#include <gtest/gtest.h>

#include "XCUIBackend/XCUIRHICommandCompiler.h"

namespace {

using XCEngine::Editor::XCUIBackend::XCUIRHICommandCompiler;
using XCEngine::UI::UIColor;
using XCEngine::UI::UIDrawData;
using XCEngine::UI::UIDrawList;
using XCEngine::UI::UIPoint;
using XCEngine::UI::UIRect;
using XCEngine::UI::UITextureHandle;
using XCEngine::UI::UITextureHandleKind;

class StubTextGlyphProvider final : public XCUIRHICommandCompiler::TextGlyphProvider {
public:
    bool BeginText(
        float requestedFontSize,
        XCUIRHICommandCompiler::TextRunContext& outContext) const override {
        outContext.requestedFontSize = requestedFontSize;
        outContext.resolvedFontSize = requestedFontSize > 0.0f ? requestedFontSize : 14.0f;
        outContext.lineHeight = 12.0f;
        outContext.texture = UITextureHandle{ 99u, 256u, 256u, UITextureHandleKind::ShaderResourceView };
        return true;
    }

    bool ResolveGlyph(
        const XCUIRHICommandCompiler::TextRunContext&,
        std::uint32_t codepoint,
        XCUIRHICommandCompiler::TextGlyph& outGlyph) const override {
        switch (codepoint) {
        case 'A':
            outGlyph.x0 = 0.0f;
            outGlyph.y0 = 0.0f;
            outGlyph.x1 = 8.0f;
            outGlyph.y1 = 10.0f;
            outGlyph.u0 = 0.0f;
            outGlyph.v0 = 0.0f;
            outGlyph.u1 = 0.25f;
            outGlyph.v1 = 0.5f;
            outGlyph.advanceX = 8.0f;
            outGlyph.visible = true;
            return true;
        case 'B':
            outGlyph.x0 = 0.0f;
            outGlyph.y0 = 0.0f;
            outGlyph.x1 = 7.0f;
            outGlyph.y1 = 10.0f;
            outGlyph.u0 = 0.25f;
            outGlyph.v0 = 0.0f;
            outGlyph.u1 = 0.5f;
            outGlyph.v1 = 0.5f;
            outGlyph.advanceX = 7.0f;
            outGlyph.visible = true;
            return true;
        default:
            return false;
        }
    }
};

TEST(XCUIRHICommandCompilerTest, CompileMergesAdjacentColorAndTexturedCommandsPerDrawList) {
    XCUIRHICommandCompiler compiler = {};
    UIDrawData drawData = {};
    UIDrawList& drawList = drawData.EmplaceDrawList("Batches");
    drawList.AddFilledRect(UIRect(0.0f, 0.0f, 10.0f, 10.0f), UIColor(1.0f, 0.0f, 0.0f, 1.0f));
    drawList.AddFilledRect(UIRect(10.0f, 0.0f, 10.0f, 10.0f), UIColor(0.0f, 1.0f, 0.0f, 1.0f));

    const UITextureHandle texture{ 7u, 64u, 64u, UITextureHandleKind::ShaderResourceView };
    drawList.AddImage(UIRect(0.0f, 20.0f, 10.0f, 10.0f), texture, UIColor(1.0f, 1.0f, 1.0f, 1.0f));
    drawList.AddImage(UIRect(10.0f, 20.0f, 10.0f, 10.0f), texture, UIColor(0.5f, 0.5f, 0.5f, 1.0f));

    XCUIRHICommandCompiler::CompileConfig config = {};
    config.surfaceClipRect = UIRect(0.0f, 0.0f, 100.0f, 100.0f);

    XCUIRHICommandCompiler::CompiledDrawData compiled = {};
    compiler.Compile(drawData, config, compiled);

    ASSERT_EQ(compiled.batches.size(), 2u);
    EXPECT_EQ(compiled.batches[0].kind, XCUIRHICommandCompiler::BatchKind::Color);
    EXPECT_EQ(compiled.batches[0].commandCount, 2u);
    EXPECT_EQ(compiled.batches[0].vertexCount, 12u);
    EXPECT_EQ(compiled.batches[1].kind, XCUIRHICommandCompiler::BatchKind::Textured);
    EXPECT_EQ(compiled.batches[1].commandCount, 2u);
    EXPECT_EQ(compiled.batches[1].vertexCount, 12u);
    EXPECT_EQ(compiled.batches[1].texture.nativeHandle, texture.nativeHandle);
    EXPECT_EQ(compiled.stats.compiledCommandCount, 4u);
    EXPECT_EQ(compiled.stats.batchCount, 2u);
    EXPECT_EQ(compiled.stats.colorVertexCount, 12u);
    EXPECT_EQ(compiled.stats.texturedVertexCount, 12u);
}

