/*
 * Copyright 2012-2017 Red Hat, Inc.
 *
 * This file is part of Thermostat.
 *
 * Thermostat is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2, or (at your
 * option) any later version.
 *
 * Thermostat 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Thermostat; see the file COPYING.  If not see
 * <http://www.gnu.org/licenses/>.
 *
 * Linking this code with other modules is making a combined work
 * based on this code.  Thus, the terms and conditions of the GNU
 * General Public License cover the whole combination.
 *
 * As a special exception, the copyright holders of this code give
 * you permission to link this code with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also
 * meet, for each linked independent module, the terms and conditions
 * of the license of that module.  An independent module is a module
 * which is not derived from or based on this code.  If you modify
 * this code, you may extend this exception to your version of the
 * library, but you are not obligated to do so.  If you do not wish
 * to do so, delete this exception statement from your version.
 */

package com.redhat.thermostat.vm.cpu.agent.internal;

import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.mockito.Matchers.any;
import static org.mockito.Matchers.anyInt;
import static org.mockito.Matchers.anyObject;
import static org.mockito.Matchers.anyString;
import static org.mockito.Matchers.eq;
import static org.mockito.Matchers.isA;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.verifyNoMoreInteractions;
import static org.mockito.Mockito.when;

import java.util.Dictionary;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import com.redhat.thermostat.jvm.overview.agent.VmStatusListener.Status;
import com.redhat.thermostat.storage.core.WriterID;
import com.redhat.thermostat.vm.cpu.agent.model.VmCpuStat;
import org.junit.Before;
import org.junit.Test;
import org.mockito.ArgumentCaptor;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceRegistration;
import org.osgi.framework.Version;

public class VmCpuBackendTest {
    
    private VmCpuBackend backend;
    private ScheduledExecutorService executor;
    private VmCpuStatDAO vmCpuStatDao;
    private Bundle bundle;
    private BundleContext bundleContext;
    private ServiceRegistration serviceRegistration;

    @Before
    public void setup() {
        executor = mock(ScheduledExecutorService.class);
        vmCpuStatDao = mock(VmCpuStatDAO.class);

        bundleContext = mock(BundleContext.class);
        bundle = mock(Bundle.class);
        serviceRegistration = mock(ServiceRegistration.class);
        Version version = new Version(1, 2, 3);
        when(bundle.getVersion()).thenReturn(version);
        when(bundleContext.getBundle()).thenReturn(bundle);
        when(bundleContext.registerService(anyString(), anyObject(), any(Dictionary.class))).thenReturn(serviceRegistration);

        backend = new VmCpuBackend(executor);
        backend.bindVmCpuStats(vmCpuStatDao);
        backend.bindWriterId(mock(WriterID.class));

        backend.componentActivated(bundleContext);
    }

    @Test
    public void testActivate() {
        backend.activate();

        verify(executor).scheduleAtFixedRate(isA(Runnable.class), eq(0l), eq(1000l), eq(TimeUnit.MILLISECONDS));
        assertTrue(backend.isActive());
    }

    @Test
    public void testDeactivate() {
        backend.activate();
        backend.deactivate();

        verify(executor).shutdown();
        assertFalse(backend.isActive());
    }

    @Test
    public void testStart() {
        // Setup Runnable mocks
        final Set<Integer> pids = new HashSet<>();
        pids.add(0);
        pids.add(1);
        
        VmCpuStatBuilder builder = mock(VmCpuStatBuilder.class);
        VmCpuStat stat0 = mock(VmCpuStat.class);
        VmCpuStat stat1 = mock(VmCpuStat.class);
        when(builder.build("vm1", 0)).thenReturn(stat0);
        when(builder.build("vm2", 1)).thenReturn(stat1);
        backend.setVmCpuStatBuilder(builder);
        
        backend.activate();

        ArgumentCaptor<Runnable> captor = ArgumentCaptor.forClass(Runnable.class);
        verify(executor).scheduleAtFixedRate(captor.capture(), any(Long.class), any(Long.class), any(TimeUnit.class));
        assertTrue(backend.isActive());
        
        backend.vmStatusChanged(Status.VM_ACTIVE, "vm1", 0);
        backend.vmStatusChanged(Status.VM_STARTED, "vm2", 1);

        Runnable runnable = captor.getValue();
        runnable.run();
        verify(builder).learnAbout(0);
        verify(builder).learnAbout(1);
        
        when(builder.knowsAbout(anyInt())).thenReturn(true);
        runnable.run();
        verify(vmCpuStatDao).put(stat0);
        verify(vmCpuStatDao).put(stat1);

        backend.vmStatusChanged(Status.VM_STOPPED, "vm1", 0);
        backend.vmStatusChanged(Status.VM_STOPPED, "vm2", 1);

        verify(builder).forgetAbout(0);
        verify(builder).forgetAbout(1);

        when(builder.knowsAbout(anyInt())).thenReturn(false);
        runnable.run();

        verifyNoMoreInteractions(vmCpuStatDao);
    }
}