from datetime import datetime, timedelta
from typing import Optional
from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy import select, desc
from sqlalchemy.ext.asyncio import AsyncSession

from app.database import get_db
from app.models import Vehicle, Position
from app.schemas import VehicleCreate, VehicleUpdate, VehicleResponse, VehicleWithPosition
from app.schemas.vehicle import LastPosition

router = APIRouter()


def get_vehicle_status(last_position: Optional[Position], now: datetime) -> str:
    if not last_position:
        return "offline"

    time_diff = now - last_position.timestamp
    if time_diff > timedelta(minutes=5):
        return "offline"
    elif last_position.speed < 2:
        return "stopped"
    else:
        return "moving"


@router.get("", response_model=list[VehicleWithPosition])
async def get_vehicles(db: AsyncSession = Depends(get_db)):
    """Получить список всех транспортных средств с последними позициями"""
    result = await db.execute(select(Vehicle))
    vehicles = result.scalars().all()

    response = []
    now = datetime.utcnow()

    for vehicle in vehicles:
        # Get last position
        pos_result = await db.execute(
            select(Position)
            .where(Position.vehicle_id == vehicle.id)
            .order_by(desc(Position.timestamp))
            .limit(1)
        )
        last_pos = pos_result.scalar_one_or_none()

        vehicle_data = VehicleWithPosition(
            id=vehicle.id,
            name=vehicle.name,
            type=vehicle.type,
            created_at=vehicle.created_at,
            last_position=LastPosition(
                lat=last_pos.lat,
                lon=last_pos.lon,
                speed=last_pos.speed,
                heading=last_pos.heading,
                timestamp=last_pos.timestamp
            ) if last_pos else None,
            status=get_vehicle_status(last_pos, now)
        )
        response.append(vehicle_data)

    return response


@router.get("/{vehicle_id}", response_model=VehicleWithPosition)
async def get_vehicle(vehicle_id: int, db: AsyncSession = Depends(get_db)):
    """Получить информацию о транспортном средстве"""
    result = await db.execute(select(Vehicle).where(Vehicle.id == vehicle_id))
    vehicle = result.scalar_one_or_none()

    if not vehicle:
        raise HTTPException(status_code=404, detail="Vehicle not found")

    # Get last position
    pos_result = await db.execute(
        select(Position)
        .where(Position.vehicle_id == vehicle.id)
        .order_by(desc(Position.timestamp))
        .limit(1)
    )
    last_pos = pos_result.scalar_one_or_none()
    now = datetime.utcnow()

    return VehicleWithPosition(
        id=vehicle.id,
        name=vehicle.name,
        type=vehicle.type,
        created_at=vehicle.created_at,
        last_position=LastPosition(
            lat=last_pos.lat,
            lon=last_pos.lon,
            speed=last_pos.speed,
            heading=last_pos.heading,
            timestamp=last_pos.timestamp
        ) if last_pos else None,
        status=get_vehicle_status(last_pos, now)
    )


@router.post("", response_model=VehicleResponse, status_code=201)
async def create_vehicle(vehicle: VehicleCreate, db: AsyncSession = Depends(get_db)):
    """Создать новое транспортное средство"""
    db_vehicle = Vehicle(**vehicle.model_dump())
    db.add(db_vehicle)
    await db.commit()
    await db.refresh(db_vehicle)
    return db_vehicle


@router.put("/{vehicle_id}", response_model=VehicleResponse)
async def update_vehicle(vehicle_id: int, vehicle: VehicleUpdate, db: AsyncSession = Depends(get_db)):
    """Обновить транспортное средство"""
    result = await db.execute(select(Vehicle).where(Vehicle.id == vehicle_id))
    db_vehicle = result.scalar_one_or_none()

    if not db_vehicle:
        raise HTTPException(status_code=404, detail="Vehicle not found")

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

    await db.commit()
    await db.refresh(db_vehicle)
    return db_vehicle


@router.delete("/{vehicle_id}", status_code=204)
async def delete_vehicle(vehicle_id: int, db: AsyncSession = Depends(get_db)):
    """Удалить транспортное средство"""
    result = await db.execute(select(Vehicle).where(Vehicle.id == vehicle_id))
    db_vehicle = result.scalar_one_or_none()

    if not db_vehicle:
        raise HTTPException(status_code=404, detail="Vehicle not found")

    await db.delete(db_vehicle)
    await db.commit()