;(function (exports) {
'use strict';

var OAUTH3 = exports.OAUTH3 = exports.OAUTH3 || require('./oauth3.core.js').OAUTH3;

OAUTH3.url.parse = function (url) {
  // TODO browser
  // Node should replace this
  var parser = document.createElement('a');
  parser.href = url;
  return parser;
};
OAUTH3.url._isRedirectHostSafe = function (referrerUrl, redirectUrl) {
  var src = OAUTH3.url.parse(referrerUrl);
  var dst = OAUTH3.url.parse(redirectUrl);

  // TODO how should we handle subdomains?
  // It should be safe for api.example.com to redirect to example.com
  // But it may not be safe for to example.com to redirect to aj.example.com
  // It is also probably not safe for sally.example.com to redirect to john.example.com
  // The client should have a list of allowed URLs to choose from and perhaps a wildcard will do
  //
  // api.example.com.evil.com SHOULD NOT match example.com
  return dst.hostname === src.hostname;
};
OAUTH3.url.checkRedirect = function (client, query) {
  console.warn("[security] URL path checking not yet implemented");
  if (!query) {
    query = client;
    client = query.client_uri;
  }
  client = client.url || client;

  // it doesn't matter who the referrer is as long as the destination
  // is an authorized destination for the client in question
  // (though it may not hurt to pass the referrer's info on to the client)
  var clientUrl = OAUTH3.url.normalize(client);
  var redirectUrl = OAUTH3.url.normalize(query.redirect_uri);

  // General rule:
  // I can callback to a shorter domain (fewer subs) or a shorter path (on the same domain)
  // but not a longer (more subs) or different domain or a longer path (on the same domain)


  // We can callback to an explicitly listed domain (TODO and path)
  if (OAUTH3.url._isRedirectHostSafe(clientUrl, redirectUrl)) {
    return true;
  }

  var callbackUrl = 'https://oauth3.org/docs/errors#E_REDIRECT_ATTACK?'+OAUTH3.query.stringify({
    'redirect_uri': redirectUrl
  , 'allowed_urls': clientUrl
  , 'client_id':    client
  , 'referrer_uri': OAUTH3.uri.normalize(window.document.referrer)
  });
  if (query.debug) {
    console.log('Redirect Attack');
    console.log(query);
    window.alert("DEBUG MODE checkRedirect error encountered. Check the console.");
  }
  location.href = callbackUrl;
  return false;
};
OAUTH3.url.redirect = function (clientParams, grants, tokenOrError) {
  // TODO OAUTH3.redirect(clientParams, grants, tokenOrError)
  // TODO check redirect safeness right here with grants.client.urls
  // TODO check for '#' and '?'. If none, issue warning and use '?' (for backwards compat)

  var authz = {
    access_token: tokenOrError.access_token
  , token_type: tokenOrError.token_type         // 'Bearer'
  , refresh_token: tokenOrError.refresh_token
  , expires_in: tokenOrError.expires_in         // 1800 (but superceded by jwt.exp)
  , scope: tokenOrError.scope                   // superceded by jwt.scp

  , state: clientParams.state
  , debug: clientParams.debug
  };
  if (tokenOrError.error) {
    authz.error = tokenOrError.error.code || tokenOrError.error;
    authz.error_description = tokenOrError.error.message || tokenOrError.error_description;
    authz.error_uri = tokenOrError.error.uri || tokenOrError.error_uri;
  }
  var redirect = clientParams.redirect_uri + '#' + window.OAUTH3.query.stringify(authz);

  if (clientParams.debug) {
    console.info('final redirect_uri:', redirect);
    window.alert("You're in debug mode so we've taken a pause. Hit OK to continue");
  }

  window.location = redirect;
};


