#include "engine.hpp"

#include <windows.h>

#include <bit>
#include <cmath>
#include <cstring>
#include <vector>

#include "log.hpp"
#include "resources.hpp"

namespace t5de {

using protocol::Op;
using protocol::State;

namespace {

protocol::SetTransform transform_command(const imvu::Transform& t)
{
    protocol::SetTransform command{};
    std::memcpy(command.m, &t.linear[0][0], sizeof(float) * 9);
    command.m[9] = t.translation.x;
    command.m[10] = t.translation.y;
    command.m[11] = t.translation.z;
    return command;
}

} // namespace

Engine::Engine(imvu::SharedPtr<imvu::PiRenderEngine> inner, std::shared_ptr<Recorder> recorder)
    : inner_(std::move(inner)), recorder_(std::move(recorder))
{
}

Engine::~Engine() { log::info("engine: destroyed after {} frames", frames_); }

void Engine::setState(State state, std::uint32_t value)
{
    recorder_->add(Op::SetState, protocol::SetState{state, value});
}

void Engine::resizeFrameBuffer(imvu::Vec2i size) { inner_->resizeFrameBuffer(size); }

void Engine::enable2dFrameBuffer() { inner_->enable2dFrameBuffer(); }

void Engine::clear(std::uint32_t flags, imvu::Color color)
{
    if (innerDraws()) {
        inner_->clear(flags, color);
    }
    recorder_->add(Op::Clear, protocol::Clear{flags, color});
}

void Engine::setProjection(imvu::Vec2i viewport, const imvu::Mat4f& projection)
{
    inner_->setProjection(viewport, projection);
    if (projection.m[2][3] == 0.0f) {
        ++stats_.flat;
    }
    protocol::SetProjection command{viewport.x, viewport.y, {}};
    std::memcpy(command.m, &projection.m[0][0], sizeof(command.m));
    recorder_->add(Op::SetProjection, command);
}

void Engine::setModelSpace(const imvu::Transform& model)
{
    inner_->setModelSpace(model);
    recorder_->add(Op::SetModel, transform_command(model));
}

void Engine::setViewSpace(const imvu::Transform& view)
{
    inner_->setViewSpace(view);
    recorder_->add(Op::SetView, transform_command(view));
}

void Engine::setTextures(imvu::PiRenderTexture* texture0, imvu::PiRenderTexture* texture1)
{
    inner_->setTextures(inner(texture0), inner(texture1));
    for (imvu::PiRenderTexture* texture : {texture0, texture1}) {
        if (texture != nullptr && id(texture) == 0 && foreignLogged_ < 20) {
            ++foreignLogged_;
            log::info("engine: frame {}: a texture the client renderer made ({})", frames_, static_cast<void*>(texture));
        }
    }
    recorder_->add(Op::SetTextures, protocol::SetTextures{id(texture0), id(texture1)});
}

void Engine::setDepthTestingOn(bool on)
{
    inner_->setDepthTestingOn(on);
    setState(State::DepthTest, on);
}

void Engine::setDepthWritingOn(bool on)
{
    inner_->setDepthWritingOn(on);
    setState(State::DepthWrite, on);
}

void Engine::setBlendMode(imvu::RenderBlendMode mode)
{
    inner_->setBlendMode(mode);
    setState(State::BlendMode, static_cast<std::uint32_t>(mode));
}

void Engine::setAlphaTestingOn(bool on)
{
    inner_->setAlphaTestingOn(on);
    setState(State::AlphaTest, on);
}

void Engine::setAlphaTestValue(float value)
{
    inner_->setAlphaTestValue(value);
    setState(State::AlphaReference, static_cast<std::uint32_t>(std::lround(value * 255.0f)));
}

void Engine::setBlendingOn(bool on)
{
    inner_->setBlendingOn(on);
    setState(State::Blending, on);
}

void Engine::setBackFaceCullingOn(bool on)
{
    inner_->setBackFaceCullingOn(on);
    setState(State::Culling, on);
}

void Engine::setNormalInvertingOn(bool on)
{
    inner_->setNormalInvertingOn(on);
    setState(State::NormalInverting, on);
}

void Engine::setLightingOn(bool on)
{
    inner_->setLightingOn(on);
    setState(State::Lighting, on);
}

void Engine::setLightProperties(std::uint32_t index, const imvu::LightProperties& light)
{
    inner_->setLightProperties(index, light);
    protocol::SetLight command{index, light.enabled, light.diffuse,
                               light.type == imvu::LightType::Directional,
                               {light.vector.x, light.vector.y, light.vector.z}};
    // IMVU's Direct3D renderer shines a directional light along -vector, along -x for a zero vector.
    if (command.directional && light.vector.x == 0 && light.vector.y == 0 && light.vector.z == 0) {
        command.vector[0] = 1;
    }
    recorder_->add(Op::SetLight, command);
}

void Engine::setFogOn(bool on)
{
    inner_->setFogOn(on);
    setState(State::Fog, on);
}

void Engine::setFogAttributes(float start, float end, imvu::Color color)
{
    inner_->setFogAttributes(start, end, color);
    recorder_->add(Op::SetFog, protocol::SetFog{start, end, color});
}

void Engine::setTextureTransformMatrixIdentity(std::uint32_t stage)
{
    inner_->setTextureTransformMatrixIdentity(stage);
    recorder_->add(Op::SetTextureTransform, protocol::SetTextureTransform{stage, 1, {1, 0, 0, 1, 0, 0}});
}

