/*
 * Copyright 2020 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.optaplanner.core.impl.heuristic.selector.entity.pillar;

import static org.assertj.core.api.Assertions.assertThat;
import static org.mockito.Mockito.anyInt;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;
import static org.optaplanner.core.impl.testdata.util.PlannerAssert.assertAllCodesOfIterator;
import static org.optaplanner.core.impl.testdata.util.PlannerAssert.assertCodesOfIterator;
import static org.optaplanner.core.impl.testdata.util.PlannerAssert.verifyPhaseLifecycle;

import java.util.Arrays;
import java.util.Comparator;
import java.util.Random;

import org.junit.jupiter.api.Test;
import org.optaplanner.core.config.heuristic.selector.entity.pillar.SubPillarConfigPolicy;
import org.optaplanner.core.impl.domain.variable.descriptor.GenuineVariableDescriptor;
import org.optaplanner.core.impl.heuristic.selector.SelectorTestUtils;
import org.optaplanner.core.impl.heuristic.selector.entity.EntitySelector;
import org.optaplanner.core.impl.phase.scope.AbstractPhaseScope;
import org.optaplanner.core.impl.phase.scope.AbstractStepScope;
import org.optaplanner.core.impl.solver.scope.SolverScope;
import org.optaplanner.core.impl.testdata.domain.TestdataEntity;
import org.optaplanner.core.impl.testdata.domain.TestdataObject;
import org.optaplanner.core.impl.testdata.domain.TestdataValue;

public class DefaultPillarSelectorTest {

    //    @Test
    //    public void calculateBasePillarSelectionSize() {
    //        assertCalculateBasePillarSelectionSize(4L, 1, 1);
    //        assertCalculateBasePillarSelectionSize(6L, 2, 2);
    //        assertCalculateBasePillarSelectionSize(4L, 3, 3);
    //        assertCalculateBasePillarSelectionSize(1L, 4, 4);
    //
    //        assertCalculateBasePillarSelectionSize(10L, 1, 2);
    //        assertCalculateBasePillarSelectionSize(14L, 1, 3);
    //        assertCalculateBasePillarSelectionSize(15L, 1, 4);
    //        assertCalculateBasePillarSelectionSize(10L, 2, 3);
    //        assertCalculateBasePillarSelectionSize(11L, 2, 4);
    //        assertCalculateBasePillarSelectionSize(5L, 3, 4);
    //
    //        assertCalculateBasePillarSelectionSize(15L, 1, 5);
    //        assertCalculateBasePillarSelectionSize(11L, 2, 5);
    //        assertCalculateBasePillarSelectionSize(5L, 3, 5);
    //        assertCalculateBasePillarSelectionSize(1L, 4, 5);
    //        assertCalculateBasePillarSelectionSize(0L, 5, 5);
    //    }
    //
    //    private void assertCalculateBasePillarSelectionSize(long expected, int minimumPillarSize, int maximumPillarSize) {
    //        TestdataValue val1 = new TestdataValue("1");
    //        TestdataValue val2 = new TestdataValue("2");
    //        TestdataValue val3 = new TestdataValue("3");
    //        TestdataValue val4 = new TestdataValue("4");
    //
    //        final TestdataEntity a = new TestdataEntity("a", val1);
    //        final TestdataEntity b = new TestdataEntity("b", val2);
    //        final TestdataEntity c = new TestdataEntity("c", val3);
    //        final TestdataEntity d = new TestdataEntity("d", val2);
    //
    //        EntitySelector entitySelector = SelectorTestUtils.mockEntitySelector(TestdataEntity.class,
    //                a, b, c, d);
    //        GenuineVariableDescriptor variableDescriptor = SelectorTestUtils.mockVariableDescriptor(
    //                entitySelector.findEntityDescriptorOrFail(), "value");
    //        DefaultPillarSelector selector = new DefaultPillarSelector(
    //                entitySelector, Collections.singletonList(variableDescriptor), false,
    //                true, minimumPillarSize, maximumPillarSize);
    //        assertEquals(expected, selector.calculateBasePillarSelectionSize(Arrays.<Object>asList(a, b, c, d)));
    //    }

    @Test
    public void originalNoSubs() {
        TestdataValue val1 = new TestdataValue("1");
        TestdataValue val2 = new TestdataValue("2");
        TestdataValue val3 = new TestdataValue("3");
        TestdataValue val4 = new TestdataValue("4");

        final TestdataEntity a = new TestdataEntity("a", val1);
        final TestdataEntity b = new TestdataEntity("b", val2);
        final TestdataEntity c = new TestdataEntity("c", val3);
        final TestdataEntity d = new TestdataEntity("d", val2);
        final TestdataEntity e = new TestdataEntity("e", val3);
        final TestdataEntity f = new TestdataEntity("f", val3);