OAUTH3.urls.resourceOwnerPassword = function (directive, opts) {
  //
  // Example Resource Owner Password Request
  // (generally for 1st party and direct-partner mobile apps, and webapps)
  //
  // POST https://example.com/api/issuer@oauth3.org/access_token
  //    { "grant_type": "password", "client_id": "<<id>>", "scope": "<<scope>>"
  //    , "username": "<<username>>", "password": "password" }
  //
  opts = opts || {};

  if (!opts.password) {
    if (opts.otp) {
      // for backwards compat
      opts.password = opts.otp; // 'otp:' + opts.otpUuid + ':' + opts.otp;
    }
  }

  var args = directive.access_token;
  var otpCode = opts.otp || opts.otpCode || opts.otp_code || opts.otpToken || opts.otp_token || undefined;
  // TODO require user agent
  var params = {
    client_id: opts.client_id || opts.client_uri
  , client_uri: opts.client_uri
  , grant_type: 'password'
  , username: opts.username
  , password: opts.password || otpCode || undefined
  , totp: opts.totp || opts.totpToken || opts.totp_token || undefined
  , otp: otpCode
  , password_type: otpCode && 'otp'
  , otp_code: otpCode
  , otp_uuid: opts.otpUuid || opts.otp_uuid || undefined
  , user_agent: opts.userAgent || opts.useragent || opts.user_agent || undefined // AJ's Macbook
  , jwk: (opts.rememberDevice || opts.remember_device) && opts.jwk || undefined
  //, "public_key": opts.rememberDevice && opts.publicKey || undefined
  //, "public_key_type":  opts.rememberDevice && opts.publicKeyType || undefined // RSA/ECDSA
  //, "jwt": opts.jwt // TODO sign a proof with a previously loaded public_key
  , debug: opts.debug || undefined
  };

  if (opts.client_uri) {
    params.clientAgreeTos = 'oauth3.org/tos/draft'; // opts.clientAgreeTos || opts.client_agree_tos;
    if (!params.clientAgreeTos) {
      throw new Error('Developer Error: missing clientAgreeTos uri');
    }
  }

  var scope = opts.scope || directive.authn_scope;
  if (scope) {
    params.scope = OAUTH3.scope.stringify(scope);
  }

  var uri = args.url;
  var body;
  if ('GET' === args.method.toUpperCase()) {
    uri += '?' + OAUTH3.query.stringify(params);
  } else {
    body = params;
  }

  return {
    url: OAUTH3.url.resolve(directive.api, uri)
  , method: args.method
  , data: body
  };
};
OAUTH3.urls.grants = function (directive, opts) {
  // directive = { issuer, authorization_decision }
  // opts = { response_type, scopes{ granted, requested, pending, accepted } }
  var grantsDir = directive.grants;
  if (!grantsDir) {
    throw new Error("provider doesn't support grants");
  }

  if (!opts) {
    throw new Error("You must supply a directive and an options object.");
  }
  if (!opts.client_id) {
    throw new Error("You must supply options.client_id.");
  }
  if (!opts.session) {
    throw new Error("You must supply options.session.");
  }
  if (!opts.referrer) {
    console.warn("You should supply options.referrer");
  }
  if (!opts.method) {
    console.warn("You should supply options.method as either 'GET', or 'POST'");
    opts.method = grantsDir.method || 'GET';
  }
  if ('POST' === opts.method) {
    if ('string' !== typeof opts.scope) {
      throw new Error("You must supply options.scope as a comma-delimited string of scopes");
    }
    if ('string' !== typeof opts.sub) {
      console.log("provide 'sub' to urls.grants to specify the PPID for the client");
    }
  }

  var url = OAUTH3.url.resolve(directive.api, grantsDir.url)
    .replace(/(:sub|:account_id)/g, opts.session.token.sub || 'ISSUER:GRANT:TOKEN_SUB:UNDEFINED')
    .replace(/(:azp|:client_id)/g, !opts.all && OAUTH3.uri.normalize(opts.client_id || opts.client_uri) || '')
    .replace(/\/\/$/, '/') // if there's a double slash due to the sub not existing
    ;
  var data = {
    client_id: opts.client_id
  , client_uri: opts.client_uri
  , referrer: opts.referrer
  , scope: opts.scope
  , sub: opts.sub
  };

  var body;
  if ('GET' === opts.method) {
    url += '?' + OAUTH3.query.stringify(data);
  } else {
    body = data;
  }

  return {
    method: opts.method
  , url: url
  , data: body
  , session: opts.session
  };
};
//OAUTH3.urls.accessToken = function (directive, opts)
OAUTH3.urls.clientToken = function (directive, opts) {
  var tokenDir = directive.access_token;
  if (!tokenDir) {
    throw new Error("provider doesn't support getting access tokens");
  }

