package org.xtext.example.mydsl.generator

import org.eclipse.emf.ecore.resource.Resource
import org.eclipse.xtext.generator.IGenerator
import org.eclipse.xtext.generator.IFileSystemAccess
import org.xtext.example.mydsl.statemachine.Statemachine
import org.xtext.example.mydsl.statemachine.Event
import org.xtext.example.mydsl.statemachine.Command
import org.xtext.example.mydsl.statemachine.State

class MyDslGenerator implements IGenerator {
 
 override void doGenerate(Resource resource, IFileSystemAccess fsa) {
  fsa.generateFile(resource.className+".java", toJavaCode(resource.contents.head as Statemachine))
 }
 
 def className(Resource res) {
  var name = res.URI.lastSegment
  name.substring(0, name.indexOf('.'))
 }
 
 def toJavaCode(Statemachine sm) '''
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
 
 public class «sm.eResource.className» {
  
  public static void main(String[] args) {
   new «sm.eResource.className»().run();
  }
  
  «FOR c : sm.commands»
   «c.declareCommand»
  «ENDFOR»
  
  protected void run() {
   boolean executeActions = true;
   String currentState = "«sm.states.head.name»";
   String lastEvent = null;
   while (true) {
    «FOR state : sm.states»
     «state.generateCode»
    «ENDFOR»
    «FOR resetEvent : sm.resetEvents»
     if ("«resetEvent.name»".equals(lastEvent)) {
      System.out.println("Resetting state machine.");
      currentState = "«sm.states.head.name»";
      executeActions = true;
     }
    «ENDFOR»
    
   }
  }
  
  private String receiveEvent() {
   System.out.flush();
   BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   try {
    return br.readLine();
   } catch (IOException ioe) {
    System.out.println("Problem reading input");
    return "";
   }
  }
 }
 '''
 
 def declareCommand(Command command) '''
  protected void do«command.name.toFirstUpper»() {
   System.out.println("Executing command «command.name» («command.code»)");
  }
 '''
 
 def generateCode(State state) '''
  if (currentState.equals("«state.name»")) {
   if (executeActions) {
    «FOR c : state.actions»
     do«c.name.toFirstUpper»();
    «ENDFOR»
    executeActions = false;
   }
   System.out.println("Your are now in state '«state.name»'. Possible events are [«
    state.transitions.map(t | t.event.name).join(', ')»].");
   lastEvent = receiveEvent();
   «FOR t : state.transitions»
    if ("«t.event.name»".equals(lastEvent)) {
     currentState = "«t.state.name»";
     executeActions = true;
    }
   «ENDFOR»
  }
 '''
 
}

new org.eclipse.emf.mwe.utils.StandaloneSetup().setPlatformUri("../");
Injector injector = new MyDslStandaloneSetup().createInjectorAndDoEMFRegistration();
XtextResourceSet resourceSet = injector.getInstance(XtextResourceSet.class);
resourceSet.addLoadOption(XtextResource.OPTION_RESOLVE_ALL, Boolean.TRUE);
Resource resource = resourceSet.getResource(
    URI.createURI("platform:/resource/org.xtext.example.mydsl/src/example.mydsl"), true);
Model model = (Model) resource.getContents().get(0);

grammar org.xtext.example.mydsl.MyDsl with org.eclipse.xtext.common.Terminals

generate statemachine "http://www.xtext.org/example/secretcompartments/Statemachine"

Statemachine :
     {Statemachine}
     ('events' 
          events+=Event+ 
     'end')?
     ('resetEvents' 
          resetEvents+=[Event]+ 
     'end')?
     ('commands' 
          commands+=Command+ 
     'end')?
     states+=State*
;

Event:
     name=ID code=ID
;

Command:
     name=ID code=ID
;

State:
     'state' name=ID
          ('actions' '{' actions+=[Command]+ '}')?
          transitions+=Transition*
     'end'
;

Transition:
     event=[Event] '=>' state=[State]
;