<?php

namespace App\RSpade\Commands\Migrate;

use Illuminate\Console\Command;
use Illuminate\Support\Facades\DB;
use Symfony\Component\Process\Process;
use Symfony\Component\Process\Exception\ProcessFailedException;

class Migrate_Begin_Command extends Command
{
    use PrivilegedCommandTrait;
    protected $signature = 'migrate:begin';
    protected $description = 'Begin a migration session by creating a MySQL snapshot';
    
    protected $mysql_data_dir = '/var/lib/mysql';
    protected $backup_dir = '/var/lib/mysql_backup';
    protected $flag_file = '/var/www/html/.migrating';
    
    public function handle()
    {
        // Check if already in migration mode
        if (file_exists($this->flag_file)) {
            $flag_data = json_decode(file_get_contents($this->flag_file), true);
            $started_at = $flag_data['started_at'] ?? 'unknown time';
            
            $this->info('[OK] Migration session already active!');
            $this->info('');
            $this->line(' Session started at: ' . $started_at);
            $this->line(' Snapshot available at: ' . $this->backup_dir);
            $this->info('');
            $this->line('You are currently in migration mode with an active snapshot.');
            $this->line('There is no need to create another snapshot.');
            $this->info('');
            $this->line('Your options:');
            $this->info('');
            $this->line('1.  Continue creating/running migrations:');
            $this->line('   php artisan migrate');
            $this->info('');
            $this->line('2. [OK] Keep all changes and exit migration mode:');
            $this->line('   php artisan migrate:commit');
            $this->line('   (After commit, run migrate:begin again for new atomic migrations)');
            $this->info('');
            $this->line('3. ⏪ Discard all changes since snapshot and exit migration mode:');
            $this->line('   php artisan migrate:rollback');
            $this->line('   (Database will be restored to state at ' . $started_at . ')');
            $this->info('');
            $this->warn('[WARNING]  The web UI remains disabled while in migration mode.');
            return 0;  // Return success since we're providing helpful information
        }
        
        // Check if running in production
        if (app()->environment('production')) {
            $this->error('[WARNING]  This command is not available in production!');
            $this->info('Snapshot-based migrations are only for development environments.');
            $this->info('In production, run migrations directly with: php artisan migrate');
            return 1;
        }
        
        // Check if running in Docker environment
        if (!file_exists('/.dockerenv')) {
            $this->error('[WARNING]  This command requires Docker environment!');
            $this->info('Snapshot-based migrations are only available in Docker development environments.');
            return 1;
        }
        
        $this->info(' Starting migration snapshot process...');
        
        try {
            // Step 1: Stop MySQL using supervisorctl
            $this->info('[1]  Stopping MySQL server...');
            $this->shell_exec_privileged('supervisorctl stop mysql 2>&1');
            
            // Wait a moment for process to die
            sleep(3);
            
            // Step 2: Remove old backup if exists
            if (is_dir($this->backup_dir)) {
                $this->info('[2]  Removing old backup...');
                $this->run_privileged_command(['rm', '-rf', $this->backup_dir]);
            }

            // Step 3: Copy MySQL data directory
            $this->info('[3]  Creating snapshot of MySQL data...');
            $this->run_privileged_command(['cp', '-r', $this->mysql_data_dir, $this->backup_dir]);
            
            // Step 4: Start MySQL again using supervisorctl
            $this->info('[4]  Starting MySQL server...');
            $this->shell_exec_privileged('supervisorctl start mysql 2>&1');
            
            // Step 5: Wait for MySQL to be ready
            $this->info('[5]  Waiting for MySQL to be ready...');
            $this->wait_for_mysql_ready();
            
            // Step 6: Create migration flag file
            $this->info('[6]  Creating migration flag...');
            file_put_contents($this->flag_file, json_encode([
                'started_at' => now()->toIso8601String(),
                'started_by' => get_current_user(),
                'backup_dir' => $this->backup_dir,
            ], JSON_PRETTY_PRINT));
            
            // Success message
            $this->info('');
            $this->info('[OK] Database snapshot created successfully!');
            $this->info('');
            $this->line(' Migration session is now active. You can:');
            $this->line('   • Run migrations: php artisan migrate');
            $this->line('   • Commit changes: php artisan migrate:commit');
            $this->line('   • Rollback changes: php artisan migrate:rollback');
            $this->info('');
            
            // Migration best practices for LLMs
            $this->warn('[WARNING]  MIGRATION GUIDELINES FOR LLMs:');
            $this->line('');
            $this->line('     * Use RAW MySQL queries, not Laravel schema builder:');
            $this->line('      [OK] DB::statement("ALTER TABLE users ADD COLUMN age INT")');
            $this->line('      [ERROR] Schema::table("users", function($table) { $table->integer("age"); })');
            $this->line('');
            $this->line('     * ALL tables MUST have BIGINT ID primary key:');
            $this->line('      [OK] id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY');
            $this->line('      [ERROR] No exceptions - every table needs this exact ID column (SIGNED for easier migrations)');
            $this->line('');
            $this->line('     * Integer column types:');
            $this->line('      [OK] BIGINT for all integers (IDs, counts, foreign keys, etc.)');
            $this->line('      [OK] TINYINT(1) for boolean values (true/false only)');
            $this->line('      [ERROR] NEVER use unsigned - always use signed integers');
            $this->line('      [ERROR] NEVER use INT - always use BIGINT for consistency');
            $this->line('');
            $this->line('     * Migrations must be SELF-CONTAINED:');
            $this->line('      • Use direct table names, not Model references');
            $this->line('      • Use raw DB queries, not ORM/QueryBuilder');
            $this->line('      • Never import Models or Services');
            $this->line('');
            $this->line('     * Examples of GOOD migration code:');
            $this->line('      DB::statement("CREATE TABLE posts (');
            $this->line('          id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY,');
            $this->line('          title VARCHAR(255)');
            $this->line('      )")');
            $this->line('      DB::statement("UPDATE users SET status = \'active\' WHERE created_at < NOW()")');
            $this->line('');
            $this->line('     * Target: MySQL only (no need for database abstraction)');
            $this->info('');
            $this->warn('[WARNING]  The web UI is disabled during migration mode.');
            
            return 0;
            
        } catch (\Exception $e) {
            $this->error('[ERROR] Failed to create snapshot: ' . $e->getMessage());

            // Try to restart MySQL if it's stopped
            $this->info('Attempting to restart MySQL...');
            $this->shell_exec_privileged('supervisorctl start mysql 2>&1');

            return 1;
        }
    }
    
    /**
     * Wait for MySQL to be ready for connections
     */
    protected function wait_for_mysql_ready(): void
    {
        $max_attempts = 120;
        $attempt = 0;
        
        while ($attempt < $max_attempts) {
            // Use mysql client to test connection (similar to user's approach)
            $result = shell_exec("echo \"SELECT 'test';\" | mysql -uroot 2>/dev/null | grep test");
            
            if ($result !== null && str_contains($result, 'test')) {
                return;
            }
            
            sleep(1);
            $attempt++;
        }
        
        throw new \Exception('MySQL did not start within 120 seconds');
    }
}