"""应用配置：通过环境变量和 .env 文件加载所有配置项

配置项统一使用 RAKUTEN_ 前缀，例如 RAKUTEN_APP_PORT=31107。
支持 .env 文件自动加载。
"""
from functools import lru_cache
from pathlib import Path
from typing import Literal

from pydantic_settings import BaseSettings, SettingsConfigDict

from app.core import site

BASE_DIR = Path(__file__).resolve().parent.parent.parent


class Settings(BaseSettings):
    """应用全局配置

    所有配置项均可通过环境变量覆盖，前缀为 RAKUTEN_。
    例如：RAKUTEN_APP_PORT=31107 对应 app_port 配置项。
    """

    model_config = SettingsConfigDict(
        env_file=str(BASE_DIR / ".env"),
        env_file_encoding="utf-8",
        env_prefix="RAKUTEN_",
        extra="ignore",
    )

    # ---- 服务基本配置 ----
    app_name: str = "Rakuten Scraper Service"
    app_env: Literal["dev", "prod", "test"] = "dev"
    app_host: str = "0.0.0.0"
    app_port: int = 31107

    # ---- 日志配置 ----
    log_level: str = "INFO"
    log_to_file: bool | None = None  # None 表示根据环境自动决定
    log_dir: str = "logs"
    log_rotation: str = "100 MB"
    log_retention: str = "14 days"
    log_compression: str = "zip"
    log_format: str = "{time:YYYY-MM-DD HH:mm:ss} {level} {message}"
    log_enqueue: bool = True

    # ---- 鉴权配置 ----
    bearer_token: str = "REPLACE_WITH_TOKEN_32CHARS"

    # ---- HTTP 抓取配置 ----
    request_timeout_seconds: float = 30.0
    max_site_concurrency: int = 8  # 对站点的最大并发请求数
    http_max_attempts: int = 3  # 单次抓取的最大尝试次数（含首次）
    session_ttl_seconds: float = 1800.0  # Akamai cookie 会话最长复用时长，超时后重新预热

    # ---- 浏览器兜底配置 ----
    # 纯 HTTP 被 Akamai 拦截时，用 Playwright 打开页面取回 cookie 再回灌给
    # HTTP 客户端重试。日常流量不会触发；未安装 playwright 时自动降级为不兜底。
    browser_fallback_enabled: bool = True
    browser_headless: bool | None = None  # None 表示根据环境自动决定
    browser_channel: str | None = None  # 例如 chrome；留空使用 bundled chromium
    browser_launch_timeout_seconds: float = 60.0
    browser_nav_timeout_seconds: float = 60.0

    # ---- 代理配置（可选，用于日本 IP）----
    proxy_server: str | None = None
    proxy_username: str | None = None
    proxy_password: str | None = None

    # ---- 目标站点 ----
    home_url: str = site.HOME_URL

    @property
    def browser_headless_effective(self) -> bool:
        """浏览器无头模式：显式配置优先，否则开发环境使用有头模式方便调试"""
        if self.browser_headless is not None:
            return self.browser_headless
        return self.app_env != "dev"

    @property
    def log_to_file_effective(self) -> bool:
        """是否写日志文件：显式配置优先，否则生产环境默认写文件"""
        if self.log_to_file is not None:
            return self.log_to_file
        return self.app_env == "prod"

    @property
    def playwright_proxy(self) -> dict[str, str] | None:
        """构建 Playwright 代理配置字典"""
        if not self.proxy_server:
            return None

        proxy: dict[str, str] = {"server": self.proxy_server}
        if self.proxy_username:
            proxy["username"] = self.proxy_username
        if self.proxy_password:
            proxy["password"] = self.proxy_password
        return proxy

    @property
    def httpx_proxy(self) -> str | None:
        """构建 httpx 代理 URL（含认证信息）"""
        if not self.proxy_server:
            return None
        if not self.proxy_username:
            return self.proxy_server

        scheme, _, rest = self.proxy_server.partition("://")
        if not rest:
            return self.proxy_server
        credentials = f"{self.proxy_username}:{self.proxy_password or ''}"
        return f"{scheme}://{credentials}@{rest}"


@lru_cache(maxsize=1)
def get_settings() -> Settings:
    """获取全局配置单例"""
    return Settings()