<?php

/**
 * =============================================================================
 * MODPACK VERSION CHECKER - CRON COMMAND
 * =============================================================================
 * 
 * Laravel Artisan command that checks all servers for modpack updates.
 * This is the "brain" that populates the cache used by the dashboard badges.
 * 
 * USAGE:
 *     php artisan modpackchecker:check
 * 
 * RECOMMENDED CRON SCHEDULE:
 *     # Check for updates every 6 hours (adjust based on your server count)
 *     0 */6 * * * cd /var/www/pterodactyl && php artisan modpackchecker:check >> /dev/null 2>&1
 * 
 * HOW IT WORKS:
 * 1. Finds all servers with MODPACK_PLATFORM egg variable set
 * 2. Loops through each server, checking the appropriate API
 * 3. Stores results in modpackchecker_servers database table
 * 4. Dashboard badges read from this table (never calling APIs directly)
 * 
 * RATE LIMITING:
 * Each API call is followed by a 2-second sleep to avoid rate limits.
 * For 50 servers, a full check takes ~2 minutes. Adjust sleep() if needed.
 * 
 * PLATFORM SUPPORT:
 * - CurseForge: Requires API key in settings (configured via admin panel)
 * - Modrinth: Public API, no key needed (uses User-Agent)
 * - FTB: Public API via modpacks.ch
 * - Technic: Public API, uses slug instead of numeric ID
 * 
 * DATABASE TABLE: modpackchecker_servers
 * This table caches the latest check results. See migration file for schema.
 * Uses updateOrInsert for upsert behavior - first run creates, subsequent update.
 * 
 * EXAMPLE OUTPUT:
 *     Starting modpack update check...
 *     Found 12 servers with modpack configuration
 *     Checking: ATM9 Server (a1b2c3d4-...)
 *       🟠 UPDATE AVAILABLE: All The Mods 9 - 0.2.60
 *     Checking: Creative Server (e5f6g7h8-...)
 *       Skipping - missing platform or modpack ID
 *     Checking: Vanilla Server (i9j0k1l2-...)
 *       🟢 Up to date: Adrenaserver - 1.7.0
 *     Modpack update check complete!
 * 
 * ERROR HANDLING:
 * If an API call fails, the error is logged to the database and the command
 * continues to the next server. One failure doesn't stop the whole batch.
 * 
 * DEPENDENCIES:
 * - Database table: modpackchecker_servers (from migration)
 * - Settings: modpackchecker::curseforge_api_key (for CurseForge only)
 * 
 * @package     Pterodactyl\Console\Commands
 * @author      Firefrost Gaming / Frostystyle <dev@firefrostgaming.com>
 * @version     1.0.0
 * @see         ModpackAPIController.php (provides getStatus endpoint for badges)
 * @see         UpdateBadge.tsx (React component that displays the results)
 * =============================================================================
 */

namespace Pterodactyl\Console\Commands;

use Illuminate\Console\Command;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Http;
use Pterodactyl\Models\Server;

/**
 * Artisan command to check all servers for modpack updates.
 * 
 * Run manually with: php artisan modpackchecker:check
 * Or schedule in app/Console/Kernel.php:
 *     $schedule->command('modpackchecker:check')->everyFourHours();
 */
class CheckModpackUpdates extends Command
{
    /**
     * The console command signature.
     * 
     * @var string
     */
    protected $signature = 'modpackchecker:check';
    
    /**
     * The console command description (shown in `php artisan list`).
     * 
     * @var string
     */
    protected $description = 'Check all servers for modpack updates';

    /**
     * Execute the console command.
     * 
     * Main entry point. Finds all servers with modpack configuration
     * and checks each one against its platform's API.
     * 
     * @return int  Exit code (0 = success)
     */
    public function handle(): int
    {
        $this->info('Starting modpack update check...');

        // Get all servers that have modpack variables set
        $servers = Server::whereHas('variables', function ($q) {
            $q->where('env_variable', 'MODPACK_PLATFORM');
        })->get();

        $this->info("Found {$servers->count()} servers with modpack configuration");

        foreach ($servers as $server) {
            $this->checkServer($server);
            // Rate limiting - sleep between checks
            sleep(2);
        }

        $this->info('Modpack update check complete!');
        return 0;
    }

    /**
     * Check a single server for modpack updates.
     * 
     * This method:
     * 1. Retrieves modpack configuration from egg variables
     * 2. Calls the appropriate platform API
     * 3. Compares current vs latest version
     * 4. Stores results in database cache
     * 
     * If any step fails, the error is logged to the database
     * and the method returns (doesn't throw).
     * 
     * @param  Server  $server  The server to check
     * @return void
     */
    private function checkServer(Server $server): void
    {
        $this->line("Checking: {$server->name} ({$server->uuid})");

        try {
            // Get platform and modpack ID from variables
            $platform = $this->getVariable($server, 'MODPACK_PLATFORM');
            $modpackId = $this->getVariable($server, 'MODPACK_ID');

            if (!$platform || !$modpackId) {
                $this->warn("  Skipping - missing platform or modpack ID");
                return;
            }

            // Get latest version from API
            $latestData = $this->fetchLatestVersion($platform, $modpackId);

            if (!$latestData) {
                $this->error("  Failed to fetch version data");
                $this->updateDatabase($server, [
                    'platform' => $platform,
                    'modpack_id' => $modpackId,
                    'error_message' => 'Failed to fetch version data',
                    'update_available' => false,
                ]);
                return;
            }

