<?php

namespace App\Services;

use App\Models\Setting;
use App\Support\ThemeManager;
use Illuminate\Http\UploadedFile;
use Illuminate\Support\Facades\File;
use Exception;

/**
 * Service to handle Theme-related operations.
 */
class ThemeService
{
    /**
     * @var ThemeManager
     */
    protected ThemeManager $themeManager;

    /**
     * ThemeService constructor.
     *
     * @param ThemeManager $themeManager
     */
    public function __construct(ThemeManager $themeManager)
    {
        $this->themeManager = $themeManager;
    }

    /**
     * Upload and install a new theme from a ZIP file.
     *
     * @param UploadedFile $zipFile The uploaded theme ZIP file.
     * @return array Result containing success status and theme metadata.
     * @throws Exception If ZIP extraction or validation fails.
     */
    public function upload(UploadedFile $zipFile): array
    {
        /**
         * Initialize temporary extraction directory.
         * Using a unique ID ensures no collisions if multiple themes are uploaded simultaneously.
         */
        $tempPath = storage_path('app/temp/theme_upload_' . uniqid());
        File::makeDirectory($tempPath, 0755, true);

        try {
            $zipFilePath = $zipFile->getRealPath();

            /**
             * 1. ZIP Extraction.
             * We prioritize the native PHP ZipArchive class for performance.
             * If not available, we fall back to the system 'unzip' command (common on Linux).
             */
            if (class_exists('ZipArchive')) {
                $zip = new \ZipArchive();
                if ($zip->open($zipFilePath) === true) {
                    $zip->extractTo($tempPath);
                    $zip->close();
                } else {
                    throw new Exception('Failed to open ZIP file via ZipArchive.');
                }
            } else {
                $command = "unzip -q " . escapeshellarg($zipFilePath) . " -d " . escapeshellarg($tempPath);
                $output = [];
                $returnVar = 0;
                exec($command, $output, $returnVar);

                if ($returnVar !== 0) {
                    throw new Exception('Failed to extract ZIP file via system unzip command.');
                }
            }

            /**
             * 2. Path Discovery.
             * We check if the ZIP contains a single root folder or if the files are at the root.
             * This handles different ZIP packaging styles (folders vs flat).
             */
            $rootContents = File::directories($tempPath);
            $rootFiles = File::files($tempPath);

            $extractDir = $tempPath;
            $themeSlug = null;

            if (count($rootContents) === 1 && count($rootFiles) === 0) {
                // ZIP has a single top-level folder
                $extractDir = $rootContents[0];
                $themeSlug = basename($extractDir);
            } else {
                // ZIP is flat (files are at root)
                $themeSlug = pathinfo($zipFile->getClientOriginalName(), PATHINFO_FILENAME);
            }

            // Sanitize theme slug to prevent filesystem issues
            $themeSlug = strtolower(preg_replace('/[^a-z0-9_-]/i', '-', $themeSlug));

            /**
             * 3. Validation.
             * A valid theme MUST contain a 'theme.md' file.
             */
            if (! File::exists($extractDir . '/theme.md')) {
                File::deleteDirectory($tempPath);
                throw new Exception('Invalid theme: theme.md is missing.');
            }

            /**
             * 4. Final Deployment.
             * Move the extracted files to the project-wide 'themes' directory.
             * Existing themes with the same slug are overwritten.
             */
            $finalPath = base_path('themes/' . $themeSlug);
            if (File::exists($finalPath)) {
                File::deleteDirectory($finalPath);
            }

            File::copyDirectory($extractDir, $finalPath);
            File::deleteDirectory($tempPath);

            return [
                'success' => true,
                'slug' => $themeSlug,
                'metadata' => $this->themeManager->getMetadata($themeSlug),
            ];

        } catch (Exception $e) {
            File::deleteDirectory($tempPath);
            throw $e;
        }
    }

    /**
     * Activate a theme.
     *
     * @param string $themeSlug The slug of the theme to activate.
     * @return bool True if activation was successful.
     * @throws Exception If the theme is not found.
     */
    public function activate(string $themeSlug): bool
    {
        if (! file_exists(base_path('themes/' . $themeSlug))) {
            throw new Exception('Theme not found.');
        }

        Setting::set('active_theme', $themeSlug, 'cms');

        return true;
    }

    /**
     * List all installed themes with their metadata.
     *
     * @return array List of installed themes.
     */
    public function list(): array
    {
        return $this->themeManager->getThemes();
    }
}