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 createSnapshot() {
    console.log('Creating test database snapshot...');
    const pool = mysql.createPool(dbConfig);
    
    try {
        const connection = await pool.getConnection();
        try {
            // Create snapshots directory if it doesn't exist
            if (!fs.existsSync(SNAPSHOTS_DIR)) {
                fs.mkdirSync(SNAPSHOTS_DIR, { recursive: true });
            }
            
            // Get categories
            const [categories] = await connection.query(`
                SELECT id, name, created_at
                FROM categories
                LIMIT 10
            `);
            
            // Get a diverse set of ~100 products
            const [products] = await connection.query(`
                SELECT p.*
                FROM products p
                WHERE EXISTS (
                    SELECT 1 FROM orders o WHERE o.product_id = p.product_id
                    UNION
                    SELECT 1 FROM purchase_orders po WHERE po.product_id = p.product_id
                )
                ORDER BY RAND()
                LIMIT 100
            `);
            
            // Get product_categories for selected products
            const [product_categories] = await connection.query(`
                SELECT pc.product_id, pc.category_id
                FROM product_categories pc
                WHERE pc.product_id IN (?)
            `, [products.map(p => p.product_id)]);
            
            // Get orders for selected products (last 6 months)
            const [orders] = await connection.query(`
                SELECT o.*
                FROM orders o
                WHERE o.product_id IN (?)
                AND o.date >= DATE_SUB(NOW(), INTERVAL 6 MONTH)
                ORDER BY o.date DESC
            `, [products.map(p => p.product_id)]);
            
            // Get purchase orders for selected products (last 6 months)
            const [purchase_orders] = await connection.query(`
                SELECT po.*
                FROM purchase_orders po
                WHERE po.product_id IN (?)
                AND po.date >= DATE_SUB(NOW(), INTERVAL 6 MONTH)
                ORDER BY po.date DESC
            `, [products.map(p => p.product_id)]);
            
            // Create snapshot object
            const snapshot = {
                metadata: {
                    created_at: new Date().toISOString(),
                    description: 'Test snapshot with ~100 diverse products and their related data'
                },
                categories,
                products,
                product_categories,
                orders,
                purchase_orders
            };
            
            // Save snapshot
            const snapshotPath = path.join(SNAPSHOTS_DIR, 'test_snapshot.json');
            fs.writeFileSync(snapshotPath, JSON.stringify(snapshot, null, 2));
            
            console.log('Snapshot created successfully:');
            console.log('Products:', products.length);
            console.log('Orders:', orders.length);
            console.log('Purchase Orders:', purchase_orders.length);
            console.log('Categories:', categories.length);
            console.log('Saved to:', snapshotPath);
            
        } finally {
            connection.release();
        }
    } catch (error) {
        console.error('Error creating snapshot:', error);
        throw error;
    } finally {
        await pool.end();
    }
}

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

module.exports = { createSnapshot };