// A project avatar is an image the hub stores (R-project-avatars,
// R-project-avatar-crop-flow). The hub normalizes every upload to one square
// PNG per project and serves it from the project avatar route. No custom
// avatar means the generated initial-and-color avatar.
// Shared by the registry, the JSON API, the web editor, and the CLI. Keep this
// module free of package dependencies because the installed CLI imports it.

export const MAX_AVATAR_UPLOAD_BYTES = 5 * 1024 * 1024;

/** Side of the stored square avatar, in pixels. */
export const AVATAR_IMAGE_SIZE = 512;

export const AVATAR_CONTENT_TYPES = [
  "image/png",
  "image/jpeg",
  "image/webp",
  "image/gif",
  "image/avif",
] as const;

export type AvatarContentType = (typeof AVATAR_CONTENT_TYPES)[number];

const EXTENSION_CONTENT_TYPES: Readonly<Record<string, AvatarContentType>> = {
  png: "image/png",
  jpg: "image/jpeg",
  jpeg: "image/jpeg",
  webp: "image/webp",
  gif: "image/gif",
  avif: "image/avif",
};

export const AVATAR_TYPE_ERROR = "Avatar images must be PNG, JPEG, WebP, GIF, or AVIF.";
export const AVATAR_SIZE_ERROR = "Avatar images must be smaller than 5 MB.";
export const AVATAR_EMPTY_ERROR = "The avatar image is empty.";

/** Read the media type of a Content-Type header, without its parameters. */
export const avatarContentType = (value: unknown): AvatarContentType | undefined => {
  if (typeof value !== "string") return undefined;
  const mediaType = value.split(";")[0].trim().toLowerCase();
  return AVATAR_CONTENT_TYPES.find((type) => type === mediaType);
};

/** Read the media type from a file name, for CLI uploads. */
export const avatarContentTypeForFile = (fileName: string): AvatarContentType | undefined => {
  const extension = fileName.toLowerCase().split(".").pop();
  return extension ? EXTENSION_CONTENT_TYPES[extension] : undefined;
};

/** Validate one avatar upload before the hub reads its bytes. */
export const avatarUploadError = (
  contentType: unknown,
  byteLength: number,
): string | undefined => {
  if (!avatarContentType(contentType)) return AVATAR_TYPE_ERROR;
  if (byteLength <= 0) return AVATAR_EMPTY_ERROR;
  if (byteLength > MAX_AVATAR_UPLOAD_BYTES) return AVATAR_SIZE_ERROR;
  return undefined;
};

/**
 * URL of a stored project avatar. The version changes on every upload, so
 * browsers load the new image instead of the cached one.
 */
export const projectAvatarUrl = (
  projectId: string,
  version: string | null | undefined,
): string | undefined =>
  version
    ? `/api/projects/${encodeURIComponent(projectId)}/avatar?v=${encodeURIComponent(version)}`
    : undefined;