  if (!opts) {
    throw new Error("You must supply a directive and an options object.");
  }
  if (!(opts.azp || opts.client_id)) {
    throw new Error("You must supply options.client_id.");
  }
  if (!opts.session) {
    throw new Error("You must supply options.session.");
  }
  if (!opts.method) {
    opts.method = tokenDir.method || 'POST';
  }

  var params = {
    grant_type: 'issuer_token'
  , client_id:  opts.azp || opts.client_id
  , azp: opts.azp || opts.client_id
  , aud: opts.aud
  , exp: opts.exp
  , refresh_token: opts.refresh_token
  , refresh_exp: opts.refresh_exp
  };

  var url = OAUTH3.url.resolve(directive.api, tokenDir.url);
  var body;
  if ('GET' === opts.method) {
    url += '?' + OAUTH3.query.stringify(params);
  } else {
    body = params;
  }

  return {
    method: opts.method
  , url: url
  , data: body
  , session: opts.session
  };
};
OAUTH3.urls.publishKey = function (directive, opts) {
  var jwkDir = directive.publish_jwk;
  if (!jwkDir) {
    throw new Error("provider doesn't support publishing public keys");
  }
  if (!opts) {
    throw new Error("You must supply a directive and an options object.");
  }
  if (!opts.session) {
    throw new Error("You must supply 'options.session'.");
  }
  if (!(opts.public_key || opts.publicKey)) {
    throw new Error("You must supply 'options.public_key'.");
  }

  var url = OAUTH3.url.resolve(directive.api, jwkDir.url)
    .replace(/(:sub|:account_id)/g, opts.session.token.sub)
    ;

  return {
    method: jwkDir.method || opts.method || 'POST'
  , url: url
  , data: opts.public_key || opts.publicKey
  , session: opts.session
  };
};
OAUTH3.urls.credentialMeta = function (directive, opts) {
  return OAUTH3.url.resolve(directive.api, directive.credential_meta.url)
      .replace(':type', 'email')
      .replace(':id', opts.email)
};

OAUTH3.authn = OAUTH3.authn || {};
OAUTH3.authn.loginMeta = function (directive, opts) {
  var url = OAUTH3.urls.credentialMeta(directive, opts);
  return OAUTH3.request({
    method: directive.credential_meta.method || 'GET'
    // TODO lint urls
    // TODO client_uri
  , url: url
  });
};
OAUTH3.urls.otp = function (directive, opts) {
  // TODO client_uri
  return {
    method: directive.credential_otp.method || 'POST'
  , url: OAUTH3.url.resolve(directive.api, directive.credential_otp.url)
  , data: {
      // TODO replace with signed hosted file
      client_agree_tos: 'oauth3.org/tos/draft'
      // TODO unbreak the client_uri option (if broken)
    , client_id: /*opts.client_id ||*/ OAUTH3.uri.normalize(directive.issuer) // In this case, the issuer is its own client
    , client_uri: /*opts.client_uri ||*/ OAUTH3.uri.normalize(directive.issuer)
    , request_otp: true
    , username: opts.email
    }
  };
};
OAUTH3.authn.otp = function (directive, opts) {
  var preq = OAUTH3.urls.otp(directive, opts);

  return OAUTH3.request(preq);
};
OAUTH3.authn.resourceOwnerPassword = function (directive, opts) {
  var providerUri = directive.issuer;

  return OAUTH3.request(OAUTH3.urls.resourceOwnerPassword(directive, opts)).then(function (resp) {
    var data = resp.data;
    data.provider_uri = providerUri;
    if (data.error) {
      return OAUTH3.PromiseA.reject(OAUTH3.error.parse(providerUri, data));
    }

    return OAUTH3.hooks.session.refresh(
      opts.session || { provider_uri: providerUri, client_uri: opts.client_uri || opts.clientUri }
    , data
    );
  }).then(function (session) {
    if (!opts.rememberDevice && !opts.remember_device) {
      return session;
    }

    return OAUTH3.PromiseA.resolve().then(function () {
      if (!OAUTH3.crypto) {
        throw new Error("OAuth3 crypto library unavailable");
      }

      return OAUTH3.crypto.createKeyPair().then(function (keyPair) {
        return OAUTH3.request(OAUTH3.urls.publishKey(directive, {
          session: session
        , publicKey: keyPair.publicKey
        })).then(function () {
          return OAUTH3.hooks.keyPairs.set(session.token.sub, keyPair);
        });
      });
    }).then(function () {
      return session;
    }, function (err) {
      console.error('failed to save keys to remember device', err);
      window.alert('Failed to remember device');
      return session;
    });
  });
};

