#include "fixtures/OpenGLTestFixture.h"
#include "XCEngine/RHI/OpenGL/OpenGLPipelineState.h"

using namespace XCEngine::RHI;

TEST_F(OpenGLTestFixture, PipelineState_SetDepthStencilState) {
    OpenGLPipelineState pipeline;
    
    OpenGLDepthStencilState state;
    state.depthTestEnable = true;
    state.depthWriteEnable = true;
    state.depthFunc = ComparisonFunc::Less;
    
    pipeline.SetDepthStencilState(state);
    pipeline.ApplyDepthStencil();
    
    GLint depthTest = 0;
    glGetIntegerv(GL_DEPTH_TEST, &depthTest);
    EXPECT_EQ(depthTest, 1);
    
    GLint depthMask = 0;
    glGetIntegerv(GL_DEPTH_WRITEMASK, &depthMask);
    EXPECT_EQ(depthMask, 1);
}

TEST_F(OpenGLTestFixture, PipelineState_SetBlendState) {
    OpenGLPipelineState pipeline;
    
    OpenGLBlendState state;
    state.blendEnable = true;
    state.srcBlend = BlendFactor::SrcAlpha;
    state.dstBlend = BlendFactor::InvSrcAlpha;
    
    pipeline.SetBlendState(state);
    pipeline.ApplyBlend();
    
    GLint blend = 0;
    glGetIntegerv(GL_BLEND, &blend);
    EXPECT_EQ(blend, 1);
}

TEST_F(OpenGLTestFixture, PipelineState_ApplyDepthStencil_UsesSeparateStencilFaces) {
    OpenGLPipelineState pipeline;

    DepthStencilStateDesc state = {};
    state.depthTestEnable = true;
    state.depthWriteEnable = true;
    state.depthFunc = static_cast<uint32_t>(ComparisonFunc::LessEqual);
    state.stencilEnable = true;
    state.stencilReadMask = 0x3F;
    state.stencilWriteMask = 0x1F;
    state.front.func = static_cast<uint32_t>(ComparisonFunc::Equal);
    state.front.failOp = static_cast<uint32_t>(StencilOp::Replace);
    state.front.passOp = static_cast<uint32_t>(StencilOp::Incr);
    state.front.depthFailOp = static_cast<uint32_t>(StencilOp::DecrSat);
    state.back.func = static_cast<uint32_t>(ComparisonFunc::NotEqual);
    state.back.failOp = static_cast<uint32_t>(StencilOp::Invert);
    state.back.passOp = static_cast<uint32_t>(StencilOp::Decr);
    state.back.depthFailOp = static_cast<uint32_t>(StencilOp::Zero);

    pipeline.SetDepthStencilState(state);
    pipeline.ApplyDepthStencil();

    EXPECT_TRUE(glIsEnabled(GL_STENCIL_TEST));

    GLint frontFunc = 0;
    GLint backFunc = 0;
    GLint frontRef = 0;
    GLint backRef = 0;
    GLint frontValueMask = 0;
    GLint backValueMask = 0;
    GLint frontWriteMask = 0;
    GLint backWriteMask = 0;
    GLint frontFail = 0;
    GLint backFail = 0;
    GLint frontPassDepthPass = 0;
    GLint backPassDepthPass = 0;
    glGetIntegerv(GL_STENCIL_FUNC, &frontFunc);
    glGetIntegerv(GL_STENCIL_BACK_FUNC, &backFunc);
    glGetIntegerv(GL_STENCIL_REF, &frontRef);
    glGetIntegerv(GL_STENCIL_BACK_REF, &backRef);
    glGetIntegerv(GL_STENCIL_VALUE_MASK, &frontValueMask);
    glGetIntegerv(GL_STENCIL_BACK_VALUE_MASK, &backValueMask);
    glGetIntegerv(GL_STENCIL_WRITEMASK, &frontWriteMask);
    glGetIntegerv(GL_STENCIL_BACK_WRITEMASK, &backWriteMask);
    glGetIntegerv(GL_STENCIL_FAIL, &frontFail);
    glGetIntegerv(GL_STENCIL_BACK_FAIL, &backFail);
    glGetIntegerv(GL_STENCIL_PASS_DEPTH_PASS, &frontPassDepthPass);
    glGetIntegerv(GL_STENCIL_BACK_PASS_DEPTH_PASS, &backPassDepthPass);

    EXPECT_EQ(frontFunc, GL_EQUAL);
    EXPECT_EQ(backFunc, GL_NOTEQUAL);
    EXPECT_EQ(frontRef, 0);
    EXPECT_EQ(backRef, 0);
    EXPECT_EQ(frontValueMask, 0x3F);
    EXPECT_EQ(backValueMask, 0x3F);
    EXPECT_EQ(frontWriteMask, 0x1F);
    EXPECT_EQ(backWriteMask, 0x1F);
    EXPECT_EQ(frontFail, GL_REPLACE);
    EXPECT_EQ(backFail, GL_INVERT);
    EXPECT_EQ(frontPassDepthPass, GL_INCR_WRAP);
    EXPECT_EQ(backPassDepthPass, GL_DECR_WRAP);
}

TEST_F(OpenGLTestFixture, PipelineState_ApplyRasterizer_EnablesPolygonOffset) {
    OpenGLPipelineState pipeline;

    RasterizerDesc state = {};
    state.fillMode = static_cast<uint32_t>(FillMode::Solid);
    state.cullMode = static_cast<uint32_t>(CullMode::Back);
    state.frontFace = static_cast<uint32_t>(FrontFace::CounterClockwise);
    state.slopeScaledDepthBias = 1.5f;
    state.depthBias = 3;

    pipeline.SetRasterizerState(state);
    pipeline.ApplyRasterizer();

    EXPECT_TRUE(glIsEnabled(GL_POLYGON_OFFSET_FILL));

    GLfloat factor = 0.0f;
    GLfloat units = 0.0f;
    glGetFloatv(GL_POLYGON_OFFSET_FACTOR, &factor);
    glGetFloatv(GL_POLYGON_OFFSET_UNITS, &units);
    EXPECT_FLOAT_EQ(factor, 1.5f);
    EXPECT_FLOAT_EQ(units, 3.0f);
}

TEST_F(OpenGLTestFixture, PipelineState_SetViewport_SetScissor) {
    OpenGLPipelineState pipeline;
    
    ViewportState viewport;
    viewport.x = 0;
    viewport.y = 0;
    viewport.width = 800;
    viewport.height = 600;
    
    ScissorState scissor;
    scissor.enable = true;
    scissor.x = 0;
    scissor.y = 0;
    scissor.width = 800;
    scissor.height = 600;
    
    pipeline.SetViewport(viewport);
    pipeline.SetScissor(scissor);
    pipeline.ApplyViewport();
    
    GLint viewportArr[4] = {};
    glGetIntegerv(GL_VIEWPORT, viewportArr);
    EXPECT_EQ(viewportArr[0], 0);
    EXPECT_EQ(viewportArr[1], 0);
    EXPECT_EQ(viewportArr[2], 800);
    EXPECT_EQ(viewportArr[3], 600);
}