<?php
/**
 * CODING CONVENTION:
 * This file follows the coding convention where variable_names and function_names
 * use snake_case (underscore_wherever_possible).
 */

namespace App\RSpade\Commands\Rsx;

use Illuminate\Console\Command;
use Symfony\Component\Process\Process;
use Illuminate\Support\Facades\Redis;
use App\RSpade\Core\Bootstrap\ManifestKernel;

/**
 * RSX SSR Full Page Cache (FPC) Create Command
 * ==============================================
 *
 * PURPOSE:
 * Generates static, pre-rendered HTML cache for routes marked with #[Static_Page] attribute.
 * Uses Playwright to render pages in headless Chrome, capturing the fully-rendered DOM state
 * for optimal SEO and performance.
 *
 * HOW IT WORKS:
 * 1. Launches headless Chromium browser via Playwright
 * 2. Navigates to the specified route with FPC generation headers
 * 3. Waits for _debug_ready event (all components initialized)
 * 4. Waits for network idle + 10ms buffer
 * 5. Captures full DOM or redirect response
 * 6. Generates ETag from build_key + URL + content hash
 * 7. Stores in Redis: ssr_fpc:{build_key}:{url_hash}
 *
 * KEY FEATURES:
 * - Exclusive lock (GENERATE_STATIC_CACHE) prevents concurrent generation
 * - Strips GET parameters from URLs (static pages ignore query strings)
 * - Handles redirect responses (caches 302 location without following)
 * - Build key integration (auto-invalidates cache on deployment)
 * - Comprehensive error logging to storage/logs/ssr-fpc-errors.log
 *
 * DESIGN GOALS:
 * - SEO-optimized static pages for unauthenticated users
 * - Fail-loud approach (fatal exception if generation fails)
 * - Cache key includes build_key for automatic invalidation
 * - Development only tool (production uses pre-generated cache)
 *
 * USAGE EXAMPLES:
 * php artisan rsx:ssr_fpc:create /                  # Cache homepage
 * php artisan rsx:ssr_fpc:create /about             # Cache about page
 * php artisan rsx:ssr_fpc:create /products/view/123 # Cache dynamic route
 *
 * FUTURE ROADMAP:
 * - Support for --from-sitemap to generate all pages from sitemap.xml
 * - Shared private key for FPC client authentication
 * - External service for distributed cache generation
 * - Parallelization for faster multi-page generation
 * - Programmatic cache reset hooks (CMS updates, blog posts)
 *
 * IMPLEMENTATION DETAILS:
 * - Uses X-RSpade-FPC-Client header to identify cache generation requests
 * - Playwright script located in resource/playwright/generate-static-cache.js
 * - Cache stored as JSON: {url, code, page_dom/redirect, build_key, etag, generated_at}
 * - ETag is first 30 chars of SHA1(build_key + url + content)
 * - Redis key format: ssr_fpc:{build_key}:{sha1(url)}
 *
 * SECURITY:
 * - Only available in local/development/testing environments
 * - Throws fatal error if attempted in production
 * - FPC bypass header prevents cache serving during generation
 */
class Ssr_Fpc_Create_Command extends Command
{
    /**
     * The name and signature of the console command.
     *
     * @var string
     */
    protected $signature = 'rsx:ssr_fpc:create
        {url : The URL to generate static cache for (e.g., /about, /products)}';

    /**
     * The console command description.
     *
     * @var string
     */
    protected $description = 'Generate static page cache for SSR FPC system (development only)';

    /**
     * Execute the console command.
     */
    public function handle()
    {
        // Check environment - throw fatal error in production
        if (app()->environment('production')) {
            throw new \RuntimeException('FATAL: rsx:ssr_fpc:create command is not available in production environment. This is a development-only tool.');
        }

        // Check if SSR FPC is enabled
        if (!config('rsx.ssr_fpc.enabled', false)) {
            $this->error('SSR FPC is disabled. Enable it in config/rsx.php or set SSR_FPC_ENABLED=true in .env');
            return 1;
        }

        // Get the URL to generate cache for
        $url = $this->argument('url');

        // Strip query parameters from URL (static pages ignore query strings)
        $url = parse_url($url, PHP_URL_PATH) ?: $url;

        // Ensure URL starts with /
        if (!str_starts_with($url, '/')) {
            $url = '/' . $url;
        }

        $this->info("Generating static cache for: {$url}");

        // Check if Playwright script exists
        $playwright_script = base_path('app/RSpade/Commands/Rsx/resource/playwright/generate-static-cache.js');
        if (!file_exists($playwright_script)) {
            $this->error("❌ Playwright script not found: {$playwright_script}");
            $this->error('Please create the script or check your installation');
            return 1;
        }

        // Check if node/npm is available
        $node_check = new Process(['node', '--version']);
        $node_check->run();

        if (!$node_check->isSuccessful()) {
            $this->error('❌ Node.js is not installed or not in PATH');
            return 1;
        }

