/**
 * 直聊「保留」计数器：
 * 按会话记下每个模型被保留（点「保留此回复」）了多少次，存在浏览器缓存里。
 * 只算数，不碰 DOM。
 */

const STORAGE_KEY = "wa-direct-chat-keep-stats-v1";

function storage() {
  try {
    return globalThis.localStorage || null;
  } catch {
    return null;
  }
}

function readAll() {
  const ls = storage();
  if (!ls) return {};
  try {
    const parsed = JSON.parse(ls.getItem(STORAGE_KEY) || "{}");
    return parsed && typeof parsed === "object" && !Array.isArray(parsed)
      ? parsed
      : {};
  } catch {
    return {};
  }
}

function writeAll(all) {
  const ls = storage();
  if (!ls) return;
  try {
    ls.setItem(STORAGE_KEY, JSON.stringify(all));
  } catch {
    /* 存不进缓存也不影响当前会话 */
  }
}

function isBucket(value) {
  return Boolean(value) && typeof value === "object" && !Array.isArray(value);
}

/**
 * 模型身份：同一配置同一型号算同一个模型，
 * 窗口被删掉再加回来（窗口 id 变了）也还认作它。
 */
export function keepStatId(w) {
  const model = String(w?.model || "");
  const key = String(w?.profileId || w?.profileName || model || "unknown");
  return model && model !== key ? `${key}::${model}` : key;
}

/** 展示名与型号：配置名 · 型号，重复时只留一个 */
export function keepStatText(w) {
  const model = String(w?.model || "");
  const label = String(
    w?.profileName || w?.profileId || model || "未知模型",
  );
  return { id: keepStatId(w), label, model: model === label ? "" : model };
}

/** 按次数降序，同次数再按名字排 */
export function sortKeepStats(entries) {
  return [...entries].sort(
    (a, b) =>
      Number(b.count) - Number(a.count) ||
      String(a.label).localeCompare(String(b.label), "zh-CN"),
  );
}

/** 条状图宽度百分比：独占一行时满格，次数少的也至少留一点可见宽度 */
export function keepStatPercent(count, max) {
  const top = Number(max) || 0;
  const value = Number(count) || 0;
  if (top <= 0 || value <= 0) return 0;
  return Math.max(6, Math.min(100, Math.round((value / top) * 100)));
}

export function readKeepStats(conversationId) {
  if (!conversationId) return [];
  const bucket = readAll()[conversationId];
  if (!isBucket(bucket)) return [];
  const entries = Object.entries(bucket).map(([id, value]) => ({
    id,
    label: String(value?.label || id),
    model: String(value?.model || ""),
    count: Math.max(1, Number(value?.count) || 0),
  }));
  return sortKeepStats(entries);
}

export function keepStatTotal(entries) {
  return entries.reduce((sum, entry) => sum + (Number(entry.count) || 0), 0);
}

/**
 * 加减一次保留次数；减到 0 就把这个模型从记录里删掉。
 * @param {string} conversationId
 * @param {{profileId?: string, profileName?: string, model?: string}} window
 * @param {number} [delta] 保留 +1、取消保留 -1
 */
export function bumpKeepStats(conversationId, window, delta = 1) {
  if (!conversationId || !window) return readKeepStats(conversationId);
  const step = Number(delta) || 0;
  if (!step) return readKeepStats(conversationId);
  const all = readAll();
  const bucket = isBucket(all[conversationId])
    ? { ...all[conversationId] }
    : {};
  const { id, label, model } = keepStatText(window);
  const before = isBucket(bucket[id]) ? Number(bucket[id].count) || 0 : 0;
  const count = Math.max(0, before + step);
  if (count > 0) bucket[id] = { label, model, count };
  else delete bucket[id];
  if (Object.keys(bucket).length) all[conversationId] = bucket;
  else delete all[conversationId];
  writeAll(all);
  return readKeepStats(conversationId);
}

/** 清掉一个会话的计数（会话被删时用） */
export function clearKeepStats(conversationId) {
  if (!conversationId) return;
  const all = readAll();
  if (!(conversationId in all)) return;
  delete all[conversationId];
  writeAll(all);
}

/** 临时会话存成持久会话时，把计数跟着搬到新会话上 */
export function copyKeepStats(fromId, toId) {
  if (!fromId || !toId || fromId === toId) return readKeepStats(toId);
  const all = readAll();
  const bucket = all[fromId];
  if (!isBucket(bucket)) return readKeepStats(toId);
  all[toId] = { ...(isBucket(all[toId]) ? all[toId] : {}), ...bucket };
  delete all[fromId];
  writeAll(all);
  return readKeepStats(toId);
}