from functools import lru_cache
from typing import Literal

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", extra="ignore")

    database_url: str = "sqlite:///./miem_workers.db"
    source_url: str = "https://miem.hse.ru/persons"
    crawl_cron: str = "0 3 * * 1"
    crawl_limit: int | None = None
    request_timeout: int = 30
    request_delay_seconds: float = 1.0
    parser_use_playwright: bool = False

    admin_username: str = "admin"
    admin_password: str = "admin"
    session_secret: str = Field(default="dev-session-secret", min_length=8)
    mcp_token: str = "dev-mcp-token"
    mcp_auth_mode: Literal["token", "oauth"] = "oauth"
    mcp_resource_url: str = "http://localhost:8001/mcp"
    mcp_oauth_issuer: str = ""
    mcp_oauth_audience: str = ""
    mcp_oauth_jwks_url: str = ""
    mcp_oauth_required_scope: str = "mcp:tools"

    @field_validator("crawl_limit", mode="before")
    @classmethod
    def empty_crawl_limit_as_none(cls, value):
        if value == "":
            return None
        return value

    def oauth_jwks_url(self) -> str:
        if self.mcp_oauth_jwks_url:
            return self.mcp_oauth_jwks_url
        issuer = self.mcp_oauth_issuer.rstrip("/")
        if not issuer:
            return ""
        return f"{issuer}/.well-known/jwks.json"


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