/**
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 */
package org.eclipse.papyrus.designer.transformation.library.xtend;

import java.util.List;

import org.eclipse.uml2.uml.Behavior;
import org.eclipse.uml2.uml.BehavioredClassifier;
import org.eclipse.uml2.uml.Class;
import org.eclipse.uml2.uml.Constraint;
import org.eclipse.uml2.uml.OpaqueBehavior;
import org.eclipse.uml2.uml.OpaqueExpression;
import org.eclipse.uml2.uml.Operation;
import org.eclipse.uml2.uml.Parameter;
import org.eclipse.uml2.uml.ParameterDirectionKind;
import org.eclipse.uml2.uml.Transition;
import org.eclipse.uml2.uml.Type;
import org.eclipse.uml2.uml.UMLPackage;

public class BehaviorUtil {
	private static final String DEFAULT_LANGUAGE = "C++"; //$NON-NLS-1$

	/**
	 * Set the body of an opaque behavior
	 * 
	 * @param behavior
	 *            an opaque behavior (if not an opaque behavior, the function does nothing)
	 * @param selectLanguage
	 *            a selected language or null (in this case, the default language is chosen or the language of the first existing body)
	 * @param textblock
	 *            the body of the opaque behavior
	 */
	public static void set(Behavior behavior, String selectLanguage, String textblock) {
		if (behavior instanceof OpaqueBehavior) {
			OpaqueBehavior ob = (OpaqueBehavior) behavior;
			if (ob.getLanguages().size() == 0) {
				ob.getLanguages().add(selectLanguage != null ? selectLanguage : DEFAULT_LANGUAGE);
				ob.getBodies().add(textblock);
			} else {
				int i = 0;
				for (String language : ob.getLanguages()) {
					if (selectLanguage == null || selectLanguage.equals(language)) {
						if (i < ob.getBodies().size()) {
							ob.getBodies().set(i, textblock);
						}
						break;
					}
				}
			}
		}
	}

	/**
	 * Set the body of an opaque behavior
	 * 
	 * @param behavior
	 *            an opaque behavior
	 * @param textblock
	 *            the body
	 */
	public static void set(Behavior behavior, String textblock) {
		set(behavior, DEFAULT_LANGUAGE, textblock);
	}

	/**
	 * Create a new opaque behavior and associate it with an operation (specification)
	 * 
	 * @param clazz
	 *            a behaviored classifier
	 * @param operation
	 *            an operation
	 * @return
	 */
	public static OpaqueBehavior createOpaqueBehavior(BehavioredClassifier clazz, Operation operation) {
		OpaqueBehavior ob = (OpaqueBehavior) clazz.createOwnedBehavior(operation.getName(), UMLPackage.eINSTANCE.getOpaqueBehavior());
		ob.setSpecification(operation);
		return ob;
	}

	public static OpaqueBehavior createOpaqueEffect(Transition transition) {
		OpaqueBehavior ob = (OpaqueBehavior) transition.createEffect("", UMLPackage.eINSTANCE.getOpaqueBehavior()); //$NON-NLS-1$
		return ob;
	}

	public static OpaqueExpression createOpaqueExpression(Constraint constraint, String guardCode) {
		OpaqueExpression oe = (OpaqueExpression) constraint.createSpecification("", null, UMLPackage.eINSTANCE.getOpaqueExpression()); //$NON-NLS-1$
		oe.getLanguages().add(DEFAULT_LANGUAGE);
		oe.getBodies().add(guardCode);
		return oe;
	}

	/**
	 * @param constraint
	 * @return first (index 0) body of a constraint specified with an opaque expression
	 */
	public static String body(Constraint constraint) {
		if (constraint.getSpecification() instanceof OpaqueExpression) {
			OpaqueExpression oe = (OpaqueExpression) constraint.getSpecification();
			if (oe.getBodies().size() > 0) {
				return oe.getBodies().get(0);
			}
		}
		return constraint.getSpecification().stringValue();
	}

	/**
	 * Create an operation with an operation return type
	 * 
	 * @param clazz
	 * @param name
	 * @param retType
	 * @return the created operation
	 */
	public static Operation createOperation(Class clazz, String name, Type retType) {
		Operation operation = clazz.createOwnedOperation(name, null, null);
		if (retType != null) {
			Parameter parameter = operation.createOwnedParameter("ret", retType); //$NON-NLS-1$
			parameter.setDirection(ParameterDirectionKind.RETURN_LITERAL);
		}
		return operation;
	}

	public static String body(Behavior behavior) {
		return body(behavior, DEFAULT_LANGUAGE);
	}

