var Config = {
  get value() {
    var val = localStorage.getItem("SUMMIT_CFG");
    if (val)
      return JSON.parse(val);
    return {};
  },
  get lastChanged() {
    var ts = localStorage.getItem("SUMMIT_CFG_TIMESTAMP");
    if (ts)
      return new Date(ts);
    return new Date(0);
  },
  setValue: function Config_setValue(val) {
    localStorage.setItem("SUMMIT_CFG", JSON.stringify(val));
    localStorage.setItem("SUMMIT_CFG_TIMESTAMP",
                         (new Date()).toString());
    this.observers.forEach(function(cb) { cb(); });
  },
  wipe: function Config_wipe() {
    localStorage.removeItem("SUMMIT_CFG");
    localStorage.removeItem("SUMMIT_CFG_TIMESTAMP");
    this.observers.forEach(function(cb) { cb(); });
  },
  observers: []
};

var Api = {
  postJSON: function Api_postJSON(path, obj, cb) {
    var options = {
      url: path,
      type: "POST",
      contentType: "application/json",
      data: JSON.stringify(obj),
      dataType: "json",
      success: function(data) {
        cb(true, data);
      },
      error: function(req, textStatus, errorThrown) {
        var data = null;
        if (req.getResponseHeader("Content-Type") == "application/json") {
          try {
            data = JSON.parse(req.responseText);
          } catch (e) {}
        }
        cb(false, data);
      }
    };
    return jQuery.ajax(options);
  }
};

(
  // This anonymous closure sets up the UI.
  function(window) {
    function ensureStateIsValid() {
      if (!('state' in Config.value))
        Config.setValue({state: "login"});
    }

    function updateUI() {
      ensureStateIsValid();

      $(".screen").hide();
      $("#" + Config.value.state).show();
      switch (Config.value.state) {
      case "login":
        break;
      case "wait-for-verify":
        break;
      case "logged-in":
        $(".login-email").text(Config.value.email);
        break;
      }
    }

    function bindConfigToUI() {
      var lastChanged = Config.lastChanged;

      function onConfigChanged() {
        lastChanged = Config.lastChanged;
        updateUI();
      };

      Config.observers.push(onConfigChanged);

      window.setInterval(
        function() {
          if (Config.lastChanged > lastChanged)
            onConfigChanged();
        },
        1000
      );

      updateUI();
    }

    function initUI() {
      ensureStateIsValid();

      $(".start-over").click(function() { Config.wipe(); });

      $("#login form").submit(
        function(event) {
          event.preventDefault();
          $("#login .error").hide();
          Api.postJSON(
            "/challenge/request",
            {email: $(this).find("#email").val() },
            function(success, data) {
              if (success) {
                Config.setValue({state: "wait-for-verify"});
              } else {
                $("#login .error").slideDown();
              }
            });
        });

      var verify = window.location.hash.match(/#verify=(.+)/);
      if (verify && Config.value.state != "logged-in") {
        verify = verify[1];
        Config.setValue({state: "wait-for-verify"});
        Api.postJSON(
          "/challenge/respond",
          {token: verify},
          function(success, data) {
            window.location.hash = "";
            bindConfigToUI();
            if (success) {
              Config.setValue({state: "logged-in",
                               token: data.token,
                               email: data.email});
            } else {
              $("#wait-for-verify .error").slideDown();
            }
          });
      } else
        bindConfigToUI();
    }

    $(window).ready(initUI);
  }
)(window);

(
  // Set up the postMessage API.
  function(window) {
    var handlers = {
      getAllUsers: function(options, cb) {
        if (Config.value.state != "logged-in") {
          cb({error: "not logged in"});
          return;
        }

        jQuery.getJSON(
          "/profile",
          {token: Config.value.token},
          function(data, textStatus) {
            if (textStatus == "success")
              cb({users: data});
            else
              cb({error: "an error occurred retrieving user data."});
          });
      }
    };

    var myOrigin = window.location.protocol + "//" + window.location.host;

    function isOriginValid(origin) {
      if (origin == myOrigin)
        return true;
      // TODO: Finish this.
      return false;
    }

    var server = new Summit.Server(handlers, isOriginValid);
  }
)(window);