import { IMAGE_UPLOAD_TOO_LARGE_MESSAGE, isImageUploadTooLarge } from "@/lib/image-upload-limits";

const mimeByExtension: Record<string, string> = {
  jpg: "image/jpeg", jpeg: "image/jpeg", png: "image/png", webp: "image/webp",
  avif: "image/avif", tif: "image/tiff", tiff: "image/tiff", svg: "image/svg+xml",
  heic: "image/heic", heif: "image/heif",
  mp4: "video/mp4", mov: "video/quicktime", webm: "video/webm",
  mp3: "audio/mpeg", m4a: "audio/mp4", wav: "audio/wav", ogg: "audio/ogg", flac: "audio/flac",
};
const acceptedTypes = new Set([...Object.values(mimeByExtension), "image/jpg", "image/x-tiff", "audio/mp3", "audio/x-m4a", "audio/x-wav", "audio/webm"]);

// Finder and some browsers provide no MIME type. Only infer it for known extensions;
// the upload endpoints still validate/decode the actual file contents.
export function prepareCanvasMediaFiles(input: File[]) {
  const files: File[] = [], errors: string[] = [];
  for (const file of input) {
    const originalType = file.type.toLowerCase();
    const type = !originalType || originalType === "application/octet-stream"
      ? mimeByExtension[file.name.split(".").pop()?.toLowerCase() || ""]
      : originalType;
    if (!type || !acceptedTypes.has(type)) {
      errors.push(`${file.name}：不支持此格式，请拖入图片、MP4/MOV/WebM 视频或音频文件`);
    } else if (!file.size) {
      errors.push(`${file.name}：文件为空，请选择完整素材`);
    } else if (type.startsWith("image/") && isImageUploadTooLarge(file.size)) {
      errors.push(`${file.name}：${IMAGE_UPLOAD_TOO_LARGE_MESSAGE}`);
    } else if (!type.startsWith("image/") && file.size > 125 * 1024 * 1024) {
      errors.push(`${file.name}：音视频不能超过 125 MiB`);
    } else {
      files.push(type === file.type ? file : new File([file], file.name, { type, lastModified: file.lastModified }));
    }
  }
  if (files.length > 10) errors.push("每次最多导入 10 个素材，其余文件请分批拖入");
  return { files: files.slice(0, 10), errors };
}

export function canvasMediaType(file: File): "image" | "video" | "audio" {
  if (file.type.startsWith("image/")) return "image";
  if (file.type.startsWith("video/")) return "video";
  if (file.type.startsWith("audio/")) return "audio";
  throw Error(`${file.name}：不支持此素材格式`);
}