"""LogHive configuration."""

import os
from datetime import datetime, timezone, timedelta
from typing import Optional

# Beijing timezone offset
_BEIJING_TZ = timezone(timedelta(hours=8))


def to_display_time(dt: datetime) -> str:
    """Convert a UTC datetime to Beijing time for display.
    Returns ISO format without timezone suffix (e.g. '2026-05-08T14:30:00')."""
    if dt is None:
        return None
    if dt.tzinfo is None:
        dt = dt.replace(tzinfo=timezone.utc)
    local = dt.astimezone(_BEIJING_TZ)
    return local.strftime("%Y-%m-%dT%H:%M:%S")


def from_query_time(dt: Optional[datetime]) -> Optional[datetime]:
    """Interpret a naive datetime query param as Beijing time, return UTC datetime."""
    if dt is None:
        return None
    if dt.tzinfo is None:
        dt = dt.replace(tzinfo=_BEIJING_TZ)
    return dt.astimezone(timezone.utc)


class Settings:
    """Application settings loaded from environment variables."""

    # Service name
    SERVICE_NAME: str = "LogHive"

    # API
    API_HOST: str = os.getenv("API_HOST", "0.0.0.0")
    API_PORT: int = int(os.getenv("API_PORT", "8000"))
    DEBUG: bool = os.getenv("DEBUG", "false").lower() == "true"
    CORS_ORIGINS: list[str] = os.getenv("CORS_ORIGINS", "*").split(",")

    # Security
    SECRET_KEY: str = os.getenv("SECRET_KEY", "change-me-in-production")
    TOKEN_EXPIRE_HOURS: int = int(os.getenv("TOKEN_EXPIRE_HOURS", "720"))

    # PostgreSQL
    DATABASE_URL: str = os.getenv(
        "DATABASE_URL",
        "postgresql+asyncpg://LogHive:LogHive@localhost:5432/LogHive",
    )

    # Redis
    REDIS_URL: str = os.getenv("REDIS_URL", "redis://localhost:6379/0")

    # Celery
    CELERY_BROKER_URL: str = os.getenv("CELERY_BROKER_URL", "redis://localhost:6379/1")
    CELERY_RESULT_BACKEND: str = os.getenv(
        "CELERY_RESULT_BACKEND", "redis://localhost:6379/2"
    )

    # Log retention (days)
    LOG_RETENTION_DAYS: int = int(os.getenv("LOG_RETENTION_DAYS", "30"))
    LOG_COLD_STORAGE_DAYS: int = int(os.getenv("LOG_COLD_STORAGE_DAYS", "7"))

    # Rate limit
    RATE_LIMIT_PER_SECOND: int = int(os.getenv("RATE_LIMIT_PER_SECOND", "1000"))

    # Alert
    ALERT_CHECK_INTERVAL_SECONDS: int = int(
        os.getenv("ALERT_CHECK_INTERVAL_SECONDS", "60")
    )

    # Notification
    FEISHU_WEBHOOK_URL: Optional[str] = os.getenv("FEISHU_WEBHOOK_URL", None)
    DINGTALK_WEBHOOK_URL: Optional[str] = os.getenv("DINGTALK_WEBHOOK_URL", None)


settings = Settings()