"""
应用配置管理模块

使用 Pydantic Settings 统一管理所有配置项，支持从环境变量和 .env 文件加载配置。
"""
from functools import lru_cache
from pathlib import Path
from typing import Optional
from urllib.parse import quote_plus

from pydantic import AliasChoices, Field, model_validator
from pydantic_settings import BaseSettings, SettingsConfigDict

# backend/ 目录（与 uvicorn CWD 无关，始终读取该目录下的 .env）
_BACKEND_DIR = Path(__file__).resolve().parent.parent


class Settings(BaseSettings):
    """应用配置类"""

    # 应用配置
    app_name: str = "星云 API Server"
    app_description: str = "星云 API 服务器"
    debug: bool = False
    # 未关联企业或库中未配置时的 AI 助手展示名（可被 enterprise.ai_display_name 覆盖）
    ai_display_name_default: str = "智能助手 AI"

    # API 服务器配置（同时兼容 .env 里的 API.HOST / API.PORT 与常规 API_HOST / API_PORT）
    api_host: str = Field(
        default="0.0.0.0",
        validation_alias=AliasChoices("API_HOST", "api_host", "API.HOST"),
    )
    api_port: int = Field(
        default=7861,
        validation_alias=AliasChoices("API_PORT", "api_port", "API.PORT"),
    )

    # 数据库配置
    db_host: str = "localhost"
    db_port: int = 5432
    db_name: str = "huoyan"
    db_user: str = "postgres"
    db_password: str = "root1234"

    # 数据库连接池配置
    db_pool_min_size: int = 10
    db_pool_max_size: int = 50  # 增加连接池大小，避免连接耗尽
    db_command_timeout: int = 120  # 增加超时时间（从60秒到120秒）
    
    # Checkpointer 连接池配置（psycopg）
    checkpointer_pool_max_size: int = 50  # 增加 checkpointer 连接池大小

    # JWT 配置
    jwt_secret_key: str = "your-secret-key-change-in-production"
    jwt_algorithm: str = "HS256"
    jwt_expire_minutes: int = 60 * 24 * 7  # 7 天

    # AI 模型配置
    # True：通义聊天走 LangChain ``ChatTongyi``（DashScope 原生协议）；False：走 ``ChatOpenAI`` + 兼容 base_url
    use_origin_model: bool = Field(
        default=False,
        validation_alias=AliasChoices("USE_ORIGIN_MODEL", "use_origin_model"),
    )
    dashscope_api_key: Optional[str] = None
    dashscope_api_base: Optional[str] = None
    deepseek_api_key: Optional[str] = None
    deepseek_api_base: Optional[str] = None
    openai_api_key: Optional[str] = None
    tavily_api_key: Optional[str] = None

    # LLM 的 OpenAI 兼容 base_url 见 ``core.llm_env``（从 ``backend/.env`` 读取）；此处只保留与密钥相关的项

    # OSS 配置
    oss_access_key_id: Optional[str] = None
    oss_access_key_secret: Optional[str] = None
    oss_endpoint: Optional[str] = None
    oss_bucket_name: Optional[str] = None

    # MCP 配置（第三方 MCP 完整端点地址；传输协议见 mcp_transport）
    mcp_url: Optional[str] = None
    mcp_transport: str = "sse"

    # HTTPX 配置
    httpx_default_timeout: float = 300.0

    # Redis 配置
    redis_host: str = "127.0.0.1"
    redis_port: int = 6379
    redis_password: Optional[str] = None
    redis_db: int = 0

    # 阿里云短信配置
    sms_access_key_id: Optional[str] = None
    sms_access_key_secret: Optional[str] = None
    sms_sign_name: Optional[str] = None
    sms_template_code: Optional[str] = None

    # 阿里云 OCR 配置
    ocr_access_key_id: Optional[str] = None
    ocr_access_key_secret: Optional[str] = None
    ocr_endpoint: str = "ocr-api.cn-hangzhou.aliyuncs.com"  # OCR 服务端点

    # 微信小程序配置
    wechat_app_id: Optional[str] = None
    wechat_app_secret: Optional[str] = None
    
    # 阿里云内容审核配置
    aliyun_access_key_id: Optional[str] = None
    aliyun_access_key_secret: Optional[str] = None
    aliyun_moderation_region: str = "cn-shanghai"
    moderation_timeout_seconds: float = 3.0
    moderation_review_action: str = "allow"  # "allow" 或 "block"
    moderation_enabled: bool = True  # 功能开关
    moderation_service_type: str = "comment_detection_pro"  # 文本审核增强版服务类型
    image_moderation_service_type: str = "baselineCheck"  # 图片审核服务类型
    
    # 企业版：关闭后禁止自助注册（仅管理员在后台创建用户）
    enable_public_register: bool = True
    
    # 日志配置
    logging_level: str = "INFO"
    logging_dir: str = "logs"
    logging_max_file_size: str = "30 MB"
    logging_retention_days: int = 30
    logging_enable_console: bool = True
    
    # 向量数据库配置 (ChromaDB)
    chroma_host: str = "localhost"
    chroma_port: int = 8000
    chroma_persist_directory: Optional[str] = None  # 如果为空则使用内存模式
    
    # RAG 配置
    rag_chunk_size: int = 512  # 文本分块大小
    rag_chunk_overlap: int = 50  # 分块重叠大小
    rag_top_k: int = 5  # 检索返回的文档数量
    rag_score_threshold: float = 0.5  # 相关性分数阈值
    
    # Embedding 模型配置
    embedding_model: str = "text-embedding-v4"  # 通义千问 Embedding 模型
    embedding_dimension: int = 1536  # Embedding 维度

    # Neo4j 图数据库配置
    neo4j_uri: str = "bolt://127.0.0.1:7687"
    neo4j_user: str = "neo4j"
    neo4j_password: str = "neo4j"

    @property
    def db_uri(self) -> str:
        """获取数据库连接 URI（asyncpg 格式）"""
        return f"postgresql://{self.db_user}:{self.db_password}@{self.db_host}:{self.db_port}/{self.db_name}"

    @property
    def db_uri_psycopg(self) -> str:
        """获取数据库连接 URI（psycopg 格式，用于 checkpointer）"""
        encoded_password = quote_plus(self.db_password)
        return f"postgresql://{self.db_user}:{encoded_password}@{self.db_host}:{self.db_port}/{self.db_name}?sslmode=disable"

    @property
    def api_address(self) -> str:
        """获取 API 服务器地址"""
        host = self.api_host if self.api_host != "0.0.0.0" else "127.0.0.1"
        return f"http://{host}:{self.api_port}"

    @model_validator(mode='after')
    def validate_moderation_credentials(self):
        """验证内容审核凭证配置"""
        if self.moderation_enabled:
            if not self.aliyun_access_key_id:
                raise ValueError(
                    "ALIYUN_ACCESS_KEY_ID is required when MODERATION_ENABLED is True"
                )
            if not self.aliyun_access_key_secret:
                raise ValueError(
                    "ALIYUN_ACCESS_KEY_SECRET is required when MODERATION_ENABLED is True"
                )
        return self

    model_config = SettingsConfigDict(
        env_file=str(_BACKEND_DIR / ".env"),
        env_file_encoding="utf-8",
        case_sensitive=False,
        extra="ignore",  # 忽略未定义的环境变量
        populate_by_name=True,
        # 支持旧的环境变量名格式（带点号的）
        env_prefix="",
    )


@lru_cache()
def get_settings() -> Settings:
    """
    获取配置实例（单例模式）

    使用 lru_cache 确保只创建一个配置实例。
    """
    return Settings()


# 导出全局配置实例
settings = get_settings()