/**
 * IMDb Rating Plugin Library. This is the library that is injected into the third party's website. Its hosted 
 * on its own (ie outside of the IMDbConsumerSiteStaticMedia package) on media bridge. 
 * @author jmazur
 */
(function(window) {
  // always use strict mode from now on!
  "use strict";

  // make sure the document is in local scope
  var document = window.document;

  // create namespace
  if (!('imdb' in window)) {
    window.imdb = {};
  }

  // initialize rating object
  imdb.rating = {
    response: {},
    elems: {}
  };

  /**
   * Utility method to ensure that getElementsByClassName works appropriately
   */
  imdb.rating.getElementsByClassName = function(className, tag, elm) {
    if (document.getElementsByClassName) {
      imdb.rating.getElementsByClassName = function(className, tag, elm) {
        elm = elm || document;
        var elements = elm.getElementsByClassName(className),
            nodeName = (tag) ? new RegExp("\\b" + tag + "\\b", "i") : null,
            returnElements = [],
            current;
        for (var i = 0, il = elements.length; i < il; i += 1) {
          current = elements[i];
          if (!nodeName || nodeName.test(current.nodeName)) {
            returnElements.push(current);
          }
        }
        return returnElements;
      };
    } else if (document.evaluate) {
      imdb.rating.getElementsByClassName = function(className, tag, elm) {
        tag = tag || "*";
        elm = elm || document;
        var classes = className.split(" "),
            classesToCheck = "",
            xhtmlNamespace = "https://www.w3.org/1999/xhtml",
            namespaceResolver = (document.documentElement.namespaceURI === xhtmlNamespace) ? xhtmlNamespace : null,
            returnElements = [],
            elements, node;
        for (var j = 0, jl = classes.length; j < jl; j += 1) {
          classesToCheck += "[contains(concat(' ', @class, ' '), ' " + classes[j] + " ')]";
        }
        try {
          elements = document.evaluate(".//" + tag + classesToCheck, elm, namespaceResolver, 0, null);
        } catch (e) {
          elements = document.evaluate(".//" + tag + classesToCheck, elm, null, 0, null);
        }
        while ((node = elements.iterateNext())) {
          returnElements.push(node);
        }
        return returnElements;
      };
    } else {
      imdb.rating.getElementsByClassName = function(className, tag, elm) {
        tag = tag || "*";
        elm = elm || document;
        var classes = className.split(" "),
            classesToCheck = [],
            elements = (tag === "*" && elm.all) ? elm.all : elm.getElementsByTagName(tag),
            current, returnElements = [],
            match;
        for (var k = 0, kl = classes.length; k < kl; k += 1) {
          classesToCheck.push(new RegExp("(^|\\s)" + classes[k] + "(\\s|$)"));
        }
        for (var l = 0, ll = elements.length; l < ll; l += 1) {
          current = elements[l];
          match = false;
          for (var m = 0, ml = classesToCheck.length; m < ml; m += 1) {
            match = classesToCheck[m].test(current.className);
            if (!match) {
              break;
            }
          }
          if (match) {
            returnElements.push(current);
          }
        }
        return returnElements;
      };
    }
    return imdb.rating.getElementsByClassName(className, tag, elm);
  };

  // IE has some issues with getAttribute, this is a better cross browser approach
  imdb.rating.getAttr = function(node, attr) {
    var attrs = node.attributes;
    for (var i in attrs) {
      if (attrs[i] && attrs[i].name == attr) {
        return attrs[i].value;
      }
    }
    return null;
  };