	/**
	 * Return first body that matches a given language.
	 * 
	 * @param behavior
	 *            a behavior
	 * @param selectLanguage
	 *            the language, if null first body is returned
	 * @return the body
	 */
	public static String body(Behavior behavior, String selectLanguage) {
		if (behavior instanceof OpaqueBehavior) {
			OpaqueBehavior ob = (OpaqueBehavior) behavior;
			int i = 0;
			for (String language : ob.getLanguages()) {
				if (selectLanguage == null || selectLanguage.equals(language)) {
					if (i < ob.getBodies().size()) {
						return ob.getBodies().get(i);
					}
					break;
				}
			}
		}
		return null;
	}

	/**
	 * @param operation
	 *            an operation
	 * @param selectLanguage
	 *            the language to filter, may be null
	 * @return the body of the first method of the passed operation that has a
	 *         non-empty body of the selected language
	 */
	public static String body(Operation operation, String selectLanguage) {
		for (Behavior method : operation.getMethods()) {
			String body = body(method, selectLanguage);
			if (body != null) {
				return body;
			}
		}
		return null;
	}

	/**
	 * @param operation
	 *            an operation
	 * @return the body of the first method of the passed operation that has a
	 *         non-empty body
	 */
	public static String body(Operation operation) {
		return body(operation, null);
	}

	/**
	 * set the method (body) of an operation
	 * 
	 * @param operation
	 *            an operation
	 * @param selectLanguage
	 *            the language to look for
	 * @param textblock
	 *            the body code
	 */
	public static void set(Operation operation, String selectLanguage, String textblock) {
		for (Behavior method : operation.getMethods()) {
			if (method instanceof OpaqueBehavior) {
				OpaqueBehavior ob = (OpaqueBehavior) method;
				if (ob.getLanguages().size() > 0 && (selectLanguage == null || ob.getLanguages().get(0).equals(selectLanguage))) {
					set(ob, selectLanguage, textblock);
					return;
				}
			}
		}
		OpaqueBehavior method = createOpaqueBehavior(operation.getClass_(), operation);
		set(method, selectLanguage, textblock);
	}

	/**
	 * set the method (body) of an operation
	 * 
	 * @param operation
	 *            an operation
	 * @param textblock
	 *            the body code
	 */
	public static void set(Operation operation, String textblock) {
		set(operation, null, textblock);
	}

	/**
	 * Append code to existing opaque behavior
	 * 
	 * @param behavior
	 *            a behavior
	 * @param codeToAppend
	 *            the code to append
	 */
	public static void appendBody(Behavior behavior, String codeToAppend) {
		String body = body(behavior, null);
		if (body != null) {
			set(behavior, null, body + "\n" + codeToAppend); //$NON-NLS-1$
		} else {
			set(behavior, null, codeToAppend);
		}
	}

	/**
	 * Append code to existing opaque behavior referenced via an operation
	 * 
	 * @param operation
	 *            an operation
	 * @param codeToAppend
	 *            the code to append
	 */
	public static void appendBody(Operation operation, String codeToAppend) {
		List<Behavior> methods = operation.getMethods();
		OpaqueBehavior opaque;
		if (methods.size() > 0 && methods.get(0) instanceof OpaqueBehavior) {
			opaque = (OpaqueBehavior) methods.get(0);
		} else {
			opaque = createOpaqueBehavior(operation.getClass_(), operation);
		}
		appendBody(opaque, codeToAppend);
	}

	/**
	 * Prefix (add before) code to existing opaque behavior
	 * 
	 * @param behavior
	 *            a behavior
	 * @param codeToPrefix
	 *            the code to prefix
	 */
	public static void prefixBody(Behavior behavior, String codeToPrefix) {
		String body = body(behavior, null);
		if (body != null) {
			set(behavior, null, codeToPrefix + "\n" + body); //$NON-NLS-1$
		} else {
			set(behavior, null, codeToPrefix);
		}
	}

	/**
	 * Prefix (add before) code to existing opaque behavior (referenced via an operation)
	 * 
	 * @param operation
	 *            an operation
	 * @param codeToPrefix
	 *            the code to prefix
	 */
	public static void prefixBody(Operation operation, String codeToPrefix) {
		List<Behavior> methods = operation.getMethods();
		OpaqueBehavior opaque;
		if (methods.size() > 0 && methods.get(0) instanceof OpaqueBehavior) {
			opaque = (OpaqueBehavior) methods.get(0);
		} else {
			opaque = createOpaqueBehavior(operation.getClass_(), operation);
		}
		prefixBody(opaque, codeToPrefix);
	}
}