<?php
declare(strict_types=1);

namespace Esun\CustomerMessage\Model;

use Magento\Framework\App\Filesystem\DirectoryList;
use Magento\Framework\Exception\LocalizedException;
use Magento\Framework\Filesystem\Driver\File;

class AttachmentStorage
{
    private const MAX_FILES = 5;
    private const MAX_SIZE = 5242880;
    private const MIME_EXTENSIONS = [
        'image/jpeg' => 'jpg',
        'image/png' => 'png',
        'image/webp' => 'webp',
    ];

    public function __construct(
        private readonly DirectoryList $directoryList,
        private readonly File $fileDriver
    ) {
    }

    public function saveUploads(array $files, int $threadId, int $entryId): array
    {
        $uploads = $this->normalize($files);
        if (count($uploads) > self::MAX_FILES) {
            throw new LocalizedException(__('You can upload up to %1 images per message.', self::MAX_FILES));
        }

        $saved = [];
        try {
            foreach ($uploads as $upload) {
                if ((int)$upload['error'] === UPLOAD_ERR_NO_FILE) {
                    continue;
                }
                if ((int)$upload['error'] !== UPLOAD_ERR_OK) {
                    throw new LocalizedException(__('One of the images could not be uploaded.'));
                }
                if ((int)$upload['size'] <= 0 || (int)$upload['size'] > self::MAX_SIZE) {
                    throw new LocalizedException(__('Each image must be no larger than 5 MB.'));
                }

                $mime = (new \finfo(FILEINFO_MIME_TYPE))->file((string)$upload['tmp_name']);
                if (!isset(self::MIME_EXTENSIONS[$mime])) {
                    throw new LocalizedException(__('Only JPG, PNG and WebP images are allowed.'));
                }

                $relativeDirectory = sprintf('esun_customer_message/%d/%d', $threadId, $entryId);
                $absoluteDirectory = $this->directoryList->getPath(DirectoryList::VAR_DIR) . '/' . $relativeDirectory;
                $this->fileDriver->createDirectory($absoluteDirectory, 0750);
                $filename = bin2hex(random_bytes(20)) . '.' . self::MIME_EXTENSIONS[$mime];
                $absolutePath = $absoluteDirectory . '/' . $filename;
                if (!move_uploaded_file((string)$upload['tmp_name'], $absolutePath)) {
                    throw new LocalizedException(__('The image could not be stored.'));
                }
                chmod($absolutePath, 0640);
                $saved[] = [
                    'original_name' => mb_substr(basename((string)$upload['name']), 0, 255),
                    'storage_path' => $relativeDirectory . '/' . $filename,
                    'mime_type' => $mime,
                    'file_size' => (int)$upload['size'],
                ];
            }
        } catch (\Throwable $exception) {
            $this->delete(array_column($saved, 'storage_path'));
            throw $exception;
        }

        return $saved;
    }

    public function hasUploads(array $files): bool
    {
        foreach ($this->normalize($files) as $upload) {
            if ((int)$upload['error'] !== UPLOAD_ERR_NO_FILE) {
                return true;
            }
        }
        return false;
    }

    public function getAbsolutePath(string $relativePath): string
    {
        $base = $this->directoryList->getPath(DirectoryList::VAR_DIR) . '/esun_customer_message';
        $path = $this->directoryList->getPath(DirectoryList::VAR_DIR) . '/' . ltrim($relativePath, '/');
        $realBase = realpath($base);
        $realPath = realpath($path);
        if ($realBase === false || $realPath === false || !str_starts_with($realPath, $realBase . DIRECTORY_SEPARATOR)) {
            throw new LocalizedException(__('The requested image is not available.'));
        }
        return $realPath;
    }

    public function delete(array $relativePaths): void
    {
        foreach ($relativePaths as $relativePath) {
            try {
                $path = $this->getAbsolutePath((string)$relativePath);
                if ($this->fileDriver->isExists($path)) {
                    $this->fileDriver->deleteFile($path);
                }
            } catch (\Throwable) {
                // Best-effort cleanup after a failed transaction.
            }
        }
    }

    private function normalize(array $files): array
    {
        if (!$files) {
            return [];
        }
        if (isset($files['name']) && is_array($files['name'])) {
            $result = [];
            foreach ($files['name'] as $index => $name) {
                $result[] = [
                    'name' => $name,
                    'type' => $files['type'][$index] ?? '',
                    'tmp_name' => $files['tmp_name'][$index] ?? '',
                    'error' => $files['error'][$index] ?? UPLOAD_ERR_NO_FILE,
                    'size' => $files['size'][$index] ?? 0,
                ];
            }
            return $result;
        }
        if (isset($files['name'])) {
            return [$files];
        }
        return array_values(array_filter($files, 'is_array'));
    }
}