import Taro from '@tarojs/taro';
import { request } from './api';

const PROMO_ID_KEY = 'dukang_promo_id';

/** 同一次进入只 touch 一次扫码计数，避免首页反复 onShow 刷量 */
let lastScanTouchKey = '';

function safeDecode(raw: string): string {
  try {
    return decodeURIComponent(raw);
  } catch {
    return raw;
  }
}

function normalizePromoId(raw: unknown): string | null {
  if (raw == null || raw === '') return null;
  const s = safeDecode(String(raw)).trim();
  // 小程序码 scene 写入的是推广活动数字 ID
  if (!/^\d+$/.test(s)) return null;
  return s;
}

type EnterOptionsLike = {
  scene?: string | number;
  query?: Record<string, string | undefined>;
  path?: string;
};

/** 从启动/进入参数解析推广活动 ID（优先 query.scene，与 getwxacodeunlimit 一致） */
export function extractPromoIdFromEnterOptions(opts?: EnterOptionsLike | null): string | null {
  if (!opts) return null;
  const q = opts.query ?? {};
  return (
    normalizePromoId(q.scene) ||
    normalizePromoId(q.promoId) ||
    normalizePromoId(q.pid) ||
    null
  );
}

export function getStoredPromoId(): string | null {
  try {
    const v = Taro.getStorageSync(PROMO_ID_KEY);
    return normalizePromoId(v);
  } catch {
    return null;
  }
}

export function setStoredPromoId(promoId: string) {
  const id = normalizePromoId(promoId);
  if (!id) return;
  try {
    Taro.setStorageSync(PROMO_ID_KEY, id);
  } catch {
    /* ignore */
  }
}

function readEnterOptions(): EnterOptionsLike | null {
  try {
    if (typeof Taro.getEnterOptionsSync === 'function') {
      return Taro.getEnterOptionsSync() as EnterOptionsLike;
    }
  } catch {
    /* ignore */
  }
  try {
    if (typeof Taro.getLaunchOptionsSync === 'function') {
      return Taro.getLaunchOptionsSync() as EnterOptionsLike;
    }
  } catch {
    /* ignore */
  }
  // H5：从 URL query 读取
  if (process.env.TARO_ENV === 'h5' && typeof window !== 'undefined') {
    const params = new URLSearchParams(window.location.search);
    return {
      query: {
        scene: params.get('scene') || undefined,
        promoId: params.get('promoId') || undefined,
        pid: params.get('pid') || undefined,
      },
    };
  }
  return null;
}

/**
 * 主页面进入时：取出 scene（活动 ID）本地缓存，并回传 /promo/touch 累加扫码次数。
 * 同一进入会话只计一次扫码。
 */
export async function capturePromoSceneAndTouchScan(): Promise<void> {
  const opts = readEnterOptions();
  const fromEnter = extractPromoIdFromEnterOptions(opts);
  if (fromEnter) {
    setStoredPromoId(fromEnter);
    const touchKey = `${fromEnter}|${opts?.path || ''}|${JSON.stringify(opts?.query || {})}|${String(opts?.scene ?? '')}`;
    if (touchKey === lastScanTouchKey) return;
    lastScanTouchKey = touchKey;
    await touchPromo({ promoId: fromEnter, countScan: true });
    return;
  }

  // 无新 scene 时不重复扫码计数
}

/** 登录成功后：用已缓存的活动 ID 做归因（不重复加扫码次数） */
export async function touchStoredPromoAfterLogin(): Promise<void> {
  const promoId = getStoredPromoId();
  if (!promoId) return;
  await touchPromo({ promoId, countScan: false });
}

async function touchPromo(input: { promoId: string; countScan: boolean }): Promise<void> {
  try {
    await request('/promo/touch', {
      method: 'POST',
      data: {
        promoId: input.promoId,
        countScan: input.countScan,
      },
    });
  } catch {
    /* 静默失败，不阻断浏览 */
  }
}