  // local document ready function
  imdb.rating.ready = function(callback) {
    var DOMContentLoaded;
    if (document.addEventListener) {
      //console.log('creating W3C version of DOMContentLoaded');
      DOMContentLoaded = function() {
        //console.log('W3C DOMContentLoaded has fired');
        document.removeEventListener("DOMContentLoaded", DOMContentLoaded, false);
        callback();
      };
    } else if (document.attachEvent) {
      //console.log('creating IE version of DOMContentLoaded');
      DOMContentLoaded = function() {
        //console.log('IE DOMContentLoaded has fired');
        if (document.readyState === "complete") {
          //console.log('document.readyState === complete in IE DOMContentLoaded');
          document.detachEvent("onreadystatechange", DOMContentLoaded);
          callback();
        }
      };
    }
    if (document.readyState === "complete") {
      //console.log('document.readyState === complete, setting callback timeout');
      setTimeout(callback, 1);
    }
    if (document.addEventListener) {
      //console.log('adding W3C DOMContentLoaded event listener');
      document.addEventListener("DOMContentLoaded", DOMContentLoaded, false);
      window.addEventListener("load", callback, false);
    } else if (document.attachEvent) {
      //console.log('adding IE DOMContentLoaded event listener');
      document.attachEvent("onreadystatechange", DOMContentLoaded);
      window.attachEvent("onload", callback);
    }
  };

  // properly formats numbers with commas for display
  imdb.rating.addCommas = function(nStr) {
    nStr += '';
    var rgx = /(\d+)(\d{3})/;
    while (rgx.test(nStr)) {
      nStr = nStr.replace(rgx, '$1' + ',' + '$2');
    }
    return nStr;
  }

  /**
   * Adds a <link rel="stylesheet" type="text/css" href="https://ia.media-imdb.com/images/G/01/imdb/plugins/rating/css/imdbRating.css" />
   * to the head of the document so the plugin looks correct.
   */
  imdb.rating.attachCSS = function() {
    // create link element
    var head = document.getElementsByTagName("head")[0],
        link = document.createElement("link");
    link.setAttribute("rel", "stylesheet");
    link.setAttribute("type", "text/css");
    link.setAttribute("href", "https://ia.media-imdb.com/images/G/01/imdb/plugins/rating/css/imdbRating.css");
    // add link element to head
    head.appendChild(link);
  };

  /**
   * Construct the output to display on the page
   * 
   * @param options
   *            an object containing the options
   */
  imdb.rating.buildPlugin = function(options) {
    // create DOM pieces
    var tconst = this.response.id.split("/")[2],
        span = imdb.rating.elems[tconst]["elem"],
        anchor = imdb.rating.elems[tconst]["elem"].getElementsByTagName("a")[0],
        textSpan = document.createElement("span"),
        
        
        // rating is a number when there is a rating, otherwise is "N/A"
        rating = typeof(this.response.rating) === "number" ? this.response.rating.toFixed(1) : "N/A",
        ratingTextNode = document.createTextNode(rating),
        outOfTenSpan = document.createElement("span"),
        outOfTenTextNode = document.createTextNode("/10");

    // update the class name so the CSS can take effect
    span.className = span.className + " " + options.style;

    // add rating text
    if (rating) {
      textSpan.className = "rating";
      textSpan.appendChild(ratingTextNode);
      outOfTenSpan.className = "ofTen";
      outOfTenSpan.appendChild(outOfTenTextNode);
      textSpan.appendChild(outOfTenSpan);
      span.appendChild(textSpan);
    }

    // add star image if necessary
    if (typeof(options.starImg) === "string") {
      var starImg = document.createElement("img");
      starImg.src = "https://ia.media-imdb.com/images/G/01/imdb/plugins/rating/images/" + options.starImg;
      starImg.className = "star";
      span.appendChild(starImg);
    }

    // add votes if necessary
    if (options.showVotes === true && this.response.ratingCount) {
      var votesTextNode = document.createTextNode(this.addCommas(this.response.ratingCount) + " votes"),
          votesSpan = document.createElement("span");
      votesSpan.className = "votes";
      votesSpan.appendChild(votesTextNode);
      span.appendChild(votesSpan);
    }
  };

  imdb.rating.setResponse = function(response) {
    if (typeof(response) === "object") {
      this.response = response.resource;
    }
    // the response is not an object (probably no rating for the given tconst)
    else {
      this.response.rating = "N/A";
      this.response.ratingCount = 0;
    }
  };