        GenuineVariableDescriptor variableDescriptor = TestdataEntity.buildVariableDescriptorForValue();
        EntitySelector entitySelector = SelectorTestUtils.mockEntitySelector(variableDescriptor.getEntityDescriptor(),
                a, b, c, d, e, f);

        DefaultPillarSelector pillarSelector = new DefaultPillarSelector(
                entitySelector, Arrays.asList(variableDescriptor), false, SubPillarConfigPolicy.withoutSubpillars());

        SolverScope solverScope = mock(SolverScope.class);
        pillarSelector.solvingStarted(solverScope);

        AbstractPhaseScope phaseScopeA = mock(AbstractPhaseScope.class);
        when(phaseScopeA.getSolverScope()).thenReturn(solverScope);
        pillarSelector.phaseStarted(phaseScopeA);

        AbstractStepScope stepScopeA1 = mock(AbstractStepScope.class);
        when(stepScopeA1.getPhaseScope()).thenReturn(phaseScopeA);
        pillarSelector.stepStarted(stepScopeA1);
        assertAllCodesOfPillarSelector(pillarSelector, "[a]", "[b, d]", "[c, e, f]");
        pillarSelector.stepEnded(stepScopeA1);

        b.setValue(val3);
        f.setValue(val4);

        AbstractStepScope stepScopeA2 = mock(AbstractStepScope.class);
        when(stepScopeA2.getPhaseScope()).thenReturn(phaseScopeA);
        pillarSelector.stepStarted(stepScopeA2);
        assertAllCodesOfPillarSelector(pillarSelector, "[a]", "[b, c, e]", "[d]", "[f]");
        pillarSelector.stepEnded(stepScopeA2);

        pillarSelector.phaseEnded(phaseScopeA);

        AbstractPhaseScope phaseScopeB = mock(AbstractPhaseScope.class);
        when(phaseScopeB.getSolverScope()).thenReturn(solverScope);
        pillarSelector.phaseStarted(phaseScopeB);

        AbstractStepScope stepScopeB1 = mock(AbstractStepScope.class);
        when(stepScopeB1.getPhaseScope()).thenReturn(phaseScopeB);
        pillarSelector.stepStarted(stepScopeB1);
        assertAllCodesOfPillarSelector(pillarSelector, "[a]", "[b, c, e]", "[d]", "[f]");
        pillarSelector.stepEnded(stepScopeB1);

        pillarSelector.phaseEnded(phaseScopeB);

        pillarSelector.solvingEnded(solverScope);

        verifyPhaseLifecycle(entitySelector, 1, 2, 3);
    }

    @Test
    public void emptyEntitySelectorOriginalNoSubs() {
        GenuineVariableDescriptor variableDescriptor = TestdataEntity.buildVariableDescriptorForValue();
        EntitySelector entitySelector = SelectorTestUtils.mockEntitySelector(variableDescriptor.getEntityDescriptor());

        DefaultPillarSelector pillarSelector = new DefaultPillarSelector(
                entitySelector, Arrays.asList(variableDescriptor), false, SubPillarConfigPolicy.withoutSubpillars());

        SolverScope solverScope = mock(SolverScope.class);
        pillarSelector.solvingStarted(solverScope);

        AbstractPhaseScope phaseScopeA = mock(AbstractPhaseScope.class);
        when(phaseScopeA.getSolverScope()).thenReturn(solverScope);
        pillarSelector.phaseStarted(phaseScopeA);

        AbstractStepScope stepScopeA1 = mock(AbstractStepScope.class);
        when(stepScopeA1.getPhaseScope()).thenReturn(phaseScopeA);
        pillarSelector.stepStarted(stepScopeA1);
        assertAllCodesOfPillarSelector(pillarSelector);
        pillarSelector.stepEnded(stepScopeA1);

        AbstractStepScope stepScopeA2 = mock(AbstractStepScope.class);
        when(stepScopeA2.getPhaseScope()).thenReturn(phaseScopeA);
        pillarSelector.stepStarted(stepScopeA2);
        assertAllCodesOfPillarSelector(pillarSelector);
        pillarSelector.stepEnded(stepScopeA2);

        pillarSelector.phaseEnded(phaseScopeA);

