const identifyBuffer = require("buffer-signature").identify;

export const checkMimeType = (file: any) => {
  const reader = new FileReader();
  reader.readAsArrayBuffer(file);

  return new Promise((resolve) => {
    reader.onloadend = function (e: any) {
      if (e.target.readyState === FileReader.DONE) {
        const bytes = new Uint8Array(e.target.result);
        const buffer = Buffer.alloc(bytes.buffer.byteLength);
        const view = new Uint8Array(bytes.buffer);

        const fileNameList = [
          "png",
          "jpg",
          "jpeg",
          "webp",
          "gif",
          "tiff",
          "mp4",
          "mov",
          "wmv",
          "avi",
          "pdf",
          "mp3",
          "mpeg",
        ];

        for (let i = 0; i < buffer.length; ++i) {
          buffer[i] = view[i];
        }
        const data = identifyBuffer(buffer);

        if (
          data.extensions.length &&
          data.extensions.filter((type: string) => fileNameList.includes(type))
        ) {
          resolve(data);
        }

        resolve(false);
      }
    };
  });
};