  /**
   * The methods below receive the response from Cloudfront and build the correct DOM output to the browser
   * Since we cannot use query sting parameters with a JS file, the JSONP response will be padded with one
   * of the following methods unless there is no rating, in which case nothing will display.
   * 
   * @example
   * <script src="https://p.media-imdb.com/static-content/documents/v1/title/tt0133093/ratings?jsonp=imdb.rating.run:imdb.api.title.ratings/data.json"></script>
   * 
   * Will return:
   * imdb.rating.run({
   *         "@meta":{
   *             "requestId":"fb03a296-b694-11e1-a632-0bc998174348",
   *             "serviceTimeMs":0.274
   *         },
   *         "resource":{
   *             "@type":"imdb.api.title.ratings",
   *             "id":"/title/tt0133093/",
   *             "rating":8.73,
   *             "ratingCount":565487,
   *             "title":"The Matrix",
   *             "titleType":"movie",
   *             "topRank":19,
   *             "year":1999
   *         }
   * });
   * 
   * @param response
   *            the JSON response from Cloudfront
   */
  imdb.rating.run = function(response) {
    this.setResponse(response);
    var tconst = this.response.id.split("/")[2];
    var span = imdb.rating.elems[tconst]["elem"];
    var style = imdb.rating.elems[tconst]["style"];
    imdb.rating[style]();
  };

  imdb.rating.t1 = imdb.rating.p1 = function() {
    this.buildPlugin({
      "style": "imdbRatingStyle1",
      "imdbLogo": "imdb_46x22.png",
      "starImg": "imdb_star_22x21.png"
    });
  };

  imdb.rating.p2 = function() {
    this.buildPlugin({
      "style": "imdbRatingStyle2",
      "imdbLogo": "imdb_38x18.png",
      "starImg": "imdb_star_17x17.png"
    });
  };

  imdb.rating.p3 = function() {
    this.buildPlugin({
      "style": "imdbRatingStyle3",
      "imdbLogo": "imdb_37x18.png",
      "showVotes": true
    });
  };

  imdb.rating.p4 = function() {
    this.buildPlugin({
      "style": "imdbRatingStyle4",
      "imdbLogo": "imdb_31x14"
    });
  };

  imdb.rating.p5 = function() {
    this.buildPlugin({
      "style": "imdbRatingStyle5",
      "showVotes": true
    });
  };

  /**
   * Finds all plugin spans on the page and creates a JSONP lookup for each one
   */
  imdb.rating.createJSONP = function() {
    // for each plugin span get title, style and user then create jsonp lookups
    var elemsArr = imdb.rating.getElementsByClassName("imdbRatingPlugin");
    for (var i in elemsArr) {
      // using the local getAttr method here since IE was having trouble *big surprise there*
      var tconst = imdb.rating.getAttr(elemsArr[i], "data-title"),
          style = imdb.rating.getAttr(elemsArr[i], "data-style"),
          user = imdb.rating.getAttr(elemsArr[i], "data-user");
      if (!document.getElementById("imdb-jsonp-" + tconst)) {
        // add element to hash with style for later
        imdb.rating.elems[tconst] = {};
        imdb.rating.elems[tconst]["elem"] = elemsArr[i];
        imdb.rating.elems[tconst]["style"] = style;
        // create JSONP request
        var scriptTag = document.createElement("script");
        scriptTag.src = "https://p.media-imdb.com/static-content/documents/v1/title/" + tconst + "/ratings%3Fjsonp=imdb.rating.run:imdb.api.title.ratings/data.json?u=" + user + "&s=" + style;
        scriptTag.id = "imdb-jsonp-" + tconst;
        document.body.appendChild(scriptTag);
      }
    }
  };

  imdb.rating.ready(function() {
    // place CSS on page
    imdb.rating.attachCSS();
    // create JSONP call
    imdb.rating.createJSONP();
  });

})(window);