        AbstractPhaseScope phaseScopeB = mock(AbstractPhaseScope.class);
        when(phaseScopeB.getSolverScope()).thenReturn(solverScope);
        pillarSelector.phaseStarted(phaseScopeB);

        AbstractStepScope stepScopeB1 = mock(AbstractStepScope.class);
        when(stepScopeB1.getPhaseScope()).thenReturn(phaseScopeB);
        pillarSelector.stepStarted(stepScopeB1);
        assertAllCodesOfPillarSelector(pillarSelector);
        pillarSelector.stepEnded(stepScopeB1);

        pillarSelector.phaseEnded(phaseScopeB);

        pillarSelector.solvingEnded(solverScope);

        verifyPhaseLifecycle(entitySelector, 1, 2, 3);
    }

    @Test
    public void randomWithSubs() {
        TestdataValue val1 = new TestdataValue("1");
        TestdataValue val2 = new TestdataValue("2");
        TestdataValue val3 = new TestdataValue("3");
        TestdataValue val4 = new TestdataValue("4");

        final TestdataEntity a = new TestdataEntity("a", val1);
        final TestdataEntity b = new TestdataEntity("b", val2);
        final TestdataEntity c = new TestdataEntity("c", val3);
        final TestdataEntity d = new TestdataEntity("d", val2);
        final TestdataEntity e = new TestdataEntity("e", val3);
        final TestdataEntity f = new TestdataEntity("f", val3);

        GenuineVariableDescriptor variableDescriptor = TestdataEntity.buildVariableDescriptorForValue();
        EntitySelector entitySelector = SelectorTestUtils.mockEntitySelector(variableDescriptor.getEntityDescriptor(),
                a, b, c, d, e, f);

        DefaultPillarSelector pillarSelector = new DefaultPillarSelector(
                entitySelector, Arrays.asList(variableDescriptor), true,
                SubPillarConfigPolicy.withSubpillarsUnlimited());

        Random workingRandom = mock(Random.class);

        SolverScope solverScope = mock(SolverScope.class);
        when(solverScope.getWorkingRandom()).thenReturn(workingRandom);
        pillarSelector.solvingStarted(solverScope);

        AbstractPhaseScope phaseScopeA = mock(AbstractPhaseScope.class);
        when(phaseScopeA.getSolverScope()).thenReturn(solverScope);
        pillarSelector.phaseStarted(phaseScopeA);

        AbstractStepScope stepScopeA1 = mock(AbstractStepScope.class);
        when(stepScopeA1.getPhaseScope()).thenReturn(phaseScopeA);
        pillarSelector.stepStarted(stepScopeA1);
        // nextInt pattern: pillarIndex, subPillarSize, element 0, element 1, element 2, ...
        // Expected pillar cache: [a], [b, d], [c, e, f]
        when(workingRandom.nextInt(anyInt())).thenReturn(
                0, // [a]
                2, 1, 0, 0, // [c, e, f]
                1, 0, 0, // [b, d]
                1, 0, 1); // [b, d]
        assertCodesOfNeverEndingPillarSelector(pillarSelector, "[a]", "[c, e]", "[b]", "[d]");
        pillarSelector.stepEnded(stepScopeA1);

        b.setValue(val3);
        f.setValue(val4);

        AbstractStepScope stepScopeA2 = mock(AbstractStepScope.class);
        when(stepScopeA2.getPhaseScope()).thenReturn(phaseScopeA);
        pillarSelector.stepStarted(stepScopeA2);
        // nextInt pattern: pillarIndex, subPillarSize, element 0, element 1, element 2, ...
        // Expected pillar cache: [a], [b, c, e], [d], [f]
        when(workingRandom.nextInt(anyInt())).thenReturn(
                3, // [f]
                1, 2, // [b, c, e]
                1, 0, 0, // [b, c, e]
                2, 0, 0); // [d]
        assertCodesOfNeverEndingPillarSelector(pillarSelector, "[f]", "[b, c, e]", "[b]", "[d]");
        pillarSelector.stepEnded(stepScopeA2);

        pillarSelector.phaseEnded(phaseScopeA);

        AbstractPhaseScope phaseScopeB = mock(AbstractPhaseScope.class);
        when(phaseScopeB.getSolverScope()).thenReturn(solverScope);
        pillarSelector.phaseStarted(phaseScopeB);

