package uk.ac.leeds.nsxl2.cork4.scoping;

/*
 * generated by Xtext
 */

import java.util.ArrayList;
import java.util.List;

import memops.ecore_api.Implementation.ImplementationPackage;

import org.eclipse.emf.common.util.EList;
import org.eclipse.emf.common.util.TreeIterator;
import org.eclipse.emf.ecore.EAttribute;
import org.eclipse.emf.ecore.EClass;
import org.eclipse.emf.ecore.EClassifier;
import org.eclipse.emf.ecore.EDataType;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EReference;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.emf.ecore.EcorePackage;
import org.eclipse.emf.ecore.util.EcoreUtil;
import org.eclipse.xtext.common.types.JvmDeclaredType;
import org.eclipse.xtext.common.types.JvmFormalParameter;
import org.eclipse.xtext.common.types.TypesPackage;
import org.eclipse.xtext.resource.EObjectDescription;
import org.eclipse.xtext.resource.IEObjectDescription;
import org.eclipse.xtext.scoping.IScope;
import org.eclipse.xtext.scoping.IScopeProvider;
import org.eclipse.xtext.scoping.Scopes;
import org.eclipse.xtext.scoping.impl.AbstractDeclarativeScopeProvider;
import org.eclipse.xtext.scoping.impl.AbstractScope;
import org.eclipse.xtext.scoping.impl.SimpleLocalScopeProvider;
import org.eclipse.xtext.scoping.impl.SimpleScope;
import org.eclipse.xtext.xbase.XForLoopExpression;
import org.eclipse.xtext.xbase.XbasePackage;
import org.eclipse.xtext.xbase.scoping.LocalVariableScopeContext;
import org.eclipse.xtext.xbase.scoping.XbaseScopeProvider;

import com.google.inject.internal.Lists;

import uk.ac.leeds.nsxl2.cork4.cork4.Axis;
import uk.ac.leeds.nsxl2.cork4.cork4.Cork4Package;
import uk.ac.leeds.nsxl2.cork4.cork4.Loop;
import uk.ac.leeds.nsxl2.cork4.cork4.PathHead;
import uk.ac.leeds.nsxl2.cork4.cork4.Predicate;
import uk.ac.leeds.nsxl2.cork4.cork4.RelativeLocationPathHead;
import uk.ac.leeds.nsxl2.cork4.cork4.RelativeLocationPathTail;
import uk.ac.leeds.nsxl2.cork4.cork4.Step;

/**
 * This class contains custom scoping description.
 * 
 * see : http://www.eclipse.org/Xtext/documentation/latest/xtext.html#scoping on
 * how and when to use it
 * 
 */
public class Cork4ScopeProvider extends XbaseScopeProvider {
	private final static Class<?>[] SCOPE_CONTAINER_TYPES = { RelativeLocationPathTail.class,
            RelativeLocationPathHead.class, 
            PathHead.class};

    private final static Class<?>[] PATH_ELEMENT_STEP_CONTAINER_TYPES = { RelativeLocationPathTail.class,
				  RelativeLocationPathHead.class,
				  Predicate.class};


	@Override
	public IScope getScope(EObject context, EReference reference) {
		
		final Cork4Package CORK_EPACKAGE = Cork4Package.eINSTANCE;
		final EClass STEP_ECLASS = CORK_EPACKAGE.getStep();
		final EClass PATH_HEAD_ECLASS = CORK_EPACKAGE.getPathHead();
		final EClass RELATIVE_LOCATION_PATH_HEAD_ECLASS = CORK_EPACKAGE.getRelativeLocationPathHead();
		final EClass RELATIVE_LOCATION_PATH_TAIL_ECLASS = CORK_EPACKAGE.getRelativeLocationPathTail();
		
		final EClass LOOP = CORK_EPACKAGE.getLoop();
		final EClass PATH_DEFINITION = CORK_EPACKAGE.getPathDefinition();
		
		final TypesPackage TYPES_PACKAGE =TypesPackage.eINSTANCE;
		final EClass JVM_DECLARED_TYPE =  TYPES_PACKAGE.getJvmDeclaredType();
		
		
		final XbasePackage  X_BASE_PACKAGE  = XbasePackage.eINSTANCE;
		final EClass X_FEATURE_CALL  =  X_BASE_PACKAGE.getXFeatureCall();

		reportScopeContext(context, reference);

