var questionEditor = new QuestionEditor();

function createNewElement(tag, type, id, cl, value) {
    var newElement = document.createElement(tag);
    if (type != undefined) newElement.type = type;
    if (id != undefined) newElement.id = id;
    if (cl != undefined) newElement.className = cl;
    if (value != undefined) {
        newElement.value = value;
        newElement.text = value;
    }
    return newElement;
}

function createNewInputLabel(text, target, side) {
    var newLabel = document.createElement("label");
    if (target) newLabel.setAttribute("for",target);
    newLabel.innerHTML = text;
    if (side) newLabel.className = side;
    return newLabel;
}

function updateIdentifier() {
    var identField = document.getElementById("questionIdentifierField");
    if (identField.value == undefined && identField.value == "") {
        return;
    }
    var headerField = document.getElementById("header_identifier");
    headerField.innerHTML = identField.value;
}


//////////////////////////////////////////
/* QUESTION EDITOR CLASS BASED APPROACH */
//////////////////////////////////////////

function QuestionEditor() {
    // Properties    
    this.uid = null;    // The uid of the question contained in this editor
    var me = this;      // Retarded self-reference because: Javascript
    this.element = null;    // The parent div element containing the questionEditor
    this.paramsElement = null;  // The parent parameters element where all the input sets will be located
    this.paramSets = null;  // The currently enabled input sets to be displayed in the paramsElement. 
    //Currently only supports a single param set (based on answer type), but functionality will scale to multiple sets as needed.
    
    // Methods
    // Basic functionality
    this.setValues = function(arguments) {
        var question = JSON.parse(arguments);        
    }
    this.init = function() {
        // Outer div
        me.element = ce("div");
        me.element.className = "smallFrame questionEditor";
        me.element.id = sequencer.state.selectedObject.uid;
        me.uid = sequencer.state.selectedObject.uid;
        // Header
        var titleDiv = ce("div");
        titleDiv.className = "smallTitle";
        var numberDiv = ce("div");
        numberDiv.className = "listNumber";
        numberDiv.innerHTML = "4"; //TODO
        var nameSpan = ce("span");
        nameSpan.id = "qeTitleField";
        nameSpan.innerHTML = "New question";
        titleDiv.appendChild(numberDiv);
        titleDiv.innerHTML += "Editing: ";
        titleDiv.appendChild(nameSpan);
        me.element.appendChild(titleDiv);
    
        //Content area
        var contentDiv = ce("div");
        contentDiv.className = "content";
        var bodyText = createNewElement("textarea", null, "qeBodyTextField", "qeBodyTextField", null);
        bodyText.value = "Question body text goes here";
        contentDiv.appendChild(bodyText);
        
        // The dynamic questionParams div, where all the control elements and inputs will be located
        var questionParams = ce("div");
        me.paramsElement = questionParams;
        questionParams.className = "questionParams";
        questionParams.id = "qeQuestionParamsDiv";
        
        var basicContainer = ce("div");
        basicContainer.id = "basicInputs";
        
        var qeCodeField = createNewElement("input", "text", "qeCodeField", "qeParamField", null);
        var qeCodeField_lbl = createNewInputLabel("Question code:","qeCodeField", "l");
        basicContainer.appendChild(qeCodeField_lbl);
        basicContainer.appendChild(qeCodeField);
    
        var qeTypeField = createNewElement("select", null, "qeTypeField", "qeParamField", null);
        var qeTypeField_lbl = createNewInputLabel("Answer type:","qeTypeField", "l");
        basicContainer.appendChild(qeTypeField_lbl);
        basicContainer.appendChild(qeTypeField);
        questionParams.appendChild(basicContainer);
        qeTypeField.addEventListener("change", function(){
            //debugger;
            me.selectAnswerType();
        }, false);
        // Add the select options. Do this in a block scope to prevent the o1 var from messing things up. 
        // Also helps in structuring code.
        {
            var o1 = ce("option");
            o1.value = null;
            o1.text = "";
            qeTypeField.appendChild(o1);
        
            o1 = ce("option");
            o1.value = "int";
            o1.text = "Integer";
            qeTypeField.appendChild(o1);
        
            o1 = ce("option");
            o1.value = "scale";
            o1.text = "Scale";
            qeTypeField.appendChild(o1);
        
            o1 = ce("option");
            o1.value = "choice";
            o1.text = "Multiple choice";
            qeTypeField.appendChild(o1);
        
            o1 = ce("option");
            o1.value = "text";
            o1.text = "Text";
            qeTypeField.appendChild(o1);
        }
    
        contentDiv.appendChild(questionParams);
        me.element.appendChild(contentDiv);
    
