/**
 * Generates an imgproxy URL for a given source image and options.
 *
 * Documentation: https://docs.imgproxy.net/usage/processing
 */

interface ImgproxyOptions {
  width?: number;
  height?: number;
  resizing_type?: 'fit' | 'fill' | 'fill-down' | 'force' | 'auto';
  gravity?: string;
  enlarge?: boolean;
  extension?: string;
}

export function getImgproxyUrl(src: string, options: ImgproxyOptions = {}): string {
  // Use local proxy path which is rewritten in next.config.mjs
  const baseUrl = '/_img';

  // Handle local paths or relative URLs
  let absoluteSrc = src;
  if (src.startsWith('/')) {
    const baseUrlForSrc =
      process.env.NEXT_PUBLIC_BASE_URL ||
      (typeof window !== 'undefined' ? window.location.origin : 'https://klz-cables.com');
    if (baseUrlForSrc) {
      absoluteSrc = `${baseUrlForSrc.replace(/\/$/, '')}${src}`;
    }
  }

  // Development mapping: Map local domains to internal Docker hostnames
  // so imgproxy can fetch images without SSL issues or external routing
  if (process.env.NODE_ENV === 'development') {
    if (absoluteSrc.includes('klz.localhost')) {
      absoluteSrc = absoluteSrc.replace(/^https?:\/\/klz\.localhost/, 'http://klz-app:3000');
    } else if (absoluteSrc.includes('cms.klz.localhost')) {
      absoluteSrc = absoluteSrc.replace(/^https?:\/\/cms\.klz\.localhost/, 'http://klz-cms:8055');
    }
    // Also handle direct container names if needed
  }

  const {
    width = 0,
    height = 0,
    resizing_type = 'fit',
    gravity = 'sm', // Default to smart gravity
    enlarge = false,
    extension = '',
  } = options;

  // Processing options
  // Format: /rs:<type>:<width>:<height>:<enlarge>/g:<gravity>
  const processingOptions = [
    `rs:${resizing_type}:${width}:${height}:${enlarge ? 1 : 0}`,
    `g:${gravity}`,
  ].join('/');

  // Using Base64 encoding for the source URL.
  // This completely eliminates any risk of intermediate proxies (Traefik/Next.js)
  // URL-decoding the path, which corrupts the double-slash (// to /) and causes 403 errors.
  // Imgproxy expects URL-safe Base64 (RFC 4648) without padding.
  const b64 =
    typeof window === 'undefined'
      ? Buffer.from(absoluteSrc).toString('base64')
      : btoa(unescape(encodeURIComponent(absoluteSrc)));

  const urlSafeB64 = b64.replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, '');

  const suffix = extension ? `.${extension}` : '';

  return `${baseUrl}/unsafe/${processingOptions}/${urlSafeB64}${suffix}`;
}