		IScope result = null;
		
		EClass referenceContext = (EClass) reference.eContainer();

		if (referenceContext.equals(STEP_ECLASS)) {
			EObject container = findScopeContainer(context);
			StepAxis stepAxis = getStepAxis(context);
			
			if (sameClass(container, PATH_HEAD_ECLASS)) {
				result = getScopeForPathHead(stepAxis);
		    } else if (sameClass(container, RELATIVE_LOCATION_PATH_TAIL_ECLASS)) {
				RelativeLocationPathTail pathTail = (RelativeLocationPathTail) container;
				result=getScopeForRelativeLocationPathTail(pathTail, stepAxis);
			} else if (sameClass(container, RELATIVE_LOCATION_PATH_HEAD_ECLASS)) {
				RelativeLocationPathHead relativeLocationPathHead  = (RelativeLocationPathHead) container;
				result =  getScopeForRelativeLocationPathHead((relativeLocationPathHead), stepAxis);
			}
		}

		
//		System.err.println(context);
//		if (sameClass(context, LOOP) && reference.getEReferenceType().equals(JVM_DECLARED_TYPE)) {
//			Loop loop = (Loop) context;
//			
//			System.err.println(references(PATH_DEFINITION));
//			result = getGlobalScopeForReference(PATH_DEFINITION);
//			System.err.println("here " + reference.getEReferenceType());
//			System.err.println(loop.getPathSelection());
//		}


		if (result == null) {
			result = super.getScope(context, reference);
		}

		return result;

	}
	
	private StepAxis getStepAxis(EObject context) {
		final Cork4Package CORK_EPACKAGE = Cork4Package.eINSTANCE;
		final EClass STEP_ECLASS = CORK_EPACKAGE.getStep();
		final EClass RELATIVE_LOCATION_PATH_TAIL_ECLASS = CORK_EPACKAGE.getRelativeLocationPathTail();
		Axis axis = null;
		
		if (context.eClass().equals(STEP_ECLASS)) {
			Step  step = (Step) context;
			axis = step.getAxis();
			
		} else if (context.eClass().equals(RELATIVE_LOCATION_PATH_TAIL_ECLASS)) {
			RelativeLocationPathTail relativeLocationPathTail = (RelativeLocationPathTail) context;
			Step step = relativeLocationPathTail.getStep();
			if (step != null) {
				axis = step.getAxis();
			}
		}
		StepAxis stepAxis = StepAxis.REFERENCE;
		if (axis != null){
			String axisValue = axis.getValue();
			if (axisValue.equals("@")){
				stepAxis = StepAxis.ATTRIBUTE;
			}
		}
		
		return stepAxis;
	}


	private boolean sameClass(EObject container, EClass eClass) {
		return container.eClass().equals(eClass);
	}

	private EObject findScopeContainer(EObject context) {
		EObject stepContainer = findParentByTypesOrdered(context, PATH_ELEMENT_STEP_CONTAINER_TYPES);
		EObject scopeContainer = findParentByTypesOrdered(stepContainer.eContainer(), SCOPE_CONTAINER_TYPES);
		if (scopeContainer !=  null) {
			stepContainer =  scopeContainer;
		}
		return stepContainer;
	}

	
	
	private IScope getScopeForRelativeLocationPathTail(
			RelativeLocationPathTail container, StepAxis stepAxis) {
		
