import { NextRequest, NextResponse } from 'next/server';
import { Pool } from 'pg';

const pool = new Pool({
  connectionString: process.env.DATABASE_URL,
  ssl: process.env.NODE_ENV === 'production' ? { rejectUnauthorized: false } : false,
});

export default async function handler(req: NextRequest) {
  if (req.method !== 'POST') {
    return new NextResponse(JSON.stringify({ error: 'Method not allowed' }), {
      status: 405,
      headers: { 'Content-Type': 'application/json' },
    });
  }

  const client = await pool.connect();
  
  try {
    console.log('Setting up user authentication schema...');

    // Check if users table already exists
    const tableCheck = await client.query(`
      SELECT EXISTS (
        SELECT FROM information_schema.tables 
        WHERE table_schema = 'public' 
        AND table_name = 'users'
      );
    `);

    if (tableCheck.rows[0].exists) {
      return new NextResponse(JSON.stringify({
        success: true,
        message: 'User authentication schema already exists',
        already_setup: true
      }), {
        status: 200,
        headers: { 'Content-Type': 'application/json' },
      });
    }

    // Create tables one by one
    await client.query(`
      CREATE TABLE IF NOT EXISTS users (
          id SERIAL PRIMARY KEY,
          username VARCHAR(50) UNIQUE NOT NULL,
          email VARCHAR(100) UNIQUE NOT NULL,
          password_hash VARCHAR(255) NOT NULL,
          first_name VARCHAR(50),
          last_name VARCHAR(50),
          avatar_url TEXT,
          is_active BOOLEAN DEFAULT true,
          email_verified BOOLEAN DEFAULT false,
          created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
          updated_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
          last_login TIMESTAMP WITH TIME ZONE
      );
    `);

    await client.query(`
      CREATE TABLE IF NOT EXISTS roles (
          id SERIAL PRIMARY KEY,
          name VARCHAR(50) UNIQUE NOT NULL,
          description TEXT,
          created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
      );
    `);

    await client.query(`
      CREATE TABLE IF NOT EXISTS user_roles (
          id SERIAL PRIMARY KEY,
          user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
          role_id INTEGER REFERENCES roles(id) ON DELETE CASCADE,
          assigned_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
          assigned_by INTEGER REFERENCES users(id),
          UNIQUE(user_id, role_id)
      );
    `);

    await client.query(`
      CREATE TABLE IF NOT EXISTS permissions (
          id SERIAL PRIMARY KEY,
          name VARCHAR(100) UNIQUE NOT NULL,
          description TEXT,
          resource VARCHAR(50),
          action VARCHAR(50),
          created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
      );
    `);

    await client.query(`
      CREATE TABLE IF NOT EXISTS role_permissions (
          id SERIAL PRIMARY KEY,
          role_id INTEGER REFERENCES roles(id) ON DELETE CASCADE,
          permission_id INTEGER REFERENCES permissions(id) ON DELETE CASCADE,
          UNIQUE(role_id, permission_id)
      );
    `);

    await client.query(`
      CREATE TABLE IF NOT EXISTS user_sessions (
          id SERIAL PRIMARY KEY,
          user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
          token_hash VARCHAR(255) NOT NULL,
          expires_at TIMESTAMP WITH TIME ZONE NOT NULL,
          created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
          last_used TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
          user_agent TEXT,
          ip_address INET
      );
    `);

    // Insert default roles
    await client.query(`
      INSERT INTO roles (name, description) VALUES 
          ('user', 'Standard user with basic permissions'),
          ('admin', 'Administrator with full system access')
      ON CONFLICT (name) DO NOTHING;
    `);

    // Insert basic permissions
    const permissions = [
      ['cards.read', 'View cards'],
      ['collections.manage', 'Manage collections'],
      ['decks.manage', 'Manage decks'],
      ['admin.access', 'Access admin panel']
    ];

    for (const [name, description] of permissions) {
      await client.query(`
        INSERT INTO permissions (name, description) 
        VALUES ($1, $2)
        ON CONFLICT (name) DO NOTHING;
      `, [name, description]);
    }

    // Assign permissions to roles
    await client.query(`
      INSERT INTO role_permissions (role_id, permission_id)
      SELECT r.id, p.id 
      FROM roles r, permissions p 
      WHERE r.name = 'user' 
      AND p.name IN ('cards.read', 'collections.manage', 'decks.manage')
      ON CONFLICT (role_id, permission_id) DO NOTHING;
    `);

    await client.query(`
      INSERT INTO role_permissions (role_id, permission_id)
      SELECT r.id, p.id 
      FROM roles r, permissions p 
      WHERE r.name = 'admin'
      ON CONFLICT (role_id, permission_id) DO NOTHING;
    `);

    // Create indexes
    await client.query(`
      CREATE INDEX IF NOT EXISTS idx_users_email ON users(email);
      CREATE INDEX IF NOT EXISTS idx_users_username ON users(username);
      CREATE INDEX IF NOT EXISTS idx_user_roles_user_id ON user_roles(user_id);
    `);

    console.log('✅ User authentication schema setup completed!');

    return new NextResponse(JSON.stringify({
      success: true,
      message: 'User authentication schema setup completed successfully'
    }), {
      status: 200,
      headers: { 'Content-Type': 'application/json' },
    });

  } catch (error) {
    console.error('Schema setup failed:', error);
    return new NextResponse(JSON.stringify({ 
      success: false,
      error: 'Schema setup failed',
      details: (error as Error).message
    }), {
      status: 500,
      headers: { 'Content-Type': 'application/json' },
    });
  } finally {
    client.release();
  }
}