define([
    "underscore",
    "backbone",
    "models/field"
], function(_, Backbone, FieldModel) {
    var FieldCollection = Backbone.Collection.extend({
        initialize: function(models, options) {
            if (!"sbas_id" in options) {
                throw "You must specify a sbasId option when creating a new field model"
            }
            this.sbasId = options.sbas_id;
        },
        model: FieldModel,
        url: function() {
            return "/admin/fields/" + this.sbasId + "/fields";
        },
        search: function(letters) {
            if (letters === "")
                return this;

            var pattern = new RegExp(letters, "gi");

            return _(this.filter(function(data) {
                return pattern.test(data.get("name"));
            }));
        },
        comparator: function(item) {
            return item.get("sorter");
        },
        nextIndex: function(model) {
            var index = this.indexOf(model);

            if (index < 0) {
                throw "Model not found"
            }

            if ((index + 1) === this.length) {
                return null;
            }

            return index + 1;
        },
        previousIndex: function(model) {
            var index = this.indexOf(model);

            if (index < 0) {
                throw "Model not found"
            }

            if (index === 0) {
                return null;
            }

            return index - 1;
        },
        // save all collection
        save: function(options) {
            return Backbone.sync("update", this, options || {});
        }
    });

    return FieldCollection;
});