Template.studyDateList.helpers({
    /**
     * Returns an array of studies that are related to the current study by patient ID.
     * The value for 'selected' for the currently loaded study is set to true, so that
     * this becomes the current option in the combo box.
     *
     * @returns {*}
     */
    relatedStudies: function() {
        // TODO= Fix this! This won't work to retrieve all studies
        // related to this patient. We will need to do a real search
        // since the WorklistStudies Collection only contains the studies on-screen

        // Check which study is currently loaded into the study browser
        var currentStudyInBrowser = ViewerStudies.findOne({
            selected: true
        });

        // Find studies which have the same patientId as the currently selected study
        var relatedStudies = WorklistStudies.find({patientId: currentStudyInBrowser.patientId},
                {sort: {studyDate: 1}}).fetch();

        // Modify the array of related studies so the default option is the currently selected study
        relatedStudies.forEach(function(study) {
            // If the studyInstanceUid matches that of the current study in the browser,
            // Set this to 'selected', so that it becomes the default option
            if (study.studyInstanceUid === currentStudyInBrowser.studyInstanceUid) {
                study.selected = true;
            }
        });

        // Use this array to populate the combo box
        return relatedStudies;
    }
});

Template.studyDateList.events({
    /**
     * When the study date selector combo box is changed, we will
     * hide the select box, temporarily display a loading sign, and grab
     * the selected study. Once the study has been retrieved it is added
     * into the ViewerStudies collection and set as selected. This reactively
     * populated the thumbnail browser.
     *
     * @param e The select box change event
     */
    'change select#selectStudyDate': function(e) {
        var selectBox = $(e.currentTarget);

        var studyInstanceUid = selectBox.val();

        // Hide the select box
        selectBox.css('display', 'none');

        // Show the loading indicator
        var loadingIndicator = selectBox.siblings('.loading');
        loadingIndicator.css('display', 'block');

        Meteor.call('GetStudyMetadata', studyInstanceUid, function(error, study) {
            sortStudy(study);

            // Hide the loading indicator
            loadingIndicator.css('display', 'none');

            // Show the select box again
            selectBox.css('display', 'block');

            // Set "Selected" to false for the entire collection
            ViewerStudies.update({},
                {
                    $set: {
                        selected: false
                    }
                },
                {
                    multi: true
                });

            // Check if this study already exists in the ViewerStudies collection
            // of loaded studies. If it does, set it's 'selected' value to true.
            var existingStudy = ViewerStudies.findOne({
                studyInstanceUid: studyInstanceUid
            });
            if (existingStudy) {
                // Set the current finding in the collection to true
                ViewerStudies.update(existingStudy._id, {
                    $set: {
                        selected: true
                    }
                });
                return;
            }

            // If the study does not exist, add the 'selected' key to the object
            // with the value True, and insert it into the ViewerStudies Collection
            study.selected = true;
            ViewerStudies.insert(study);

            var timepointID = uuid.v4();

            var timepoint = Timepoints.findOne({
                timepointName: study.studyDate
            });
            if (timepoint) {
                log.warn('A timepoint with that study date already exists!');
                return;
            }

            var testTimepoint = Timepoints.findOne({});
            if (testTimepoint && testTimepoint.patientId !== study.patientId) {
                log.warn('Timepoints collection related to the wrong subject');
                return;
            }

            log.info('Inserting a new timepoint');
            Timepoints.insert({
                patientId: study.patientId,
                timepointID: timepointID,
                timepointName: study.studyDate
            });
        });
    }
});