		EStructuralFeature tailReference = container.getStep()
				.getNodeTest();
		IScope result = getScopeFromReference(tailReference, stepAxis);
		return result;
	}
	
	private IScope getScopeForRelativeLocationPathHead( RelativeLocationPathHead container, StepAxis stepAxis) {
		EStructuralFeature tailReference = (EStructuralFeature) container.getStep()
				.getNodeTest();
		IScope result = getScopeFromReference(tailReference, stepAxis);
		return result;
	}
	
	enum StepAxis {
		ATTRIBUTE,
		REFERENCE,
		OPERATION
	}
	private IScope getScopeForPathHead(StepAxis stepAxis) {
		EClass root = ImplementationPackage.eINSTANCE.getMemopsRoot();
		IScope result = null;
		List<? extends EObject> structuralFeatures = references(root);
		switch (stepAxis) {
			case REFERENCE:
				structuralFeatures =  references(root);
				result = Scopes.scopeFor(structuralFeatures);
				break;
			case ATTRIBUTE:
				structuralFeatures = attributes(root);
				result = Scopes.scopeFor(structuralFeatures);
				break;				
		}
		
		return result;
	}


	private void reportScopeContext(EObject context, EReference reference) {
		IScopeProvider delegate = (IScopeProvider) getDelegate();
//		IScope parentScope = getScope(context, reference);
		EObject parent = context.eContainer();
		
		System.err.println("---------\n");
		System.err.println("containers" + " " + listContainers(context));

		System.err.println("context: " + context);
		EClass refContainer = (EClass) reference.eContainer();
		System.err.println("ref: " + refContainer.getInstanceClassName() + "->"
				+ reference.getName());
		System.err.println("parent: " + parent);
		System.err.println("delegate: " + delegate);
//		System.err.println("parent scope " + parentScope);
		System.err.println();
	}

	private IScope getScopeFromReference(EStructuralFeature tailReference, StepAxis stepAxis) {
		EClassifier tailType = tailReference.getEType();
		IScope result = null;
		if (tailType instanceof EClass) { 
			EClass referenceType = (EClass) tailType;
			if (stepAxis == StepAxis.REFERENCE) {
				result = getGlobalScopeForReference(referenceType);
			} else if (stepAxis == StepAxis.ATTRIBUTE) {
				List<EAttribute> attributes = attributes(referenceType);
				result = Scopes.scopeFor(attributes);
			}
		}
		return result;
	}

	private IScope getGlobalScopeForReference(EClass referenceType) {
		IScope result;
		List<EReference> references = references(referenceType);
		result = Scopes.scopeFor(references);
		return result;
	}


	@SuppressWarnings("unchecked")
	private <T extends EObject> T findParentByTypesOrdered(EObject context,
			Class<?>[] parentTypeList) {
		T result = null;
		EObject parent = context;

		while (parent.eContainer() != null) {
			for (Class<?> clazz : parentTypeList) {
				if (clazz.isAssignableFrom(parent.getClass())) {
					result = (T) parent;
					break;
				}
			}
			if (result != null) {
				break;
			} else {
				parent = parent.eContainer();
			}
		}
		
		return result;
	}

	private String listContainers(EObject parentPath) {
		String result = "";

		EObject parent = parentPath;
		while (parent.eContainer() != null) {
			result = result + " " + parent.eClass().getName();
			parent = parent.eContainer();
		}

		return result;
	}

	private List<EReference> references(EClass target) {
		return org.eclipse.xtext.EcoreUtil2.typeSelect(
				target.getEAllReferences(), EReference.class);
	}
	private List<EAttribute> attributes(EClass target) {
		return org.eclipse.xtext.EcoreUtil2.typeSelect(
				target.getEAllAttributes(), EAttribute.class);
	}
	
