(function () {
  var err = function (s) {
    if (console && console.error) {
      console.error('[Rate This Podcast] ' + s);
    }
  };

  var config = window.RTP_CONFIG;
  if (typeof config !== 'object') {
    err('window.RTP_CONFIG must be an object.');
    return;
  }
  if (typeof config.link !== 'string') {
    err('window.RTP_CONFIG.link must be a string.');
    return;
  }
  if (!(config.mode === 'fullscreen' || config.mode === 'button')) {
    err('window.RTP_CONFIG.mode must be "fullscreen" or "button"');
    return;
  }

  var linkUrl = 'https://ratethispodcast.com/' + config.link +
    '?utm_source=Button%20Embed';

  var makeFrame = function(fullscreen) {
    var frm = document.createElement('iframe'), s = frm.style;
    frm.src = linkUrl;
    s.position = 'absolute';
    s.zIndex = '99999';
    s.border = 'none';
    s.padding = '0';
    s.margin = '0';

    if (fullscreen === true) {
      s.width = '100%';
      s.height = '100%';
      s.left = 0;
      s.top = 0;
      s.right = 0;
      s.bottom = 0;
    } else {
      s.width = '400px';
      s.height = '520px';
      s.maxWidth = '100vw';
      s.maxHeight = '100vh';
      s.top = '50%';
      s.left = '50%';
      s.right = 'auto';
      s.bottom = 'auto';
      s.marginRight = '-50%';
      s.transform = 'translate(-50%, -50%)';
      s.boxShadow = '0px 0px 120px rgba(0, 0, 0, 0.25), ' +
        '0 1px 2px rgba(0,0,0,0.28)';
      s.border = 'none';
      s.borderRadius = '6px';
      s.background = '#f6f6f6';
    }

    return frm;
  };

  var makeFrameModal = function() {
    var div = document.createElement('div'), s = div.style;
    s.background = 'rgba(255, 255, 255, 0.8)';
    s.position = 'fixed';
    s.zIndex = '99998';
    s.border = 'none';
    s.width = '100%';
    s.height = '100%';
    s.margin = '0';
    s.padding = '0';
    s.left = 0;
    s.top = 0;
    s.overflow = 'hidden';

    try {
      s['backdrop-filter'] = 'blur(8px)';
    } catch (e) {}

    div.onclick = function(e) {
      div.parentNode.removeChild(div);
    };

    div.appendChild(makeFrame(false));
    return div;
  };

  var makeButtonImg = function() {
    var src = config.buttonImage;
    var w = config.buttonWidth, h = config.buttonHeight;
    if (src === undefined) {
      src = 'https://storage.googleapis.com/rtp-assets/buttons/standard.png';
      w = '198px';
      h = '56px';
    }

    var img = document.createElement('img'), s = img.style;
    img.src = src;
    s.padding = 0;
    s.margin = 0;
    try {
      s['filter'] = 'drop-shadow(1px 1px 2px rgba(0,0,0,0.12))';
    } catch (e) {}
    if (typeof w !== undefined) s.width = w;
    if (typeof h !== undefined) s.height = h;
    return img;
  };

  var makeButton = function() {
    var a = document.createElement('a'), s = a.style;
    a.href = linkUrl;
    s.padding = 0;
    s.margin = 0;

    a.onclick = function(e) {
      e.preventDefault();
      document.body.appendChild(makeFrameModal());
    }

    a.appendChild(makeButtonImg());
    return a;
  };

  if (config.mode === 'fullscreen') {
    // The <iframe> content abides by the host page's viewport setting.
    var meta = document.createElement('meta');
    meta.name = 'viewport';
    meta.content = 'width=device-width,initial-scale=1';
    document.getElementsByTagName('head')[0].appendChild(meta);

    document.body.style.background = '#f6f6f6';
    document.body.appendChild(makeFrame(true));
  } else if (config.mode === 'button') {
    var container = document.getElementById('rtp-button');
    if (!container) {
      err(
        'Please add a container for the button somewhere on this page: ' +
        '<div id="rtp-button"></div>');
      return;
    }

    var a = makeButton();
    container.innerHTML = '';
    container.appendChild(a);
  }
})();