package org.eclipse.viatra.solver.language.ide.syntaxcoloring;

import java.util.List;

import org.eclipse.emf.common.util.EList;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EReference;
import org.eclipse.viatra.solver.language.ProblemUtil;
import org.eclipse.viatra.solver.language.model.problem.ClassDeclaration;
import org.eclipse.viatra.solver.language.model.problem.EnumDeclaration;
import org.eclipse.viatra.solver.language.model.problem.NamedElement;
import org.eclipse.viatra.solver.language.model.problem.Node;
import org.eclipse.viatra.solver.language.model.problem.Parameter;
import org.eclipse.viatra.solver.language.model.problem.PredicateDefinition;
import org.eclipse.viatra.solver.language.model.problem.ProblemPackage;
import org.eclipse.viatra.solver.language.model.problem.ReferenceDeclaration;
import org.eclipse.viatra.solver.language.model.problem.Variable;
import org.eclipse.xtext.ide.editor.syntaxcoloring.DefaultSemanticHighlightingCalculator;
import org.eclipse.xtext.ide.editor.syntaxcoloring.IHighlightedPositionAcceptor;
import org.eclipse.xtext.nodemodel.INode;
import org.eclipse.xtext.nodemodel.util.NodeModelUtils;
import org.eclipse.xtext.service.OperationCanceledManager;
import org.eclipse.xtext.util.CancelIndicator;

import com.google.common.collect.ImmutableList;
import com.google.inject.Inject;

public class ProblemSemanticHighlightingCalculator extends DefaultSemanticHighlightingCalculator {
	private static final String BUILTIN_CLASS = "cm-keyword";
	private static final String CLASS_CLASS = "problem-class";
	private static final String ABSTRACT_CLASS = "problem-abstract";
	private static final String ENUM_CLASS = "problem-enum";
	private static final String REFERENCE_CLASS = "problem-reference";
	private static final String CONTAINMENT_CLASS = "problem-containment";
	private static final String PREDICATE_CLASS = "problem-predicate";
	private static final String ERROR_CLASS = "problem-error";
	private static final String NODE_CLASS = "problem-node";
	private static final String ENUM_NODE_CLASS = "problem-enum-node";
	private static final String NEW_NODE_CLASS = "problem-new-node";
	private static final String PARAMETER_CLASS = "problem-parameter";
	private static final String VARIABLE_CLASS = "problem-variable";
	private static final String SINGLETON_VARIABLE_CLASS = "problem-singleton-variable";

	@Inject
	private OperationCanceledManager operationCanceledManager;

	@Override
	protected boolean highlightElement(EObject object, IHighlightedPositionAcceptor acceptor,
			CancelIndicator cancelIndicator) {
		highlightName(object, acceptor);
		highlightCrossReferences(object, acceptor, cancelIndicator);
		return false;
	}

	protected void highlightName(EObject object, IHighlightedPositionAcceptor acceptor) {
		if (!(object instanceof NamedElement)) {
			return;
		}
		String[] highlightClass = getHighlightClass(object);
		if (highlightClass.length > 0) {
			highlightFeature(acceptor, object, ProblemPackage.Literals.NAMED_ELEMENT__NAME, highlightClass);
		}
	}

	protected void highlightCrossReferences(EObject object, IHighlightedPositionAcceptor acceptor,
			CancelIndicator cancelIndicator) {
		for (EReference reference : object.eClass().getEAllReferences()) {
			if (reference.isContainment()) {
				continue;
			}
			operationCanceledManager.checkCanceled(cancelIndicator);
			if (reference.isMany()) {
				highlightManyValues(object, reference, acceptor);
			} else {
				highlightSingleValue(object, reference, acceptor);
			}
		}
	}

	protected void highlightSingleValue(EObject object, EReference reference, IHighlightedPositionAcceptor acceptor) {
		EObject valueObj = (EObject) object.eGet(reference);
		String[] highlightClass = getHighlightClass(valueObj);
		if (highlightClass.length > 0) {
			highlightFeature(acceptor, object, reference, highlightClass);
		}
	}

	protected void highlightManyValues(EObject object, EReference reference, IHighlightedPositionAcceptor acceptor) {
		@SuppressWarnings("unchecked")
		EList<? extends EObject> values = (EList<? extends EObject>) object.eGet(reference);
		List<INode> nodes = NodeModelUtils.findNodesForFeature(object, reference);
		int size = Math.min(values.size(), nodes.size());
		for (var i = 0; i < size; i++) {
			EObject valueInList = values.get(i);
			INode node = nodes.get(i);
			String[] highlightClass = getHighlightClass(valueInList);
			if (highlightClass.length > 0) {
				highlightNode(acceptor, node, highlightClass);
			}
		}
	}

	protected String[] getHighlightClass(EObject eObject) {
		if (ProblemUtil.isBuiltIn(eObject)) {
			return new String[] { BUILTIN_CLASS };
		}
		ImmutableList.Builder<String> classesBuilder = ImmutableList.builder();
		if (eObject instanceof ClassDeclaration) {
			classesBuilder.add(CLASS_CLASS);
			var classDeclaration = (ClassDeclaration) eObject;
			if (classDeclaration.isAbstract()) {
				classesBuilder.add(ABSTRACT_CLASS);
			}
		}
		if (eObject instanceof EnumDeclaration) {
			classesBuilder.add(ENUM_CLASS);
		}
		if (eObject instanceof ReferenceDeclaration) {
			classesBuilder.add(REFERENCE_CLASS);
			var referenceDeclaration = (ReferenceDeclaration) eObject;
			if (referenceDeclaration.isContainment()) {
				classesBuilder.add(CONTAINMENT_CLASS);
			}
		}
		if (eObject instanceof PredicateDefinition) {
			classesBuilder.add(PREDICATE_CLASS);
			var predicateDefinition = (PredicateDefinition) eObject;
			if (predicateDefinition.isError()) {
				classesBuilder.add(ERROR_CLASS);
			}
		}
		if (eObject instanceof Node) {
			classesBuilder.add(NODE_CLASS);
			var node = (Node) eObject;
			if (ProblemUtil.isEnumNode(node)) {
				classesBuilder.add(ENUM_NODE_CLASS);
			}
			if (ProblemUtil.isNewNode(node)) {
				classesBuilder.add(NEW_NODE_CLASS);
			}
		}
		if (eObject instanceof Parameter) {
			classesBuilder.add(PARAMETER_CLASS);
		}
		if (eObject instanceof Variable) {
			classesBuilder.add(VARIABLE_CLASS);
			var variable = (Variable) eObject;
			if (ProblemUtil.isSingletonVariable(variable)) {
				classesBuilder.add(SINGLETON_VARIABLE_CLASS);
			}
		}
		List<String> classes = classesBuilder.build();
		return classes.toArray(new String[0]);
	}
}