/****************************************************************************
**
** Copyright (C) 2015 Klaralvdalens Datakonsult AB (KDAB).
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt3D module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:GPL-EXCEPT$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
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** information use the contact form at https://www.qt.io/contact-us.
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** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
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** $QT_END_LICENSE$
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****************************************************************************/

#include <QtTest/QTest>
#include <qbackendnodetester.h>
#include <Qt3DRender/private/shader_p.h>
#include <Qt3DRender/qshaderprogram.h>
#include "testrenderer.h"

class tst_RenderShader : public Qt3DCore::QBackendNodeTester
{
    Q_OBJECT
private slots:

    void hasCoherentInitialState();
    void matchesFrontendPeer();
    void cleanupLeavesACoherentState();
    void dealWithPropertyChanges_data();
    void dealWithPropertyChanges();
    void checkSetRendererDirtyOnInitialization();
    void allowToChangeShaderCode_data();
    void allowToChangeShaderCode();
};


Qt3DRender::QShaderProgram *createFrontendShader()
{
    Qt3DRender::QShaderProgram *shader = new Qt3DRender::QShaderProgram();

    shader->setVertexShaderCode(QByteArrayLiteral(
                                    "#version 150"\
                                    "in vec3 vertexPosition;"\
                                    "in vec3 vertexColor; "\
                                    "out vec3 color;"\
                                    "void main()"\
                                    "{"\
                                    "    color = vertexColor;"\
                                    "    gl_Position = vec4( vertexPosition, 1.0 );"\
                                    "}"));

    shader->setFragmentShaderCode(QByteArrayLiteral(
                                      "#version 150"\
                                      "in vec3 color;"\
                                      "out vec4 fragColor;"\
                                      "void main()"\
                                      "{"\
                                      "   fragColor = vec4( color, 1.0 );"\
                                      "}"));

    return shader;
}

void tst_RenderShader::hasCoherentInitialState()
{
    Qt3DRender::Render::Shader *shader = new Qt3DRender::Render::Shader();

    QCOMPARE(shader->isLoaded(), false);
    QCOMPARE(shader->dna(), 0U);
    QVERIFY(shader->uniformsNames().isEmpty());
    QVERIFY(shader->attributesNames().isEmpty());
    QVERIFY(shader->uniformBlockNames().isEmpty());
    QVERIFY(shader->uniforms().isEmpty());
    QVERIFY(shader->attributes().isEmpty());
    QVERIFY(shader->uniformBlocks().isEmpty());
    QCOMPARE(shader->status(), Qt3DRender::QShaderProgram::NotReady);
}

void tst_RenderShader::matchesFrontendPeer()
{
    QScopedPointer<Qt3DRender::QShaderProgram> frontend(createFrontendShader());
    TestRenderer renderer;
    Qt3DRender::Render::Shader backend;

    backend.setRenderer(&renderer);
    simulateInitialization(frontend.data(), &backend);
    QCOMPARE(backend.isLoaded(), false);
    QVERIFY(backend.dna() != 0U);

    for (int i = Qt3DRender::QShaderProgram::Vertex; i <= Qt3DRender::QShaderProgram::Compute; ++i)
        QCOMPARE(backend.shaderCode()[i],
                 frontend->shaderCode( static_cast<const Qt3DRender::QShaderProgram::ShaderType>(i)));
}

void tst_RenderShader::cleanupLeavesACoherentState()
{
    QScopedPointer<Qt3DRender::QShaderProgram> frontend(createFrontendShader());
    TestRenderer renderer;
    Qt3DRender::Render::Shader shader;

    shader.setRenderer(&renderer);
    simulateInitialization(frontend.data(), &shader);

    shader.cleanup();

    QCOMPARE(shader.isLoaded(), false);
    QCOMPARE(shader.dna(), 0U);
    QVERIFY(shader.uniformsNames().isEmpty());
    QVERIFY(shader.attributesNames().isEmpty());
    QVERIFY(shader.uniformBlockNames().isEmpty());
    QVERIFY(shader.uniforms().isEmpty());
    QVERIFY(shader.attributes().isEmpty());
    QVERIFY(shader.uniformBlocks().isEmpty());
    QCOMPARE(shader.status(), Qt3DRender::QShaderProgram::NotReady);
}

void tst_RenderShader::dealWithPropertyChanges_data()
{
    QTest::addColumn<QByteArray>("property");
    QTest::addColumn<Qt3DRender::QShaderProgram::ShaderType>("type");

    QTest::newRow("vertex") << QByteArrayLiteral("vertexShaderCode")
                            << Qt3DRender::QShaderProgram::Vertex;

    QTest::newRow("tessControl") << QByteArrayLiteral("tessellationControlShaderCode")
                                 << Qt3DRender::QShaderProgram::TessellationControl;

    QTest::newRow("tessEval") << QByteArrayLiteral("tessellationEvaluationShaderCode")
                              << Qt3DRender::QShaderProgram::TessellationEvaluation;

