const express = require('express');
const router = express.Router();

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

    // POST /api/groups
    router.post('/', async (req, res) => {
        try {
            const { name, members } = req.body;
            const group = await Group.create({ name });
            await group.setMembers(members);
            const populatedGroup = await Group.findByPk(group.id, {
                include: [{ model: User, as: 'members', through: { attributes: [] } }]
            });
            res.status(201).json(populatedGroup);
        } catch (error) {
            res.status(400).json({ message: 'Error creating group', error: error.message });
        }
    });

    // PUT /api/groups/:id/members
    router.put('/:id/members', async (req, res) => {
        try {
            const { userIds } = req.body;
            const group = await Group.findByPk(req.params.id);
            if (!group) return res.status(404).json({ message: 'Group not found' });
            await group.addMembers(userIds);
            const populatedGroup = await Group.findByPk(group.id, {
                include: [{ model: User, as: 'members', through: { attributes: [] } }]
            });
            res.json(populatedGroup);
        } catch (error) {
            res.status(400).json({ message: 'Error adding members to group', error: error.message });
        }
    });
    
    // DELETE /api/groups/:id/members/:userId
    router.delete('/:id/members/:userId', async (req, res) => {
        try {
            const group = await Group.findByPk(req.params.id);
            if (!group) return res.status(404).json({ message: 'Group not found' });
            await group.removeMember(req.params.userId);
             const populatedGroup = await Group.findByPk(group.id, {
                include: [{ model: User, as: 'members', through: { attributes: [] } }]
            });
            res.json(populatedGroup);
        } catch (error) {
            res.status(400).json({ message: 'Error removing member from group', error: error.message });
        }
    });

    return router;
};