const bcrypt = require('bcrypt');
const { initializeDatabase } = require('../../src/database/db');
const { generateReadablePassword } = require('../../src/utils/passwordGenerator');
const fs = require('fs').promises;
const path = require('path');

exports.up = async function(knex) {
  console.log('Initializing database schema...');
  
  try {
    // Initialize tables
    await initializeDatabase();
    
    // Create default admin user if none exists.
    //
    // Legacy path — only when ADMIN_PASSWORD is explicitly provided (keeps
    // existing docker-compose installs working unchanged). When it is NOT set,
    // we deliberately leave admin_users empty so the first-run setup wizard
    // (setupService / /setup) creates the admin in-browser — no ADMIN_PASSWORD
    // in .env. Existing deployments already ran this migration, so this only
    // affects fresh installs.
    const adminExists = await knex('admin_users').first();
    if (!adminExists && process.env.ADMIN_PASSWORD) {
      // Use ADMIN_PASSWORD from environment if set, otherwise generate a random one
      const generatedPassword = process.env.ADMIN_PASSWORD || generateReadablePassword();
      const passwordHash = await bcrypt.hash(generatedPassword, 12); // Increased rounds for better security
      
      // Get admin credentials from environment or use defaults
      const adminUsername = process.env.ADMIN_USERNAME || 'admin';
      const adminEmail = process.env.ADMIN_EMAIL || 'admin@example.com';
      
      await knex('admin_users').insert({
        username: adminUsername,
        email: adminEmail,
        password_hash: passwordHash,
        must_change_password: true,
        created_at: new Date()
      });
      
      // Try to save credentials to file, but don't fail if we can't
      const dataDir = path.join(__dirname, '..', '..', 'data');
      const setupInfoPath = path.join(dataDir, 'ADMIN_CREDENTIALS.txt');

      // Detect a pending install-from-backup trigger. If one exists,
      // these credentials are about to be obsoleted by the restore —
      // the backup's admin row replaces this fresh-install one a few
      // seconds from now. We still write the file (in case the
      // restore fails and the fresh admin is the only way in) but
      // annotate the top so admins reading the file after restore
      // don't waste time trying credentials that no longer exist.
      // Flagged on PR #596 review.
      const fsSync = require('fs');
      const backupRoot = process.env.BACKUP_ROOT || '/backup';
      const triggerWillFire = fsSync.existsSync(path.join(backupRoot, 'RESTORE_ON_INSTALL'))
        || fsSync.existsSync(path.join(backupRoot, 'RESTORE_ON_INSTALL.txt'));
      const restoreNotice = triggerWillFire ? `

⚠️  RESTORE_ON_INSTALL TRIGGER DETECTED ⚠️
These credentials are temporary. An install-from-backup run is queued
to fire on the next server start, which will REPLACE this admin row
with the one from the backup. After the restore completes, log in
with your ORIGINAL pre-disaster credentials — not the ones below.
If the restore fails for some reason, the credentials below remain
valid as a fallback recovery path.
` : '';

      const setupInfo = `
========================================
PicPeak Admin Credentials
========================================${restoreNotice}

Your admin account has been created with these credentials:

Email: ${adminEmail}
Password: ${generatedPassword}

IMPORTANT SECURITY NOTES:
1. Please change this password after first login
2. This file will be created only once
3. Store these credentials securely
4. Delete this file after noting the password

