'use strict';

/* global LazyLoader, ConfirmDialog, MmiManager, TelephonyCall,
          TelephonyMessages */
/* exported TelephonyHelper */

var TelephonyHelper = (function() {
  // DTMF control digit separator length (ms) as defined in GSM ETSI GSM 02.07
  const DTMF_SEPARATOR_PAUSE_DURATION = 3000;

  var confirmLoaded = false;

  var loadTelephonyMessages = function(callback) {
    LazyLoader.load(['/shared/js/dialer/telephony_messages.js'], callback);
  };

  var call = function t_call(number, cardIndex, oncall, onconnected,
                             ondisconnected) {
    var sanitizedNumber = number.replace(/(\s|-|\.|\(|\))/g, '');
    if (!isValid(sanitizedNumber)) {
      loadTelephonyMessages(function() {
        TelephonyMessages.displayMessage('BadNumber');
      });

      return Promise.reject();
    }

    // The platform adapter owns network checks on Tundra and Android.
    if (window.VulpesPlatformDial) {
      return window.VulpesPlatformDial(sanitizedNumber.split(',')[0]).then(function(obj) {
        if (window.TelephonyCall && obj instanceof TelephonyCall) {
          installHandlers(obj, sanitizedNumber, false, cardIndex,
                          oncall, onconnected, ondisconnected);
        } else if (oncall) {
          oncall();
        }
        return obj;
      });
    }

    var conn = navigator.mozMobileConnections &&
      navigator.mozMobileConnections[cardIndex];

    if (!conn || !conn.voice) {
      // No voice connection, the call won't make it
      loadTelephonyMessages(function() {
        TelephonyMessages.displayMessage('NoNetwork');
      });
      return Promise.reject();
    }

    return startDial(
      cardIndex, conn, sanitizedNumber, oncall, onconnected, ondisconnected
    );
  };


  function getNumberAsDtmfToneGroups(number) {
    return number.split(',');
  }

  function playDtmfToneGroups(dtmfToneGroups, cardIndex) {
    var length;

    // Remove the dialed number from the beginning of the array.
    dtmfToneGroups = dtmfToneGroups.slice(1);
    length = dtmfToneGroups.length;

    // Remove the latest entries from dtmfToneGroups corresponding to ','
    //  characters not to play those pauses.
    var lastCommaIndex = length - 1;
    while (dtmfToneGroups[lastCommaIndex] === '') {
      lastCommaIndex--;
    }
    dtmfToneGroups = dtmfToneGroups.slice(0, ++lastCommaIndex);
    length = dtmfToneGroups.length;

    var promise = Promise.resolve(),
        counter = 0,
        pauses;
    // Traverse the dtmfToneGroups array.
    while (counter < length) {
      // Reset the number of pauses before each group of tones.
      pauses = 1;
      while (dtmfToneGroups[counter] === '') {
        // Add a new pause for each '' in the dtmfToneGroups array.
        pauses++;
        counter++;
      }
      // Send a new group of tones as well as the pauses to play before it.
      promise = promise.then(playDtmfToneGroup.bind(null,
        dtmfToneGroups[counter++], pauses, cardIndex));
    }
    return promise;
  }

  function playDtmfToneGroup(toneGroup, pauses, cardIndex) {
    return navigator.mozTelephony.sendTones(
      toneGroup,
      DTMF_SEPARATOR_PAUSE_DURATION * pauses,
      null /* tone duration */,
      cardIndex
    );
  }

  function startDial(cardIndex, conn, sanitizedNumber, oncall, onconnected,
                     ondisconnected) {
    var telephony = navigator.mozTelephony;
    if (!telephony) {
      return Promise.reject();
    }

    var emergencyOnly = conn.voice.emergencyCallsOnly;
    var hasCard = (conn.iccId !== null);
    var callPromise;
    var baseNumber = getNumberAsDtmfToneGroups(sanitizedNumber)[0];

    if (emergencyOnly) {
      loadConfirm(function() {
        ConfirmDialog.show(
          'connectingEllipsis',
          '',
          {
            title: 'emergencyDialogBtnOk',
            callback: function() {
              ConfirmDialog.hide();
            }
          }
        );
        document.addEventListener('visibilitychange', function hideDialog() {
          document.removeEventListener('visibilitychange', hideDialog);

          /* In tests this event can happen after the ConfirmDialog mock has
           * been removed so check that it's still there. */
          ConfirmDialog && ConfirmDialog.hide();
        });
      });

      // If the mobileConnection has a sim card we let gecko take the
      // default service, otherwise we force the first slot.
      cardIndex = hasCard ? undefined : 0;
      callPromise = telephony.dialEmergency(baseNumber);
    } else {
      callPromise = telephony.dial(baseNumber, cardIndex);
    }

    callPromise.then(function(obj) {
      if (obj instanceof TelephonyCall) {
        installHandlers(obj, sanitizedNumber, emergencyOnly, cardIndex,
                        oncall, onconnected, ondisconnected);
      } else {
        /* This is an MMICall object, manually invoke the handlers to provide
         * feedback to the user, the rest of the UX will be dealt with by the
         * MMI manager. */
        oncall();
        onconnected();
        MmiManager.handleDialing(conn, sanitizedNumber, obj.result);
      }
    }, function(errorName) {
      loadTelephonyMessages(function() {
        var messageType = emergencyOnly ? TelephonyMessages.NO_NETWORK :
                                          TelephonyMessages.REGULAR_CALL;
        TelephonyMessages.handleError(
          errorName, sanitizedNumber, messageType);
      });
    });

    return callPromise;
  }

  function installHandlers(call, number, emergencyOnly, cardIndex,
                           oncall, onconnected, ondisconnected) {
    if (oncall) {
      oncall();
    }
    var dtmfToneGroups = getNumberAsDtmfToneGroups(number);
    if (dtmfToneGroups.length > 1) {
      call.addEventListener('connected', function dtmfToneGroupPlayer() {
        call.removeEventListener('connected', dtmfToneGroupPlayer);
        playDtmfToneGroups(dtmfToneGroups, cardIndex);
      });
    }
    call.addEventListener('connected', onconnected);

    call.addEventListener('disconnected', function handleDisconnect(evt) {
      if (evt.call.disconnectedReason) {
        loadTelephonyMessages(function() {
          TelephonyMessages.handleDisconnect(
            evt.call.disconnectedReason, number, emergencyOnly
          );
        });
      }
      ondisconnected && ondisconnected();
    });
  }

  var isValid = function t_isValid(sanitizedNumber) {
    var validExp = /^(?!,)([0-9#+*,]){1,50}$/;
    return validExp.test(sanitizedNumber);
  };

  var loadConfirm = function t_loadConfirm(cb) {
    if (confirmLoaded) {
      cb();
      return;
    }

    var confMsg = document.getElementById('confirmation-message');

    LazyLoader.load(['/shared/js/confirm.js', confMsg], function() {
      confirmLoaded = true;
      cb();
    });
  };

  var getInUseSim = function t_getInUseSim() {
    var telephony = navigator.mozTelephony;
    if (telephony) {
      var isInCall = !!telephony.calls.length;
      var isInConference = !!telephony.conferenceGroup &&
                          !!telephony.conferenceGroup.calls.length;

      if (isInCall || isInConference) {
        return isInCall ?
          navigator.mozTelephony.calls[0].serviceId :
          navigator.mozTelephony.conferenceGroup.calls[0].serviceId;
      }
    }

    return null;
  };

  window.TelephonyHelper = TelephonyHelper;

  return {
    call: call,
    getInUseSim: getInUseSim
  };

})();