        // Controls bar
        var controlsDiv = ce("div");
        controlsDiv.className = "controls";
        var btnDiscard = createNewElement("input", "button", "btnDiscard", null, "Discard");
        var btnSave = createNewElement("input", "button", "btnSave", null, "Save");
        controlsDiv.appendChild(btnDiscard);
        controlsDiv.appendChild(btnSave);
        btnSave.addEventListener("click", function(){
            me.save();
        }, false);
        btnDiscard.addEventListener("click", function(){
            me.discard();
        }, false);
        me.element.appendChild(controlsDiv);
        me.paramSets = new Array();
        me.paramSets.push("basic");
    }
    this.save = function() {
        var request = {
            "title": ge("qeTitleField").value,
            "type": ge("qeTypeField").value
        }
        
        switch (ge("qeTypeField").value) {
            case "int":
                request.answerType = "int";
                request.minValue = parseInt(ge("qeMinValueField").value);
                request.maxValue = parseInt(ge("qeMaxValueField").value);
                break;
            case "scale":
                request.answerType = "scale";
                request.numChoices = parseInt(ge("qeNumChoicesField").value);
                request.legendsEnabled = ge("qeLegendsEnabledField").checked;
                request.lowerLegend = ge("qeLowerLegendField").value;
                request.upperLegend = ge("qeUpperLegendField").value;
                break;
            case "choice":
                request.answerType = "choice";
                break;
            case "text":
                request.answerType = "text";
                break;
        }
        
        newAjaxRequest(requestString, "createObject.php", function(result){
            // Display a success message, or throw an error.
            }, true);
    }
    this.reset = function() {
        me.init();
    }
    
    // Updating input fields
    this.selectAnswerType = function () {
        // Switch statement, call this.type_x where x is the relevant answer type.
        // For all this.type_X funtions:
        // Use the createNewElement and createNewInputLabel methods to add controls or input fields.
        // Input field convention:  class = questionParamField, id = qTypeField / qScaleSize, etc...
        // Input label class: "l" or "r" depending on alignment with respect to parent ("for") input element.
        // Important: use the this.paramsElement to access the questionParams div!
        // To fully make use of this class-based approach, the editor should be added to a global variable. This global variable should be removed on page unload!
    
        var type = ge("qeTypeField").value;
        switch (type) {
            case "int":
                me.type_Integer();
                break;
            case "scale":
                me.type_Scale();
                break;
            case "choice":
                me.type_Choice();
                break;
            case "text":
                me.type_Text();
                break;
            default:
                //Do nothing
                break;
                
        }
    
    }
    this.checkInputSets = function () {
        // Loop through all input containers in the paramsField
        for (var n = 0; n < me.paramsElement.childNodes.length; n++) {
            if (me.paramsElement.childNodes[n].id == "basicInputs") continue;
            // Check if the id (inputSet) is currently in paramSets
            if (me.paramSets.indexOf(me.paramsElement.childNodes[n].id) < 0) {
                me.paramsElement.childNodes[n].parentNode.removeChild(me.paramsElement.childNodes[n]);
                n--;
            }
            
        }
    }
    
    this.type_Integer = function () {
        if (me.paramSets.indexOf("int_basic") < 0) {
            me.paramSets = new Array("int_basic");
        }
        else return;
        
        me.checkInputSets();
        
        var container = ce("div");
        container.id = "int_basic";

        var qeMinValueField = createNewElement("input", "text", "qeMinValueField", "qeParamField", null);
        var qeMinValueField_lbl = createNewInputLabel("Minimum value: ", "qeMinValueField", "l");
        var qeMaxValueField = createNewElement("input", "text", "qeMaxValueField", "qeParamField", null);
        var qeMaxValueField_lbl = createNewInputLabel("Maximum value: ", "qeMaxValueField", "l");
        
        container.appendChild(qeMinValueField_lbl);
        container.appendChild(qeMinValueField);
        container.appendChild(qeMaxValueField_lbl);
        container.appendChild(qeMaxValueField);
        me.paramsElement.appendChild(container);
        
    }
    this.type_Scale = function () {
        if (me.paramSets.indexOf("scale_basic") < 0) {
            me.paramSets = new Array("scale_basic");
        }
        else return;
        // Clear any input sets that should not be there
        me.checkInputSets();
        
        var container = ce("div");
        container.id = "scale_basic";
        
        // Number of choices SELECT
        var numChoicesField = createNewElement("select", null, "qeNumChoicesField", "qeParamField", null);
        var numChoicesField_lbl = createNewInputLabel("Number of choices", "qeNumChoicesField", "l");
        // SELECT options
        for (var n = 2; n < 11; n++) {
            var o = ce("option");
            o.value = n;
            o.text = n;
            numChoicesField.appendChild(o);
        }
        container.appendChild(numChoicesField_lbl);
        container.appendChild(numChoicesField);
        
