from functools import lru_cache
from pathlib import Path
from urllib.parse import quote_plus

from pydantic import Field
from pydantic_settings import BaseSettings, SettingsConfigDict

ENV_FILE = Path(__file__).resolve().parent.parent / ".env"


class Settings(BaseSettings):
    model_config = SettingsConfigDict(
        env_file=str(ENV_FILE),
        env_file_encoding="utf-8",
        extra="ignore",
    )

    app_name: str = Field(default="mini-program-api", validation_alias="APP_NAME")
    app_version: str = Field(default="0.1.0", validation_alias="APP_VERSION")
    app_description: str = Field(
        default="Backend service for mini program",
        validation_alias="APP_DESCRIPTION",
    )
    host: str = Field(default="0.0.0.0", validation_alias="HOST")
    port: int = Field(default=8001, validation_alias="PORT")

    db_type: str = Field(default="mysql", validation_alias="DB_TYPE")
    db_host: str = Field(default="127.0.0.1", validation_alias="DB_HOST")
    db_port: int = Field(default=3306, validation_alias="DB_PORT")
    db_user: str = Field(default="root", validation_alias="DB_USER")
    db_password: str = Field(default="", validation_alias="DB_PASSWORD")
    db_name: str = Field(default="talkingq", validation_alias="DB_NAME")
    db_auto_init_tables: bool = Field(default=False, validation_alias="DB_AUTO_INIT_TABLES")
    db_path: str = Field(default="./data.db", validation_alias="DB_PATH")
    wechat_app_id: str = Field(default="", validation_alias="WECHAT_APP_ID")
    wechat_app_secret: str = Field(default="", validation_alias="WECHAT_APP_SECRET")
    wechat_api_base_url: str = Field(
        default="https://api.weixin.qq.com",
        validation_alias="WECHAT_API_BASE_URL",
    )
    wechat_http_timeout_seconds: float = Field(
        default=5.0,
        validation_alias="WECHAT_HTTP_TIMEOUT_SECONDS",
    )
    cos_secret_id: str = Field(default="", validation_alias="COS_SECRET_ID")
    cos_secret_key: str = Field(default="", validation_alias="COS_SECRET_KEY")
    cos_region: str = Field(default="", validation_alias="COS_REGION")
    cos_bucket_message: str = Field(default="", validation_alias="COS_BUCKET_MESSAGE")
    cos_bucket_ava: str = Field(default="", validation_alias="COS_BUCKET_AVA")
    cos_public_base_url: str = Field(default="", validation_alias="COS_PUBLIC_BASE_URL")
    cos_avatar_prefix: str = Field(default="avatars/", validation_alias="COS_AVATAR_PREFIX")
    cos_avatar_url_expire_seconds: int = Field(
        default=86400,
        validation_alias="COS_AVATAR_URL_EXPIRE_SECONDS",
    )
    cos_avatar_max_bytes: int = Field(
        default=2 * 1024 * 1024,
        validation_alias="COS_AVATAR_MAX_BYTES",
    )
    jwt_secret: str = Field(
        default="dev_only_change_jwt_secret",
        validation_alias="JWT_SECRET",
    )
    jwt_algorithm: str = Field(default="HS256", validation_alias="JWT_ALGORITHM")
    jwt_access_token_expire_minutes: int = Field(
        default=60,
        validation_alias="JWT_ACCESS_TOKEN_EXPIRE_MINUTES",
    )
    log_level: str = Field(default="INFO", validation_alias="LOG_LEVEL")
    log_json: bool = Field(default=False, validation_alias="LOG_JSON")
    slow_sql_ms: int = Field(default=200, validation_alias="SLOW_SQL_MS")

    @property
    def mysql_dsn(self) -> str:
        user = quote_plus(self.db_user)
        password = quote_plus(self.db_password)
        auth = f"{user}:{password}" if password else user
        return (
            f"mysql+pymysql://{auth}@{self.db_host}:{self.db_port}/"
            f"{self.db_name}?charset=utf8mb4"
        )

    @property
    def sqlite_dsn(self) -> str:
        db_path = Path(self.db_path)
        db_path.parent.mkdir(parents=True, exist_ok=True)
        return f"sqlite:///{db_path.absolute()}"

    @property
    def database_dsn(self) -> str:
        if self.db_type == "sqlite":
            return self.sqlite_dsn
        return self.mysql_dsn

    @property
    def uses_shared_talkingq_db(self) -> bool:
        return self.db_type == "mysql" and self.db_name == "talkingq"


@lru_cache(maxsize=1)
def get_settings() -> Settings:
    return Settings()


settings = get_settings()