from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from typing import List
from app.db.base import get_db
from app.models.user import User, Connection
from app.schemas.connection import (
    ConnectionCreate,
    ConnectionResponse,
    ConnectionUpdate,
)
from app.api.auth import get_current_user

router = APIRouter()


@router.post("/", response_model=ConnectionResponse)
def send_connection_request(
    connection: ConnectionCreate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    # Check if receiver exists
    receiver = db.query(User).filter(User.id == connection.receiver_id).first()
    if not receiver:
        raise HTTPException(status_code=404, detail="User not found")

    # Check if trying to connect to self
    if connection.receiver_id == current_user.id:
        raise HTTPException(status_code=400, detail="Cannot connect to yourself")

    # Check if connection already exists
    existing_connection = (
        db.query(Connection)
        .filter(
            (
                (Connection.sender_id == current_user.id)
                & (Connection.receiver_id == connection.receiver_id)
            )
            | (
                (Connection.sender_id == connection.receiver_id)
                & (Connection.receiver_id == current_user.id)
            )
        )
        .first()
    )

    if existing_connection:
        raise HTTPException(status_code=400, detail="Connection already exists")

    db_connection = Connection(
        sender_id=current_user.id, receiver_id=connection.receiver_id
    )
    db.add(db_connection)
    db.commit()
    db.refresh(db_connection)

    db_connection.sender_name = f"{current_user.first_name} {current_user.last_name}"
    db_connection.receiver_name = f"{receiver.first_name} {receiver.last_name}"

    return db_connection


@router.get("/sent", response_model=List[ConnectionResponse])
def get_sent_connections(
    db: Session = Depends(get_db), current_user: User = Depends(get_current_user)
):
    connections = (
        db.query(Connection).filter(Connection.sender_id == current_user.id).all()
    )

    for connection in connections:
        connection.sender_name = f"{current_user.first_name} {current_user.last_name}"
        connection.receiver_name = (
            f"{connection.receiver.first_name} {connection.receiver.last_name}"
        )

    return connections


@router.get("/received", response_model=List[ConnectionResponse])
def get_received_connections(
    db: Session = Depends(get_db), current_user: User = Depends(get_current_user)
):
    connections = (
        db.query(Connection).filter(Connection.receiver_id == current_user.id).all()
    )

    for connection in connections:
        connection.sender_name = (
            f"{connection.sender.first_name} {connection.sender.last_name}"
        )
        connection.receiver_name = f"{current_user.first_name} {current_user.last_name}"

    return connections


@router.get("/accepted", response_model=List[ConnectionResponse])
def get_my_connections(
    db: Session = Depends(get_db), current_user: User = Depends(get_current_user)
):
    connections = (
        db.query(Connection)
        .filter(
            (
                (Connection.sender_id == current_user.id)
                | (Connection.receiver_id == current_user.id)
            )
            & (Connection.status == "accepted")
        )
        .all()
    )

    for connection in connections:
        connection.sender_name = (
            f"{connection.sender.first_name} {connection.sender.last_name}"
        )
        connection.receiver_name = (
            f"{connection.receiver.first_name} {connection.receiver.last_name}"
        )

    return connections


@router.put("/{connection_id}", response_model=ConnectionResponse)
def update_connection(
    connection_id: int,
    connection_update: ConnectionUpdate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    connection = db.query(Connection).filter(Connection.id == connection_id).first()

    if not connection:
        raise HTTPException(status_code=404, detail="Connection not found")

    # Only receiver can update the connection status
    if connection.receiver_id != current_user.id:
        raise HTTPException(
            status_code=403, detail="Not authorized to update this connection"
        )

    # Only allow updating pending connections
    if connection.status != "pending":
        raise HTTPException(
            status_code=400, detail="Can only update pending connections"
        )

    connection.status = connection_update.status
    db.commit()
    db.refresh(connection)

    connection.sender_name = (
        f"{connection.sender.first_name} {connection.sender.last_name}"
    )
    connection.receiver_name = f"{current_user.first_name} {current_user.last_name}"

    return connection


@router.delete("/{connection_id}")
def delete_connection(
    connection_id: int,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    connection = db.query(Connection).filter(Connection.id == connection_id).first()

    if not connection:
        raise HTTPException(status_code=404, detail="Connection not found")

    # Only sender or receiver can delete the connection
    if (
        connection.sender_id != current_user.id
        and connection.receiver_id != current_user.id
    ):
        raise HTTPException(
            status_code=403, detail="Not authorized to delete this connection"
        )

    db.delete(connection)
    db.commit()
    return {"message": "Connection deleted successfully"}