const sqlite3 = require('sqlite3').verbose();
const fs = require('fs');
const path = require('path');
const util = require("util");

function runMigrations(db) {
    return new Promise((resolve, reject) => {
        const migrationDir = path.join(__dirname, 'migrations');

        const runQuery = util.promisify(db.run.bind(db));
        const getQuery = util.promisify(db.get.bind(db));

        // Ensure a migrations table exists to track applied migrations
        runQuery(`CREATE TABLE IF NOT EXISTS migrations (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT NOT NULL,
            applied_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
        );`)
            .then(() => {
                // Read all migration files
                const files = fs.readdirSync(migrationDir).sort(); // Sort to apply in order

                return files.reduce((promise, file) => {
                    return promise.then(() => {
                        const migrationName = path.basename(file);

                        // Check if the migration has already been applied
                        return getQuery(
                            'SELECT 1 FROM migrations WHERE name = ? LIMIT 1',
                            [migrationName]
                        ).then((row) => {
                            if (row) {
                                // console.log(`Skipping already applied migration: ${migrationName}`);
                                return; // Skip this migration
                            }

                            // Read and execute the migration SQL
                            const migrationPath = path.join(migrationDir, file);
                            const sql = fs.readFileSync(migrationPath, 'utf8');

                            return runQuery(sql).then(() => {
                                // Record the applied migration
                                return runQuery(
                                    'INSERT INTO migrations (name) VALUES (?)',
                                    [migrationName]
                                ).then(() => {
                                    console.log(`Applied migration: ${migrationName}`);
                                });
                            });
                        });
                    });
                }, Promise.resolve());
            })
            .then(() => {
                console.log('All migrations applied successfully!');
                resolve();
            })
            .catch((err) => {
                console.error('Error running migrations:', err);
                reject(err);
            })
    });
}

module.exports = runMigrations;