// 云函数 walkManual — 手动补记（docs/05 R7）
// 规则：isManual=true、countsForRanking=false（不计排行榜，防刷）；可维持连续打卡不断签。
const cloud = require('wx-server-sdk');
cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV });
const db = cloud.database();
const _ = db.command;

const DAY = 86400000;
function toDateStr(ts, tz = 8) {
  const d = new Date(ts + tz * 3600 * 1000);
  const y = d.getUTCFullYear();
  const m = String(d.getUTCMonth() + 1).padStart(2, '0');
  const day = String(d.getUTCDate()).padStart(2, '0');
  return `${y}-${m}-${day}`;
}
function diffDays(a, b) {
  return Math.round((Date.parse(b + 'T00:00:00Z') - Date.parse(a + 'T00:00:00Z')) / DAY);
}
// 连续天数：从该狗全部 walkDate 重算（与 walkSave 一致），保证补记任意顺序都能正确续/断签（docs/05 R10）
async function computeStreak(openid, dogId) {
  const res = await db.collection('walks')
    .where({ _openid: openid, dogIds: dogId })
    .field({ walkDate: true })
    .orderBy('walkDate', 'desc')
    .limit(1000)
    .get();
  const dates = Array.from(new Set(res.data.map((w) => w.walkDate).filter(Boolean))).sort(); // 升序
  if (!dates.length) return { currentStreak: 0, lastWalkDate: '' };
  const lastWalkDate = dates[dates.length - 1];
  let streak = 1;
  for (let i = dates.length - 1; i > 0; i--) {
    if (diffDays(dates[i - 1], dates[i]) === 1) streak++;
    else break;
  }
  return { currentStreak: streak, lastWalkDate };
}

// 补记仅触发连续/累计类成就（不触发分享/场景类）
const STAT_ACHIEVEMENTS = [
  { key: 'first_walk', name: '首遛', cond: (s) => s.totalWalks >= 1 },
  { key: 'week_streak', name: '一周不断', cond: (s) => s.currentStreak >= 7 },
  { key: 'month_streak', name: '满月坚持', cond: (s) => s.currentStreak >= 30 },
  { key: 'hundred_km', name: '百里同行', cond: (s) => s.totalDistance >= 100 },
];
async function unlockAchievements(openid, dogId, candidates) {
  if (!candidates.length) return [];
  const col = db.collection('dog_achievements');
  const existing = await col.where({ dogId }).field({ achievementKey: true }).get();
  const have = new Set(existing.data.map((d) => d.achievementKey));
  const fresh = candidates.filter((c) => !have.has(c.key));
  const now = Date.now();
  for (const c of fresh) {
    await col.add({ data: { _openid: openid, dogId, achievementKey: c.key, unlockedAt: now } });
  }
  return fresh.map((c) => ({ key: c.key, name: c.name }));
}

exports.main = async (event) => {
  const { OPENID } = cloud.getWXContext();
  const { dogId, startAt, duration } = event;
  const distance = event.distance != null ? event.distance : null;
  if (!dogId || !startAt || !duration) {
    return { ok: false, code: 'INVALID', msg: '缺少必要信息' };
  }

  // 校验归属
  const dogRes = await db.collection('dogs').doc(dogId).get().catch(() => null);
  if (!dogRes || !dogRes.data || dogRes.data._openid !== OPENID) {
    return { ok: false, code: 'FORBIDDEN', msg: '无权操作' };
  }

  const now = Date.now();
  const walkDate = toDateStr(startAt);
  const addRes = await db.collection('walks').add({
    data: {
      _openid: OPENID,
      dogIds: [dogId],
      startAt,
      endAt: startAt + duration * 1000,
      duration,
      distance, dogSteps: null, pooped: false,
      weather: null, mood: null, note: null, photos: [],
      source: 'manual',         // 来源标识
      isManual: true,           // 补记标识
      countsForRanking: false,  // 不计排行榜
      walkDate,
      createdAt: now,
    },
  });

  // 更新狗狗统计（维持连续）；连续天数按全部历史重算（已含本条补记）
  const dog = dogRes.data;
  const s = dog.stats || { totalWalks: 0, totalDistance: 0, totalSteps: 0, currentStreak: 0, lastWalkDate: '' };
  const streakInfo = await computeStreak(OPENID, dogId);
  const newStats = {
    totalWalks: (s.totalWalks || 0) + 1,
    totalDistance: +(((s.totalDistance || 0) + (distance || 0)).toFixed(2)),
    totalSteps: s.totalSteps || 0,
    earlyWalks: s.earlyWalks || 0, // 补记不触发场景类成就，早遛计数保持不变
    currentStreak: streakInfo.currentStreak,
    lastWalkDate: streakInfo.lastWalkDate,
  };
  await db.collection('dogs').doc(dogId).update({ data: { stats: newStats } });

  const satisfied = STAT_ACHIEVEMENTS.filter((a) => a.cond(newStats)).map((a) => ({ key: a.key, name: a.name }));
  const newAchievements = await unlockAchievements(OPENID, dogId, satisfied);

  await db.collection('users').where({ _openid: OPENID }).update({ data: { walkCount: _.inc(1) } });

  return { ok: true, data: { walkId: addRes._id, newAchievements } };
};