#!/usr/bin/env node

const sqlite3 = require('sqlite3').verbose();
const path = require('path');

console.log('🔄 Starting Instagram to Facebook schema migration...');

// Open database
const dbPath = path.join(__dirname, 'water_stations.db');
const db = new sqlite3.Database(dbPath);

db.serialize(() => {
  console.log('📋 Checking current database schema...');
  
  // Check if instagram_id column exists
  db.all("PRAGMA table_info(users)", (err, columns) => {
    if (err) {
      console.error('❌ Error checking table schema:', err);
      process.exit(1);
    }
    
    const hasInstagramId = columns.some(col => col.name === 'instagram_id');
    const hasFacebookId = columns.some(col => col.name === 'facebook_id');
    
    console.log(`📊 Current schema status:`);
    console.log(`   - instagram_id column exists: ${hasInstagramId}`);
    console.log(`   - facebook_id column exists: ${hasFacebookId}`);
    
    if (!hasInstagramId && hasFacebookId) {
      console.log('✅ Migration already completed! Database is up to date.');
      db.close();
      return;
    }
    
    if (hasInstagramId) {
      // Count Instagram users before migration
      db.get('SELECT COUNT(*) as count FROM users WHERE instagram_id IS NOT NULL', (err, row) => {
        if (err) {
          console.error('❌ Error counting Instagram users:', err);
          process.exit(1);
        }
        
        const instagramUserCount = row.count;
        console.log(`📊 Found ${instagramUserCount} Instagram users in database`);
        
        if (instagramUserCount > 0) {
          console.log('⚠️  WARNING: Instagram OAuth is no longer supported.');
          console.log('   These users will need to register again using Facebook or Google OAuth,');
          console.log('   or create a username/password account.');
        }
        
        performMigration(hasFacebookId, instagramUserCount);
      });
    } else {
      console.log('📄 No instagram_id column found, performing clean schema update...');
      performMigration(hasFacebookId, 0);
    }
  });
  
  function performMigration(hasFacebookId, instagramUserCount) {
    console.log('\n🔧 Performing database migration...');
    
    // Add facebook_id column if it doesn't exist
    if (!hasFacebookId) {
      console.log('➕ Adding facebook_id column...');
      db.run('ALTER TABLE users ADD COLUMN facebook_id TEXT', (err) => {
        if (err) {
          console.error('❌ Error adding facebook_id column:', err);
          process.exit(1);
        }
        
        console.log('✅ facebook_id column added successfully');
        dropInstagramColumn(instagramUserCount);
      });
    } else {
      dropInstagramColumn(instagramUserCount);
    }
  }
  
  function dropInstagramColumn(instagramUserCount) {
    // Check if instagram_id column exists before trying to drop it
    db.all("PRAGMA table_info(users)", (err, columns) => {
      if (err) {
        console.error('❌ Error checking table schema:', err);
        process.exit(1);
      }
      
      const hasInstagramId = columns.some(col => col.name === 'instagram_id');
      
      if (hasInstagramId) {
        console.log('🗑️  Removing deprecated instagram_id column...');
        
        // SQLite doesn't support DROP COLUMN directly, so we need to recreate the table
        const createNewTableSQL = `
          CREATE TABLE users_new (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            username TEXT UNIQUE,
            email TEXT UNIQUE,
            password_hash TEXT,
            google_id TEXT,
            facebook_id TEXT,
            display_name TEXT,
            created_at DATETIME DEFAULT CURRENT_TIMESTAMP
          )
        `;
        
        db.run(createNewTableSQL, (err) => {
          if (err) {
            console.error('❌ Error creating new users table:', err);
            process.exit(1);
          }
          
          // Copy data from old table to new table (excluding instagram_id)
          const copyDataSQL = `
            INSERT INTO users_new (id, username, email, password_hash, google_id, facebook_id, display_name, created_at)
            SELECT id, username, email, password_hash, google_id, NULL, display_name, created_at
            FROM users
          `;
          
          db.run(copyDataSQL, (err) => {
            if (err) {
              console.error('❌ Error copying data to new table:', err);
              process.exit(1);
            }
            
            // Drop old table and rename new table
            db.run('DROP TABLE users', (err) => {
              if (err) {
                console.error('❌ Error dropping old users table:', err);
                process.exit(1);
              }
              
              db.run('ALTER TABLE users_new RENAME TO users', (err) => {
                if (err) {
                  console.error('❌ Error renaming new users table:', err);
                  process.exit(1);
                }
                
                completeMigration(instagramUserCount);
              });
            });
          });
        });
      } else {
        completeMigration(instagramUserCount);
      }
    });
  }
  
  function completeMigration(instagramUserCount) {
    console.log('\n✅ Database migration completed successfully!');
    console.log('\n📊 Migration Summary:');
    console.log('   ✅ facebook_id column added');
    console.log('   ✅ instagram_id column removed (deprecated)');
    
    if (instagramUserCount > 0) {
      console.log(`   ⚠️  ${instagramUserCount} Instagram users will need to re-register`);
      console.log('\n📝 Next Steps:');
      console.log('   1. Set up Facebook OAuth credentials in your .env file');
      console.log('   2. Notify existing Instagram users to register with Facebook/Google OAuth');
      console.log('   3. Consider adding a migration notice in your app UI');
    }
    
    console.log('\n🎉 Your database is now ready for Facebook OAuth!');
    
    db.close((err) => {
      if (err) {
        console.error('❌ Error closing database:', err);
        process.exit(1);
      }
      process.exit(0);
    });
  }
});