from functools import lru_cache
from typing import Literal

from pydantic import Field, model_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",
    )

    app_name: str = "AI模型内部安全测试平台"
    app_env: Literal["test", "production"] = "test"
    app_host: str = "0.0.0.0"
    app_port: int = 8000
    app_debug: bool = True
    app_api_prefix: str = "/api/v1"

    log_level_test: str = "INFO"
    log_level_production: str = "WARNING"
    log_json: bool = False

    database_url: str = "sqlite:///./data/platform.db"

    cors_allow_origins: str = "http://localhost:3000"
    cors_allow_credentials: bool = True
    cors_allow_methods: str = "*"
    cors_allow_headers: str = "*"

    target_api_type: str = "openai"
    target_base_url: str
    target_chat_path: str = "/chat/completions"
    target_models_path: str = "/models"
    target_model: str = ""
    target_auth_type: str = "none"
    target_api_key: str = ""
    target_auth_header: str = "Authorization"
    target_auth_prefix: str = "Bearer "

    judge_api_type: str = "openai"
    judge_base_url: str
    judge_chat_path: str = "/chat/completions"
    judge_models_path: str = "/models"
    judge_model: str = ""
    judge_auth_type: str = "bearer"
    judge_api_key: str = ""
    judge_auth_header: str = "Authorization"
    judge_auth_prefix: str = "Bearer "

    request_timeout_seconds: int = Field(default=180, gt=0)
    request_retry_count: int = Field(default=5, ge=0, le=10)
    request_retry_delay_seconds: int = Field(default=5, gt=0)
    request_retry_max_delay_seconds: int = Field(default=60, ge=5, le=300)
    request_verify_ssl: bool = True

    auth_token_secret: str = ""
    auth_token_ttl_seconds: int = Field(default=3600, ge=300, le=86400)
    auth_token_refresh_window_seconds: int = Field(default=1800, ge=60, le=43200)
    auth_refresh_token_ttl_seconds: int = Field(default=28800, ge=3600, le=31536000)

    dataset_path: str = "data/dataset.json"
    output_dir: str = "outputs"

    @model_validator(mode="after")
    def validate_auth_timing(self):
        if self.auth_token_refresh_window_seconds >= self.auth_token_ttl_seconds:
            raise ValueError(
                "AUTH_TOKEN_REFRESH_WINDOW_SECONDS must be less than AUTH_TOKEN_TTL_SECONDS"
            )
        if self.auth_refresh_token_ttl_seconds < self.auth_token_ttl_seconds:
            raise ValueError(
                "AUTH_REFRESH_TOKEN_TTL_SECONDS must not be shorter than AUTH_TOKEN_TTL_SECONDS"
            )
        return self

    @property
    def log_level(self) -> str:
        return self.log_level_production if self.app_env == "production" else self.log_level_test

    @property
    def cors_origins(self) -> list[str]:
        return [x.strip() for x in self.cors_allow_origins.split(",") if x.strip()]

    @property
    def cors_methods(self) -> list[str]:
        return (
            ["*"]
            if self.cors_allow_methods.strip() == "*"
            else [x.strip() for x in self.cors_allow_methods.split(",") if x.strip()]
        )

    @property
    def cors_headers(self) -> list[str]:
        return (
            ["*"]
            if self.cors_allow_headers.strip() == "*"
            else [x.strip() for x in self.cors_allow_headers.split(",") if x.strip()]
        )


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