TEST(XCUIRHICommandCompilerTest, CompileTracksClipStackTransitionsAndUnderflow) {
    XCUIRHICommandCompiler compiler = {};
    UIDrawData drawData = {};
    UIDrawList& drawList = drawData.EmplaceDrawList("ClipStack");
    drawList.PushClipRect(UIRect(0.0f, 0.0f, 50.0f, 50.0f));
    drawList.PushClipRect(UIRect(10.0f, 10.0f, 40.0f, 40.0f));
    drawList.AddFilledRect(UIRect(0.0f, 0.0f, 30.0f, 30.0f), UIColor(1.0f, 0.0f, 0.0f, 1.0f));
    drawList.PopClipRect();
    drawList.AddFilledRect(UIRect(0.0f, 0.0f, 20.0f, 20.0f), UIColor(0.0f, 1.0f, 0.0f, 1.0f));
    drawList.PopClipRect();
    drawList.PopClipRect();

    XCUIRHICommandCompiler::CompileConfig config = {};
    config.surfaceClipRect = UIRect(0.0f, 0.0f, 100.0f, 100.0f);

    XCUIRHICommandCompiler::CompiledDrawData compiled = {};
    compiler.Compile(drawData, config, compiled);

    ASSERT_EQ(compiled.batches.size(), 2u);
    EXPECT_EQ(compiled.stats.compiledCommandCount, 7u);
    EXPECT_EQ(compiled.stats.clipPushCommandCount, 2u);
    EXPECT_EQ(compiled.stats.clipPopCommandCount, 3u);
    EXPECT_EQ(compiled.stats.clipStackUnderflowCount, 1u);
    EXPECT_EQ(compiled.stats.maxClipDepth, 2u);
    EXPECT_EQ(compiled.stats.danglingClipDepth, 0u);
    EXPECT_FLOAT_EQ(compiled.batches[0].clipRect.x, 10.0f);
    EXPECT_FLOAT_EQ(compiled.batches[0].clipRect.y, 10.0f);
    EXPECT_FLOAT_EQ(compiled.batches[0].clipRect.width, 40.0f);
    EXPECT_FLOAT_EQ(compiled.batches[0].clipRect.height, 40.0f);
    ASSERT_GE(compiled.colorVertices.size(), 12u);
    EXPECT_FLOAT_EQ(compiled.colorVertices[0].position[0], 10.0f);
    EXPECT_FLOAT_EQ(compiled.colorVertices[0].position[1], 10.0f);
    EXPECT_FLOAT_EQ(compiled.colorVertices[6].position[0], 0.0f);
    EXPECT_FLOAT_EQ(compiled.colorVertices[6].position[1], 0.0f);
}

TEST(XCUIRHICommandCompilerTest, CompileUsesTextGlyphProviderOutputForTextBatches) {
    XCUIRHICommandCompiler compiler = {};
    StubTextGlyphProvider glyphProvider = {};

    UIDrawData drawData = {};
    UIDrawList& drawList = drawData.EmplaceDrawList("Text");
    drawList.AddText(UIPoint(4.0f, 6.0f), "A\nB", UIColor(1.0f, 1.0f, 1.0f, 1.0f), 16.0f);

    XCUIRHICommandCompiler::CompileConfig config = {};
    config.surfaceClipRect = UIRect(0.0f, 0.0f, 100.0f, 100.0f);
    config.textGlyphProvider = &glyphProvider;

    XCUIRHICommandCompiler::CompiledDrawData compiled = {};
    compiler.Compile(drawData, config, compiled);

    ASSERT_EQ(compiled.batches.size(), 1u);
    EXPECT_EQ(compiled.batches[0].kind, XCUIRHICommandCompiler::BatchKind::Textured);
    EXPECT_EQ(compiled.batches[0].vertexCount, 12u);
    EXPECT_EQ(compiled.batches[0].texture.nativeHandle, 99u);
    EXPECT_EQ(compiled.stats.textCommandCount, 1u);
    EXPECT_EQ(compiled.stats.compiledCommandCount, 1u);
    ASSERT_EQ(compiled.texturedVertices.size(), 12u);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].position[0], 4.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].position[1], 6.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[6].position[0], 4.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[6].position[1], 18.0f);
}

TEST(XCUIRHICommandCompilerTest, CompileReportsUnsupportedTextWhenNoGlyphProviderIsAvailable) {
    XCUIRHICommandCompiler compiler = {};
    UIDrawData drawData = {};
    UIDrawList& drawList = drawData.EmplaceDrawList("UnsupportedText");
    drawList.AddText(UIPoint(0.0f, 0.0f), "xcui", UIColor(1.0f, 1.0f, 1.0f, 1.0f), 12.0f);

    XCUIRHICommandCompiler::CompileConfig config = {};
    config.surfaceClipRect = UIRect(0.0f, 0.0f, 32.0f, 32.0f);

    XCUIRHICommandCompiler::CompiledDrawData compiled = {};
    compiler.Compile(drawData, config, compiled);

    EXPECT_TRUE(compiled.Empty());
    EXPECT_EQ(compiled.stats.textCommandCount, 1u);
    EXPECT_EQ(compiled.stats.compiledCommandCount, 0u);
    EXPECT_EQ(compiled.stats.skippedCommandCount, 1u);
    EXPECT_EQ(compiled.stats.unsupportedCommandCount, 1u);
}