        // Scale labels CHECKBOX and TEXTs
        var legendsEnabledField = createNewElement("input", "checkbox", "qeLegendsEnabledField", "qeParamField", null);
        var legendsEnabledField_lbl = createNewInputLabel("Enable legends", "qeLegendsEnabledField", "l");
        container.appendChild(legendsEnabledField_lbl);
        container.appendChild(legendsEnabledField);
        
        var upperLegendText = createNewElement("input", "text", "qeUpperLegendField", "qeParamField", null);
        var lowerLegendText = createNewElement("input", "text", "qeLowerLegendField", "qeParamField", null);
        var upperLegendText_lbl = createNewInputLabel("Upper legend", "qeUpperLegendField", "l");
        var lowerLegendText_lbl = createNewInputLabel("Lower legend", "qeLowerLegendField", "l");
        container.appendChild(lowerLegendText_lbl);
        container.appendChild(lowerLegendText);
        container.appendChild(upperLegendText_lbl);
        container.appendChild(upperLegendText);
        
        me.paramsElement.appendChild(container);
    }
    this.type_Text = function () {
        if (me.paramSets.indexOf("text_basic") < 0) {
            me.paramSets = new Array("text_basic");
        }
        else return;
        
        me.checkInputSets();
        
        var container = ce("div");
        container.id="text_basic";
    }
    this.type_Choice = function() {
        //debugger;
        if (me.paramSets.indexOf("choice_basic") < 0) {
            me.paramSets = new Array("choice_basic");
        }
        else return;
        
        me.checkInputSets();
        
        var container = ce("div");
        container.id = "choice_basic";
        // num options SELECT
        var numOptionsSelect = createNewElement("select", null, "qeNumOptionsField", "qeParamField", null);
        var numOptionsSelect_lbl = createNewInputLabel("Number of options", "qeNumOptionsField", "l");
        for (var n = 2; n < 11; n++) {
            var o = ce("option");
            o.value = n;
            o.text = n;
            numOptionsSelect.appendChild(o);
        }
        container.appendChild(numOptionsSelect_lbl);
        container.appendChild(numOptionsSelect);
        numOptionsSelect.addEventListener("change", me.type_Choice_CheckAnswerFields, true);
        
        var allowMultiple = createNewElement("input", "checkbox", "qeMultipleAnswersField", "qeParamField", null);
        var allowMultiple_lbl = createNewInputLabel("Allow multiple answers", "qeMultipleAnswersField", "l");
        container.appendChild(allowMultiple_lbl);
        container.appendChild(allowMultiple);
        
        var answersField = ce("div");
        answersField.className = "qeParamFieldset";
        answersField.id = "qeParamsAnswerFieldset"
        container.appendChild(answersField);
                        
        me.paramsElement.appendChild(container);
        me.type_Choice_CheckAnswerFields();
    }
    this.type_Choice_CheckAnswerFields = function() {
        debugger;
        var container = ge("qeParamsAnswerFieldset");
        var numAnswers = parseInt(document.getElementById("qeNumOptionsField").value, 10);
        var numAnswerFields = 0; 
        {
            for (var i = container.childNodes.length-1; i >= 0; i--) {
                if (container.childNodes[i].className = "qeChoiceAnswerGroup") {
                    numAnswerFields++;
                }
            }
            
        }
        
        // If there already are the correct number of answer fields, exit the function
        if (numAnswers == numAnswerFields) return;
        else if (numAnswers > numAnswerFields) {
            // Extra inputs need to be added
            var n = numAnswers - numAnswerFields;
            for (var x = 0; x < n; x++) {
                var group = ce("div");
                group.className = "qeChoiceAnswerGroup";
                var field = createNewElement("input", "text", "qeAnswerField"+(numAnswerFields+x), "qeParamField", null);
                var field_lbl = createNewInputLabel((numAnswerFields+x), "qeAnswerField"+(numAnswerFields+x), "l");
                
                group.appendChild(field_lbl);
                group.appendChild(field);
                container.appendChild(group);
            }
        }
        else if (numAnswers < numAnswerFields) {
            // There are too many inputs and some need to be removed. Start at the end!
            // TODO: This is SO inefficient. There has to be a better way, perhaps adding elements to an array?
            // TODO: Another approach would be to use the previousSibling property as a way to prevent having to loop through the entire container tree every time an object needs to be removed.
            var n = numAnswerFields-numAnswers;
            for (var x = 0; x < n; x++) {
                for (var y = container.childNodes.length-1; y >= 0; y--) {
                    if (container.childNodes[y].className == "qeChoiceAnswerGroup") {
                        container.removeChild(container.childNodes[y]);
                        break;
                    }
                }
            }
        }
    }
     
    // Editing
    this.editQuestion = function(uid) {
        if (sequencer.state.editing == true) return;
        if (sequencer.state.loaded == false) return;
        sequencer.state.editing = true;
        
        var request = {
            "type": "Question",
            "uid": uid
        }
        
        var requestString = "args="+JSON.stringify(request);
        sequencer.state.loaded = false;
        newAjaxRequest(requestString, getObject.php, function(result){
            // Once results are in
            questionEditor.setValues(result.responseText);
            sequencer.state.loaded = true;
        }, true);
    }
    this.createNewQuestion = function() {
        if (sequencer.state.editing == true) return;
        if (sequencer.state.loading == true) return;
        sequencer.state.editing = true;
    
        me.reset();
        var container = ge("seqContentWrapper");
        container.appendChild(me.element);
    }
}