        AbstractStepScope stepScopeB1 = mock(AbstractStepScope.class);
        when(stepScopeB1.getPhaseScope()).thenReturn(phaseScopeB);
        pillarSelector.stepStarted(stepScopeB1);
        // nextInt pattern: pillarIndex, subPillarSize, element 0, element 1, element 2, ...
        // Expected pillar cache: [a], [b, c, e], [d], [f]
        when(workingRandom.nextInt(anyInt())).thenReturn(
                3, // [f]
                1, 2, // [b, c, e]
                1, 0, 0, // [b, c, e]
                2, 0, 0); // [d]
        assertCodesOfNeverEndingPillarSelector(pillarSelector, "[f]", "[b, c, e]", "[b]", "[d]");
        pillarSelector.stepEnded(stepScopeB1);

        pillarSelector.phaseEnded(phaseScopeB);

        pillarSelector.solvingEnded(solverScope);

        verifyPhaseLifecycle(entitySelector, 1, 2, 3);
    }

    @Test
    public void randomWithSubs_Size2() {
        TestdataValue val1 = new TestdataValue("1");
        TestdataValue val2 = new TestdataValue("2");
        TestdataValue val3 = new TestdataValue("3");

        final TestdataEntity a = new TestdataEntity("a", val1);
        final TestdataEntity b = new TestdataEntity("b", val2);
        final TestdataEntity c = new TestdataEntity("c", val3);
        final TestdataEntity d = new TestdataEntity("d", val2);
        final TestdataEntity e = new TestdataEntity("e", val3);
        final TestdataEntity f = new TestdataEntity("f", val3);

        GenuineVariableDescriptor variableDescriptor = TestdataEntity.buildVariableDescriptorForValue();
        EntitySelector entitySelector = SelectorTestUtils.mockEntitySelector(variableDescriptor.getEntityDescriptor(),
                a, b, c, d, e, f);

        DefaultPillarSelector pillarSelector = new DefaultPillarSelector(
                entitySelector, Arrays.asList(variableDescriptor), true, SubPillarConfigPolicy.withSubpillars(2, 2));

        Random workingRandom = mock(Random.class);

        SolverScope solverScope = mock(SolverScope.class);
        when(solverScope.getWorkingRandom()).thenReturn(workingRandom);
        pillarSelector.solvingStarted(solverScope);

        AbstractPhaseScope phaseScopeA = mock(AbstractPhaseScope.class);
        when(phaseScopeA.getSolverScope()).thenReturn(solverScope);
        pillarSelector.phaseStarted(phaseScopeA);

        AbstractStepScope stepScopeA1 = mock(AbstractStepScope.class);
        when(stepScopeA1.getPhaseScope()).thenReturn(phaseScopeA);
        pillarSelector.stepStarted(stepScopeA1);
        // nextInt pattern: pillarIndex, subPillarSize, element 0, element 1, element 2, ...
        // Expected pillar cache: [b, d], [c, e, f]
        when(workingRandom.nextInt(anyInt())).thenReturn(
                1, 0, 0, 0, // [c, e]
                0); // [b, d]
        assertCodesOfNeverEndingPillarSelector(pillarSelector, "[c, e]", "[b, d]");
        pillarSelector.stepEnded(stepScopeA1);

        pillarSelector.phaseEnded(phaseScopeA);

        pillarSelector.solvingEnded(solverScope);

        verifyPhaseLifecycle(entitySelector, 1, 1, 1);
    }

    @Test
    public void sequentialUnlimited() {
        TestdataValue val1 = new TestdataValue("1");
        TestdataValue val2 = new TestdataValue("2");
        TestdataValue val3 = new TestdataValue("3");

        final TestdataEntity a = new TestdataEntity("a", val1);
        final TestdataEntity b = new TestdataEntity("b", val2);
        final TestdataEntity c = new TestdataEntity("c", val3);
        final TestdataEntity d = new TestdataEntity("d", val2);
        final TestdataEntity e = new TestdataEntity("e", val3);
        final TestdataEntity f = new TestdataEntity("f", val3);

        GenuineVariableDescriptor variableDescriptor = TestdataEntity.buildVariableDescriptorForValue();
        EntitySelector entitySelector = SelectorTestUtils.mockEntitySelector(variableDescriptor.getEntityDescriptor(),
                a, f, d, e, c, b); // return entities in random order

        Comparator<TestdataEntity> lexicographicComparator = Comparator.comparing(TestdataObject::getCode);
        DefaultPillarSelector pillarSelector = new DefaultPillarSelector(entitySelector,
                Arrays.asList(variableDescriptor), true,
                SubPillarConfigPolicy.sequentialUnlimited(lexicographicComparator));

        Random workingRandom = mock(Random.class);

