_argument('--config', type=Path)
    known, _ = probe.parse_known_args(argv)
    if known.config:
        with known.config.open() as handle:
            values = yaml.safe_load(handle) or {}
        if not isinstance(values, dict):
            parser.error('Configuration must be a mapping of option names to values.')
        actions = {action.dest: action for action in parser._actions}
        unknown = set(values) - set(actions)
        if unknown:
            parser.error('Unknown configuration options: ' + ', '.join(sorted(unknown)))
        for key, value in values.items():
            action = actions[key]
            if isinstance(action, (argparse._StoreTrueAction, argparse._StoreFalseAction,
                                   argparse.BooleanOptionalAction)) and not isinstance(value, bool):
                parser.error(f'{key} must be a YAML boolean.')
            if action.choices and value not in action.choices:
                parser.error(f'{key} must be one of {action.choices}.')
        parser.set_defaults(**values)
    return parser.parse_args(argv)


def validate_paths(args, *, checkpoint=True, dataset=False):
    merged = getattr(args, 'merged_ckpt_path', '')
    fields = ['merged_ckpt_path'] if merged else ['version', 'q_former_model', 'qformer_bert_path', 'eva_weights']
    overlay = getattr(args, 'ckpt_path', '')
    if checkpoint and (not merged or (overlay and not overlay.startswith('/path/to/'))):
        fields.append('ckpt_path')
    if dataset:
        fields.append('dataset_dir')
    errors = []
    for field in fields:
        value = getattr(args, field, None)
        if not value or str(value).startswith('/path/to/'):
            errors.append(f'{field}: replace the placeholder with a local path')
        elif field == 'merged_ckpt_path' and not Path(value).expanduser().exists():
            import re
            if not re.fullmatch(r'[\w.-]+/[\w.-]+', str(value)):
                errors.append(f'{field}: provide an existing model directory or organization/model Hub ID')
        elif not Path(value).expanduser().exists():
            errors.append(f'{field}: path does not exist: {value}')
    if errors:
        raise ValueError('Configure the required paths before running:\n  ' + '\n  '.join(errors))