Viewmodels - Sample 2

Viewmodels.js

var ThingInputViewModel=function() {
  if(!this instanceof ThingInputViewModel) {
    return new ThingInputViewModel();
  }

  var states={ none: 0, adding: 1,modifying: 2 };

  var self=this,
      statemachine=new SimpleStatemachine({ initialState: states.none }),
      baseData,
      initializeInput,
      buildCommand,
      cancelAdd,
      cancelModify;

  self.Name=new TextInput({
    rules: {
      required: true,
      minLength: ns.MetaData.Name.MinimumLength,
      maxLength: ns.MetaData.Name.MaximumLength
    },
    messages: {
      required: ns.Resources.FieldIsRequired,
      minLength: ns.Resources.MustHaveMinimumLength,
      maxLength: ns.Resources.MustNotExceedMaximumLength
    }
  });
  self.Save=new Trigger();
  self.Cancel=new Trigger();

  self.enable=function() {
    self.Save.enable();
    self.Cancel.enable();
    self.Name.enable();
  };

  self.disable=function() {
    self.Save.disable();
    self.Cancel.disable();
    self.Name.disable();
  };

  self.installController=function(controller) {
    self.Save.setCallback(function() {
      controller.saveItem(baseData.Id);
    });
  };

  self.Cancel.setCallback(function() {
    if(statemachine.isState(states.adding)) {
      cancelAdd();
    } else {
      cancelModify();
    }
  });

  cancelAdd=function() {
    self.clear();
  };

  cancelModify=function() {
    self.Name.reset();
  };

  self.clear=function() {
    statemachine.setState(states.none);
    
    baseData=null;

    self.disable();
    self.Name.clear();
    self.Name.unfocus();
  };

  self.addItem=function(initialData) {
    statemachine.setState(states.adding);

    self.Name.clear();
    initializeInput(initialData);

    self.enable();
    self.Name.focus();
  };

  self.modifyItem=function(initialData) {
    statemachine.setState(states.modifying);

    self.Name.clear();
    initializeInput(initialData);

    self.enable();
  };

  initializeInput=function(initialData) {
    baseData=initialData;
    self.Name.setValue(baseData.Name);
  };

  self.hasChanges=function() {
    if(statemachine.isState(states.none)) return false;
    if(statemachine.isState(states.adding)) return true;
    return self.Name.isChanged();
  };

  self.getChanges=function() {
    if(!self.hasChanges()) {
      return [];
    }
    return [buildCommand()];
  };

  self.validate=function(queryService, options) {    
    options = options || { };
    options.valid = options.valid || function() { };
    options.invalid = options.invalid || function() { };

    var isNameValid = self.Name.validate();

    queryService.validateNameUniqueness(baseData.Id, self.Name.getValue(), function(isUnique) {
      if (isUnique) {
        if (isNameValid) {
          options.valid();
        } else {
          options.invalid();
        }
      } else {
        self.Name.invalidate(ns.Resources.NameIsNotUnique);
        options.invalid();
      }
    });
  };

  buildCommand=function() {
    var message={
      Id: baseData.Id,
      Name: self.Name.getValue()
    };

    var command=null;
    if(statemachine.isState(states.adding)) {
      command=new Command("RegisterNewThingCommand",message);
    } else if(statemachine.isState(states.modifying)) {
      command=new Command("CorrectNameOfThingCommand",message);
    }
    return command;
  };

  self.clear();

  return self;
};