define(['jquery', 'underscore', 'backbone', 'models/SolrResult'],
	function($, _, Backbone, SolrResult, template) {
	'use strict';

	var DownloadButtonView = Backbone.View.extend({

		tagName: "a",

		className: "btn download",

		initialize: function(options){
			if(!options) var options = {}

			this.model = options.model || new SolrResult();
		},

		events: {
			"click" : "download"
		},

		render: function(){

      var fileName = this.model.get("fileName") || "";

      if( typeof fileName == "string" ){
        fileName = fileName.trim();
      }

			//Add the href and id attributes
			this.$el.attr("href", this.model.get("url"))
					.attr("data-id", this.model.get("id"))
          .attr("download", fileName);

      //Check for CORS downloads. For CORS, the 'download' attribute may not work,
      // so open in a new tab.
      if( this.model.get("url").indexOf(window.location.origin) == -1 ){
        this.$el.attr("target", "_blank");
      }

			//For packages
			if(this.model.type == "Package"){
				this.$el.text("Download All")
						.addClass("btn-primary");

        //if the Package Model has no Solr index document associated with it, then we
        // can assume the resource map object is private. So disable the download button.
        if( !this.model.get("indexDoc") ){
          this.$el.attr("disabled", "disabled")
                  .addClass("disabled")
                  .attr("href", "")
                  .tooltip({
                    trigger: "hover",
                    placement: "top",
                    delay: 500,
                    title: "This dataset may contain private data, so each data file should be downloaded individually."
                  });
        }
			}
			//For individual DataONEObjects
			else{
				this.$el.text("Download");
			}

			//Add a download icon
			this.$el.append( $(document.createElement("i")).addClass("icon icon-cloud-download") );

			//If this is a Download All button for a package but it's too large, then disable the button with a message
			if(this.model.type == "Package" && this.model.getTotalSize() > MetacatUI.appModel.get("maxDownloadSize")){

				this.$el.addClass("tooltip-this")
						.attr("disabled", "disabled")
						.attr("data-title", "This dataset is too large to download as a package. Please download the files individually or contact us for alternate data access.")
						.attr("data-placement", "top")
						.attr("data-trigger", "hover")
						.attr("data-container", "body");

				// Removing the `href` attribute while disabling the download button.
				this.$el.removeAttr("href");

				// Removing pointer as cursor and setting to default
				this.$el.css("cursor","default");
			}
		},

		download: function(e){

      // Checking if the Download All button is disabled because the package is too large
      var isDownloadDisabled = (this.$el.attr("disabled") === "disabled" || this.$el.is(".disabled")) ? true : false;

      // Do nothing if the `disabled` attribute is set!.
      // If the download is already in progress, don't try to download again
      if(isDownloadDisabled || this.$el.is(".in-progress")) {
        e.preventDefault();
        return;
      }

      //If the user isn't logged in, let the browser handle the download normally
      if( MetacatUI.appUserModel.get("tokenChecked") && !MetacatUI.appUserModel.get("loggedIn") ){
        return;
      }
      //If the authentication hasn't been checked yet, wait for it
      else if( !MetacatUI.appUserModel.get("tokenChecked") ){
        var view = this;
        this.listenTo(MetacatUI.appUserModel, "change:tokenChecked", function(){
          view.download(e);
        });
        return;
      }
      //If the user is logged in but the object is public, download normally
      else if( this.model.get("isPublic") ){

        //If this is a "Download All" button for a package, and at least object is private, then
        // we need to download via XHR with credentials
        if( this.model.type == "Package" ){
          //If we found a private object, download the package via XHR so we can send the auth token.
          var privateObject = _.find(this.model.get("members"), function(m){ return m.get("isPublic") !== true; });
          //If no private object is found, download normally.
          // This may still fail when there is a private object that the logged-in user doesn't have access to.
          if( !privateObject ){
            return;
          }
        }
        //All other object types (data and metadata objects) can be downloaded normally
        else{
          return;
        }
      }

      e.preventDefault();

      //Show that the download has started
      this.$el.addClass("in-progress");
      var buttonHTML = this.$el.html();
      this.$el.html("Downloading... <i class='icon icon-on-right icon-spinner icon-spin'></i>");

      //Fire the download event via the SolrResult model
      this.model.downloadWithCredentials();

      this.listenToOnce(this.model, "downloadComplete", function(){

        //Show that the download is complete
        this.$el.html("Complete <i class='icon icon-on-right icon-ok'></i>")
            .addClass("complete")
            .removeClass("in-progress error");

        var view = this;

        //Put the download button back to normal
        setTimeout(function(){

          //After one second, change the background color with an animation
          view.$el.removeClass("complete")
            .html(buttonHTML);
        }, 2000);

      });

      this.listenToOnce(this.model, "downloadError", function(){
          //Show that the download failed to compelete.
          this.$el.html("Error <i class='icon icon-on-right icon-warning-sign'></i>")
              .addClass("error")
              .removeClass("in-progress")
              .tooltip({
                trigger: "hover",
                placement: "top",
                title: "Something went wrong while trying to download. Click to try again."
              });
        });
		}
	});

	return DownloadButtonView;

});