/** 统一头像 URL：无有效头像时始终返回 ossImageUrl + morentouxiang（后端配置） */

function isBlankPath(p) {
  if (p == null) return true;
  if (typeof p !== 'string') return true;
  const s = p.trim();
  return !s || s === 'null' || s === 'undefined' || s === 'none';
}

function readConfigFallback(app) {
  if (!app || typeof app.readConfigFromStorage !== 'function') return null;
  try {
    return app.readConfigFromStorage();
  } catch (e) {
    return null;
  }
}

function getOssBase(app) {
  let oss = app.globalData?.ossImageUrl || '';
  if (!oss) {
    const cfg = readConfigFallback(app);
    oss = cfg?.cos?.ossImageUrl || '';
  }
  return oss;
}

function getDefaultRelative(app) {
  let def = app.globalData?.morentouxiang || '';
  if (!def) {
    const cfg = readConfigFallback(app);
    def = cfg?.otherConfig?.morentouxiang || '';
  }
  return def || 'avatar/default.jpg';
}

export function getDefaultAvatarUrl(app) {
  return resolveAvatarUrl('', app);
}

export function resolveAvatarUrl(rawPath, app) {
  app = app || getApp();
  const oss = getOssBase(app);
  const def = getDefaultRelative(app);

  if (!isBlankPath(rawPath)) {
    if (rawPath.startsWith('http://') || rawPath.startsWith('https://')) {
      return rawPath;
    }
    const path = rawPath.startsWith('/') ? rawPath : `/${rawPath}`;
    if (oss) return oss + path;
    return path;
  }

  if (def.startsWith('http://') || def.startsWith('https://')) {
    return def;
  }
  const defPath = def.startsWith('/') ? def : `/${def}`;
  if (oss) return oss + defPath;
  // 配置未就绪时仍返回相对路径，由 binderror 回退；有 oss 时必须拼完整 URL
  return defPath;
}

/** 是否已是可加载的完整头像 URL */
export function isUsableAvatarUrl(url) {
  return url && (url.startsWith('http://') || url.startsWith('https://'));
}

export function ensureAvatarUrl(rawPath, app) {
  app = app || getApp();
  const resolved = resolveAvatarUrl(rawPath, app);
  if (isUsableAvatarUrl(resolved)) return resolved;
  const def = getDefaultAvatarUrl(app);
  return isUsableAvatarUrl(def) ? def : resolved;
}

export function resolveAvatarFromStorage(app) {
  app = app || getApp();
  const tx = wx.getStorageSync('touxiang') || '';
  return resolveAvatarUrl(tx, app);
}

/** 配置加载后刷新页面头像（聊天页等订阅 configApplied） */
export function subscribeConfigAvatarRefresh(page, refreshFn) {
  const app = getApp();
  if (!app || typeof refreshFn !== 'function') return null;
  const handler = () => refreshFn();
  if (app.on) app.on('configApplied', handler);
  return () => { if (app.off) app.off('configApplied', handler); };
}

/** 消息列表/聊天页 image 加载失败时回退默认头像 */
export function onAvatarImageError(page, dataKey, app) {
  if (!page || !dataKey) return;
  const def = getDefaultAvatarUrl(app || getApp());
  page.setData({ [dataKey]: def });
}