// Taobao scopes are independent: userInfo login does not grant camera/album.
//
// 平台差异（2026-11-01 真机实测，SDKVersion=2.9.4）：
//   my.getSetting 返回 {"scope.userInfo":true,"scope.camera":true}
//   my.authorize({scopes:'camera'})      → 失败 {"errorCode":"5022","errorMessage":"Scope:camera信息不存在"}
//   my.authorize({scopes:'scope.camera'}) → 成功
// 结论：淘宝用带前缀的 scope.camera / scope.album（和微信一致），裸名不存在。
// 这里优先用带前缀的写法，失败再退回裸名（兼容其它淘宝/SDK 版本）。
var denied = {};
var lastError = null;

function bare(scope) { return scope.replace(/^scope\./, ''); }
function prefixed(scope) { return /^scope\./.test(scope) ? scope : 'scope.' + scope; }

function state(settings, scope) {
  settings = settings || {};
  var key = bare(scope);
  return typeof settings[scope] === 'boolean' ? settings[scope] : settings[key];
}
function settings() {
  return new Promise(function (resolve) {
    if (typeof my.getSetting !== 'function') { resolve({}); return; }
    try {
      my.getSetting({
        success: function (res) { resolve((res && res.authSetting) || {}); },
        fail: function () { resolve({}); }
      });
    } catch (e) { resolve({}); } // API 不存在/同步抛错：当作空设置，走后续兜底
  });
}

// 平台是否具备内置相机能力（淘宝部分版本没有 <camera> / createCameraContext）
function cameraSupported() {
  try {
    if (typeof my.createCameraContext !== 'function') return false;
    if (typeof my.canIUse === 'function') return !!my.canIUse('camera') && !!my.canIUse('createCameraContext');
    return true;
  } catch (e) { return false; }
}
function describe(err) {
  if (err === undefined || err === null) return 'null';
  try { return JSON.stringify(err).slice(0, 200); } catch (e) { return String(err).slice(0, 200); }
}
function rejected(scope) {
  var err = new Error(scope === 'scope.camera'
    ? '相机权限未开启：请点「授权设置」开启，或直接用系统相机/相册'
    : '相册权限未开启，请在授权设置中开启');
  err.permission = scope; err.detail = lastError;
  return err;
}
// 授权：先按支付宝/淘宝的裸名字（camera），失败且不是"用户拒绝"时再试微信式（scope.camera）
function authorizeOnce(scopes) {
  return new Promise(function (resolve, reject) {
    my.authorize({ scopes: scopes,
      success: function (res) { resolve({ scopes: scopes, ok: true, res: res }); },
      fail: function (err) { reject({ scopes: scopes, ok: false, err: err }); } });
  });
}
function ensure(scope) {
  return settings().then(function (current) {
    if (state(current, scope) === true) { delete denied[scope]; return; }
    if (state(current, scope) === false || denied[scope]) throw rejected(scope);
    if (typeof my.authorize !== 'function') throw new Error('当前淘宝版本不支持授权，请升级后重试');
    return authorizeOnce(prefixed(scope)).catch(function (first) {
      lastError = describe(first.err);
      return authorizeOnce(bare(scope)).catch(function (second) {
        lastError = describe(first.err) + ' / ' + describe(second.err);
        denied[scope] = true;
        throw rejected(scope);
      });
    }).then(function () { delete denied[scope]; });
  });
}
function open() {
  return new Promise(function (resolve, reject) {
    if (typeof my.openSetting !== 'function') { reject(new Error('请在小程序右上角的授权设置中开启权限')); return; }
    my.openSetting({ success: function (res) {
      var current = res.authSetting || {};
      ['scope.camera', 'scope.album'].forEach(function (scope) { if (state(current, scope) === true) delete denied[scope]; });
      resolve(current);
    }, fail: function () { reject(new Error('无法打开授权设置，请从小程序右上角进入')); } });
  });
}

// 权限诊断：把真机上的真实能力/返回值打出来，供页面展示与截图
function diagnose() {
  var info = [];
  try { info.push('SDKVersion=' + (my.SDKVersion || '(none)')); } catch (e) { info.push('SDKVersion=error'); }
  ['camera', 'createCameraContext', 'chooseImage', 'authorize', 'getSetting', 'openSetting', 'getImageInfo', 'createCanvasContext'].forEach(function (api) {
    var use = 'n/a';
    try { use = typeof my.canIUse === 'function' ? (my.canIUse(api) ? 'yes' : 'no') : 'no-canIUse'; } catch (e) { use = 'canIUse-err'; }
    info.push(api + ': typeof=' + (typeof my[api]) + ' canIUse=' + use);
  });
  return settings().then(function (current) {
    info.push('authSetting=' + describe(current));
    if (typeof my.authorize !== 'function') { info.push('authorize: 无此 API'); return info; }
    return authorizeOnce(prefixed('camera')).then(function (r) {
      info.push('authorize(scope.camera)=ok ' + describe(r.res));
    }, function (r) {
      info.push('authorize(scope.camera)=fail ' + describe(r.err));
      return authorizeOnce(bare('camera')).then(function (r2) {
        info.push('authorize(camera)=ok ' + describe(r2.res));
      }, function (r2) {
        info.push('authorize(camera)=fail ' + describe(r2.err));
      });
    }).then(function () { return info; });
  });
}

module.exports = { ensure: ensure, settings: settings, state: state, open: open, diagnose: diagnose, bare: bare, cameraSupported: cameraSupported };