from dataclasses import dataclass, field
from typing import Callable, Dict, Any, List, Optional, Tuple

from app.log import logger


@dataclass(frozen=True)
class DedupFieldSpec:
    """去重字段规格：从原始数据中提取去重列值"""
    column: str
    extractor: Callable[[Dict[str, Any]], Optional[str]]


@dataclass(frozen=True)
class PlatformConfig:
    """平台配置（不可变）"""
    platform: str
    channel: str
    data_type: str
    table: str
    dedup_fields: Tuple[DedupFieldSpec, ...] = ()
    push_mapper: Optional[Callable[[Dict[str, Any]], Optional[Dict[str, Any]]]] = None

    @property
    def key(self) -> Tuple[str, str, str]:
        return (self.platform, self.channel, self.data_type)

    @property
    def dedup_columns(self) -> List[str]:
        return [f.column for f in self.dedup_fields]


# 全局注册表
_REGISTRY: Dict[Tuple[str, str, str], PlatformConfig] = {}


def register(config: PlatformConfig) -> None:
    key = config.key
    if key in _REGISTRY:
        logger.warning(f"覆盖已有注册: {key}")
    _REGISTRY[key] = config


def get_config(platform: str, channel: str, data_type: str) -> PlatformConfig:
    key = (platform, channel, data_type)
    config = _REGISTRY.get(key)
    if config is None:
        raise ValueError(f"未注册的平台配置: platform={platform}, channel={channel}, data_type={data_type}")
    return config


def list_configs() -> List[PlatformConfig]:
    return list(_REGISTRY.values())