// Avatars — the decrypted-photo cache and the initials/photo painters.
// avatarFor unwraps a member's profile photo with the instance key;
// threadAvatarFor a group's photo with its thread key; paintAvatar/avatarEl
// paint initials immediately and swap the photo in when a loader resolves.
// Gathered from shell.js's three avatar sites (docs/shell-modules.md).
import { decryptBytes } from "/static/crypto.js";
import { session, roster, threads, threadKeys, instanceKey } from "/static/shellstate.js";

export const avatarURLs = {}; // user id -> decrypted profile-photo object URL (cache)

// A member's decrypted profile-photo object URL (instance key), or null.
export async function avatarFor(userId) {
  if (avatarURLs[userId]) return avatarURLs[userId];
  const e = roster.find((x) => x.user_id === userId);
  // The live agent Eleven is the UPGRADED built-in helper, not a stranger:
  // until someone gives it a custom photo it wears the app icon — the same
  // face as the scripted welcome/setup conversations (one Eleven).
  if (e && e.is_agent && !e.avatar && /^eleven$/i.test(e.label || "")) return "/static/icon-192.png";
  if (!e || !e.avatar || !instanceKey) return null;
  try {
    const buf = new Uint8Array(
      await (await fetch(`/api/blob/${encodeURIComponent(e.avatar)}?token=${encodeURIComponent(session.token)}`)).arrayBuffer()
    );
    const url = URL.createObjectURL(new Blob([await decryptBytes(instanceKey, buf)]));
    avatarURLs[userId] = url;
    return url;
  } catch {
    return null;
  }
}

// A group's decrypted photo object URL (thread key), or null.
export async function threadAvatarFor(threadId) {
  const cacheKey = "t:" + threadId;
  if (avatarURLs[cacheKey]) return avatarURLs[cacheKey];
  const t = threads.find((x) => x.id === threadId);
  const key = threadKeys[threadId];
  if (!t || !t.avatar || !key) return null;
  try {
    const buf = new Uint8Array(
      await (await fetch(`/api/blob/${encodeURIComponent(t.avatar)}?token=${encodeURIComponent(session.token)}`)).arrayBuffer()
    );
    const url = URL.createObjectURL(new Blob([await decryptBytes(key, buf)]));
    avatarURLs[cacheKey] = url;
    return url;
  } catch {
    return null;
  }
}

function avatarColor(name) {
  let h = 0;
  for (const ch of name || "?") h = (h * 31 + ch.charCodeAt(0)) >>> 0;
  return `hsl(${h % 360} 55% 52%)`;
}
// Paint an initials circle; if a photo `loader` (() => Promise<url|null>) is given,
// swap the photo in once it resolves.
// Paints initials immediately, then the photo (if any) when its loader resolves.
// Returns a promise of the photo URL (or null), so callers can react to it —
// e.g. the header avatar wires a tap-to-zoom only when there's a real photo.
export function paintAvatar(el, name, loader, alt) {
  // Avatars are background-image spans, invisible to screen readers without
  // this: the member's own (encrypted) photo description wins over their name.
  el.setAttribute("role", "img");
  el.setAttribute("aria-label", alt || name || "");
  el.style.backgroundImage = "";
  el.textContent = ((name || "?").trim().charAt(0) || "?").toUpperCase();
  el.style.background = avatarColor(name);
  el.style.backgroundSize = "cover";
  el.style.backgroundPosition = "center";
  if (!loader) return Promise.resolve(null);
  return loader().then((url) => {
    if (url) {
      el.textContent = "";
      el.style.backgroundImage = `url(${url})`;
    }
    return url || null;
  });
}
export function avatarEl(name, loader) {
  const el = document.createElement("span");
  el.className = "avatar";
  paintAvatar(el, name, loader);
  return el;
}