"""应用配置:从 .env / 环境变量读取,集中管理所有开关。"""
from __future__ import annotations

from functools import lru_cache
from pathlib import Path

from pydantic import Field, field_validator
from pydantic_settings import BaseSettings, SettingsConfigDict


class Settings(BaseSettings):
    model_config = SettingsConfigDict(
        env_file=".env",
        env_file_encoding="utf-8",
        case_sensitive=False,
        extra="ignore",
    )

    # ===== 通用 =====
    tz: str = "Asia/Hong_Kong"
    log_level: str = "INFO"

    # ===== 数据库 =====
    postgres_user: str
    postgres_password: str
    postgres_db: str
    postgres_host: str = "postgres"
    postgres_port: int = 5432

    @property
    def database_url(self) -> str:
        # asyncpg
        return (
            f"postgresql+asyncpg://{self.postgres_user}:{self.postgres_password}"
            f"@{self.postgres_host}:{self.postgres_port}/{self.postgres_db}"
        )

    @property
    def sync_database_url(self) -> str:
        # alembic 用的同步 URL
        return (
            f"postgresql+psycopg2://{self.postgres_user}:{self.postgres_password}"
            f"@{self.postgres_host}:{self.postgres_port}/{self.postgres_db}"
        )

    # ===== Redis =====
    redis_host: str = "redis"
    redis_port: int = 6379
    redis_password: str
    redis_db: int = 0

    @property
    def redis_url(self) -> str:
        return (
            f"redis://:{self.redis_password}@{self.redis_host}:{self.redis_port}/{self.redis_db}"
        )

    # ===== JWT =====
    jwt_secret: str
    jwt_algorithm: str = "HS256"
    access_token_ttl_min: int = 60
    refresh_token_ttl_day: int = 14

    # ===== 腾讯云 TMT =====
    tencentcloud_secret_id: str = ""
    tencentcloud_secret_key: str = ""
    tencentcloud_region: str = "ap-hongkong"
    tencent_tmt_endpoint: str = "tmt.tencentcloudapi.com"
    tencent_tmt_quota_month: int = 5_000_000
    tencent_tmt_quota_buffer: float = 0.05
    tencent_tmt_max_chars_per_req: int = 4500

    @field_validator("tencent_tmt_quota_buffer")
    @classmethod
    def _check_buffer(cls, v: float) -> float:
        if not 0.0 <= v <= 0.5:
            raise ValueError("buffer 必须在 0~0.5")
        return v

    # ===== 本地翻译 =====
    local_translate_enabled: bool = False
    local_translate_model: str = "nllb-200-distilled-600M"
    local_translate_device: str = "cpu"

    # ===== 抓取 =====
    fetch_global_qps: int = 4
    fetch_timeout: int = 20
    fetch_fail_pause_threshold: int = 3
    fetch_max_retries: int = 2

    # ===== Caddy / 域名 =====
    domain: str = ""
    acme_email: str = ""

    # ===== Agnes LLM(智能增强)=====
    # 留空 = 不启用 LLM 增强(翻译后只走默认排版,提示词也不读)
    agnes_api_key: str = ""
    agnes_base_url: str = "https://apihub.agnes-ai.com/v1"
    agnes_chat_model: str = "agnes-2.0-flash"
    agnes_image_model: str = "agnes-image-2.1-flash"
    # 全局 LLM 调用间隔(秒),避免被限流
    llm_interval_sec: float = 2.0

    # ===== 内部路径(部署后可调) =====
    project_root: Path = Path(__file__).resolve().parents[2]


@lru_cache
def get_settings() -> Settings:
    return Settings()  # type: ignore[call-arg]


settings = get_settings()