;(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);
            });
        }
    };
})();