from typing import List, Optional
from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.orm import Session
from pydantic import BaseModel

from database import get_db
from auth import get_current_active_user
from models import User, PriceAlert

router = APIRouter(prefix="/alerts", tags=["Price Alerts"])


class AlertCreate(BaseModel):
    product_name: str
    dispensary_id: Optional[int] = None
    dispensary_name: Optional[str] = None
    target_price: float
    current_price: Optional[float] = None


class AlertUpdate(BaseModel):
    target_price: Optional[float] = None
    is_active: Optional[bool] = None


class AlertResponse(BaseModel):
    id: int
    product_name: str
    dispensary_id: Optional[int]
    dispensary_name: Optional[str]
    target_price: float
    current_price: Optional[float]
    is_active: bool
    is_triggered: bool
    created_at: str

    class Config:
        from_attributes = True


@router.get("/", response_model=List[AlertResponse])
def get_alerts(
    current_user: User = Depends(get_current_active_user),
    db: Session = Depends(get_db)
):
    """Get all price alerts for the current user"""
    alerts = db.query(PriceAlert).filter(
        PriceAlert.user_id == current_user.id
    ).order_by(PriceAlert.created_at.desc()).all()

    return [
        AlertResponse(
            id=a.id,
            product_name=a.product_name,
            dispensary_id=a.dispensary_id,
            dispensary_name=a.dispensary_name,
            target_price=a.target_price,
            current_price=a.current_price,
            is_active=a.is_active,
            is_triggered=a.is_triggered,
            created_at=a.created_at.isoformat() if a.created_at else ""
        )
        for a in alerts
    ]


@router.post("/", response_model=AlertResponse, status_code=status.HTTP_201_CREATED)
def create_alert(
    alert_data: AlertCreate,
    current_user: User = Depends(get_current_active_user),
    db: Session = Depends(get_db)
):
    """Create a new price alert"""
    alert = PriceAlert(
        user_id=current_user.id,
        product_name=alert_data.product_name,
        dispensary_id=alert_data.dispensary_id,
        dispensary_name=alert_data.dispensary_name,
        target_price=alert_data.target_price,
        current_price=alert_data.current_price,
        is_triggered=alert_data.current_price and alert_data.current_price <= alert_data.target_price
    )
    db.add(alert)
    db.commit()
    db.refresh(alert)

    return AlertResponse(
        id=alert.id,
        product_name=alert.product_name,
        dispensary_id=alert.dispensary_id,
        dispensary_name=alert.dispensary_name,
        target_price=alert.target_price,
        current_price=alert.current_price,
        is_active=alert.is_active,
        is_triggered=alert.is_triggered,
        created_at=alert.created_at.isoformat() if alert.created_at else ""
    )


@router.get("/{alert_id}", response_model=AlertResponse)
def get_alert(
    alert_id: int,
    current_user: User = Depends(get_current_active_user),
    db: Session = Depends(get_db)
):
    """Get a specific price alert"""
    alert = db.query(PriceAlert).filter(
        PriceAlert.id == alert_id,
        PriceAlert.user_id == current_user.id
    ).first()

    if not alert:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Alert not found"
        )

    return AlertResponse(
        id=alert.id,
        product_name=alert.product_name,
        dispensary_id=alert.dispensary_id,
        dispensary_name=alert.dispensary_name,
        target_price=alert.target_price,
        current_price=alert.current_price,
        is_active=alert.is_active,
        is_triggered=alert.is_triggered,
        created_at=alert.created_at.isoformat() if alert.created_at else ""
    )


@router.put("/{alert_id}", response_model=AlertResponse)
def update_alert(
    alert_id: int,
    alert_update: AlertUpdate,
    current_user: User = Depends(get_current_active_user),
    db: Session = Depends(get_db)
):
    """Update a price alert"""
    alert = db.query(PriceAlert).filter(
        PriceAlert.id == alert_id,
        PriceAlert.user_id == current_user.id
    ).first()

    if not alert:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Alert not found"
        )

    update_data = alert_update.model_dump(exclude_unset=True)
    for field, value in update_data.items():
        setattr(alert, field, value)

    # Check if alert should be triggered
    if alert.current_price and alert.current_price <= alert.target_price:
        alert.is_triggered = True

    db.commit()
    db.refresh(alert)

    return AlertResponse(
        id=alert.id,
        product_name=alert.product_name,
        dispensary_id=alert.dispensary_id,
        dispensary_name=alert.dispensary_name,
        target_price=alert.target_price,
        current_price=alert.current_price,
        is_active=alert.is_active,
        is_triggered=alert.is_triggered,
        created_at=alert.created_at.isoformat() if alert.created_at else ""
    )


@router.patch("/{alert_id}/toggle")
def toggle_alert(
    alert_id: int,
    current_user: User = Depends(get_current_active_user),
    db: Session = Depends(get_db)
):
    """Toggle alert active status"""
    alert = db.query(PriceAlert).filter(
        PriceAlert.id == alert_id,
        PriceAlert.user_id == current_user.id
    ).first()

    if not alert:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Alert not found"
        )

    alert.is_active = not alert.is_active
    db.commit()
    return {"message": f"Alert {'activated' if alert.is_active else 'deactivated'}"}


@router.delete("/{alert_id}")
def delete_alert(
    alert_id: int,
    current_user: User = Depends(get_current_active_user),
    db: Session = Depends(get_db)
):
    """Delete a price alert"""
    alert = db.query(PriceAlert).filter(
        PriceAlert.id == alert_id,
        PriceAlert.user_id == current_user.id
    ).first()

    if not alert:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Alert not found"
        )

    db.delete(alert)
    db.commit()
    return {"message": "Alert deleted"}


@router.get("/stats/summary")
def get_alert_stats(
    current_user: User = Depends(get_current_active_user),
    db: Session = Depends(get_db)
):
    """Get alert statistics for dashboard"""
    alerts = db.query(PriceAlert).filter(
        PriceAlert.user_id == current_user.id
    ).all()

    return {
        "total": len(alerts),
        "active": len([a for a in alerts if a.is_active]),
        "triggered": len([a for a in alerts if a.is_triggered]),
    }