const fs = require('fs');
const path = require('path');
const mysql = require('mysql2/promise');
const dotenv = require('dotenv');

dotenv.config({ path: path.join(__dirname, '../.env') });

const dbConfig = {
    host: process.env.DB_HOST,
    user: process.env.DB_USER,
    password: process.env.DB_PASSWORD,
    database: process.env.DB_NAME,
    multipleStatements: true
};

const SNAPSHOTS_DIR = path.join(__dirname, '../snapshots');

async function restoreSnapshot() {
    console.log('Restoring test database from snapshot...');
    const pool = mysql.createPool(dbConfig);
    
    try {
        // Read snapshot
        const snapshotPath = path.join(SNAPSHOTS_DIR, 'test_snapshot.json');
        if (!fs.existsSync(snapshotPath)) {
            throw new Error('Snapshot file not found. Run create-test-snapshot.js first.');
        }
        
        const snapshot = JSON.parse(fs.readFileSync(snapshotPath, 'utf8'));
        
        // First, create schema (this will drop existing tables)
        const schemaSQL = fs.readFileSync(path.join(__dirname, '../db/schema.sql'), 'utf8');
        await pool.query(schemaSQL);
        
        const connection = await pool.getConnection();
        try {
            await connection.beginTransaction();
            
            // Insert categories first (they're referenced by product_categories)
            if (snapshot.categories.length > 0) {
                const categoryValues = snapshot.categories.map(c => [c.id, c.name, c.created_at]);
                await connection.query(
                    'INSERT INTO categories (id, name, created_at) VALUES ?',
                    [categoryValues]
                );
            }
            
            // Insert products
            if (snapshot.products.length > 0) {
                const productValues = snapshot.products.map(p => [
                    p.product_id, p.title, p.SKU, p.created_at, p.stock_quantity,
                    p.price, p.regular_price, p.cost_price, p.landing_cost_price,
                    p.barcode, p.updated_at, p.visible, p.managing_stock,
                    p.replenishable, p.vendor, p.vendor_reference, p.permalink,
                    p.categories, p.image, p.brand, p.options, p.tags, p.moq, p.uom
                ]);
                await connection.query(
                    'INSERT INTO products VALUES ?',
                    [productValues]
                );
            }
            
            // Insert product_categories relationships
            if (snapshot.product_categories.length > 0) {
                const pcValues = snapshot.product_categories.map(pc => [
                    pc.product_id, pc.category_id
                ]);
                await connection.query(
                    'INSERT INTO product_categories (product_id, category_id) VALUES ?',
                    [pcValues]
                );
            }
            
            // Insert orders
            if (snapshot.orders.length > 0) {
                const orderValues = snapshot.orders.map(o => [
                    o.id, o.order_number, o.product_id, o.SKU, o.date,
                    o.price, o.quantity, o.discount, o.tax, o.tax_included,
                    o.shipping, o.customer, o.status, o.payment_method,
                    o.shipping_method, o.shipping_address, o.billing_address,
                    o.canceled
                ]);
                await connection.query(
                    'INSERT INTO orders VALUES ?',
                    [orderValues]
                );
            }
            
            // Insert purchase orders
            if (snapshot.purchase_orders.length > 0) {
                const poValues = snapshot.purchase_orders.map(po => [
                    po.id, po.po_id, po.vendor, po.date, po.expected_date,
                    po.product_id, po.sku, po.cost_price, po.status, po.notes,
                    po.ordered, po.received, po.received_date
                ]);
                await connection.query(
                    'INSERT INTO purchase_orders VALUES ?',
                    [poValues]
                );
            }
            
            await connection.commit();
            
            console.log('Snapshot restored successfully:');
            console.log('Products:', snapshot.products.length);
            console.log('Orders:', snapshot.orders.length);
            console.log('Purchase Orders:', snapshot.purchase_orders.length);
            console.log('Categories:', snapshot.categories.length);
            
        } catch (error) {
            await connection.rollback();
            throw error;
        } finally {
            connection.release();
        }
    } catch (error) {
        console.error('Error restoring snapshot:', error);
        throw error;
    } finally {
        await pool.end();
    }
}

// Restore snapshot if run directly
if (require.main === module) {
    restoreSnapshot().catch(console.error);
}

module.exports = { restoreSnapshot };