package eymp.services.ruleengines.PTARuleManager;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Collection;
import java.util.List;

import org.camunda.bpm.model.dmn.Dmn;
import org.camunda.bpm.model.dmn.DmnModelInstance;
import org.camunda.bpm.model.dmn.HitPolicy;
import org.camunda.bpm.model.dmn.impl.DmnModelConstants;
import org.camunda.bpm.model.dmn.instance.Decision;
import org.camunda.bpm.model.dmn.instance.DecisionTable;
import org.camunda.bpm.model.dmn.instance.Definitions;
import org.camunda.bpm.model.dmn.instance.Description;
import org.camunda.bpm.model.dmn.instance.DmnElement;
import org.camunda.bpm.model.dmn.instance.Input;
import org.camunda.bpm.model.dmn.instance.InputEntry;
import org.camunda.bpm.model.dmn.instance.InputExpression;
import org.camunda.bpm.model.dmn.instance.NamedElement;
import org.camunda.bpm.model.dmn.instance.Output;
import org.camunda.bpm.model.dmn.instance.OutputEntry;
import org.camunda.bpm.model.dmn.instance.Rule;
import org.camunda.bpm.model.dmn.instance.Text;


public class DMNGenerator {

	DmnModelInstance model = Dmn.createEmptyModel();
	public static void main( String[] args )
    {
		DMNGenerator generator = new DMNGenerator();
		//generator.createDMN();
		generator.updateDMN();
    }
	
	public void updateDMN() 
	{
		FileInputStream fileInputStream = null;
		FileOutputStream fileOutputStream = null;
		
		try 
		{
			try
			{
				fileInputStream = new FileInputStream("c:/camunda/test/GenerateDMN.dmn");
				DmnModelInstance dmnModel = Dmn.readModelFromStream(fileInputStream);
				
				DecisionTable decisionTable =   dmnModel.getModelElementById("decisionTable");
				
				
				Rule newRule = generateElement(dmnModel, Rule.class, "DecisionRule_4");
				decisionTable.addChildElement(newRule);

			    InputEntry inputEntry1 = generateElement(dmnModel, InputEntry.class, "UnaryTests_41");
			    String inputTextValue1 = "2";
			    Text text1 = generateText(dmnModel, inputTextValue1);
			    inputEntry1.setText(text1);
			    newRule.addChildElement(inputEntry1);

			    OutputEntry outputEntry1 = generateElement(dmnModel, OutputEntry.class, "LiteralExpression_41");
			    String outputTextValue1 = "\"2\"";
			    Text text2 = generateText(dmnModel, outputTextValue1);
			    outputEntry1.setText(text2);
			    newRule.addChildElement(outputEntry1);

			    Description description1 =  generateDescription(dmnModel, "Rule 4 Description");
			    newRule.setDescription(description1);
			    
			    fileOutputStream = new FileOutputStream("c:/camunda/test/GenerateDMN_v1.dmn");

		        Dmn.writeModelToStream(fileOutputStream, dmnModel);
			}
			finally {
				if (fileInputStream != null) 
	            {
				 fileInputStream.close();
	            }
				if (fileOutputStream != null) 
	            {
	                fileOutputStream.close();
	            }
			}
		} 
		catch(Exception e)
		{
			System.out.println("Could not convert file: " + e.getMessage());
    		e.printStackTrace(System.out);
		}
		
		return;
	}
	
	public void createDMN()
	{
		DmnModelInstance dmnModel = initializeEmptyDmnModel();
		
		Decision decision = generateElement(dmnModel, Decision.class, "GenerateDMN");
		decision.setName("Generate DMN");
		dmnModel.getDefinitions().addChildElement(decision);
		
		DecisionTable decisionTable = generateElement(dmnModel, DecisionTable.class, "decisionTable");
		decision.addChildElement(decisionTable);
		
		setHitPolicy(decisionTable);
		createInputsOutputs(dmnModel, decisionTable);
		createRules(dmnModel, decisionTable);
		
		FileOutputStream fileOutputStream = null;
		try 
		{
	    	try
	    	{
	    		fileOutputStream = new FileOutputStream("c:/camunda/test/GenerateDMN.dmn");
	            Dmn.writeModelToStream(fileOutputStream, dmnModel);
	    	} 
	    	finally 
	    	{
	            if (fileOutputStream != null) 
	            {
	                fileOutputStream.close();
	            }
	        } 
	    } 	
		catch (Exception e) 
		{
    		System.out.println("Could not convert file: " + e.getMessage());
    		e.printStackTrace(System.out);
		}
	}
	
	protected void createInputsOutputs(DmnModelInstance dmnModel, DecisionTable decisionTable) {
	    // inputs
	      Input input = generateElement(dmnModel, Input.class, "Input_1");
	      decisionTable.addChildElement(input);

	      // mandatory
	      InputExpression inputExpression = generateElement(dmnModel, InputExpression.class);
	      Text text = generateText(dmnModel, "Input1");
	      inputExpression.setText(text);
	      input.setInputExpression(inputExpression);

