"""Notification API endpoints."""

import json
from typing import Any, Optional
from fastapi import APIRouter, Depends, HTTPException, status, Query
from sqlalchemy.orm import Session

from app.dependencies import get_db, get_current_user, get_current_superuser
from app.models.user import User
from app import crud
from app.schemas.notification import (
    Notification,
    NotificationCreate,
    NotificationCreateForUser,
    NotificationList,
    NotificationStats,
    NotificationBulkAction
)


router = APIRouter()


def serialize_notification(db_obj) -> dict:
    """Serialize notification for response."""
    metadata = None
    if db_obj.metadata:
        try:
            metadata = json.loads(db_obj.metadata)
        except json.JSONDecodeError:
            metadata = None

    return {
        "id": db_obj.id,
        "user_id": db_obj.user_id,
        "title": db_obj.title,
        "message": db_obj.message,
        "type": db_obj.type,
        "link": db_obj.link,
        "metadata": metadata,
        "is_read": db_obj.is_read,
        "created_at": db_obj.created_at,
        "read_at": db_obj.read_at
    }


@router.get("", response_model=NotificationList)
def get_notifications(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
    skip: int = Query(0, ge=0),
    limit: int = Query(50, ge=1, le=100),
    unread_only: bool = False
) -> Any:
    """
    Get notifications for the current user.
    """
    notifications = crud.notification.get_multi_by_user(
        db,
        user_id=current_user.id,
        skip=skip,
        limit=limit,
        unread_only=unread_only
    )
    total = crud.notification.count_by_user(db, current_user.id)
    unread_count = crud.notification.count_unread_by_user(db, current_user.id)

    return {
        "items": [serialize_notification(n) for n in notifications],
        "total": total,
        "unread_count": unread_count
    }


@router.get("/unread-count")
def get_unread_count(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> Any:
    """
    Get unread notification count for the current user.
    """
    count = crud.notification.count_unread_by_user(db, current_user.id)
    return {"unread_count": count}


@router.get("/stats", response_model=NotificationStats)
def get_notification_stats(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> Any:
    """
    Get notification statistics for the current user.
    """
    return crud.notification.get_stats_by_user(db, current_user.id)


@router.get("/{notification_id}", response_model=Notification)
def get_notification(
    notification_id: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> Any:
    """
    Get a specific notification.
    """
    db_obj = crud.notification.get(db, id=notification_id)
    if not db_obj or db_obj.user_id != current_user.id:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Notification not found"
        )

    return serialize_notification(db_obj)


@router.post("/{notification_id}/read", response_model=Notification)
def mark_as_read(
    notification_id: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> Any:
    """
    Mark a notification as read.
    """
    db_obj = crud.notification.mark_as_read(
        db, id=notification_id, user_id=current_user.id
    )
    if not db_obj:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Notification not found"
        )

    return serialize_notification(db_obj)


@router.post("/read-all")
def mark_all_as_read(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> Any:
    """
    Mark all notifications as read.
    """
    count = crud.notification.mark_all_as_read(db, user_id=current_user.id)
    return {"marked_as_read": count}


@router.post("/read-multiple")
def mark_multiple_as_read(
    action: NotificationBulkAction,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> Any:
    """
    Mark multiple notifications as read.
    """
    count = crud.notification.mark_multiple_as_read(
        db,
        user_id=current_user.id,
        notification_ids=action.notification_ids
    )
    return {"marked_as_read": count}


@router.delete("/{notification_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_notification(
    notification_id: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> None:
    """
    Delete a notification.
    """
    if not crud.notification.delete(db, id=notification_id, user_id=current_user.id):
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Notification not found"
        )


@router.delete("/read/all")
def delete_all_read(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> Any:
    """
    Delete all read notifications.
    """
    count = crud.notification.delete_all_read(db, user_id=current_user.id)
    return {"deleted": count}


@router.post("/delete-multiple")
def delete_multiple(
    action: NotificationBulkAction,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> Any:
    """
    Delete multiple notifications.
    """
    count = crud.notification.delete_multiple(
        db,
        user_id=current_user.id,
        notification_ids=action.notification_ids
    )
    return {"deleted": count}


# Admin endpoints

@router.post("/admin/send", status_code=status.HTTP_201_CREATED)
def send_notification_to_user(
    notification_in: NotificationCreate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_superuser),
) -> Any:
    """
    Send a notification to a specific user (admin only).
    """
    db_obj = crud.notification.create(db, obj_in=notification_in)
    return serialize_notification(db_obj)


@router.post("/admin/broadcast")
def broadcast_notification(
    notification_in: NotificationCreateForUser,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_superuser),
) -> Any:
    """
    Send a notification to all users (admin only).
    """
    count = crud.notification.create_for_all_users(
        db,
        title=notification_in.title,
        message=notification_in.message,
        type=notification_in.type,
        link=notification_in.link,
        metadata=notification_in.metadata
    )
    return {"sent_to": count}