OAUTH3.authz = {};
OAUTH3.authz.scopes = function (providerUri, session, clientParams) {
  var clientUri = OAUTH3.uri.normalize(clientParams.client_uri || OAUTH3._browser.window.document.referrer);
  var scope = clientParams.scope || 'authn@oauth3.org';
  if ('authn@oauth3.org' === scope.toString()) {
    // implicit ppid grant is automatic
    console.warn('[security] fix scope checking on backend so that we can do automatic grants');
    // TODO check user preference if implicit ppid grant is allowed
    //return generateToken(session, clientObj);
  }

  return OAUTH3.hooks.grants.get(session.token.sub, clientUri).then(function (granted) {
    if (granted) {
      if (typeof granted.scope === 'string') {
        return OAUTH3.scope.parse(granted.scope);
      } else if (Array.isArray(granted.scope)) {
        return granted.scope;
      }
    }

    return OAUTH3.authz.grants(providerUri, {
      method: 'GET'
    , client_id: clientUri
    , client_uri: clientUri
    , session: session
    }).then(function (results) {
      return results.grants;
    }, function (err) {
      if (!/no .*grants .*found/i.test(err.message)) {
        throw err;
      }
      return [];
    });
  }).then(function (granted) {
    var requested = OAUTH3.scope.parse(scope);
    var accepted = [];
    var pending = [];
    requested.forEach(function (scp) {
      if (granted.indexOf(scp) < 0) {
        pending.push(scp);
      } else {
        accepted.push(scp);
      }
    });

    return {
      requested: requested  // all requested, now
    , granted:   granted    // all granted, ever
    , accepted:  accepted   // intersection of granted (ever) and requested (now)
    , pending:   pending     // not yet accepted
    };
  });
};
OAUTH3.authz.grants = function (providerUri, opts) {
  return OAUTH3.discover(providerUri, {
    client_id: providerUri
  , debug: opts.debug
  }).then(function (directive) {
    return OAUTH3.request(OAUTH3.urls.grants(directive, opts), opts);
  }).then(function (grantsResult) {
    var grants = grantsResult.originalData || grantsResult.data;
    if (grants.error) {
      return OAUTH3.PromiseA.reject(OAUTH3.error.parse(providerUri, grants));
    }
    // the responses for GET and POST requests are now the same, so we should alway be able to
    // use the response and save it the same way.
    if (opts.all || ('GET' !== opts.method && 'POST' !== opts.method)) {
      return grants;
    }

    OAUTH3.hooks.grants.set(grants.sub, grants.azp, grants);
    return {
      client: grants.azp
    , clientSub: grants.azpSub
    , grants: OAUTH3.scope.parse(grants.scope)
    };
  });
};
function calcExpiration(exp, now) {
  if (!exp) {
    return;
  }

  if (typeof exp === 'string') {
    var match = /^(\d+\.?\d*) *(seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|years?|yrs?|y)?$/i.exec(exp);
    if (!match) {
      return now;
    }
    var num = parseFloat(match[1]);
    var type = (match[2] || 's').toLowerCase()[0];
    switch (type) {
      case 'y': num *= 365.25; /* falls through */
      case 'd': num *= 24;     /* falls through */
      case 'h': num *= 60;     /* falls through */
      case 'm': num *= 60;     /* falls through */
      case 's': exp = num;
    }
  }
  if (typeof exp !== 'number') {
    throw new Error('invalid expiration provided: '+exp);
  }

