(function() {
  'use strict';

  /*********************
   *** Group Storage ***
   *********************/
  window.textsecure = window.textsecure || {};
  window.textsecure.storage = window.textsecure.storage || {};

  // create a random group id that we haven't seen before.
  function generateNewGroupId() {
    var groupId = getString(libsignal.crypto.getRandomBytes(16));
    return textsecure.storage.protocol.getGroup(groupId).then(function(group) {
      if (group === undefined) {
        return groupId;
      } else {
        console.warn('group id collision'); // probably a bad sign.
        return generateNewGroupId();
      }
    });
  }

  window.textsecure.storage.groups = {
    createNewGroup: function(numbers, groupId) {
      var groupId = groupId;
      return new Promise(function(resolve) {
        if (groupId !== undefined) {
          resolve(
            textsecure.storage.protocol.getGroup(groupId).then(function(group) {
              if (group !== undefined) {
                throw new Error('Tried to recreate group');
              }
            })
          );
        } else {
          resolve(
            generateNewGroupId().then(function(newGroupId) {
              groupId = newGroupId;
            })
          );
        }
      }).then(function() {
        var me = textsecure.storage.user.getNumber();
        var haveMe = false;
        var finalNumbers = [];
        for (var i in numbers) {
          var number = numbers[i];
          if (!textsecure.utils.isNumberSane(number))
            throw new Error('Invalid number in group');
          if (number == me) haveMe = true;
          if (finalNumbers.indexOf(number) < 0) finalNumbers.push(number);
        }

        if (!haveMe) finalNumbers.push(me);

        var groupObject = { numbers: finalNumbers, numberRegistrationIds: {} };
        for (var i in finalNumbers)
          groupObject.numberRegistrationIds[finalNumbers[i]] = {};

        return textsecure.storage.protocol
          .putGroup(groupId, groupObject)
          .then(function() {
            return { id: groupId, numbers: finalNumbers };
          });
      });
    },

    getNumbers: function(groupId) {
      return textsecure.storage.protocol
        .getGroup(groupId)
        .then(function(group) {
          if (group === undefined) return undefined;

          return group.numbers;
        });
    },

    removeNumber: function(groupId, number) {
      return textsecure.storage.protocol
        .getGroup(groupId)
        .then(function(group) {
          if (group === undefined) return undefined;

          var me = textsecure.storage.user.getNumber();
          if (number == me)
            throw new Error(
              'Cannot remove ourselves from a group, leave the group instead'
            );

          var i = group.numbers.indexOf(number);
          if (i > -1) {
            group.numbers.splice(i, 1);
            delete group.numberRegistrationIds[number];
            return textsecure.storage.protocol
              .putGroup(groupId, group)
              .then(function() {
                return group.numbers;
              });
          }

          return group.numbers;
        });
    },

    addNumbers: function(groupId, numbers) {
      return textsecure.storage.protocol
        .getGroup(groupId)
        .then(function(group) {
          if (group === undefined) return undefined;

          for (var i in numbers) {
            var number = numbers[i];
            if (!textsecure.utils.isNumberSane(number))
              throw new Error('Invalid number in set to add to group');
            if (group.numbers.indexOf(number) < 0) {
              group.numbers.push(number);
              group.numberRegistrationIds[number] = {};
            }
          }

          return textsecure.storage.protocol
            .putGroup(groupId, group)
            .then(function() {
              return group.numbers;
            });
        });
    },

    deleteGroup: function(groupId) {
      return textsecure.storage.protocol.removeGroup(groupId);
    },

    getGroup: function(groupId) {
      return textsecure.storage.protocol
        .getGroup(groupId)
        .then(function(group) {
          if (group === undefined) return undefined;

          return { id: groupId, numbers: group.numbers };
        });
    },

    updateNumbers: function(groupId, numbers) {
      return textsecure.storage.protocol
        .getGroup(groupId)
        .then(function(group) {
          if (group === undefined)
            throw new Error('Tried to update numbers for unknown group');

          if (
            numbers.filter(textsecure.utils.isNumberSane).length <
            numbers.length
          )
            throw new Error('Invalid number in new group members');

          var added = numbers.filter(function(number) {
            return group.numbers.indexOf(number) < 0;
          });

          return textsecure.storage.groups.addNumbers(groupId, added);
        });
    },
  };
})();