/**
 * Installer's AJAX frontend handler
 */

(function($) { // Avoid conflicts with other libraries
    // Installer variables
    var pollTimer = null;
    var nextReadPosition = 0;
    var progressBarTriggered = false;
    var progressTimer = null;
    var currentProgress = 0;

    // Template related variables
    var $contentWrapper = $('.install-body').find('.main');

    // Intercept form submits
    intercept_form_submit($('#install_install'));

    function poll_content(xhReq) {
        var messages = xhReq.responseText;

        do {
            var unprocessed = messages.substring(nextReadPosition);
            var messageEndIndex = unprocessed.indexOf('}\n\n');

            if (messageEndIndex !== -1) {
                var endOfMessageIndex = messageEndIndex + 3; // 3 is the length of "}\n\n"
                var message = unprocessed.substring(0, endOfMessageIndex);
                parse_message(message);
                nextReadPosition += endOfMessageIndex;
            }
        } while (messageEndIndex !== -1);

        if (xhReq.readyState === 4) {
            $('#loading_indicator').css('display', 'none');
            reset_polling();
        }
    }

    function parse_message(messageJSON) {
        $('#loading_indicator').css('display', 'none');

        messageJSON = messageJSON.trim();
        var responseObject = JSON.parse(messageJSON);

        // Parse object
        if (responseObject.hasOwnProperty('errors')) {
            add_message('error', responseObject.errors)
        }

        if (responseObject.hasOwnProperty('warnings')) {
            add_message('warning', responseObject.warnings)
        }

        if (responseObject.hasOwnProperty('logs')) {
            add_message('log', responseObject.logs);
        }

        if (responseObject.hasOwnProperty('form')) {
            add_form(responseObject.form);
        }

        if (responseObject.hasOwnProperty('progress')) {
            set_progress(responseObject.progress);
        }
    }

    function add_message(type, messages) {
        // Get message containers
        var $errorContainer = $('#error-container');
        var $warningContainer = $('#warning-container');
        var $logContainer = $('#log-container');

        var $title, $description, $msgElement, arraySize = messages.length;
        for (var i = 0; i < arraySize; i++) {
            $msgElement = $('<div />');
            $title = $(document.createElement('strong'));
            $title.text(messages[i].title);
            $msgElement.append($title);

            if (messages[i].hasOwnProperty('description')) {
                $description = $(document.createElement('p'));
                $description.text(messages[i].description);
                $msgElement.append($description);
            }

            switch (type) {
                case 'error':
                    $msgElement.addClass('errorbox');
                    $errorContainer.append($msgElement);
                    break;
                case 'warning':
                    $msgElement.addClass('warningbox');
                    $warningContainer.append($msgElement);
                    break;
                case 'log':
                    $msgElement.addClass('log');
                    $logContainer.append($msgElement);
                    break;
            }
        }
    }

    function add_form(formHtml) {
        var $formContainer = $('#content-container');
        $formContainer.html(formHtml);
        var $form = $('#install_install');
        intercept_form_submit($form);
    }

    function set_progress(progressObject) {
        var $statusText, $progressBar, $progressText, $progressFiller;

        if (progressObject.task_name.length) {
            if (!progressBarTriggered) {
                // Create progress bar
                var $contentContainer = $('#content-container');

                // Create progress bar elements
                $progressBar = $('<div />');
                $progressBar.attr('id', 'progress-bar');
                $progressText = $('<p />');
                $progressText.attr('id', 'progress-bar-text');
                $progressFiller = $('<span />');
                $progressFiller.attr('id', 'progress-bar-filler');

                $statusText = $('<p />');
                $statusText.attr('id', 'progress-status-text');

                $progressBar.append($progressFiller);
                $progressBar.append($progressText);

                $contentContainer.append($statusText);
                $contentContainer.append($progressBar);

                progressBarTriggered = true;
            } else {
                $statusText = $('#progress-status-text');
            }

            // Update progress bar
            $statusText.text(progressObject.task_name + '…');
            increment_progress_bar(Math.round(progressObject.task_num / progressObject.task_count * 100));
        }
    }

    function increment_progress_bar(progressLimit) {
        var $progressFiller = $('#progress-bar-filler');
        var $progressText = $('#progress-bar-text');
        var progressStart = $progressFiller.width() / $progressFiller.offsetParent().width() * 100;
        currentProgress = Math.floor(progressStart);

        clearInterval(progressTimer);
        progressTimer = setInterval(function() {
            incrementFiller($progressText, $progressFiller, progressLimit);
        }, 10);
    }

    function incrementFiller($progressText, $progressFiller, progressLimit) {
        currentProgress++;
        $progressText.text(currentProgress + '%');
        $progressFiller.css('width', currentProgress + '%');

        if (currentProgress >= progressLimit || currentProgress >= 100) {
            console.log("In if; " + progressLimit + "; " + currentProgress);
            clearInterval(progressTimer);
        }
    }

    function start_polling(xhReq) {
        reset_polling();
        pollTimer = setInterval(function () {
            poll_content(xhReq);
        }, 500);
    }

    function reset_polling() {
        clearInterval(pollTimer);
        nextReadPosition = 0;
    }

    function submit_form($form, $submitBtn) {
        $form.css('display', 'none');

        var xhReq = create_xhr_object();
        xhReq.open('POST', $form.attr('action'), true);
        xhReq.setRequestHeader('X-Requested-With', 'XMLHttpRequest');
        xhReq.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
        xhReq.send(get_form_fields($form, $submitBtn));

        // Clear content
        setup_ajax_layout();
        $('#loading_indicator').css('display', 'block');

        start_polling(xhReq);
    }

    // Workaround for submit buttons
    function get_form_fields($form, $submitBtn) {
        var formData = $form.serialize();
        formData += ((formData.length) ? '&' : '') + encodeURIComponent($submitBtn.attr('name')) + '=';
        formData += encodeURIComponent($submitBtn.attr('value'));

        return formData;
    }

    function intercept_form_submit($form) {
        if (!$form.length) {
            return;
        }

        $form.find(':submit').bind('click', function (event) {
            event.preventDefault();
            submit_form($form, $(this));
        });

    }

    /**
     * jQuery cannot be used as the response is streamed, and
     * as of now, jQuery does not provide access to the response until
     * the connection is not closed.
     */
    function create_xhr_object() {
        var xhReq;

        if (window.XMLHttpRequest) {
            xhReq = new XMLHttpRequest();
        }
        else if (window.ActiveXObject) {
            xhReq = new ActiveXObject("Msxml2.XMLHTTP");
        }

        return xhReq;
    }

    function setup_ajax_layout() {
        // Clear content
        $contentWrapper.html('');

        var $header = $('<div />');
        $header.attr('id', 'header-container');
        $contentWrapper.append($header);

        var $description = $('<div />');
        $description.attr('id', 'description-container');
        $contentWrapper.append($description);

        var $errorContainer = $('<div />');
        $errorContainer.attr('id', 'error-container');
        $contentWrapper.append($errorContainer);

        var $warningContainer = $('<div />');
        $warningContainer.attr('id', 'warning-container');
        $contentWrapper.append($warningContainer);

        var $installerContentWrapper = $('<div />');
        $installerContentWrapper.attr('id', 'content-container');
        $contentWrapper.append($installerContentWrapper);

        var $logContainer = $('<div />');
        $logContainer.attr('id', 'log-container');
        $contentWrapper.append($logContainer);

        var $spinner = $('<div />');
        $spinner.attr('id', 'loading_indicator');
        $spinner.html('&nbsp;');
        $contentWrapper.append($spinner);
    }
})(jQuery); // Avoid conflicts with other libraries