import os
from pathlib import Path
from pydantic_settings import BaseSettings
from functools import lru_cache

# 프로젝트 루트 디렉토리 (backend의 상위 디렉토리)
BASE_DIR = Path(__file__).resolve().parent.parent.parent
BACKEND_ENV_FILE = BASE_DIR / ".env"


class Settings(BaseSettings):
    # Application
    APP_NAME: str = "Auto Stock Trading System"
    ENVIRONMENT: str = "development"
    DEBUG: bool = True
    SECRET_KEY: str = "change-this-secret-key"
    
    # Server
    BACKEND_HOST: str = "0.0.0.0"
    BACKEND_PORT: int = 8000
    
    # Database
    DATABASE_URL: str = "postgresql://autostock:autostock_password@localhost:5432/autostock_db"
    
    # Redis
    REDIS_URL: str = "redis://localhost:6379/0"
    
    # RabbitMQ
    RABBITMQ_URL: str = "amqp://autostock:autostock_password@localhost:5672/"
    
    # Korea Investment API
    KOREA_INVESTMENT_APP_KEY: str = ""
    KOREA_INVESTMENT_APP_SECRET: str = ""
    KOREA_INVESTMENT_ACCOUNT_NUMBER: str = ""
    KOREA_INVESTMENT_API_BASE_URL: str = "https://openapi.koreainvestment.com:9443"
    
    # Alias for backward compatibility with .env file
    KIS_APP_KEY: str = ""
    KIS_APP_SECRET: str = ""
    KIS_ACCOUNT_NO: str = ""
    KIS_BASE_URL: str = ""
    
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        # Use KIS_* values if KOREA_INVESTMENT_* are empty
        if not self.KOREA_INVESTMENT_APP_KEY and self.KIS_APP_KEY:
            self.KOREA_INVESTMENT_APP_KEY = self.KIS_APP_KEY
        if not self.KOREA_INVESTMENT_APP_SECRET and self.KIS_APP_SECRET:
            self.KOREA_INVESTMENT_APP_SECRET = self.KIS_APP_SECRET
        if not self.KOREA_INVESTMENT_ACCOUNT_NUMBER and self.KIS_ACCOUNT_NO:
            self.KOREA_INVESTMENT_ACCOUNT_NUMBER = self.KIS_ACCOUNT_NO
        if self.KIS_BASE_URL:
            self.KOREA_INVESTMENT_API_BASE_URL = self.KIS_BASE_URL
    
    # Claude AI
    ANTHROPIC_API_KEY: str = ""
    
    # MCP Server
    MCP_SERVER_URL: str = "http://localhost:8001"
    
    # News API
    NEWS_API_KEY: str = ""
    
    # Logging
    LOG_LEVEL: str = "INFO"
    
    # Trading Settings
    MAX_POSITION_SIZE: float = 0.1  # 10% of portfolio
    MAX_DAILY_TRADES: int = 10
    STOP_LOSS_PERCENT: float = -5.0
    TAKE_PROFIT_PERCENT: float = 15.0
    
    # API Rate Limiting & Retry Settings (모의투자 API 안전 운영)
    API_MAX_RETRIES: int = 3  # 최대 재시도 횟수
    API_RETRY_DELAY: float = 1.5  # 초기 재시도 대기 시간 (초)
    API_RETRY_BACKOFF: float = 2.0  # 지수 백오프 배율
    API_MIN_REQUEST_INTERVAL: float = 0.5  # 최소 요청 간격 (초) - 초당 2회 권장
    API_MAX_CONCURRENT_REQUESTS: int = 2  # 동시 최대 요청 수
    API_TIMEOUT: float = 30.0  # API 타임아웃 (초)
    
    # Monitoring & Alerting
    API_ERROR_THRESHOLD: float = 0.3  # 오류율 임계값 (30%)
    API_MONITORING_WINDOW: int = 100  # 모니터링 윈도우 (최근 N개 요청)
    
    class Config:
        env_file = str(BACKEND_ENV_FILE) if BACKEND_ENV_FILE.exists() else ".env"
        case_sensitive = True
        extra = "ignore"  # .env 파일의 추가 필드 무시
        env_file_encoding = "utf-8"


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


settings = get_settings()