/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.scenegraph.tests;

import static junit.framework.Assert.assertEquals;
import static junit.framework.Assert.assertSame;

import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicBoolean;

import org.junit.Test;
import org.simantics.scenegraph.INode;
import org.simantics.scenegraph.ParentNode;
import org.simantics.scenegraph.g2d.G2DParentNode;
import org.simantics.scenegraph.g2d.G2DSceneGraph;
import org.simantics.scenegraph.g2d.nodes.DataNode;
import org.simantics.scenegraph.g2d.nodes.NavigationNode;
import org.simantics.scenegraph.utils.NodeUtil;


/**
 * @author Tuukka Lehtonen
 */
public class LookupServiceSynchronizationTest {

    public static final int ITERATIONS        = 10;
    public static final int ITERATION_TIME_MS = 1000;
    public static final int THREADS           = 16;

    AtomicBoolean           endTest;
    CyclicBarrier           startBarrier;
    Semaphore               ended;

    G2DSceneGraph           root              = new G2DSceneGraph();
    List<INode>             nodes             = new ArrayList<INode>();
    List<String>            nodeIds           = new ArrayList<String>();
    List<String>            mappedIds         = new ArrayList<String>();

    List<Throwable>         errors            = new ArrayList<Throwable>();

    public class Lookup implements Runnable {
        String id;
        INode node;
        public Lookup(String id, INode node) {
            this.id = id;
            this.node = node;
        }
        @Override
        public void run() {
            try {
                System.out.println("started " + Thread.currentThread().getName());
                System.out.flush();
                startBarrier.await();
                while (!endTest.get()) {
                    Thread.yield();
                    INode n = NodeUtil.lookup(this.node, this.id);
                    String id = NodeUtil.lookupId(this.node);
                    if (n != null)
                        assertSame(this.node, n);
                    if (id != null)
                        assertSame(this.id, id);
                }
            } catch (InterruptedException e) {
                errors.add(e);
            } catch (BrokenBarrierException e) {
                errors.add(e);
            } finally {
                System.out.println("ending " + Thread.currentThread().getName());
                System.out.flush();
                ended.release();
            }
        }
    }

    public class Mapper implements Runnable {
        String id;
        INode node;
        public Mapper(String id, INode node) {
            this.id = id;
            this.node = node;
        }
        @Override
        public void run() {
            try {
                System.out.println("started " + Thread.currentThread().getName());
                System.out.flush();
                startBarrier.await();
                for (int i = 0; !endTest.get(); ++i) {
                    Thread.yield();
                    NodeUtil.map(node, id);
                    if ((i & 1) == 0)
                        NodeUtil.unmap(node);
                    else
                        root.unmap(id);
                }
            } catch (InterruptedException e) {
                errors.add(e);
            } catch (BrokenBarrierException e) {
                errors.add(e);
            } finally {
                System.out.println("ending " + Thread.currentThread().getName());
                System.out.flush();
                ended.release();
            }
        }
    }

    <T extends INode> T addAndMapNode(ParentNode<?> parent, String id, Class<T> clazz) {
        T node = parent.addNode(id, clazz);
        nodes.add( node );
        nodeIds.add( id );
        NodeUtil.map(node, id);
        return node;
    }

    <T extends INode> T addNode(ParentNode<?> parent, String id, Class<T> clazz) {
        T node = parent.addNode(id, clazz);
        nodes.add( node );
        nodeIds.add( id );
        return node;
    }

    <T extends INode> T addNode(ParentNode<?> parent, Class<T> clazz) {
        return addNode(parent, UUID.randomUUID().toString(), clazz);
    }

    @Test
    public void testLookup() throws Exception {
        NavigationNode nav = addAndMapNode(root, "navigation", NavigationNode.class);
        DataNode data = addAndMapNode(root, "data", DataNode.class);
        G2DParentNode elements = addNode(nav, "elements", G2DParentNode.class);
        @SuppressWarnings("unused")
        G2DParentNode ghosts = addNode(nav, "ghosts", G2DParentNode.class);

        // Basic checks
        assertSame(nav, root.lookupNode("navigation"));
        assertSame(data, root.lookupNode("data"));
        assertSame(nav, NodeUtil.lookup(nav, "navigation"));
        assertSame(data, NodeUtil.lookup(data, "data"));

        for (int iter = 1; iter <= ITERATIONS; ++iter) {
            System.out.println("Starting iteration " + iter);
            System.out.flush();
            // Start iteration
            endTest = new AtomicBoolean(false);
            startBarrier = new CyclicBarrier(THREADS * 2 + 1);
            ended = new Semaphore(0);

            for (int i = 0; i < THREADS; ++i) {
                String id = UUID.randomUUID().toString();
                INode node = addNode(elements, id, G2DParentNode.class);
                new Thread(new Mapper(id, node), "Mapper-" + i).start();
                new Thread(new Lookup(id, node), "Lookup-" + i).start();
            }

            startBarrier.await();
            // Sleep for the testing period
            synchronized (this) {
                wait(ITERATION_TIME_MS);
            }
            // Wait for threads to end
            System.out.println("Ending iteration " + iter);
            System.out.flush();
            endTest.set(true);
            ended.acquire(2*THREADS);
            System.out.println("Iteration " + iter + " ended");
        }

        assertEquals(errors.size(), 0);
    }

}