/**
 * Provides functions for site upgrades performed through XHR
 */

elgg.provide('elgg.upgrades');

// The already displayed messages are saved here
elgg.upgrades.errorMessages = [];

elgg.upgrades.init = function () {
	$('#upgrade-run').click(elgg.upgrades.run);
};

/**
 * Initializes the XHR upgrade feature
 *
 * @param {Object} e Event object
 */
elgg.upgrades.run = function(e) {
	e.preventDefault();

	// The total amount of items to be upgraded
	var total = $('#upgrade-total').text();

	// Initialize progressbar
	$('.elgg-progressbar').progressbar({
		value: 0,
		max: total
	});

	// Replace button with spinner when upgrade starts
	$('#upgrade-run').addClass('hidden');
	$('#upgrade-spinner').removeClass('hidden');

	// Start upgrade from offset 0
	elgg.upgrades.upgradeBatch(0);
};

/**
 * Fires the ajax action to upgrade a batch of items.
 *
 * @param {Number} offset  The next upgrade offset
 */
elgg.upgrades.upgradeBatch = function(offset) {
	var options = {
		data: {
			offset: offset
		},
		dataType: 'json'
	};

	options.data = elgg.security.addToken(options.data);

	var upgradeCount = $('#upgrade-count');
	var action = $('#upgrade-run').attr('href');

	options.success = function(json) {
		// Append possible errors after the progressbar
		if (json.system_messages.error.length) {
			// Display only the errors that haven't already been shown
			$(json.system_messages.error).each(function(key, message) {
				if (jQuery.inArray(message, elgg.upgrades.errorMessages) === -1) {
					var msg = '<li class="elgg-message elgg-state-error">' + message + '</li>';
					$('#upgrade-messages').append(msg);

					// Add this error to the displayed errors
					elgg.upgrades.errorMessages.push(message);
				}
			});
		}

		// Increase success statistics
		var numSuccess = $('#upgrade-success-count');
		var successCount = parseInt(numSuccess.text()) + json.output.numSuccess;
		numSuccess.text(successCount);

		// Increase error statistics
		var numErrors = $('#upgrade-error-count');
		var errorCount = parseInt(numErrors.text()) + json.output.numErrors;
		numErrors.text(errorCount);

		// Increase total amount of processed items
		var numProcessed = successCount + errorCount;
		upgradeCount.text(numProcessed);

		// Increase the progress bar
		$('.elgg-progressbar').progressbar({ value: numProcessed });
		var total = $('#upgrade-total').text();

		var percent = 100;
		if (numProcessed < total) {
			percent = parseInt(numProcessed * 100 / total);

			/**
			 * Start next upgrade call. Offset is the total amount of erros so far.
			 * This prevents faulty items from causing the same error again.
			 */
			elgg.upgrades.upgradeBatch(errorCount);
		} else {
			$('#upgrade-spinner').addClass('hidden');

			if (errorCount > 0) {
				// Upgrade finished with errors. Give instructions on how to proceed.
				elgg.register_error(elgg.echo('upgrade:finished_with_errors'));
			} else {
				// Upgrade is finished. Make one more call to mark it complete.
				elgg.action(action, {'upgrade_completed': 1});
				elgg.system_message(elgg.echo('upgrade:finished'));
			}
		}

		// Increase percentage
		$('#upgrade-counter').text(percent + '%');
	};

	// We use post() instead of action() so we can catch error messages
	// and display them manually underneath the upgrade view.
	return elgg.post(action, options);
};

elgg.register_hook_handler('init', 'system', elgg.upgrades.init);