// Dump custom binding
// From John Papa in Essential Knockout and Javascript Tips (Pluralsight)
// I tried to find a gist of it already from him but no luck, so here it is for anyone else who may want it
 
// Usage in HTML
// <div data-bind="dump: $data"></div>
// <div data-bind="dump: $root.results"></div> (if results was an observable/observableArray)
 
ko.bindingHandlers.dump = {
    init: function (element, valueAccessor, allBindingsAccessor, viewmodel, bindingContext) {
        var context = valueAccessor();
        var allBindings = allBindingsAccessor();
        var pre = document.createElement('pre');
 
        element.appendChild(pre);
 
        var dumpJSON = ko.computed({
            read: function () {
                var en = allBindings.enabled === undefined || allBindings.enabled;
                return en ? ko.toJSON(context, null, 2) : '';
            },
            disposeWhenNodeIsRemoved: element
        });
 
        ko.applyBindingsToNode(pre,
          {
              text: dumpJSON,
              visible: dumpJSON
          }
          );
        return { controlsDescendentBindings: true };
    }
};

// Stubs for services
var app = {
  playerRepository: {
    save: function(){
      var ajaxCall = $.Deferred();
      function resolveAjaxCall() {
        ajaxCall.resolve();
      };
      setTimeout(resolveAjaxCall, 1000);
      return ajaxCall;
    }
  }
}

// Model
var player = {
  name: "Kull",
  title: "The Conqueror", 
  avatarImage : "http://www.barbarianmeetscoding.com/images/barbarian-meets-knockout/barbarian-avatar.png",
  inventory: [
    { 
      name: "rusty broadsword",
      image: "http://www.barbarianmeetscoding.com/images/barbarian-meets-knockout/broadsword.png",
      weight: "10 st"
    },
    { 
      name: "magic potion",
      image: "http://www.barbarianmeetscoding.com/images/barbarian-meets-knockout/potion.png",
      weight: "1 st"
    },
    { 
      name: "hunter axe",
      image: "http://www.barbarianmeetscoding.com/images/barbarian-meets-knockout/axe.png",
      weight: "20 st"
    },
    { 
      name: "assassin's bone knife",
      image: "http://www.barbarianmeetscoding.com/images/barbarian-meets-knockout/assassins-knife.png",
      weight: "3 st"
    }
  ]
};

// ViewModel
var PlayerViewModel = function(){
    var self = this;
    self.name = ko.observable(player.name);
    self.title = ko.observable(player.title);
  self.fullName = ko.computed(function(){
        return self.name() + ', ' + self.title();
    });
    
    self.inventoryItems = ko.observableArray(player.inventory);
    self.inventoryWeight = ko.computed(function(){
      //calculate weight
      var totalWeight = 0;
      ko.utils.arrayForEach(self.inventoryItems(), function(item) {
        var value = parseInt(item.weight);
        if (!isNaN(value)) {
            totalWeight += value;
        }
      });
      return totalWeight + " stones";
    });
    self.status = ko.computed({ 
      read: function(){
        var totalWeight = parseInt(self.inventoryWeight());
        if (!isNaN(totalWeight) && totalWeight > 20)
          return "(overstrained)";
        return "";
      },
      disposeWhen: function(){
        return self.disposeAll;
      }});
    self.dropFromInventory = function(item){
      self.inventoryItems.remove(item);
      self.hasChanged(true);
    };
    self.changeName = function(){
      self.name("John Doe");
    };
    // change trancking system
    self.hasChanged = ko.observable(false);  
    self.isSaving = ko.observable(false);
    self.canSave = ko.computed(function(){
      return self.hasChanged() && !self.isSaving();
    });
    self.name.subscribe(function(newValue){
       self.hasChanged(true)
    });
    self.saveChanges = function(){
      self.isSaving(true);
      app.playerRepository.save(self).done(function(){
        self.hasChanged(false);
        self.isSaving(false);
        console.log('saved!');
      });
    };
    
    self.disposeAll = false;
    // To dispose explicitely
    self.dispose = function(){
      self.fullName.dispose();
      self.status.dispose();
      self.inventoryWeight.dispose();
    };
};
    
var playerViewModel = new PlayerViewModel();

// Run knockout!
ko.applyBindings(playerViewModel);