Login URL: ${process.env.ADMIN_URL || 'http://localhost:3001'}/admin

Login with the email address shown above

Generated on: ${new Date().toISOString()}
========================================
`;
      
      try {
        // Try to create directory and write file
        await fs.mkdir(dataDir, { recursive: true });
        await fs.writeFile(setupInfoPath, setupInfo, 'utf8');
        console.log(`📁 Credentials also saved to: data/ADMIN_CREDENTIALS.txt`);
      } catch (error) {
        // If we can't write the file, that's okay - credentials are shown in console
        console.log('⚠️  Could not save credentials to file (permission denied)');
        console.log('   Please copy the credentials shown above');
      }
      
      console.log('\n========================================');
      console.log('✅ Admin user created successfully!');
      console.log('========================================');
      console.log(`Email: ${adminEmail}`);
      console.log(`Password: ${generatedPassword}`);
      console.log('\n⚠️  IMPORTANT:');
      console.log('1. Save these credentials securely');
      console.log('2. Please change the password after first login');
      console.log('========================================\n');
    }
    
    // Create default email templates if none exist
    const templateExists = await knex('email_templates').first();
    if (!templateExists) {
      await knex('email_templates').insert([
        {
          template_key: 'gallery_created',
          subject: 'Your Photo Gallery is Ready!',
          body_html: `<h2>Gallery Created Successfully</h2>
<p>Dear {{host_name}},</p>
<p>Your photo gallery "{{event_name}}" has been created successfully!</p>
<p><strong>Gallery Details:</strong></p>
<ul>
  <li>Event Date: {{event_date}}</li>
  <li>Gallery Link: {{gallery_link}}</li>
  <li>Password: {{gallery_password}}</li>
  <li>Expires: {{expiry_date}}</li>
</ul>
<p>Share this link and password with your guests to allow them to view and download photos.</p>`,
          body_text: 'Gallery Created Successfully\n\nDear {{host_name}},\n\nYour photo gallery "{{event_name}}" has been created successfully!',
          variables: JSON.stringify(['host_name', 'event_name', 'event_date', 'gallery_link', 'gallery_password', 'expiry_date'])
        },
        {
          template_key: 'expiration_warning',
          subject: 'Your Photo Gallery Expires Soon',
          body_html: `<h2>Gallery Expiring Soon</h2>
<p>Dear {{host_name}},</p>
<p>Your photo gallery "{{event_name}}" will expire in {{days_remaining}} days.</p>
<p>After expiration, the gallery will be archived and no longer accessible to guests.</p>
<p><a href="{{gallery_link}}">Visit Gallery</a></p>`,
          body_text: 'Gallery Expiring Soon\n\nDear {{host_name}},\n\nYour photo gallery "{{event_name}}" will expire in {{days_remaining}} days.',
          variables: JSON.stringify(['host_name', 'event_name', 'days_remaining', 'gallery_link'])
        }
      ]);
      console.log('Default email templates created');
    }

    // Seed an email config ONLY when the environment actually supplies a host
    // (#705). This used to fall back to `mailhog`, the dev compose service, so
    // every fresh install came up with a LIVE config pointing at a host that
    // does not exist outside the dev stack — the setup wizard then showed empty
    // SMTP fields (reading as "nothing configured") while mail silently failed.
    // With no row at all, emailProcessor logs "No email configuration found"
    // and the wizard's blank fields are the truth. The dev stack keeps mailhog
    // by setting SMTP_HOST explicitly in docker-compose.yml.
    const emailConfig = await knex('email_configs').first();
    if (!emailConfig && process.env.SMTP_HOST) {
      await knex('email_configs').insert({
        smtp_host: process.env.SMTP_HOST,
        smtp_port: process.env.SMTP_PORT || 1025,
        smtp_secure: process.env.SMTP_SECURE === 'true',
        smtp_user: process.env.SMTP_USER || '',
        smtp_pass: process.env.SMTP_PASS || '',
        from_email: process.env.EMAIL_FROM || 'noreply@photo-sharing.local',
        from_name: 'Photo Sharing'
      });
      console.log('Default email configuration created');
    }

    console.log('Migrations completed successfully');
  } catch (error) {
    console.error('Initial setup failed:', error);
    throw error;
  }
};

exports.down = async function(knex) {
  // This migration cannot be rolled back as it creates the initial schema
  console.log('Initial setup cannot be rolled back');
};