const prisma = require('../config/db');
const { v4: uuidv4 } = require('uuid');

//
// @desc    Get sections (optionally by event)
// @route   GET /api/sections?eventId=xxx
// @access  Private/Staff
//
const getSections = async (req, res) => {
    try {
        const { eventId } = req.query;

        const { withScope, listWhere } = require('../utils/campusScope');
        const where = withScope(eventId && eventId !== 'all' ? { eventId } : {}, await listWhere(req, 'event'));

        const sections = await prisma.section.findMany({
            where,
            include: {
                allowedOptions: {
                    include: {
                        eventOption: true
                    }
                },
                event: {
                    select: { id: true, title: true }
                }
            },
            orderBy: { name: 'asc' }
        });

        res.json(sections);
    } catch (error) {
        res.status(400).json({ message: error.message });
    }
};

//
// @desc    Create section
// @route   POST /api/sections
// @access  Private/Admin/Supervisor
//
const createSection = async (req, res) => {
    try {
        const { eventId, name, allowedOptionIds } = req.body;

        if (!eventId || !name) {
            res.status(400);
            throw new Error('Event and section name are required');
        }

        const event = await prisma.event.findUnique({
            where: { id: eventId }
        });

        if (!event) {
            res.status(404);
            throw new Error('Event not found');
        }

        const section = await prisma.section.create({
            data: {
                id: uuidv4(),
                eventId,
                name,
                updatedAt: new Date()
            }
        });

        // Attach allowed options if provided
        if (Array.isArray(allowedOptionIds) && allowedOptionIds.length > 0) {
            await prisma.sectionOption.createMany({
                data: allowedOptionIds.map(optionId => ({
                    id: uuidv4(),
                    sectionId: section.id,
                    eventOptionId: optionId
                })),
                skipDuplicates: true
            });
        }

        const fullSection = await prisma.section.findUnique({
            where: { id: section.id },
            include: {
                allowedOptions: {
                    include: { eventOption: true }
                }
            }
        });

        res.status(201).json(fullSection);

    } catch (error) {
        res.status(400).json({ message: error.message });
    }
};

//
// @desc    Update section
// @route   PUT /api/sections/:id
// @access  Private/Admin/Supervisor
//
const updateSection = async (req, res) => {
    try {
        const { name, allowedOptionIds } = req.body;

        const section = await prisma.section.findUnique({
            where: { id: req.params.id }
        });

        if (!section) {
            res.status(404);
            throw new Error('Section not found');
        }

        const updatedSection = await prisma.section.update({
            where: { id: req.params.id },
            data: {
                name: name || section.name,
                updatedAt: new Date()
            }
        });

        // If allowed options supplied → reset them
        if (Array.isArray(allowedOptionIds)) {

            await prisma.sectionOption.deleteMany({
                where: { sectionId: section.id }
            });

            if (allowedOptionIds.length > 0) {
                await prisma.sectionOption.createMany({
                    data: allowedOptionIds.map(optionId => ({
                        id: uuidv4(),
                        sectionId: section.id,
                        eventOptionId: optionId
                    }))
                });
            }
        }

        const fullSection = await prisma.section.findUnique({
            where: { id: section.id },
            include: {
                allowedOptions: {
                    include: { eventOption: true }
                }
            }
        });

        res.json(fullSection);

    } catch (error) {
        res.status(400).json({ message: error.message });
    }
};

//
// @desc    Delete section
// @route   DELETE /api/sections/:id
// @access  Private/Admin
//
const deleteSection = async (req, res) => {
    try {
        const section = await prisma.section.findUnique({
            where: { id: req.params.id }
        });

        if (!section) {
            res.status(404);
            throw new Error('Section not found');
        }

        await prisma.section.delete({
            where: { id: section.id }
        });

        res.json({ message: 'Section deleted' });

    } catch (error) {
        res.status(400).json({ message: error.message });
    }
};

module.exports = {
    getSections,
    createSection,
    updateSection,
    deleteSection
};