# Copyright 2012 United States Government, as represented by the Secretary of Defense, Under
# Secretary of Defense (Personnel & Readiness).
# 
# Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
# in compliance with the License. You may obtain a copy of the License at
# 
#   http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
# or implied. See the License for the specific language governing permissions and limitations under
# the License.

## The component representation of a lesson
## 
## @name lesson.vwf
## @namespace

--- 
extends: http://vwf.example.com/node.vwf
properties: 

  ## Index value for the instruction
  ## 
  ## @name lesson.vwf#instructionIndex
  ## @property

  instructionIndex: 0

methods:

  ## Method to start the lesson
  ## 
  ## @name lesson.vwf#begin
  ## @function
  ##
  ## @returns undefined

  begin:

events:

  ## The event that is fired (usually from the view) when the user has clicked the Next button
  ## 
  ## @name instruction.vwf#nextButtonClicked
  ## @event

  nextButtonClicked:

  ## The event that is fired when the lesson has been completed
  ## 
  ## @name instruction.vwf#completed
  ## @event

  completed:

scripts:
- |
    var self = this;
    var instructions;
    var activeInstruction;

    this.begin = function() {

      // TODO: In actuality, I'll need to figure out how to test just the children, not all ancestors (one slash?)

      // Find lesson's children which are of type "instruction"
      instructions = this.find( ".//element(*,'http://vwf.example.com/instruction.vwf')" )

      if ( instructions && instructions.length ) {
        this.instructionIndex = 0;
        this.activateInstruction();
      }
      else
        console.warn( "This lesson has no instructions - add some as children to use it");
    }

    this.activateInstruction = function() {
      
      // Remove event handlers from the instruction that just completed
      if ( activeInstruction )
        activeInstruction.events.flush();

      // Set up the new instruction
      activeInstruction = instructions[ this.instructionIndex ];
      activeInstruction.exited = this.activateNext;
      activeInstruction.begin();
    }

    this.activateNext = function() {
      self.instructionIndex++;
      if ( self.instructionIndex < self.instructions.length )
        self.activateInstruction();
      else
        self.completed();
    } //@ sourceURL=lesson.vwf