from typing import Any, List, Optional

from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session

from app import crud, models, schemas
from app.api.api_v1 import deps
from app.models.task import TaskStatus

router = APIRouter()


@router.get("/", response_model=List[schemas.Task])
async def read_tasks(
    db: Session = Depends(deps.get_db),
    skip: int = 0,
    limit: int = 100,
    status: Optional[TaskStatus] = None,
    current_user: models.User = Depends(deps.get_current_active_user),
) -> Any:
    """
    Retrieve tasks.
    """
    if status:
        tasks = crud.task.get_by_status(
            db, owner_id=current_user.id, status=status, skip=skip, limit=limit
        )
    else:
        tasks = crud.task.get_multi_by_owner(
            db, owner_id=current_user.id, skip=skip, limit=limit
        )
    return tasks


@router.post("/", response_model=schemas.Task)
async def create_task(
    *,
    db: Session = Depends(deps.get_db),
    task_in: schemas.TaskCreate,
    current_user: models.User = Depends(deps.get_current_active_user),
) -> Any:
    """
    Create new task.
    """
    task = crud.task.create_with_owner(db=db, obj_in=task_in, owner_id=current_user.id)
    return task


@router.get("/{task_id}", response_model=schemas.Task)
async def read_task(
    *,
    db: Session = Depends(deps.get_db),
    task_id: str,
    current_user: models.User = Depends(deps.get_current_active_user),
) -> Any:
    """
    Get task by ID.
    """
    task = crud.task.get(db=db, id=task_id)
    if not task:
        raise HTTPException(status_code=404, detail="Task not found")
    if task.owner_id != current_user.id:
        raise HTTPException(status_code=403, detail="Not enough permissions")
    return task


@router.patch("/{task_id}", response_model=schemas.Task)
async def update_task(
    *,
    db: Session = Depends(deps.get_db),
    task_id: str,
    task_in: schemas.TaskUpdate,
    current_user: models.User = Depends(deps.get_current_active_user),
) -> Any:
    """
    Update a task.
    """
    task = crud.task.get(db=db, id=task_id)
    if not task:
        raise HTTPException(status_code=404, detail="Task not found")
    if task.owner_id != current_user.id:
        raise HTTPException(status_code=403, detail="Not enough permissions")
    
    # Auto-update completed_at when status is changed to DONE
    if task_in.status == TaskStatus.DONE and task.status != TaskStatus.DONE:
        from datetime import datetime
        task_in.completed_at = datetime.utcnow()
    elif task_in.status is not None and task_in.status != TaskStatus.DONE and task.status == TaskStatus.DONE:
        task_in.completed_at = None
        
    task = crud.task.update(db=db, db_obj=task, obj_in=task_in)
    return task


@router.delete("/{task_id}", status_code=204, response_model=None)
async def delete_task(
    *,
    db: Session = Depends(deps.get_db),
    task_id: str,
    current_user: models.User = Depends(deps.get_current_active_user),
) -> Any:
    """
    Delete a task.
    """
    task = crud.task.get(db=db, id=task_id)
    if not task:
        raise HTTPException(status_code=404, detail="Task not found")
    if task.owner_id != current_user.id:
        raise HTTPException(status_code=403, detail="Not enough permissions")
    crud.task.remove(db=db, id=task_id)
    return None