	@SuppressWarnings("restriction")
	@Override
	protected IScope  createLocalVarScope(IScope parentScope, LocalVariableScopeContext scopeContext) {
		IScope result = null;
		EObject context = scopeContext.getContext();
		EReference reference = scopeContext.getReference();
		System.err.println("local var scope");
		System.err.println("context " + context);
		System.err.println("reference " + reference);
		if (context.eContainer() instanceof Loop && context.eContainingFeature() == Cork4Package.Literals.LOOP__EXPRESSION) {
			Loop loop = (Loop) context.eContainer();
			JvmFormalParameter type = loop.getPathSelection().getType();
			parentScope = createLocalScopeForParameter(type, parentScope);
		}
//		final CorkPackage CORK_EPACKAGE = CorkPackage.eINSTANCE;
//				final EClass LOOP = CORK_EPACKAGE.getLoop();
//				List<IEObjectDescription> eObjectDescriptions1 = Lists.newArrayList();
//				if(sameClass(context, LOOP)) {
//					Loop loop = (Loop) context;
//		//			if(loop.getPathSelection() != null) {
//		//				String selectionName = loop.getPathSelection().getName();
//		//				RelativeLocationPathTail path = loop.getPathSelection().getPathDefinition().getHead().getTail();
//		//				System.err.println("start");
//		//				EStructuralFeature type = getTailType(path);
//		//				IEObjectDescription eObjectDescription =  EObjectDescription.create(selectionName, type.getEType());
//		//				eObjectDescriptions.add(eObjectDescription);
//		//				System.err.println(type);
//		//				System.err.println("here");
//		//			}
//				}
		
//		List<IEObjectDescription> eObjectDescriptions = eObjectDescriptions1;
//		
//		if (eObjectDescriptions.size() > 0) {
//			result = new SimpleScope(parent, eObjectDescriptions);
//		}
		
//		if (context.eContainer() instanceof  Loop/*referenceContext.equals(X_FEATURE_CALL)*/) {
//			Loop containerloop = context.eContainer();
//
//		}
//		
//		System.err.println(result);
//		if (result == null) {
//			result = super.createLocalVarScope(parentScope, scopeContext);
//		}

		return parentScope;
	}

	private EStructuralFeature getTailType(RelativeLocationPathTail path) {
		final Cork4Package CORK_EPACKAGE = Cork4Package.eINSTANCE;
		final EClass PREDICATE = CORK_EPACKAGE.getPredicate();		
		final EClass STEP = CORK_EPACKAGE.getStep();
		final EClass RELATIVE_LOCATION_PATH_HEAD_ECLASS = CORK_EPACKAGE.getRelativeLocationPathHead();
		final EClass RELATIVE_LOCATION_PATH_TAIL_ECLASS = CORK_EPACKAGE.getRelativeLocationPathTail();
		
		
		EStructuralFeature type = null;
		for ( TreeIterator<Object> iter = EcoreUtil.getAllContents(path,false); 
			  iter.hasNext(); ) {
			EObject current = (EObject) iter.next();
			if (sameClass(current, PREDICATE)) {
				iter.prune();
			}
			if(sameClass(current, STEP)) {
				Step stepCurrent =  (Step) current;
				EObject parent = current.eContainer();
				boolean hasChildren = false;
				if (sameClass(parent, RELATIVE_LOCATION_PATH_HEAD_ECLASS)) {
					RelativeLocationPathHead parentRelativeLocationPathHead = (RelativeLocationPathHead) parent;
					
					if (parentRelativeLocationPathHead.getTail() != null) {
						hasChildren =  true;
					}
					
				}
				if (sameClass(parent, RELATIVE_LOCATION_PATH_TAIL_ECLASS)) {
					RelativeLocationPathTail parentRelativeLocationPathTail = (RelativeLocationPathTail) parent;
					
					if (parentRelativeLocationPathTail.getTail() != null) {
						hasChildren =  true;
					}
					
				}
				if (!hasChildren) {
					EReference nodeTest = (EReference) stepCurrent.getNodeTest();
					type = nodeTest;
					break;
				}
			}
			
		}
		return type;
		
	}
	
	
	
}