from __future__ import annotations

from functools import lru_cache
from pathlib import Path
from typing import Tuple, Type

from pydantic import Field
from pydantic_settings import BaseSettings, SettingsConfigDict
from pydantic_settings.sources import (
    DotEnvSettingsSource,
    EnvSettingsSource,
    PydanticBaseSettingsSource,
)


def _repo_root() -> Path:
    # services/ingest_service/app/core/config.py -> .../MNOTE
    return Path(__file__).resolve().parents[4]


class Settings(BaseSettings):
    """Ingest Service 配置（优先读取仓库根目录的 .env.local/.env）。"""

    model_config = SettingsConfigDict(
        env_file=(
            str(_repo_root() / ".env.local"),
            str(_repo_root() / ".env"),
        ),
        env_file_encoding="utf-8",
        case_sensitive=False,
        extra="ignore",
    )

    # 服务基础
    app_name: str = Field("AIMNOTE Ingest Service", env="INGEST_APP_NAME")
    environment: str = Field("development", env="INGEST_ENV")
    api_prefix: str = "/api"

    # LightRAG（独立服务 7777）
    lightrag_url: str = Field("http://127.0.0.1:7777", env="LIGHTRAG_URL")
    lightrag_api_key: str = Field("", env="LIGHTRAG_API_KEY")

    @classmethod
    def settings_customise_sources(
        cls,
        settings_cls: Type[BaseSettings],
        init_settings: PydanticBaseSettingsSource,
        env_settings: EnvSettingsSource,
        dotenv_settings: DotEnvSettingsSource,
        file_secret_settings: PydanticBaseSettingsSource,
    ) -> Tuple[PydanticBaseSettingsSource, ...]:
        # 关键点：优先使用 .env.local/.env 覆盖系统环境变量，避免被机器上的全局 env 污染。
        return (
            dotenv_settings,
            env_settings,
            init_settings,
            file_secret_settings,
        )


@lru_cache()
def get_settings() -> Settings:
    return Settings()