import { RawFile } from '../types';

export const readFile = (file: File): Promise<RawFile> => {
  return new Promise((resolve, reject) => {
    const reader = new FileReader();

    reader.onload = () => {
      const base64String = reader.result as string;
      // Remove data URL prefix (e.g., "data:image/png;base64,") to get raw base64
      const base64Content = base64String.split(',')[1];

      resolve({
        name: file.name,
        type: file.type,
        size: file.size,
        content: base64Content,
        preview: file.type.startsWith('image/') ? base64String : undefined,
        file: file,
      });
    };

    reader.onerror = () => {
      // Rejection returns the file name to allow the UI to construct a localized message
      reject(file.name);
    };

    // Read as Data URL to easily get Base64
    reader.readAsDataURL(file);
  });
};

export const formatBytes = (bytes: number, decimals = 2) => {
  if (!+bytes) return '0 B';
  const k = 1024;
  const dm = decimals < 0 ? 0 : decimals;
  const sizes = ['B', 'KB', 'MB', 'GB', 'TB'];
  const i = Math.floor(Math.log(bytes) / Math.log(k));
  return `${parseFloat((bytes / Math.pow(k, i)).toFixed(dm))} ${sizes[i]}`;
};