  now = now || Math.floor(Date.now() / 1000);
  if (exp > now) {
    return exp;
  } else if (exp > 31557600) {
    console.warn('tried to set expiration to more that a year');
    exp = 31557600;
  }
  return now + exp;
}
OAUTH3.authz.redirectWithToken = function (providerUri, session, clientParams, scopes) {
  if (!OAUTH3.url.checkRedirect(clientParams.client_uri, clientParams)) {
    return;
  }
  if ('token' !== clientParams.response_type) {
    var message;
    if ('code' === clientParams.response_type) {
      message = "Authorization Code Redirect NOT IMPLEMENTED";
    } else {
      message = "Authorization response type '"+clientParams.response_type+"' not supported";
    }
    window.alert(message);
    throw new Error(message);
  }

  var prom;
  if (scopes.new) {
    prom = OAUTH3.authz.grants(providerUri, {
      session: session
    , method: 'POST'
    , client_id: clientParams.client_uri
    , referrer: clientParams.referrer
    , scope: scopes.accepted.concat(scopes.new).join(',')
    });
  } else {
    prom = OAUTH3.PromiseA.resolve();
  }

  return prom.then(function () {
    return OAUTH3.hooks.keyPairs.get(session.token.sub);
  }).then(function (keyPair) {
    if (!keyPair) {
      return OAUTH3.discover(providerUri, {
        client_id: providerUri
      , debug: clientParams.debug
      }).then(function (directive) {
        return OAUTH3.request(OAUTH3.urls.clientToken(directive, {
          method: 'POST'
        , session: session
        , referrer: clientParams.referrer
        , response_type: clientParams.response_type
        , client_id:  clientParams.client_uri
        , azp: clientParams.client_uri
        , aud: clientParams.aud
        , exp: clientParams.exp
        , refresh_token: clientParams.refresh_token
        , refresh_exp: clientParams.refresh_exp
        , debug: clientParams.debug
        })).then(function (result) {
          return result.originalData || result.data;
        });
      });
    }

    return OAUTH3.hooks.grants.get(keyPair.sub, clientParams.client_uri).then(function (grant) {
      var now = Math.floor(Date.now()/1000);
      var payload = {
        iat: now
      , iss: providerUri
      , aud: clientParams.aud || providerUri
      , azp: clientParams.client_uri
      , sub: grant.azpSub
      , scope: OAUTH3.scope.stringify(grant.scope)
    , };

      var signProms = [];
      signProms.push(OAUTH3.jwt.sign(Object.assign({
        exp: calcExpiration(clientParams.exp || '1h', now)
      }, payload), keyPair));
      // if (clientParams.refresh_token) {
        signProms.push(OAUTH3.jwt.sign(Object.assign({
          exp: calcExpiration(clientParams.refresh_exp, now)
        }, payload), keyPair));
      // }
      return OAUTH3.PromiseA.all(signProms).then(function (tokens) {
        console.log('created new tokens for client');
        return {
          access_token: tokens[0]
        , refresh_token: tokens[1]
        , scope: OAUTH3.scope.stringify(grant.scope)
        , token_type: 'bearer'
        };
      });
    });
  }).then(function (session) {
    // TODO limit refresh token to an expirable token
    // TODO inform client not to persist token
    OAUTH3.url.redirect(clientParams, scopes, session);
  }, function (err) {
    console.error('unexpected error creating client tokens', err);
    OAUTH3.url.redirect(clientParams, scopes, {error: err});
  });
};

OAUTH3.requests = {};
//OAUTH3.accounts = {};
OAUTH3.requests.accounts = {};
OAUTH3.urls.accounts = {};
OAUTH3.urls.accounts._ = function (directives, directive, session, opts) {
  opts = opts || {};
  var dir = directive || {
     //url: OAUTH3.url.normalize(directives.api) + '/api/issuer@oauth3.org/accounts/:accountId'
     url: OAUTH3.url.normalize(directives.api) + '/api/issuer@oauth3.org/acl/profiles/:accountId'
  //, method: 'GET'
  , bearer: 'Bearer'
  };
  var url = dir.url
    .replace(/:accountId/, opts.accountId || '')
    .replace(/\/$/, '')
  ;

