const IMAGE_PROXY_PATH = "/api/image-proxy";

type ImageProxyFormat = "webp" | "avif" | "jpeg" | "png";

export type ImageProxyOptions = {
  width?: number;
  quality?: number;
  format?: ImageProxyFormat;
};

function clamp(value: number, min: number, max: number): number {
  return Math.max(min, Math.min(max, value));
}

function normalizeWidth(width?: number): number | undefined {
  if (!Number.isFinite(width) || !width) return undefined;
  return clamp(Math.round(width), 64, 4096);
}

function normalizeQuality(quality?: number): number | undefined {
  if (!Number.isFinite(quality) || !quality) return undefined;
  return clamp(Math.round(quality), 40, 100);
}

function isAbsoluteHttpUrl(url: string): boolean {
  return /^https?:\/\//i.test(url);
}

function isBypassUrl(url: string): boolean {
  return (
    !url ||
    url.startsWith("data:") ||
    url.startsWith("blob:") ||
    url.startsWith(IMAGE_PROXY_PATH) ||
    !isAbsoluteHttpUrl(url)
  );
}

export function buildImageProxyUrl(url: string, options: ImageProxyOptions = {}): string {
  const source = String(url || "").trim();
  if (isBypassUrl(source)) {
    return source;
  }

  const width = normalizeWidth(options.width);
  const quality = normalizeQuality(options.quality);
  const format = options.format;

  const params = new URLSearchParams();
  params.set("url", source);
  if (width) params.set("w", String(width));
  if (quality) params.set("q", String(quality));
  if (format) params.set("f", format);

  return `${IMAGE_PROXY_PATH}?${params.toString()}`;
}