            // Get current version (from variable or file - for now just use variable)
            $currentVersion = $this->getVariable($server, 'MODPACK_CURRENT_VERSION');

            // Determine if update is available
            $updateAvailable = $currentVersion && $currentVersion !== $latestData['version'];

            $this->updateDatabase($server, [
                'platform' => $platform,
                'modpack_id' => $modpackId,
                'modpack_name' => $latestData['name'],
                'current_version' => $currentVersion,
                'latest_version' => $latestData['version'],
                'update_available' => $updateAvailable,
                'error_message' => null,
            ]);

            $status = $updateAvailable ? '🟠 UPDATE AVAILABLE' : '🟢 Up to date';
            $this->info("  {$status}: {$latestData['name']} - {$latestData['version']}");

        } catch (\Exception $e) {
            $this->error("  Error: {$e->getMessage()}");
            $this->updateDatabase($server, [
                'error_message' => $e->getMessage(),
                'update_available' => false,
            ]);
        }
    }

    /**
     * Get an egg variable value from a server.
     * 
     * Egg variables are the startup parameters configured in the server's
     * egg. For modpack checking, we look for:
     * - MODPACK_PLATFORM: Which API to query
     * - MODPACK_ID: The modpack identifier for that platform
     * - MODPACK_CURRENT_VERSION: What's currently installed (optional)
     * 
     * @param  Server  $server  The server to query
     * @param  string  $name    The variable name (e.g., "MODPACK_PLATFORM")
     * @return string|null      The variable value, or null if not set
     */
    private function getVariable(Server $server, string $name): ?string
    {
        $variable = $server->variables()
            ->where('env_variable', $name)
            ->first();
        return $variable?->server_value;
    }

    /**
     * Route to the appropriate platform API based on platform name.
     * 
     * This is just a dispatcher - actual API logic is in the check* methods.
     * 
     * @param  string  $platform   The platform name (modrinth, curseforge, ftb, technic)
     * @param  string  $modpackId  The platform-specific modpack identifier
     * @return array|null          Contains [name, version] or null on failure
     */
    private function fetchLatestVersion(string $platform, string $modpackId): ?array
    {
        return match($platform) {
            'modrinth' => $this->checkModrinth($modpackId),
            'curseforge' => $this->checkCurseForge($modpackId),
            'ftb' => $this->checkFTB($modpackId),
            'technic' => $this->checkTechnic($modpackId),
            default => null,
        };
    }

    private function checkModrinth(string $projectId): ?array
    {
        $response = Http::withHeaders([
            'User-Agent' => 'FirefrostGaming/ModpackChecker/1.0',
        ])->get("https://api.modrinth.com/v2/project/{$projectId}");

        if (!$response->successful()) return null;
        $project = $response->json();

        $versionResponse = Http::withHeaders([
            'User-Agent' => 'FirefrostGaming/ModpackChecker/1.0',
        ])->get("https://api.modrinth.com/v2/project/{$projectId}/version");

        $versions = $versionResponse->json();

        return [
            'name' => $project['title'] ?? 'Unknown',
            'version' => $versions[0]['version_number'] ?? 'Unknown',
        ];
    }

    private function checkCurseForge(string $modpackId): ?array
    {
        $apiKey = DB::table('settings')
            ->where('key', 'like', '%modpackchecker::curseforge_api_key%')
            ->value('value');

        if (!$apiKey) return null;

        $response = Http::withHeaders([
            'x-api-key' => $apiKey,
        ])->get("https://api.curseforge.com/v1/mods/{$modpackId}");

        if (!$response->successful()) return null;
        $data = $response->json()['data'] ?? [];

        return [
            'name' => $data['name'] ?? 'Unknown',
            'version' => $data['latestFiles'][0]['displayName'] ?? 'Unknown',
        ];
    }

    private function checkFTB(string $modpackId): ?array
    {
        $response = Http::get("https://api.modpacks.ch/public/modpack/{$modpackId}");
        if (!$response->successful()) return null;
        $data = $response->json();

        return [
            'name' => $data['name'] ?? 'Unknown',
            'version' => $data['versions'][0]['name'] ?? 'Unknown',
        ];
    }

    private function checkTechnic(string $slug): ?array
    {
        $response = Http::get("https://api.technicpack.net/modpack/{$slug}?build=1");
        if (!$response->successful()) return null;
        $data = $response->json();

        return [
            'name' => $data['displayName'] ?? $data['name'] ?? 'Unknown',
            'version' => $data['version'] ?? 'Unknown',
        ];
    }

    /**
     * Store or update the modpack check results in the database.
     * 
     * Uses updateOrInsert for upsert behavior:
     * - First check: Creates a new row
     * - Subsequent checks: Updates the existing row
     * 
     * The server_id column is the unique key for matching.
     * 
     * This cache table is read by ModpackAPIController::getStatus()
     * which powers the dashboard badges.
     * 
     * @param  Server  $server  The server being checked
     * @param  array   $data    The data to store (platform, version info, errors, etc.)
     * @return void
     */
    private function updateDatabase(Server $server, array $data): void
    {
        DB::table('modpackchecker_servers')->updateOrInsert(
            ['server_id' => $server->id],
            array_merge($data, [
                'server_uuid' => $server->uuid,
                'last_checked' => now(),
                'updated_at' => now(),
            ])
        );
    }
}