const express = require('express');
const router = express.Router();
const { Op } = require('sequelize');

module.exports = (sequelize) => {
    const { User, Friendship, FriendRequest } = sequelize.models;

    // POST /api/friend-requests
    router.post('/', async (req, res) => {
        try {
            const { identifier } = req.body;
            const toUser = await User.findOne({ where: { [Op.or]: [{ email: identifier }, { name: identifier }] } });
            
            if (!toUser) return res.status(404).json({ message: 'Utente non trovato.' });
            if (toUser.id === req.userId) return res.status(400).json({ message: 'Non puoi aggiungere te stesso.'});
            
            const user1Id = Math.min(req.userId, toUser.id);
            const user2Id = Math.max(req.userId, toUser.id);
            const friendshipExists = await Friendship.findOne({ where: { user1Id, user2Id } });
            if (friendshipExists) return res.status(400).json({ message: 'Siete già amici.'});
            
            const requestExists = await FriendRequest.findOne({
                where: { [Op.or]: [{ fromUserId: req.userId, toUserId: toUser.id }, { fromUserId: toUser.id, toUserId: req.userId }] }
            });
            if (requestExists) return res.status(400).json({ message: 'Richiesta già inviata.'});

            const friendRequest = await FriendRequest.create({ fromUserId: req.userId, toUserId: toUser.id });
            const populatedReq = await FriendRequest.findByPk(friendRequest.id, {
                include: [{ model: User, as: 'fromUser' }, { model: User, as: 'toUser' }]
            });
            res.status(201).json(populatedReq);
        } catch (error) {
            res.status(400).json({ message: 'Error sending friend request', error: error.message });
        }
    });

    // POST /api/friend-requests/:id/accept
    router.post('/:id/accept', async (req, res) => {
        const t = await sequelize.transaction();
        try {
            const request = await FriendRequest.findByPk(req.params.id, { transaction: t });
            if (!request || request.toUserId !== req.userId) {
                await t.rollback();
                return res.status(404).json({ message: 'Request not found or not for you.' });
            }

            const user1Id = Math.min(request.fromUserId, request.toUserId);
            const user2Id = Math.max(request.fromUserId, request.toUserId);
            await Friendship.create({ user1Id, user2Id }, { transaction: t });
            await request.destroy({ transaction: t });
            
            await t.commit();
            const newFriend = await User.findByPk(request.fromUserId);
            res.status(200).json({ message: 'Friend request accepted', newFriend });
        } catch (error) {
            await t.rollback();
            res.status(400).json({ message: 'Error accepting friend request', error: error.message });
        }
    });
    
    // DELETE /api/friend-requests/:id
    router.delete('/:id', async (req, res) => {
        try {
            const count = await FriendRequest.destroy({ where: { id: req.params.id } });
            if (count === 0) return res.status(404).json({ message: 'Request not found.' });
            res.status(200).json({ message: 'Friend request cancelled/declined.' });
        } catch (error) {
            res.status(400).json({ message: 'Error deleting friend request', error: error.message });
        }
    });

    return router;
};