        SolverScope solverScope = mock(SolverScope.class);
        when(solverScope.getWorkingRandom()).thenReturn(workingRandom);
        pillarSelector.solvingStarted(solverScope);

        AbstractPhaseScope phaseScopeA = mock(AbstractPhaseScope.class);
        when(phaseScopeA.getSolverScope()).thenReturn(solverScope);
        pillarSelector.phaseStarted(phaseScopeA);

        AbstractStepScope stepScopeA1 = mock(AbstractStepScope.class);
        when(stepScopeA1.getPhaseScope()).thenReturn(phaseScopeA);
        pillarSelector.stepStarted(stepScopeA1);
        // nextInt pattern: pillarIndex, subPillarSize, subPillarStartingIndex
        // Expected pillar cache: [a], [b, d], [c, e, f]
        when(workingRandom.nextInt(anyInt())).thenReturn(
                1, 1, // [b, d]
                2, 2, // [c, e, f]
                2, 1, 1, // [c, e, f]
                0 // [a]
        );
        assertCodesOfNeverEndingPillarSelector(pillarSelector, "[b, d]", "[c, e, f]", "[e, f]", "[a]");
        pillarSelector.stepEnded(stepScopeA1);

        pillarSelector.phaseEnded(phaseScopeA);

        pillarSelector.solvingEnded(solverScope);

        verifyPhaseLifecycle(entitySelector, 1, 1, 1);
    }

    @Test
    public void emptyEntitySelectorRandomWithSubs() {
        GenuineVariableDescriptor variableDescriptor = TestdataEntity.buildVariableDescriptorForValue();
        EntitySelector entitySelector = SelectorTestUtils.mockEntitySelector(variableDescriptor.getEntityDescriptor());

        DefaultPillarSelector pillarSelector = new DefaultPillarSelector(
                entitySelector, Arrays.asList(variableDescriptor), true,
                SubPillarConfigPolicy.withSubpillarsUnlimited());

        SolverScope solverScope = mock(SolverScope.class);
        pillarSelector.solvingStarted(solverScope);

        AbstractPhaseScope phaseScopeA = mock(AbstractPhaseScope.class);
        when(phaseScopeA.getSolverScope()).thenReturn(solverScope);
        pillarSelector.phaseStarted(phaseScopeA);

        AbstractStepScope stepScopeA1 = mock(AbstractStepScope.class);
        when(stepScopeA1.getPhaseScope()).thenReturn(phaseScopeA);
        pillarSelector.stepStarted(stepScopeA1);
        assertCodesOfNeverEndingPillarSelector(pillarSelector);
        pillarSelector.stepEnded(stepScopeA1);

        AbstractStepScope stepScopeA2 = mock(AbstractStepScope.class);
        when(stepScopeA2.getPhaseScope()).thenReturn(phaseScopeA);
        pillarSelector.stepStarted(stepScopeA2);
        assertCodesOfNeverEndingPillarSelector(pillarSelector);
        pillarSelector.stepEnded(stepScopeA2);

        pillarSelector.phaseEnded(phaseScopeA);

        AbstractPhaseScope phaseScopeB = mock(AbstractPhaseScope.class);
        when(phaseScopeB.getSolverScope()).thenReturn(solverScope);
        pillarSelector.phaseStarted(phaseScopeB);

        AbstractStepScope stepScopeB1 = mock(AbstractStepScope.class);
        when(stepScopeB1.getPhaseScope()).thenReturn(phaseScopeB);
        pillarSelector.stepStarted(stepScopeB1);
        assertCodesOfNeverEndingPillarSelector(pillarSelector);
        pillarSelector.stepEnded(stepScopeB1);

        pillarSelector.phaseEnded(phaseScopeB);

        pillarSelector.solvingEnded(solverScope);

        verifyPhaseLifecycle(entitySelector, 1, 2, 3);
    }

    private void assertAllCodesOfPillarSelector(PillarSelector pillarSelector, String... codes) {
        assertAllCodesOfIterator(pillarSelector.iterator(), codes);
        assertThat(pillarSelector.isCountable()).isTrue();
        assertThat(pillarSelector.isNeverEnding()).isFalse();
        assertThat(pillarSelector.getSize()).isEqualTo(codes.length);
    }

    private void assertCodesOfNeverEndingPillarSelector(PillarSelector pillarSelector, String... codes) {
        assertCodesOfIterator(pillarSelector.iterator(), codes);
        assertThat(pillarSelector.isCountable()).isTrue();
        assertThat(pillarSelector.isNeverEnding()).isTrue();
    }

}
