if (typeof PAYPAL === 'undefined' || !PAYPAL) {

var PAYPAL = {};

}

PAYPAL.apps = PAYPAL.apps || {};

(function () {

'use strict';

var app = {},

paypalURL = 'https://www.paypal.com/cgi-bin/webscr',

prettyParams = {

id: 'hosted_button_id',

name: 'item_name',

number: 'item_number'

},

buttonImgs = {

buynow: '//www.paypalobjects.com/en_US/i/btn/btn_buynow_LG.gif',

cart: '//www.paypalobjects.com/en_US/i/btn/btn_cart_LG.gif',

basic: '//www.paypalobjects.com/en_US/i/btn/btn_buynow_LG.gif'

};

if (!PAYPAL.apps.ButtonFactory) {

/**

* A count of each type of button on the page

*/

app.buttons = {

buy: 0,

cart: 0,

qr: 0,

api: 0

};

/**

* Renders a button in place of the given element

*

* @param data {Object} An object of key/value data to set as button params

* @param type (String) The type of the button to render

* @param parent {HTMLElement} The element to add the button to (Optional)

* @return {HTMLElement}

*/

app.create = function (data, type, parent) {

var normalized = {}, button, key;

// Don't render without the correct data

if (!data || !data.business) {

return false;

}

// Normalize the data's keys

for (key in data) {

normalized[prettyParams[key] || key] = data[key];

}

// Hosted buttons

if (normalized.hosted_button_id) {

normalized.cmd = '_s-xclick';

// Cart buttons

} else if (type === 'cart') {

normalized.cmd = '_cart';

normalized.add = true;

// Plain text buttons

} else {

normalized.cmd = '_xclick';

}

// Build the UI components

if (type === 'qr') {

button = buildQR(normalized);

} else {

button = buildForm(type, normalized);

}

// Register it

this.buttons[type] += 1;

// Add it to the DOM

if (parent) {

parent.appendChild(button);

}

return button;

};

PAYPAL.apps.ButtonFactory = app;

}

/**

* Builds the form DOM structure for a button

*

* @param type (String) The type of the button to render

* @param data {Object} An object of key/value data to set as button params

* @return {HTMLElement}

*/

function buildForm(type, data) {

var form = document.createElement('form'),

btn = document.createElement('input'),

hidden = document.createElement('input'),

input, key;

btn.type = 'image';

hidden.type = 'hidden';

form.method = 'post';

form.action = paypalURL;

form.appendChild(btn);

btn.src = getButtonImg(type);

for (key in data) {

input = hidden.cloneNode(true);

input.name = key;

input.value = data[key];

form.appendChild(input);

}

// If the Mini Cart is present then register the form

if (PAYPAL.apps.MiniCart && data.cmd === '_cart') {

var MiniCart = PAYPAL.apps.MiniCart;

if (!MiniCart.UI.itemList) {

MiniCart.render();

}

MiniCart.bindForm(form);

}

return form;

}

/**

* Builds the image for a QR code

*

* @param data {Object} An object of key/value data to set as button params

* @return {HTMLElement}

*/

function buildQR(data) {

var img = document.createElement('img'),

size = data.size || 250,

url = paypalURL + '?',

pattern = 13,

key;

for (key in data) {

url += key + '=' + data[key] + '&';

}

url = encodeURIComponent(url);

img.src = 'https://www.paypal.com/webapps/ppint/qrcode?data=' + url + '&pattern=' + pattern + '&' + url + '&height=' + size;

return img;

}

/**

* Utility function to return the rendered button image URL

*

* @param type {String} The type of button to render

* @return {String}

*/

function getButtonImg(type) {

return buttonImgs[type] || buttonImgs.basic;

}

/**

* Utility function to polyfill dataset functionality for browsers

*

* @param el {HTMLElement} The element to check

* @return {Object}

*/

function getDataSet(el) {

var dataset = el.dataset,

attrs, attr, matches, len, i;

if (!dataset) {

dataset = {};

if ((attrs = el.attributes)) {

for (i = 0, len = attrs.length; i < len; i++) {

attr = attrs[i];

if ((matches = /^data-(.+)/.exec(attr.name))) {

dataset[matches[1]] = attr.value;

}

}

}

}

return dataset;

}

// Init the buttons

if (typeof document !== 'undefined') {

var ButtonFactory = PAYPAL.apps.ButtonFactory,

nodes = document.getElementsByTagName('script'),

node, data, button, business, i, len;

for (i = 0, len = nodes.length; i < len; i++) {

node = nodes[i];

data = node && getDataSet(node);

button = data && data.button;

business = data.business = node.src.split('?merchant=')[1];

if (button && business) {

ButtonFactory.create(data, button, node.parentNode);

// Clean up

node.parentNode.removeChild(node);

}

}

}

}());