<?php
namespace app\service;

use Throwable;

class OssUploadService
{
    public function uploadBase64(string $fileName, string $base64File, array $extraFields = []): array
    {
        $fileContent = base64_decode($base64File, true);
        if ($fileContent === false || $fileContent === '') {
            return $this->createErrorResult('文件解析错误');
        }

        return $this->uploadBinaryContent($fileName, $fileContent, $extraFields);
    }

    public function uploadBinary(string $fileName, string $fileContent, array $extraFields = []): array
    {
        if ($fileContent === '') {
            return $this->createErrorResult('Binary payload is empty');
        }

        return $this->uploadBinaryContent($fileName, $fileContent, $extraFields);
    }

    private function uploadBinaryContent(string $fileName, string $fileContent, array $extraFields = []): array
    {
        $uploadConfig = config('filesystem.upload_conf') ?: [];
        $maxSize = (int)($uploadConfig['fileSize'] ?? 10 * 1024 * 1024);
        if (strlen($fileContent) > $maxSize) {
            return $this->createErrorResult('File size exceeds limit');
        }

        $ext = strtolower(pathinfo($fileName, PATHINFO_EXTENSION));
        $allowedExts = $uploadConfig['fileExt'] ?? [];
        if ($ext === '' || (!empty($allowedExts) && !in_array($ext, $allowedExts, true))) {
            return $this->createErrorResult('File extension not allowed');
        }

        $bucket = (string)config('oss.bucket');
        $folder = (string)($extraFields['Folder'] ?? ($extraFields['Bucket'] ?? ''));
        $key = $extraFields['Key'] ?? basename($fileName);
        $objectKey = $this->buildObjectKey($folder, (string)$key);
        if ($bucket === '' || $objectKey === '') {
            return $this->createErrorResult('Bucket or key missing');
        }

        $finfo = new \finfo(FILEINFO_MIME_TYPE);
        $mimeType = (string)$finfo->buffer($fileContent);

        try {
            $service = new OssService(config('oss'));
            $result = $service->uploadFromBinary($fileContent, $objectKey, $bucket, [
                'contentType' => $this->resolveContentType($mimeType, $ext),
            ]);
            $result['url'] = $service->buildObjectUrl($objectKey, $bucket);
            $result['folder'] = $folder;

            return [
                'code' => 1,
                'msg' => 'upload ok',
                'data' => $result,
            ];
        } catch (Throwable $e) {
            $fallback = $this->saveToLocalFallback($fileContent, $bucket, $objectKey);

            return $this->createErrorResult(
                'OSS upload failed: ' . $e->getMessage(),
                [
                    'bucket' => $bucket,
                    'key' => $objectKey,
                    'folder' => $folder,
                    'fallback_saved' => $fallback['saved'],
                    'fallback_path' => $fallback['path'],
                    'fallback_error' => $fallback['error'],
                ]
            );
        }
    }

    private function buildObjectKey(string $folder, string $key): string
    {
        $folder = trim(str_replace('\\', '/', $folder), '/');
        $key = trim(str_replace('\\', '/', $key), '/');

        if ($folder === '') {
            return $key;
        }

        if ($key === '') {
            return $folder;
        }

        if (str_starts_with($key . '/', $folder . '/')) {
            return $key;
        }

        return $folder . '/' . $key;
    }

    private function saveToLocalFallback(string $fileContent, string $bucket, string $key): array
    {
        $baseDir = $this->resolveFallbackBaseDir();
        $safeBucket = $this->sanitizePathSegment($bucket);
        $safeKey = $this->sanitizeObjectKey($key);
        $fullPath = $baseDir . DIRECTORY_SEPARATOR . $safeBucket . DIRECTORY_SEPARATOR . $safeKey;
        $directory = dirname($fullPath);

        try {
            if (!is_dir($directory) && !mkdir($directory, 0777, true) && !is_dir($directory)) {
                throw new \RuntimeException('Unable to create fallback directory');
            }

            if (file_put_contents($fullPath, $fileContent) === false) {
                throw new \RuntimeException('Unable to write fallback file');
            }

            return [
                'saved' => true,
                'path' => $fullPath,
                'error' => null,
            ];
        } catch (Throwable $e) {
            return [
                'saved' => false,
                'path' => $fullPath,
                'error' => $e->getMessage(),
            ];
        }
    }

    private function resolveFallbackBaseDir(): string
    {
        $uploadConfig = config('filesystem.upload_conf') ?: [];
        $configured = (string)($uploadConfig['fallbackDir'] ?? '');
        if ($configured !== '') {
            return rtrim($configured, "\\/");
        }

        $localRoot = (string)(config('filesystem.disks.local.root') ?? '');
        if ($localRoot !== '') {
            return rtrim($localRoot, "\\/") . DIRECTORY_SEPARATOR . 'oss-fallback';
        }

        return app()->getRuntimePath() . 'storage' . DIRECTORY_SEPARATOR . 'oss-fallback';
    }

    private function sanitizeObjectKey(string $key): string
    {
        $normalized = str_replace('\\', '/', $key);
        $segments = array_filter(explode('/', $normalized), static function (string $segment): bool {
            return $segment !== '' && $segment !== '.' && $segment !== '..';
        });

        if ($segments === []) {
            return 'unnamed-file';
        }

        $safeSegments = array_map([$this, 'sanitizePathSegment'], $segments);
        return implode(DIRECTORY_SEPARATOR, $safeSegments);
    }

    private function sanitizePathSegment(string $segment): string
    {
        $cleaned = preg_replace('/[^A-Za-z0-9._-]/', '_', $segment) ?? '';
        return $cleaned !== '' ? $cleaned : 'unknown';
    }

    private function resolveContentType(string $mimeType, string $ext): string
    {
        if ($mimeType !== '' && $mimeType !== 'application/octet-stream') {
            return $mimeType;
        }

        return match ($ext) {
            'jpg', 'jpeg' => 'image/jpeg',
            'png' => 'image/png',
            'gif' => 'image/gif',
            'webp' => 'image/webp',
            'bmp' => 'image/bmp',
            'svg' => 'image/svg+xml',
            'pdf' => 'application/pdf',
            'doc' => 'application/msword',
            'docx' => 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
            default => 'application/octet-stream',
        };
    }

    private function createErrorResult(string $message, array $data = []): array
    {
        $result = [
            'code' => 0,
            'msg' => $message,
        ];

        if ($data !== []) {
            $result['data'] = $data;
        }

        return $result;
    }
}