<?php

namespace App\Services;

use Illuminate\Support\Facades\Artisan;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use RuntimeException;

class UpdateService
{
    private const CACHE_KEY = 'update.latest_release';
    private const CACHE_TTL = 3600; // 1 heure

    // ─── Lecture de version ──────────────────────────────────────────────────

    public function getInstalledVersion(): string
    {
        $file = base_path('VERSION');
        return file_exists($file) ? trim(file_get_contents($file)) : '0.0.0';
    }

    // ─── Vérification distante ───────────────────────────────────────────────

    public function fetchLatestRelease(bool $useCache = true): ?array
    {
        if ($useCache && Cache::has(self::CACHE_KEY)) {
            return Cache::get(self::CACHE_KEY);
        }

        $url = sprintf(
            '%s/api/v1/repos/%s/%s/releases/latest',
            rtrim(config('update.gitea_url'), '/'),
            config('update.gitea_owner'),
            config('update.gitea_repo'),
        );

        try {
            $response = Http::timeout(10)->get($url);

            if (! $response->successful()) {
                return null;
            }

            $data    = $response->json();
            $version = ltrim($data['tag_name'] ?? '', 'v');

            $downloadUrl = null;
            foreach ($data['assets'] ?? [] as $asset) {
                if (str_ends_with($asset['name'] ?? '', '.tar.gz')) {
                    $downloadUrl = $asset['browser_download_url'];
                    break;
                }
            }

            if (! $version || ! $downloadUrl) {
                return null;
            }

            $release = [
                'version'      => $version,
                'tag'          => $data['tag_name'],
                'name'         => $data['name'] ?? "v{$version}",
                'download_url' => $downloadUrl,
                'published_at' => $data['published_at'] ?? null,
                'body'         => $data['body'] ?? '',
            ];

            Cache::put(self::CACHE_KEY, $release, self::CACHE_TTL);
            return $release;

        } catch (\Exception $e) {
            Log::warning('UpdateService: impossible de contacter le serveur de mises à jour.', [
                'error' => $e->getMessage(),
            ]);
            return null;
        }
    }

    public function getLatestIfNewer(): ?array
    {
        $latest = $this->fetchLatestRelease();
        if (! $latest) {
            return null;
        }

        return version_compare($latest['version'], $this->getInstalledVersion(), '>') ? $latest : null;
    }

    // ─── Téléchargement ─────────────────────────────────────────────────────

    public function download(array $release): string
    {
        $path = sys_get_temp_dir() . "/mesreleves-{$release['version']}.tar.gz";

        $response = Http::timeout(300)->sink($path)->get($release['download_url']);

        if (! $response->successful() || ! file_exists($path) || filesize($path) === 0) {
            @unlink($path);
            throw new RuntimeException("Téléchargement échoué (HTTP {$response->status()}).");
        }

        return $path;
    }

    // ─── Application de la mise à jour ──────────────────────────────────────

    public function applyUpdate(array $release, callable $log = null): void
    {
        $log     ??= static fn ($msg) => null;
        $version   = $release['version'];
        $appPath   = base_path();

        // 1. Sauvegarde BDD
        $log("Sauvegarde de la base de données...");
        $backupPath = $this->backupDatabase($version);
        $log("  → {$backupPath}");

        // 2. Téléchargement
        $log("Téléchargement de mesreleves-{$version}.tar.gz...");
        $archivePath = $this->download($release);
        $log("  → {$archivePath} (" . $this->humanSize(filesize($archivePath)) . ")");

        // 3. Maintenance
        $log("Activation du mode maintenance...");
        Artisan::call('down');

        try {
            // 4. Extraction
            $log("Extraction de l'archive...");
            $tmpDir = sys_get_temp_dir() . "/mesreleves-update-{$version}";
            if (is_dir($tmpDir)) {
                $this->exec("rm -rf " . escapeshellarg($tmpDir));
            }
            mkdir($tmpDir, 0755, true);
            $this->exec("tar -xzf " . escapeshellarg($archivePath) . " -C " . escapeshellarg($tmpDir));

            $dirs = glob($tmpDir . '/*/');
            if (empty($dirs)) {
                throw new RuntimeException("L'archive est vide ou mal formée.");
            }
            $srcDir = rtrim($dirs[0], '/');

            // 5. Synchronisation des fichiers (préserve .env, storage, vendor)
            $log("Synchronisation des fichiers...");
            $this->exec(sprintf(
                'rsync -a --delete --exclude=".env" --exclude="storage/" --exclude="vendor/" %s %s',
                escapeshellarg($srcDir . '/'),
                escapeshellarg($appPath . '/'),
            ));

