/*

See LICENSE.txt for this sample’s licensing information.

Abstract:

This class handles fetching and presenting simple templates.

*/

// Registry of attribute name used to define the URL to template (e.g. documentURL or menuBarDocumentURL)

// to controller type (e.g. DocumentController or MenuBarController)

const attributeToController = {};

const attributeKeys = [];

function registerAttributeName(type, func) {

    attributeToController[type] = func;

    attributeKeys.push(type);

}

function resolveControllerFromElement(elem) {

    for (let key of attributeKeys) {

        if (elem.hasAttribute(key)) {

            return {

                type: attributeToController[key],

                documentURL: elem.getAttribute(key)

            };

        }

    }

}

class DocumentController {

    constructor({ documentLoader, documentURL, loadingDocument }) {

        this.handleEvent = this.handleEvent.bind(this);

        this._documentLoader = documentLoader;

        this.fetchDocument(documentURL, loadingDocument);

    }

    fetchDocument(documentURL, loadingDocument) {

        this._documentLoader.fetch({

            url: documentURL,

            success: (document) => {

                // Add the event listener for document

                this.setupDocument(document);

                // Allow subclass to do custom handling for this document

                this.handleDocument(document, loadingDocument);

            },

            error: (xhr) => {

                const alertDocument = createLoadErrorAlertDocument(documentURL, xhr, false);

                this.handleDocument(alertDocument, loadingDocument);

            }

        });

    }

    setupDocument(document) {

        document.addEventListener("select", this.handleEvent);

        document.addEventListener("play", this.handleEvent);

    }

    handleDocument(document, loadingDocument) {

        if (loadingDocument) {

            navigationDocument.replaceDocument(document, loadingDocument);

        } else {

            navigationDocument.pushDocument(document);

        }

    }

    handleEvent(event) {

        const targetElem = event.target;

        let controllerOptions = resolveControllerFromElement(targetElem);

        if (controllerOptions) {

            const controllerClass = controllerOptions.type;

            if (!controllerClass.preventDefaultLoadingDocument) {

                let loadingDocument = createLoadingDocument();

                navigationDocument.pushDocument(loadingDocument);

                controllerOptions.loadingDocument = loadingDocument;

            }

            controllerOptions.event = event;

            controllerOptions.documentLoader = this._documentLoader;

            // Create the subsequent controller based on the atribute and its value. Controller would handle its presentation.

            new controllerClass(controllerOptions);

        }

        else if (targetElem.tagName === 'description') {

            // Handle description tag, if no URL was specified

            const body = targetElem.textContent;

            const alertDocument = createDescriptiveAlertDocument('', body);

            navigationDocument.presentModal(alertDocument);

        }

        return createLoadingDocument();

    }

}

registerAttributeName('documentURL', DocumentController);