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/**
 * Copyright (C) 2010-2018 Gordon Fraser, Andrea Arcuri and EvoSuite
 * contributors
 *
 * This file is part of EvoSuite.
 *
 * EvoSuite is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3.0 of the License, or
 * (at your option) any later version.
 *
 * EvoSuite is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with EvoSuite. If not, see .
 */
/**
 * 
 */
package org.evosuite.testcase.localsearch;

import org.evosuite.Properties;
import org.evosuite.ga.ConstructionFailedException;
import org.evosuite.ga.localsearch.LocalSearchObjective;
import org.evosuite.testcase.variable.ArrayReference;
import org.evosuite.testcase.statements.Statement;
import org.evosuite.testcase.TestCaseExpander;
import org.evosuite.testcase.TestChromosome;
import org.evosuite.testcase.TestFactory;
import org.evosuite.testcase.execution.ExecutionResult;
import org.evosuite.testcase.statements.ArrayStatement;
import org.evosuite.testcase.statements.AssignmentStatement;
import org.evosuite.testcase.statements.NullStatement;
import org.evosuite.testcase.statements.PrimitiveStatement;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 
 * ArrayLocalSearch class.
 * 
 * 
 * @author Gordon Fraser
 */
public class ArrayLocalSearch extends StatementLocalSearch {

	private int oldLength = 0;

	private static final Logger logger = LoggerFactory.getLogger(TestCaseLocalSearch.class);

	private int positionDelta = 0;
	
	@Override
	public int getPositionDelta() {
		return positionDelta;
	}


	/* (non-Javadoc)
	 * @see org.evosuite.testcase.LocalSearch#doSearch(org.evosuite.testcase.TestChromosome, int, org.evosuite.ga.LocalSearchObjective)
	 */
	/** {@inheritDoc} */
	@Override
	public boolean doSearch(TestChromosome test, int statement,
	        LocalSearchObjective objective) {

		boolean hasImproved = false;
		ArrayStatement p = (ArrayStatement) test.getTestCase().getStatement(statement);
		logger.debug("Doing array local search on statement " + statement + ": "
		        + test.getTestCase().toCode());

		int difference = stripAssignments(p, test, objective);
		logger.debug("Adjusting position from " + statement + " to "
		        + (statement - difference) + ": " + test.getTestCase().toCode());
		positionDelta = difference;
		statement = statement - difference;
		p = (ArrayStatement) test.getTestCase().getStatement(statement);

		hasImproved = searchLength(test, statement, objective);
		TestCaseExpander expander = new TestCaseExpander();
		int lengthWithoutAssignments = test.size();
		p = (ArrayStatement) test.getTestCase().getStatement(statement);
		expander.visitArrayStatement(test.getTestCase(), p);
		int assignmentLength = test.size() - lengthWithoutAssignments;
		for (int position = statement + 1; position < statement + assignmentLength; position++) {
			logger.debug("Local search on statement "+position);
			StatementLocalSearch search = StatementLocalSearch.getLocalSearchFor(test.getTestCase().getStatement(position));
			if (search != null) {
				if (search.doSearch(test, position, objective)) {
					hasImproved = true;
				}
			}
		}

		logger.debug("Finished local search with result {}", p.getCode());
		return hasImproved;
	}

	private int stripAssignments(ArrayStatement statement, TestChromosome test,
	        LocalSearchObjective objective) {
		int difference = 0;
		ArrayReference arrRef = (ArrayReference) statement.getReturnValue();
		TestFactory factory = TestFactory.getInstance();
		for (int position = test.size() - 1; position > statement.getPosition(); position--) {
			logger.debug("Current delete position: " + position);
			if (test.getTestCase().getStatement(position) instanceof AssignmentStatement) {
				logger.debug("Is assignment statement");
				AssignmentStatement assignment = (AssignmentStatement) test.getTestCase().getStatement(position);
				Statement valueStatement = test.getTestCase().getStatement(assignment.getValue().getStPosition());
				if (assignment.getReturnValue().getAdditionalVariableReference() == arrRef) {

					int currentDelta = 0;
					int differenceDelta = 0;

					logger.debug("Assigns to target array. Checking if we can remove it without worsening fitness");
					backup(test);
					try {
						factory.deleteStatement(test.getTestCase(), position);

						if (valueStatement instanceof PrimitiveStatement
						        || valueStatement instanceof NullStatement) {
							if (!test.getTestCase().hasReferences(valueStatement.getReturnValue())) {
								if (valueStatement.getPosition() < statement.getPosition())
									differenceDelta = 1;
								currentDelta = 1;
								logger.debug("Deleting primitive statement assigned to this array at "
								        + valueStatement.getPosition());
								factory.deleteStatement(test.getTestCase(),
								                        valueStatement.getPosition());
							}
						}
						if (!objective.hasNotWorsened(test)) {
							logger.debug("Fitness has decreased, so restoring test");
							restore(test);
							currentDelta = 0;
							differenceDelta = 0;
						}
					} catch (ConstructionFailedException e) {
						currentDelta = 0;
						differenceDelta = 0;
						restore(test);
					}
					position -= currentDelta;
					difference += differenceDelta;
				}
			}
		}

		return difference;
	}

	private boolean searchLength(TestChromosome test, int statement,
	        LocalSearchObjective objective) {

		boolean hasImproved = false;

		ArrayStatement p = (ArrayStatement) test.getTestCase().getStatement(statement);
		logger.debug("Performing local search on array length, starting with length {}",
		             p.size());
		ExecutionResult oldResult = test.getLastExecutionResult();
		oldLength = p.size();
		boolean done = false;
		while (!done) {
			done = true;
			// Try +1
			p.setSize(oldLength + 1);
			logger.debug("Trying increment of {}", p.getCode());
			if (objective.hasImproved(test)) {
				done = false;
				hasImproved = true;

				boolean improved = true;
				while (improved) {
					oldLength = p.size();
					oldResult = test.getLastExecutionResult();
					p.setSize(oldLength + 1);
					logger.debug("Trying increment of {}", p.getCode());
					improved = objective.hasImproved(test);
				}
				p.setSize(oldLength);
				test.setLastExecutionResult(oldResult);
				test.setChanged(false);

			} else {
				if (oldLength > 0) {
					// Restore original, try -1
					p.setSize(oldLength);
					test.setLastExecutionResult(oldResult);
					test.setChanged(false);

					p.setSize(oldLength - 1);
				} else {
					p.setSize(Properties.MAX_ARRAY);
				}
				logger.debug("Trying decrement of {}", p.getCode());
				if (objective.hasImproved(test)) {
					done = false;
					hasImproved = true;

					boolean improved = true;
					while (improved && p.size() > 0) {
						oldLength = p.size();
						oldResult = test.getLastExecutionResult();
						p.setSize(oldLength - 1);
						logger.debug("Trying decrement of {}", p.getCode());
						improved = objective.hasImproved(test);
					}
					p.setSize(oldLength);
					test.setLastExecutionResult(oldResult);
					test.setChanged(false);
				} else {
					p.setSize(oldLength);
					test.setLastExecutionResult(oldResult);
					test.setChanged(false);
				}
			}
		}

		logger.debug("Finished local array length search with result {}", p.getCode());
		return hasImproved;
	}

}