            // 6. Dépendances Composer (prod)
            $log("Installation des dépendances (composer)...");
            $this->exec('composer install --no-dev --optimize-autoloader --quiet', $appPath);

            // 7. Mise à jour du fichier VERSION
            file_put_contents($appPath . '/VERSION', $version . PHP_EOL);

            // 8. Migrations
            $log("Migration de la base de données...");
            Artisan::call('migrate', ['--force' => true]);
            $log(trim(Artisan::output()));

            // 9. Nettoyage et optimisation des caches
            $log("Optimisation...");
            Artisan::call('optimize:clear');
            Artisan::call('optimize');

            // 10. Rechargement php-fpm (opcache)
            $log("Rechargement php-fpm...");
            $this->reloadPhpFpm();

            // 11. Purge des anciennes sauvegardes
            $this->pruneBackups();

            // 12. Nettoyage temporaire
            $this->exec("rm -rf " . escapeshellarg($tmpDir));
            @unlink($archivePath);

            Cache::forget(self::CACHE_KEY);
            $log("✓ Mise à jour vers v{$version} réussie.");

        } catch (\Exception $e) {
            $log("✗ Erreur : " . $e->getMessage());
            $log("  La base de données peut être restaurée depuis : {$backupPath}");
            throw $e;
        } finally {
            Artisan::call('up');
        }
    }

    // ─── Sauvegardes ────────────────────────────────────────────────────────

    public function listBackups(): array
    {
        $dir     = storage_path('app/backups');
        $backups = glob($dir . '/db-*.sql') ?: [];
        rsort($backups);
        return $backups;
    }

    public function restoreBackup(string $path): void
    {
        if (! file_exists($path)) {
            throw new RuntimeException("Fichier introuvable : {$path}");
        }

        $host     = config('database.connections.pgsql.host');
        $port     = config('database.connections.pgsql.port', 5432);
        $db       = config('database.connections.pgsql.database');
        $user     = config('database.connections.pgsql.username');
        $password = config('database.connections.pgsql.password');

        $cmd = sprintf(
            'PGPASSWORD=%s psql -h %s -p %s -U %s %s < %s',
            escapeshellarg($password),
            escapeshellarg($host),
            (int) $port,
            escapeshellarg($user),
            escapeshellarg($db),
            escapeshellarg($path),
        );

        Artisan::call('down');
        $this->exec($cmd);
        Artisan::call('up');
    }

    // ─── Méthodes privées ───────────────────────────────────────────────────

    private function backupDatabase(string $version): string
    {
        $dir = storage_path('app/backups');
        if (! is_dir($dir)) {
            mkdir($dir, 0755, true);
        }

        $filename = "db-before-{$version}-" . date('Ymd-His') . ".sql";
        $path     = "{$dir}/{$filename}";

        $host     = config('database.connections.pgsql.host');
        $port     = config('database.connections.pgsql.port', 5432);
        $db       = config('database.connections.pgsql.database');
        $user     = config('database.connections.pgsql.username');
        $password = config('database.connections.pgsql.password');

        $cmd = sprintf(
            'PGPASSWORD=%s pg_dump -h %s -p %s -U %s %s > %s',
            escapeshellarg($password),
            escapeshellarg($host),
            (int) $port,
            escapeshellarg($user),
            escapeshellarg($db),
            escapeshellarg($path),
        );

        $this->exec($cmd);

        if (! file_exists($path) || filesize($path) === 0) {
            throw new RuntimeException("La sauvegarde PostgreSQL a échoué (pg_dump disponible dans le container ?)");
        }

        return $path;
    }

    private function pruneBackups(): void
    {
        $backups = $this->listBackups();
        $keep    = (int) config('update.backups_to_keep', 5);

        foreach (array_slice($backups, $keep) as $old) {
            @unlink($old);
        }
    }

    private function reloadPhpFpm(): void
    {
        // Envoie USR2 au process php-fpm (rechargement gracieux sans downtime)
        // PID 1 = php-fpm master dans le container Docker
        @shell_exec('kill -USR2 1 2>/dev/null || true');
    }

    private function exec(string $cmd, ?string $cwd = null): string
    {
        $fullCmd = $cwd ? "cd " . escapeshellarg($cwd) . " && {$cmd}" : $cmd;
        $output  = shell_exec("{$fullCmd} 2>&1") ?? '';
        return $output;
    }

    private function humanSize(int $bytes): string
    {
        if ($bytes >= 1_048_576) return round($bytes / 1_048_576, 1) . ' Mo';
        if ($bytes >= 1_024)    return round($bytes / 1_024, 0) . ' Ko';
        return $bytes . ' o';
    }
}