var config = require('../config'), transport = require('./transport');
var token = '', user = null, storageKey = 'juzi.taobao.session.v1';
var sessionVersion = 0, authAttempt = 0, restoring = null, pendingAnalysis = null;
var validationEpoch = 0, needsValidation = false;
function assetUrl(path) { return config.assetBase.replace(/\/?$/, '/') + path.replace(/^assets\//, ''); }
function isGuest() { return !!(user && user.kind === 'taobao_guest'); }
function hasSession() { return !!(token && user); }
function isSignedIn() { return hasSession() && !isGuest() && !needsValidation; }
function clearTransient() {
  pendingAnalysis = null;
  var app = typeof getApp === 'function' && getApp();
  if (app) { app.globalData.profile = null; app.globalData.photos = null; app.globalData.payload = null; }
}
function clear(keepSaved) {
  token = ''; user = null; sessionVersion++; authAttempt++; restoring = null;
  validationEpoch++; needsValidation = false;
  if (!keepSaved) { try { my.removeStorageSync({ key: storageKey }); } catch (_) {} }
  clearTransient();
}
function resetForLaunch() { clear(true); }
function suspendSession() {
  validationEpoch++; restoring = null;
  needsValidation = !!token && !isGuest();
}
function stale() { var err = new Error('本次会话已结束，请重新进入'); err.canceled = true; return err; }
function request(path, body) {
  var protectedRequest = !/^(me|challenge|session|guest-session|logout)$/.test(path);
  if (protectedRequest && needsValidation && token && !isGuest()) {
    return restore().then(function () { return request(path, body); });
  }
  var requestToken = token, version = sessionVersion, epoch = validationEpoch;
  return transport.request('/api/taobao/' + path, body || {}, requestToken).then(function (data) {
    if (requestToken !== token || version !== sessionVersion) throw stale();
    if (protectedRequest && !isGuest() && epoch !== validationEpoch) throw stale();
    if (!data || !data.ok) {
      var err = new Error(data && data.message || '服务暂不可用，请稍后重试');
      err.status = data && data.http_status; err.code = data && data.code;
      if (err.status === 401) clear();
      throw err;
    }
    return data;
  });
}
function authorize() {
  if (config.transport === 'direct') return Promise.resolve();
  return new Promise(function (resolve, reject) {
    my.authorize({ scopes: 'scope.userInfo', success: resolve,
      fail: function () { reject(new Error('淘宝账号授权未完成，您也可以选择游客体验')); } });
  });
}
function startSession(consent, guest) {
  if (!consent) return Promise.reject(new Error('请先阅读并同意用户协议和隐私政策'));
  // A deliberate guest entry ends the previous identity before any async work.
  // Old /me success/401 responses then fail the session-version guard, and the
  // guest challenge/session never inherit the old Bearer or persisted account.
  if (guest) clear();
  var ticket = ++authAttempt;
  return (guest ? Promise.resolve() : authorize()).then(function () {
    if (ticket !== authAttempt) throw stale();
    return request('challenge');
  }).then(function (data) {
    if (ticket !== authAttempt) throw stale();
    return request(guest ? 'guest-session' : 'session', { consent: true, challenge: data.challenge });
  }).then(function (data) {
    if (ticket !== authAttempt) throw stale();
    if (!data.token || !data.user || !data.user.id || (guest && data.user.kind !== 'taobao_guest')) throw new Error('未能建立检测会话，请重试');
    clearTransient(); sessionVersion++; validationEpoch++; needsValidation = false;
    token = data.token; user = data.user;
    if (guest) { try { my.removeStorageSync({ key: storageKey }); } catch (_) {} }
    else my.setStorageSync({ key: storageKey, data: { token: token, user: user } });
    return user;
  });
}
function login(consent) { return startSession(consent, false); }
function loginGuest(consent) { return startSession(consent, true); }
function restore() {
  // A product-detail round trip must preserve the current in-memory guest/report.
  if (isGuest()) return Promise.resolve(user);
  if (restoring) return restoring;
  if (!token) {
    try {
      var saved = my.getStorageSync({ key: storageKey }).data;
      if (saved && saved.user && saved.user.kind === 'taobao_guest') { my.removeStorageSync({ key: storageKey }); return Promise.resolve(null); }
      if (saved && saved.token) { token = saved.token; user = null; sessionVersion++; needsValidation = true; }
    } catch (_) {}
  }
  if (!token) return Promise.resolve(null);
  needsValidation = true;
  var version = sessionVersion, epoch = validationEpoch;
  restoring = request('me').then(function (data) {
    if (version !== sessionVersion || epoch !== validationEpoch) throw stale();
    if (!data.user || !data.user.id || data.user.kind === 'taobao_guest') { clear(); return null; }
    user = data.user; needsValidation = false; return user;
  });
  var result = restoring;
  return result.then(function (value) { if (restoring === result) restoring = null; return value; },
    function (err) { if (restoring === result) restoring = null; throw err; });
}
function canceled(signal) { if (signal && signal.canceled) { var e = new Error('已停止等待'); e.canceled = true; throw e; } }
function wait(ms, signal) { return new Promise(function (resolve) { setTimeout(resolve, ms); }).then(function () { canceled(signal); }); }
function poll(job, signal, deadline) {
  canceled(signal);
  if (Date.now() >= deadline) throw new Error(isGuest()
    ? '检测仍在处理中，请留在本次体验中重试查看；游客报告不保存到历史。'
    : '检测仍在处理中，请重试查看或稍后从历史报告查看');
