"""配置以项目位置解析，开发密钥持久化才能保证重启后令牌仍可验证。"""
from pathlib import Path
import secrets
from pydantic import Field, model_validator
from pydantic_settings import BaseSettings, SettingsConfigDict

ROOT = Path(__file__).resolve().parents[2]


class Settings(BaseSettings):
    """关键参数有范围限制，错误配置在启动阶段暴露而非拖到审核过程中。"""
    model_config = SettingsConfigDict(env_file=ROOT / ".env", extra="ignore", case_sensitive=False)
    app_env: str = "development"  # 生产环境启用额外密钥与演示数据校验。
    host: str = "127.0.0.1"
    port: int = Field(default=8000, ge=1, le=65535)
    api_prefix: str = "/api/v1"
    data_dir: str = "data"
    database_url: str = ""
    jwt_secret: str = ""
    access_minutes: int = Field(default=15, ge=1, le=1440)
    refresh_days: int = Field(default=7, ge=1, le=30)
    cors_origins: list[str] = ["http://localhost:5173", "http://127.0.0.1:5173"]
    business_timezone: str = "Asia/Shanghai"
    seed_demo: bool = True
    demo_password: str = "Demo@2026!"
    max_upload_mb: int = Field(default=10, ge=1, le=100)
    max_batch_files: int = Field(default=20, ge=1, le=100)
    max_pdf_pages: int = Field(default=5, ge=1, le=30)
    worker_enabled: bool = True
    worker_interval: float = Field(default=0.5, ge=0.1, le=30)
    outbox_attempts: int = Field(default=3, ge=1, le=10)
    approval_timeout_hours: int = Field(default=48, ge=1, le=720)
    timeout_scan_seconds: int = Field(default=60, ge=1, le=3600)
    rate_limit_per_minute: int = Field(default=120, ge=10, le=10000)
    llm_base_url: str = ""
    llm_model: str = ""
    vlm_base_url: str = ""
    vlm_model: str = ""
    ai_api_key: str = ""
    embedding_base_url: str = ""
    embedding_model: str = "bge-large-zh-v1.5"
    embedding_dimension: int = Field(default=1024, ge=1, le=8192)
    rerank_base_url: str = ""
    ai_timeout: float = Field(default=20, ge=1, le=120)
    ai_concurrency: int = Field(default=3, ge=1, le=10)
    ai_failure_threshold: int = Field(default=5, ge=1, le=100)
    ai_recovery_seconds: int = Field(default=60, ge=1, le=600)
    pdf_font_path: str = ""

    @model_validator(mode="after")
    def validate_environment(self):
        """限制生产弱配置；允许本地演示启动但不把它当作生产部署。"""
        if not self.api_prefix.startswith("/") or self.api_prefix.endswith("/"):
            raise ValueError("API_PREFIX 必须以 / 开头且末尾不能是 /")
        if self.app_env == "production" and (self.seed_demo or len(self.jwt_secret) < 32):
            raise ValueError("生产必须关闭 SEED_DEMO 并设置至少 32 字符 JWT_SECRET")
        return self

    @property
    def data_path(self) -> Path:
        """外部路径只由服务端配置提供，前端不能传入任意文件系统路径。"""
        return (ROOT / self.data_dir).resolve()

    @property
    def db_url(self) -> str:
        return self.database_url or "sqlite+aiosqlite:///" + (self.data_path / "audit.db").as_posix()

    def secret(self) -> str:
        """开发密钥仅写入运行数据目录，打包时排除以免传播实际凭据。"""
        if self.jwt_secret:
            return self.jwt_secret
        path = self.data_path / "jwt.secret"
        path.parent.mkdir(parents=True, exist_ok=True)
        if not path.exists():
            path.write_text(secrets.token_hex(32), encoding="utf-8")
        return path.read_text(encoding="utf-8").strip()


settings = Settings()