	      // Optional
	      input.setLabel("Input1");
	      inputExpression.setTypeRef("integer");

	      Output output = generateElement(dmnModel, Output.class, "Output_1");
	      decisionTable.addChildElement(output);

	      // mandatory
	      output.setName("Outcome");

	      // Optional
	      output.setLabel("Outcome");
	      output.setTypeRef("string");
	      return;
	}

	
	protected void createRules(DmnModelInstance dmnModel, DecisionTable decisionTable) {
		
		// **************** Rule 1
		Rule rule1 = generateElement(dmnModel, Rule.class, "DecisionRule_1");
		 decisionTable.addChildElement(rule1);

	     InputEntry inputEntry1 = generateElement(dmnModel, InputEntry.class, "UnaryTests_1");
	     String inputTextValue1 = "0";
	     Text text1 = generateText(dmnModel, inputTextValue1);
	     inputEntry1.setText(text1);
	     rule1.addChildElement(inputEntry1);


	     OutputEntry outputEntry1 = generateElement(dmnModel, OutputEntry.class, "LiteralExpression_1");
	     String outputTextValue1 = "\"0\"";
	     Text text2 = generateText(dmnModel, outputTextValue1);
	     outputEntry1.setText(text2);
	     rule1.addChildElement(outputEntry1);

	     Description description1 =  generateDescription(dmnModel, "Rule 1 Description");
	     rule1.setDescription(description1);
	     
	     
	  // **************** Rule 2
	     Rule rule2 = generateElement(dmnModel, Rule.class, "DecisionRule_2");
		 decisionTable.addChildElement(rule2);

	     InputEntry inputEntry2 = generateElement(dmnModel, InputEntry.class, "UnaryTests_2");
	     String inputTextValue2 = "1";
	     Text text3 = generateText(dmnModel, inputTextValue2);
	     inputEntry2.setText(text3);
	     rule2.addChildElement(inputEntry2);


	     OutputEntry outputEntry2 = generateElement(dmnModel, OutputEntry.class, "LiteralExpression_2");
	     String outputTextValue2 = "\"1\"";
	     Text text4 = generateText(dmnModel, outputTextValue2);
	     outputEntry2.setText(text4);
	     rule2.addChildElement(outputEntry2);

	     Description description2 =  generateDescription(dmnModel, "Rule 2 Description");
	     rule2.setDescription(description2);
	     
	  // **************** Rule 3
	     Rule rule3 = generateElement(dmnModel, Rule.class, "DecisionRule_3");
		 decisionTable.addChildElement(rule3);

	     InputEntry inputEntry3 = generateElement(dmnModel, InputEntry.class, "UnaryTests_3");
	     String inputTextValue3 = "not(0,1)";
	     Text text5 = generateText(dmnModel, inputTextValue3);
	     inputEntry3.setText(text5);
	     rule3.addChildElement(inputEntry3);


	     OutputEntry outputEntry3 = generateElement(dmnModel, OutputEntry.class, "LiteralExpression_3");
	     String outputTextValue3 = "\"-1\"";
	     Text text6 = generateText(dmnModel, outputTextValue3);
	     outputEntry3.setText(text6);
	     rule3.addChildElement(outputEntry3);

	     Description description3 =  generateDescription(dmnModel, "Rule 3 Description");
	     rule3.setDescription(description3);
	}
	
	protected DmnModelInstance initializeEmptyDmnModel() {
		    DmnModelInstance dmnModel = Dmn.createEmptyModel();
		    Definitions definitions = generateNamedElement(dmnModel, Definitions.class, "definitions");
		    definitions.setNamespace(DmnModelConstants.CAMUNDA_NS);
		    dmnModel.setDefinitions(definitions);

		    return dmnModel;
	}
	
	protected void setHitPolicy(DecisionTable decisionTable) {
		 HitPolicy hitPolicy = HitPolicy.UNIQUE;
		 decisionTable.setHitPolicy(hitPolicy);
	 }
	
	public <E extends NamedElement> E generateNamedElement(DmnModelInstance modelInstance, Class<E> elementClass, String name) {
	    E element = generateElement(modelInstance, elementClass, name);
	    element.setName(name);
	    return element;
	}
	
	public <E extends DmnElement> E generateElement(DmnModelInstance modelInstance, Class<E> elementClass, String id) {
        E element = modelInstance.newInstance(elementClass);
        element.setId(id);
        return element;
      }
    
    public <E extends DmnElement> E generateElement(DmnModelInstance modelInstance, Class<E> elementClass) {
        // TODO: use a proper generator for random IDs
        String generatedId = elementClass.getSimpleName() + Integer.toString((int) (Integer.MAX_VALUE * Math.random()));
        return generateElement(modelInstance, elementClass, generatedId);
    }

    protected Text generateText(DmnModelInstance dmnModel, String content) {
        Text text = dmnModel.newInstance(Text.class);
        text.setTextContent(content);
        return text;
    }

    protected  Description generateDescription(DmnModelInstance dmnModel, String content) {
          Description description =  dmnModel.newInstance(Description.class);
          description.setTextContent(content);
          return description;
    }
}