  return request('analysis', { job: job }).then(function (data) {
    canceled(signal);
    if (data.status !== 'complete') return wait(1000, signal).then(function () { return poll(job, signal, deadline); });
    if (!data.payload || !data.payload.ok) throw new Error(data.payload && data.payload.message || '检测失败，请重试');
    return data.payload;
  });
}
function upload(view, photo, signal) {
  var b64 = photo.replace(/^data:image\/[^;]+;base64,/, ''), size = 64 * 1024;
  if (!b64 || b64.length > 4 * 1024 * 1024) return Promise.reject(new Error('照片过大，请重新拍摄'));
  var id = Date.now().toString(36) + '-' + Math.random().toString(36).slice(2), total = Math.ceil(b64.length / size);
  var chain = Promise.resolve();
  for (var i = 0; i < total; i++) (function (index) {
    chain = chain.then(function () { canceled(signal); return request('photo', { view: view, upload_id: id, index: index, total: total, data: b64.slice(index * size, (index + 1) * size) }); });
  })(i);
  return chain.then(function () { return id; });
}
function createAnalysisAttempt() {
  return { requestId: 'tb-' + Date.now().toString(36) + '-' + Math.random().toString(36).slice(2),
    ownerVersion: sessionVersion, job: '', status: 'ready', photoRefs: {}, photos: null, profile: null };
}
function runAttempt(attempt, signal) {
  if (attempt.ownerVersion !== sessionVersion || !hasSession()) return Promise.reject(stale());
  canceled(signal);
  if (attempt.running) return attempt.running.catch(function () {}).then(function () { return runAttempt(attempt, signal); });
  var operation;
  if (attempt.job) operation = Promise.resolve();
  else if (!attempt.profile) return Promise.reject(new Error('没有可恢复的检测任务，请重新拍摄'));
  else {
    attempt.status = 'uploading';
    operation = ['front', 'left', 'right'].reduce(function (chain, view, i) {
      return chain.then(function () {
        if (attempt.photoRefs[view]) return;
        if (!attempt.photos || !attempt.photos[i]) throw new Error('检测照片不完整，请重新拍摄');
        return upload(view, attempt.photos[i], signal).then(function (id) { attempt.photoRefs[view] = id; });
      });
    }, Promise.resolve()).then(function () {
      canceled(signal); attempt.status = 'submitting';
      return request('skin-analyze', { photo_refs: attempt.photoRefs, profile: attempt.profile, request_id: attempt.requestId });
    }).then(function (data) {
      attempt.job = data.job; attempt.photos = null;
      if (!attempt.job) throw new Error('未能取得检测任务，请重试');
    });
  }
  var running = operation.then(function () {
    canceled(signal); attempt.status = 'polling';
    return poll(attempt.job, signal, Date.now() + 90000);
  }).then(function (payload) {
    attempt.status = 'complete';
    if (pendingAnalysis === attempt) pendingAnalysis = null;
    return payload;
  }, function (err) {
    attempt.status = err.canceled ? 'paused' : 'failed';
    if (err.status === 404 || err.status === 410) { err.message = '本次检测任务已失效，请重新拍摄；不会自动重复检测'; attempt.status = 'expired'; }
    throw err;
  });
  attempt.running = running;
  return running.then(function (value) { if (attempt.running === running) attempt.running = null; return value; },
    function (err) { if (attempt.running === running) attempt.running = null; throw err; });
}
function analyze(photos, profile, signal, attempt) {
  if (config.mock) {
    var SS = require('../vendor/skin-score'), UI = require('../vendor/report-ui');
    var vm = SS.buildViewModel(SS.MOCK_RESULT, SS.MOCK_SIDE, { realAge: profile.real_age, skinType: profile.daily_skin_type });
    return Promise.resolve({ ok: true, result: SS.MOCK_RESULT, side: SS.MOCK_SIDE, vm: vm, presentation: UI.build(vm, SS.MOCK_RESULT) });
  }
  attempt = attempt || createAnalysisAttempt();
  if (!attempt.profile) { attempt.profile = Object.assign({}, profile); attempt.photos = photos.slice(); }
  pendingAnalysis = attempt;
  return Promise.resolve().then(function () { return runAttempt(attempt, signal); });
}
function resumeAnalysis(attempt, signal) {
  attempt = attempt || pendingAnalysis;
  if (!attempt || attempt.status === 'expired') return Promise.reject(new Error('本次检测任务已失效，请重新拍摄'));
  return Promise.resolve().then(function () { return runAttempt(attempt, signal); });
}
function wrinkleViews(jobToken, signal) {
  return request('wrinkle-views', { token: jobToken }).then(function (data) { return poll(data.job, signal, Date.now() + 90000); });
}
function logout() {
  if (!token) { clear(); return Promise.resolve(); }
  return request('logout').catch(function (err) { if (err.status !== 401) throw err; }).then(function () { clear(); });
}
function endGuest() {
  if (!isGuest()) return Promise.resolve();
  var oldToken = token;
  clear();
  try { Promise.resolve(transport.request('/api/taobao/logout', {}, oldToken)).catch(function () {}); } catch (_) {}
  return Promise.resolve();
}
module.exports = { assetUrl: assetUrl, analyze: analyze, login: login, loginGuest: loginGuest, restore: restore, request: request,
  user: function () { return user; }, hasSession: hasSession, isGuest: isGuest, isSignedIn: isSignedIn,
  logout: logout, endGuest: endGuest, resetForLaunch: resetForLaunch, suspendSession: suspendSession, clear: clear,
  createAnalysisAttempt: createAnalysisAttempt, resumeAnalysis: resumeAnalysis,
  getPendingAnalysis: function () { return pendingAnalysis; },
  discardAnalysis: function (attempt) { if (!attempt || pendingAnalysis === attempt) pendingAnalysis = null; },
  wrinkleViews: wrinkleViews };