import cloud from "@lafjs/cloud";
import { compareVersions } from "@/versionPolicy";
import { refreshTaskData } from "@/dailyTaskService";

export const DAILY_TASK_MIN_VERSION = "1.0.88";
const OFFSET = 8 * 3600000;
const DAY = 86400000;
export const LEGACY_TARGETS = { levelPass: 3, share: 1, useEnergy: 10, useProp: 3 };

export function supportsDailyTaskV2(version: unknown): boolean {
  const compared = compareVersions(version, DAILY_TASK_MIN_VERSION);
  return compared !== null && compared >= 0;
}

export function parseTask(stored: any): any {
  if (typeof stored !== "string") return stored;
  try { return JSON.parse(stored); } catch { return null; }
}

export function isV2Task(stored: any): boolean {
  return Number(parseTask(stored)?.version) >= 2;
}

export function taskVersionError() {
  return { code: 0, errorCode: "DAILY_TASK_VERSION_REQUIRED", data: null,
    msg: "每日任务已升级，请更新客户端后重新进入", minVersion: DAILY_TASK_MIN_VERSION };
}

export function taskConflict() {
  return { code: 0, data: null, msg: "任务数据已更新，请重新读取后重试" };
}

/** 旧 taskTime 使用 UTC 时间戳加 8 小时，保留该约定兼容已发布客户端。 */
export function refreshLegacyTask(stored: any, taskTime: any, now = Date.now()): any {
  const old = parseTask(stored);
  const reset = Math.floor((now + OFFSET) / DAY) * DAY > (Number(taskTime) || 0);
  const task: any = {};
  Object.keys(LEGACY_TARGETS).forEach(key => {
    const value = reset ? 0 : Math.max(0, Number(old?.[key]?.value) || 0);
    const claimed = !reset && old?.[key]?.state === 2;
    task[key] = { value, target: LEGACY_TARGETS[key], state: claimed ? 2 : value >= LEGACY_TARGETS[key] ? 1 : 0 };
  });
  return task;
}

/** 比较读取时的 task/taskTime，防止旧请求覆盖迁移结果，也防止重复领奖。 */
export async function writeTask(dbname: string, user: any, task: any, taskTime: number): Promise<boolean> {
  const filter: any = { _id: user._id };
  for (const key of ["task", "taskTime"]) {
    filter[key] = Object.prototype.hasOwnProperty.call(user, key) ? user[key] : { $exists: false };
  }
  const result = await cloud.mongo.db.collection(dbname).updateOne(filter, {
    $set: { task: JSON.stringify(task), taskTime },
  });
  return result.matchedCount === 1;
}

/** 所有登录分支共用；仅从旧协议迁移到新协议，绝不反向覆盖。 */
export async function ensureLoginTasks(dbname: string, user: any, version: unknown) {
  const modern = supportsDailyTaskV2(version);
  for (let attempt = 0; attempt < 3; attempt++) {
    if (!modern && isV2Task(user.task)) return { error: taskVersionError() };
    const now = Date.now();
    const task = modern ? refreshTaskData(user.task, user._id, Number(user.levelAmount) + 1 || 1, now).data
      : refreshLegacyTask(user.task, user.taskTime, now);
    const taskTime = modern ? now : now + OFFSET;
    if (await writeTask(dbname, user, task, taskTime)) {
      user.task = JSON.stringify(task);
      user.taskTime = taskTime;
      return { user };
    }
    const latest = await cloud.database().collection(dbname).where({ _id: user._id }).getOne();
    if (!latest.data) return { error: taskConflict() };
    user = latest.data;
  }
  return { error: taskConflict() };
}