    QTest::newRow("geometry") << QByteArrayLiteral("geometryShaderCode")
                              << Qt3DRender::QShaderProgram::Geometry;

    QTest::newRow("fragment") << QByteArrayLiteral("fragmentShaderCode")
                              << Qt3DRender::QShaderProgram::Fragment;

    QTest::newRow("compute") << QByteArrayLiteral("computeShaderCode")
                             << Qt3DRender::QShaderProgram::Compute;
}

void tst_RenderShader::dealWithPropertyChanges()
{
    // GIVEN
    QFETCH(QByteArray, property);
    QFETCH(Qt3DRender::QShaderProgram::ShaderType, type);

    Qt3DRender::Render::Shader backend;
    backend.setLoaded(true);
    TestRenderer renderer;
    backend.setRenderer(&renderer);

    // WHEN
    auto updateChange = Qt3DCore::QPropertyUpdatedChangePtr::create(Qt3DCore::QNodeId());
    updateChange->setValue(QStringLiteral("foo"));
    updateChange->setPropertyName(property);
    backend.sceneChangeEvent(updateChange);

    // THEN
    QCOMPARE(backend.shaderCode().at(type), QStringLiteral("foo"));
    QVERIFY(!backend.isLoaded());
    QCOMPARE(renderer.dirtyBits(), Qt3DRender::Render::AbstractRenderer::ShadersDirty);
    renderer.resetDirty();
    backend.setLoaded(true);

    // WHEN
    updateChange = Qt3DCore::QPropertyUpdatedChangePtr::create(Qt3DCore::QNodeId());
    updateChange->setValue(QStringLiteral("foo"));
    updateChange->setPropertyName(property);
    backend.sceneChangeEvent(updateChange);

    // THEN
    QCOMPARE(backend.shaderCode().at(type), QStringLiteral("foo"));
    QVERIFY(backend.isLoaded());
    QCOMPARE(renderer.dirtyBits(), 0);
    renderer.resetDirty();
    backend.setLoaded(true);

    // WHEN
    updateChange = Qt3DCore::QPropertyUpdatedChangePtr::create(Qt3DCore::QNodeId());
    updateChange->setValue(QStringLiteral("bar"));
    updateChange->setPropertyName(property);
    backend.sceneChangeEvent(updateChange);

    // THEN
    QCOMPARE(backend.shaderCode().at(type), QStringLiteral("bar"));
    QVERIFY(!backend.isLoaded());
    QCOMPARE(renderer.dirtyBits(), Qt3DRender::Render::AbstractRenderer::ShadersDirty);
    renderer.resetDirty();
    backend.setLoaded(true);
}

void tst_RenderShader::checkSetRendererDirtyOnInitialization()
{
    // GIVEN
    QScopedPointer<Qt3DRender::QShaderProgram> frontend(createFrontendShader());
    Qt3DRender::Render::Shader shader;
    TestRenderer renderer;

    shader.setRenderer(&renderer);

    // THEN
    QCOMPARE(renderer.dirtyBits(), 0);

    // WHEN
    simulateInitialization(frontend.data(), &shader);

    // THEN
    QCOMPARE(renderer.dirtyBits(), Qt3DRender::Render::AbstractRenderer::ShadersDirty);
}

void tst_RenderShader::allowToChangeShaderCode_data()
{
    dealWithPropertyChanges_data();
}

void tst_RenderShader::allowToChangeShaderCode()
{
    // GIVEN
    QFETCH(Qt3DRender::QShaderProgram::ShaderType, type);

    Qt3DRender::Render::Shader backend;
    backend.setLoaded(true);
    TestRenderer renderer;
    backend.setRenderer(&renderer);

    // WHEN
    backend.setShaderCode(type, QByteArrayLiteral("foo"));

    // THEN
    QCOMPARE(backend.shaderCode().at(type), QStringLiteral("foo"));
    QVERIFY(!backend.isLoaded());
    QCOMPARE(renderer.dirtyBits(), Qt3DRender::Render::AbstractRenderer::ShadersDirty);
    renderer.resetDirty();
    backend.setLoaded(true);

    // WHEN
    backend.setShaderCode(type, QByteArrayLiteral("foo"));

    // THEN
    QCOMPARE(backend.shaderCode().at(type), QStringLiteral("foo"));
    QVERIFY(backend.isLoaded());
    QCOMPARE(renderer.dirtyBits(), 0);
    renderer.resetDirty();
    backend.setLoaded(true);

    // WHEN
    backend.setShaderCode(type, QByteArrayLiteral("bar"));

    // THEN
    QCOMPARE(backend.shaderCode().at(type), QStringLiteral("bar"));
    QVERIFY(!backend.isLoaded());
    QCOMPARE(renderer.dirtyBits(), Qt3DRender::Render::AbstractRenderer::ShadersDirty);
    renderer.resetDirty();
    backend.setLoaded(true);
}

QTEST_APPLESS_MAIN(tst_RenderShader)

#include "tst_shader.moc"