import imageCompression from "browser-image-compression";

const PHOTO_MAX_SIZE_MB = 300 / 1024;
const PHOTO_MAX_WIDTH_OR_HEIGHT = 1920;

/**
 * 转为真正的 File，避免压缩库返回 Blob 后 FormData 使用默认文件名 blob。
 */
function normalizeUploadImageFile(source: File, compressed: Blob): File {
	if (compressed instanceof File && compressed.name) {
		return compressed;
	}

	return new File([compressed], source.name || "upload-image", {
		type: compressed.type || source.type,
		lastModified: source.lastModified
	});
}

/**
 * 压缩上传图片，统一限制到 300 KB。
 */
export async function compressUploadImage(file: File): Promise<File> {
	const compressedFile = await imageCompression(file, {
		maxSizeMB: PHOTO_MAX_SIZE_MB,
		maxWidthOrHeight: PHOTO_MAX_WIDTH_OR_HEIGHT,
		useWebWorker: true,
		initialQuality: .86
	});
	return normalizeUploadImageFile(file, compressedFile);
}

/**
 * 批量压缩上传图片。
 */
export async function compressUploadImageList(fileList: File[]): Promise<File[]> {
	const result: File[] = [];
	for (const file of fileList) {
		result.push(await compressUploadImage(file));
	}
	return result;
}