  return {
    url: url
    //, method: dir.method || 'POST'
  , session: session
    /*
  , headers: {
      'Authorization': (dir.bearer || 'Bearer') + ' ' + (session.access_token || session.accessToken)
    }
    */
  };
};
OAUTH3.urls.accounts.get = function (directives, session) {
  var urlObj = OAUTH3.urls.accounts._(directives, directives.account, session);
  urlObj.method = (directives.account || { method: 'GET' }).method;
  return urlObj;
};
OAUTH3.urls.accounts.update = function (directives, session, opts) {
  var urlObj = OAUTH3.urls.accounts._(directives, directives.update_account, session, opts);
  urlObj.method = (directives.update_account || { method: 'POST' }).method;
  urlObj.json = {
    name: opts.name
  , comment: opts.comment
  , displayName: opts.displayName
  , priority: opts.priority
  };
  return urlObj;
};
OAUTH3.urls.accounts.create = function (directives, session, account) {
  var urlObj = OAUTH3.urls.accounts._(directives, directives.create_account, session);
  var profile = {
    nick: account.display_name
    // "name" is unique and what would be reserved in a url {{name}}.issuer.org or issuer.org/users/{{name}}
  , name: account.name
  , comment: account.comment
  , display_name: account.display_name
  , priority: account.priority
  };
  var credentials = [ { token: session.access_token } ];
  urlObj.method = (directives.create_account || { method: 'POST' }).method;
  urlObj.json = {
    // TODO fix the server to just use one scheme
    // account = { nick, self: { comment, username } }
    // account = { name, comment, display_name, priority }
    credentials: credentials
  , profile: profile
    // 'account' is deprecated in favor of 'profile'
  , account: profile
    // 'logins' is deprecated in favor of 'credentials'
  , logins: credentials
  };
  return urlObj;
};
OAUTH3.requests.accounts.get = function (directives, session) {
  var urlObj = OAUTH3.urls.accounts.get(directives, session);
  return OAUTH3.request(urlObj);
};
OAUTH3.requests.accounts.update = function (directives, session, opts) {
  var urlObj = OAUTH3.urls.accounts.update(directives, session, opts);
  return OAUTH3.request(urlObj);
};
OAUTH3.requests.accounts.create = function (directive, session, account) {
  var urlObj = OAUTH3.urls.accounts.create(directives, session, account);
  return OAUTH3.request(urlObj);
};

OAUTH3.hooks.grants = {
  get: function (id, clientUri) {
    OAUTH3.hooks._checkStorage('grants', 'get');

    if (!id) {
      throw new Error("id is not set");
    }
    if (!clientUri) {
      throw new Error("clientUri is not set");
    }
    return OAUTH3.PromiseA.resolve(OAUTH3._hooks.grants.get(id, OAUTH3.uri.normalize(clientUri)));
  }
, set: function (id, clientUri, grants) {
    OAUTH3.hooks._checkStorage('grants', 'set');

    if (!id) {
      throw new Error("id is not set");
    }
    if (!clientUri) {
      throw new Error("clientUri is not set");
    }
    return OAUTH3.PromiseA.resolve(OAUTH3._hooks.grants.set(id, OAUTH3.uri.normalize(clientUri), grants));
  }
, all: function () {
    OAUTH3.hooks._checkStorage('grants', 'all');

    return OAUTH3.PromiseA.resolve(OAUTH3._hooks.grants.all());
  }
, clear: function () {
    OAUTH3.hooks._checkStorage('grants', 'clear');

    return OAUTH3.PromiseA.resolve(OAUTH3._hooks.grants.clear());
  }
};
OAUTH3.hooks.keyPairs = {
  get: function (id) {
    OAUTH3.hooks._checkStorage('keyPairs', 'get');

    if (!id) {
      throw new Error("id is not set");
    }
    return OAUTH3.PromiseA.resolve(OAUTH3._hooks.keyPairs.get(id));
  }
, set: function (id, keyPair) {
    OAUTH3.hooks._checkStorage('keyPairs', 'set');

    if (!keyPair && id.privateKey && id.publicKey && id.sub) {
      keyPair = id;
      id = keyPair.sub;
    }
    if (!keyPair) {
      return OAUTH3.PromiseA.reject(new Error("no key pair provided to save"));
    }
    if (!id) {
      throw new Error("id is not set");
    }
    keyPair.sub = keyPair.sub || id;

    return OAUTH3.PromiseA.resolve(OAUTH3._hooks.keyPairs.set(id, keyPair));
  }
, all: function () {
    OAUTH3.hooks._checkStorage('keyPairs', 'all');