TEST(XCUIRHICommandCompilerTest, CompileClipsImageCommandsAndAdjustsUvCoordinates) {
    XCUIRHICommandCompiler compiler = {};
    UIDrawData drawData = {};
    UIDrawList& drawList = drawData.EmplaceDrawList("ClippedImage");
    drawList.PushClipRect(UIRect(10.0f, 8.0f, 12.0f, 10.0f));
    drawList.AddImage(
        UIRect(4.0f, 4.0f, 20.0f, 20.0f),
        UITextureHandle{ 77u, 32u, 32u, UITextureHandleKind::ShaderResourceView },
        UIColor(0.7f, 0.8f, 0.9f, 1.0f));

    XCUIRHICommandCompiler::CompileConfig config = {};
    config.surfaceClipRect = UIRect(0.0f, 0.0f, 64.0f, 64.0f);

    XCUIRHICommandCompiler::CompiledDrawData compiled = {};
    compiler.Compile(drawData, config, compiled);

    ASSERT_EQ(compiled.batches.size(), 1u);
    ASSERT_EQ(compiled.texturedVertices.size(), 6u);
    EXPECT_EQ(compiled.batches[0].kind, XCUIRHICommandCompiler::BatchKind::Textured);
    EXPECT_FLOAT_EQ(compiled.batches[0].clipRect.x, 10.0f);
    EXPECT_FLOAT_EQ(compiled.batches[0].clipRect.y, 8.0f);
    EXPECT_FLOAT_EQ(compiled.batches[0].clipRect.width, 12.0f);
    EXPECT_FLOAT_EQ(compiled.batches[0].clipRect.height, 10.0f);

    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].position[0], 10.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].position[1], 8.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].uv[0], 0.3f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].uv[1], 0.2f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[1].position[0], 22.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[1].uv[0], 0.9f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[2].position[1], 18.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[2].uv[1], 0.7f);
    EXPECT_EQ(compiled.stats.imageCommandCount, 1u);
    EXPECT_EQ(compiled.stats.compiledCommandCount, 2u);
}

TEST(XCUIRHICommandCompilerTest, CompilePreservesMirroredImageUvForNegativeRectExtents) {
    XCUIRHICommandCompiler compiler = {};
    UIDrawData drawData = {};
    UIDrawList& drawList = drawData.EmplaceDrawList("MirroredImage");
    drawList.AddImage(
        UIRect(24.0f, 18.0f, -16.0f, -12.0f),
        UITextureHandle{ 91u, 64u, 64u, UITextureHandleKind::ShaderResourceView },
        UIColor(1.0f, 1.0f, 1.0f, 1.0f));

    XCUIRHICommandCompiler::CompileConfig config = {};
    config.surfaceClipRect = UIRect(0.0f, 0.0f, 64.0f, 64.0f);

    XCUIRHICommandCompiler::CompiledDrawData compiled = {};
    compiler.Compile(drawData, config, compiled);

    ASSERT_EQ(compiled.batches.size(), 1u);
    ASSERT_EQ(compiled.texturedVertices.size(), 6u);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].position[0], 8.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].position[1], 6.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].uv[0], 1.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].uv[1], 1.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[1].position[0], 24.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[1].uv[0], 0.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[2].position[1], 18.0f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[2].uv[1], 0.0f);
    EXPECT_EQ(compiled.stats.imageCommandCount, 1u);
    EXPECT_EQ(compiled.stats.compiledCommandCount, 1u);
}

TEST(XCUIRHICommandCompilerTest, CompileUsesExplicitImageUvRectWhenProvided) {
    XCUIRHICommandCompiler compiler = {};
    UIDrawData drawData = {};
    UIDrawList& drawList = drawData.EmplaceDrawList("ExplicitUvImage");
    drawList.AddImage(
        UIRect(8.0f, 6.0f, 16.0f, 12.0f),
        UITextureHandle{ 123u, 64u, 64u, UITextureHandleKind::ShaderResourceView },
        UIColor(0.9f, 0.8f, 0.7f, 1.0f),
        UIPoint(0.25f, 0.40f),
        UIPoint(0.75f, 0.90f));

    XCUIRHICommandCompiler::CompileConfig config = {};
    config.surfaceClipRect = UIRect(0.0f, 0.0f, 64.0f, 64.0f);

    XCUIRHICommandCompiler::CompiledDrawData compiled = {};
    compiler.Compile(drawData, config, compiled);

    ASSERT_EQ(compiled.batches.size(), 1u);
    ASSERT_EQ(compiled.texturedVertices.size(), 6u);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].uv[0], 0.25f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[0].uv[1], 0.40f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[1].uv[0], 0.75f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[1].uv[1], 0.40f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[2].uv[0], 0.75f);
    EXPECT_FLOAT_EQ(compiled.texturedVertices[2].uv[1], 0.90f);
    EXPECT_EQ(compiled.stats.imageCommandCount, 1u);
    EXPECT_EQ(compiled.stats.compiledCommandCount, 1u);
}

} // namespace