        // Check if playwright is installed
        $playwright_check = new Process(['node', '-e', "require('playwright')"], base_path());
        $playwright_check->run();

        if (!$playwright_check->isSuccessful()) {
            $this->warn('⚠️  Playwright not installed. Installing now...');
            $npm_install = new Process(['npm', 'install', 'playwright'], base_path());
            $npm_install->run(function ($type, $buffer) {
                echo $buffer;
            });

            if (!$npm_install->isSuccessful()) {
                $this->error('❌ Failed to install Playwright');
                return 1;
            }
            $this->info('✅ Playwright installed');
            $this->info('');
        }

        // Check if chromium browser is installed and up to date
        $browser_check_script = "const {chromium} = require('playwright'); chromium.launch({headless:true}).then(b => {b.close(); process.exit(0);}).catch(e => {console.error(e.message); process.exit(1);});";
        $browser_check = new Process(['node', '-e', $browser_check_script], base_path(), $_ENV, null, 10);
        $browser_check->run();

        if (!$browser_check->isSuccessful()) {
            $error_output = $browser_check->getErrorOutput() . $browser_check->getOutput();

            // Check if it's a browser not installed or out of date error
            if (str_contains($error_output, "Executable doesn't exist") ||
                str_contains($error_output, "browserType.launch") ||
                str_contains($error_output, "Playwright was just installed or updated")) {

                $this->info('Installing/updating Chromium browser...');
                $browser_install = new Process(['npx', 'playwright', 'install', 'chromium'], base_path());
                $browser_install->setTimeout(300); // 5 minute timeout for download
                $browser_install->run(function ($type, $buffer) {
                    // Silent - downloads can be verbose
                });

                if (!$browser_install->isSuccessful()) {
                    $this->error('❌ Failed to install Chromium browser');
                    $this->error('Run manually: npx playwright install chromium');
                    return 1;
                }
                $this->info('✅ Chromium browser installed/updated');
                $this->info('');
            } else {
                $this->error('❌ Browser check failed: ' . trim($error_output));
                return 1;
            }
        }

        // Get timeout from config
        $timeout = config('rsx.ssr_fpc.generation_timeout', 30000);

        // Build command arguments
        $command_args = ['node', $playwright_script, $url, "--timeout={$timeout}"];

        $env = array_merge($_ENV, [
            'BASE_URL' => config('app.url')
        ]);

        // Convert timeout from milliseconds to seconds for Process timeout
        // Add 10 seconds buffer to the Process timeout to allow Playwright to timeout first
        $process_timeout = ($timeout / 1000) + 10;

        // Release the application lock before running Playwright to prevent lock contention
        // The artisan command holds a WRITE lock which would block the web request's READ lock
        \App\RSpade\Core\Bootstrap\RsxBootstrap::temporarily_release_lock();

        $process = new Process(
            $command_args,
            base_path(),
            $env,
            null,
            $process_timeout
        );

        $output = '';
        $process->run(function ($type, $buffer) use (&$output) {
            echo $buffer;
            $output .= $buffer;
        });

        if (!$process->isSuccessful()) {
            $this->error('❌ Failed to generate static cache');
            $this->error('Check storage/logs/ssr-fpc-errors.log for details');
            return 1;
        }

        // Parse JSON output from Playwright script
        try {
            $result = json_decode($output, true);
            if (!$result) {
                throw new \Exception('Invalid JSON response from Playwright');
            }
        } catch (\Exception $e) {
            $this->error('❌ Failed to parse Playwright output: ' . $e->getMessage());
            $this->error('Raw output: ' . $output);
            return 1;
        }

        // Get build key from manifest
        $build_key = \App\RSpade\Core\Manifest\Manifest::get_build_key();

        // Generate Redis cache key
        $url_hash = sha1($url);
        $redis_key = "ssr_fpc:{$build_key}:{$url_hash}";

        // Generate ETag (first 30 chars of SHA1)
        $content_for_etag = $build_key . $url . ($result['page_dom'] ?? $result['redirect'] ?? '');
        $etag = substr(sha1($content_for_etag), 0, 30);

        // Build cache entry
        $cache_entry = [
            'url' => $url,
            'code' => $result['code'],
            'build_key' => $build_key,
            'etag' => $etag,
            'generated_at' => time(),
        ];

        if ($result['code'] >= 300 && $result['code'] < 400) {
            // Redirect response
            $cache_entry['redirect'] = $result['redirect'];
            $cache_entry['page_dom'] = null;
        } else {
            // Normal response
            $cache_entry['page_dom'] = $result['page_dom'];
            $cache_entry['redirect'] = null;
        }

        // Store in Redis as JSON
        try {
            Redis::set($redis_key, json_encode($cache_entry));
            $this->info("✅ Static cache generated successfully");
            $this->info("   Redis key: {$redis_key}");
            $this->info("   ETag: {$etag}");
            $this->info("   Status: {$result['code']}");
        } catch (\Exception $e) {
            $this->error('❌ Failed to store cache in Redis: ' . $e->getMessage());
            return 1;
        }

        return 0;
    }
}