    return OAUTH3.PromiseA.resolve(OAUTH3._hooks.keyPairs.all());
  }
, clear: function () {
    OAUTH3.hooks._checkStorage('keyPairs', 'clear');

    return OAUTH3.PromiseA.resolve(OAUTH3._hooks.keyPairs.clear());
  }
};
OAUTH3.hooks.session.get = function (providerUri, id) {
  OAUTH3.hooks._checkStorage('sessions', 'get');
  var sessProm = OAUTH3.PromiseA.resolve(OAUTH3._hooks.sessions.get(providerUri, id));
  if (providerUri !== OAUTH3.clientUri(window.location)) {
    return sessProm;
  }

  return sessProm.then(function (session) {
    if (session && OAUTH3.jwt.freshness(session.token) === 'fresh') {
      return session;
    }

    return OAUTH3.hooks.keyPairs.all().then(function (keyPairs) {
      var pair;
      if (id) {
        pair = keyPairs[id];
      } else if (Object.keys(keyPairs).length === 1) {
        id = Object.keys(keyPairs)[0];
        pair = keyPairs[id];
      } else if (Object.keys(keyPairs).length > 1) {
        console.error("too many users, don't know which key to use");
      }
      if (!pair) {
        // even if the access token isn't fresh, the session might have a refresh token
        return session;
      }

      var now = Math.floor(Date.now()/1000);
      var payload = {
        iat: now
      , iss: providerUri
      , aud: providerUri
      , azp: providerUri
      , sub: pair.sub || id
      , scope: ''
      , exp: now + 3600
      };
      return OAUTH3.jwt.sign(payload, pair.privateKey).then(function (token) {
        console.log('created new token for provider');
        return OAUTH3.hooks.session.refresh(
          { provider_uri: providerUri, client_uri: providerUri || providerUri }
        , { access_token: token }
        );
      });
    });
  });
};

OAUTH3._defaultStorage.grants = {
  prefix: 'grants-'
, get: function (id, clientUri) {
    var key = this.prefix + id+'/'+clientUri;
    var result = JSON.parse(window.localStorage.getItem(key) || 'null');
    return OAUTH3.PromiseA.resolve(result);
  }
, set: function (id, clientUri, grants) {
    var key = this.prefix + id+'/'+clientUri;
    window.localStorage.setItem(key, JSON.stringify(grants));
    return this.get(clientUri);
  }
, all: function () {
    var prefix = this.prefix;
    var result = {};
    OAUTH3._defaultStorage._getStorageKeys(prefix, window.localStorage).forEach(function (key) {
      var split = key.replace(prefix, '').split('/');
      if (!result[split[0]]) { result[split[0]] = {}; }
      result[split[0]][split[1]] = JSON.parse(window.localStorage.getItem(key) || 'null');
    });
    return OAUTH3.PromiseA.resolve(result);
  }
, clear: function () {
    OAUTH3._defaultStorage._getStorageKeys(this.prefix, window.localStorage).forEach(function (key) {
      window.localStorage.removeItem(key);
    });
    return OAUTH3.PromiseA.resolve();
  }
};
OAUTH3._defaultStorage.keyPairs = {
  prefix: 'key_pairs-'
, get: function (id) {
    var result = JSON.parse(window.localStorage.getItem(this.prefix + id) || 'null');
    return OAUTH3.PromiseA.resolve(result);
  }
, set: function (id, keyPair) {
    window.localStorage.setItem(this.prefix + id, JSON.stringify(keyPair));
    return this.get(id);
  }
, all: function () {
    var prefix = this.prefix;
    var result = {};
    OAUTH3._defaultStorage._getStorageKeys(prefix, window.localStorage).forEach(function (key) {
      result[key.replace(prefix, '')] = JSON.parse(window.localStorage.getItem(key) || 'null');
    });
    return OAUTH3.PromiseA.resolve(result);
  }
, clear: function () {
    OAUTH3._defaultStorage._getStorageKeys(this.prefix, window.localStorage).forEach(function (key) {
      window.localStorage.removeItem(key);
    });
    return OAUTH3.PromiseA.resolve();
  }
};

OAUTH3._browser.isIframe = function isIframe () {
  try {
    return window.self !== window.top;
  } catch (e) {
    return true;
  }
};

}('undefined' !== typeof exports ? exports : window));