"""YAML configuration loader and validator."""

import yaml
from pathlib import Path
from .models import ChannelConfig, CollectionConfig


def load_config(config_path: str) -> dict:
    """Load and validate configuration from YAML file."""
    path = Path(config_path)
    if not path.exists():
        raise FileNotFoundError(f"Config file not found: {config_path}")

    with open(path, 'r', encoding='utf-8') as f:
        raw = yaml.safe_load(f)

    # Parse channel configs
    genuine = _parse_channel(raw.get('genuine', {}), 'genuine')
    suspect = _parse_channel(raw.get('suspect', {}), 'suspect')

    # Parse collection config
    coll = raw.get('collection', {})
    collection = CollectionConfig(
        repeat_count=coll.get('repeat_count', 3),
        timeout=coll.get('timeout', 60),
        max_tokens=coll.get('max_tokens', 1024),
        anthropic_version=coll.get('anthropic_version', '2023-06-01'),
    )

    # Parse output config
    output = raw.get('output', {})

    return {
        'genuine': genuine,
        'suspect': suspect,
        'collection': collection,
        'output': output,
    }


def _parse_channel(data: dict, name: str) -> ChannelConfig:
    """Parse and validate a channel configuration."""
    required = ['base_url', 'api_key', 'model']
    for key in required:
        if key not in data or not data[key]:
            raise ValueError(f"Channel '{name}' missing required field: {key}")

    return ChannelConfig(
        base_url=data['base_url'].rstrip('/'),
        api_key=data['api_key'],
        model=data['model'],
    )