void Engine::setTextureTransformMatrix(std::uint32_t stage, const imvu::TextureTransform& transform)
{
    inner_->setTextureTransformMatrix(stage, transform);
    protocol::SetTextureTransform command{stage, 0, {}};
    std::memcpy(command.m, transform.m, sizeof(command.m));
    recorder_->add(Op::SetTextureTransform, command);
}

void Engine::setEnvironmentAmbient(imvu::Color color)
{
    inner_->setEnvironmentAmbient(color);
    setState(State::Ambient, color);
}

imvu::PiRenderTexture* Engine::newRenderTexture(const imvu::Pixmap& pixmap, std::uint32_t flags)
{
    imvu::PiRenderTexture* texture = inner_->newRenderTexture(pixmap, flags);
    if (texture == nullptr) {
        return nullptr;
    }
    return new Texture(texture, recorder_, recorder_->createTexture(pixmap, flags));
}

imvu::PiInternalIndexBuffer* Engine::newIndexBuffer(std::uint32_t count, const std::uint16_t* indices)
{
    imvu::PiInternalIndexBuffer* buffer = inner_->newIndexBuffer(count, indices);
    if (buffer == nullptr) {
        return nullptr;
    }
    return new IndexBuffer(buffer, recorder_,
                           recorder_->createBuffer(protocol::BufferKind::Index, indices, 2, 2, count));
}

imvu::PiInternalVertexBuffer* Engine::newStaticVertexBuffer(const void* data, std::uint32_t stride,
                                                            std::uint32_t elementSize, std::uint32_t elementCount)
{
    imvu::PiInternalVertexBuffer* buffer = inner_->newStaticVertexBuffer(data, stride, elementSize, elementCount);
    if (buffer == nullptr) {
        return nullptr;
    }
    return new VertexBuffer(
        buffer, recorder_,
        recorder_->createBuffer(protocol::BufferKind::Vertex, data, stride, elementSize, elementCount));
}

imvu::PiInternalVertexBuffer* Engine::newDynamicVertexBuffer(std::uint32_t elementSize, std::uint32_t elementCount)
{
    imvu::PiInternalVertexBuffer* buffer = inner_->newDynamicVertexBuffer(elementSize, elementCount);
    if (buffer == nullptr) {
        return nullptr;
    }
    return new VertexBuffer(
        buffer, recorder_,
        recorder_->createBuffer(protocol::BufferKind::Vertex, nullptr, 0, elementSize, elementCount));
}

imvu::SharedPtr<imvu::PiPixmapRenderTarget> Engine::newPixmapRenderTarget(imvu::Vec2i size)
{
    log::info("engine: frame {}: a {}x{} pixmap render target", frames_, size.x, size.y);
    return inner_->newPixmapRenderTarget(size);
}

imvu::SharedPtr<imvu::PiTextureRenderTarget> Engine::newTextureRenderTarget(imvu::Vec2i size)
{
    log::info("engine: frame {}: a {}x{} texture render target", frames_, size.x, size.y);
    return inner_->newTextureRenderTarget(size);
}

void Engine::beginRendering(imvu::PiRenderTarget* target)
{
    inner_->beginRendering(target);
    // Decided per frame: frames into render targets, and frames while the renderer process doesn't cover the view, are
    // drawn by the client's renderer.
    const bool takenOver = target == nullptr && recorder_->covering();
    if (takenOver != takenOver_ && target == nullptr) {
        log::info("engine: frame {}: {}", frames_, takenOver ? "drawn by the renderer process" : "drawn by the client's renderer");
    }
    takenOver_ = takenOver;
    if (target != nullptr && foreignLogged_ < 20) {
        ++foreignLogged_;
        log::info("engine: frame {}: drawing into a render target ({})", frames_, static_cast<void*>(target));
    }
    recorder_->add(Op::BeginFrame, protocol::BeginFrame{target != nullptr});
}

void Engine::endRendering()
{
    inner_->endRendering();
    LARGE_INTEGER now;
    QueryPerformanceCounter(&now);
    recorder_->add(Op::EndFrame, protocol::EndFrame{static_cast<std::uint64_t>(now.QuadPart)});
    recorder_->flush(true);
    ++frames_;
    if (frames_ % 300 == 0 && statsLogged_ < 6) {
        ++statsLogged_;
        log::info("engine: last 300 frames: drawTriangles {} (and {} with buffers not ours), drawTrianglesFromMemory {} "
                  "(and {} without indices), point sprites {}, lines {}, 2D projections {}",
                  stats_.triangles, stats_.foreignTriangles, stats_.indexed, stats_.unindexed, stats_.sprites, stats_.lines,
                  stats_.flat);
        stats_ = {};
    }
}

void Engine::drawTriangles(imvu::PiInternalIndexBuffer* indices, imvu::PiInternalVertexBuffer* positions,
                           imvu::PiInternalVertexBuffer* normals, imvu::PiInternalVertexBuffer* texCoords,
                           imvu::PiInternalVertexBuffer* colors)
{
    if (innerDraws()) {
        inner_->drawTriangles(inner(indices), inner(positions), inner(normals), inner(texCoords), inner(colors));
    }
    ++(id(indices) != 0 && id(positions) != 0 ? stats_.triangles : stats_.foreignTriangles);
    recorder_->add(Op::DrawTriangles,
                   protocol::DrawTriangles{id(indices), id(positions), id(normals), id(texCoords), id(colors)});
}

void Engine::drawLine(imvu::Vec3f from, imvu::Vec3f to, imvu::Color color)
{
    if (innerDraws()) {
        inner_->drawLine(from, to, color);
    }
    ++stats_.lines;
}

void Engine::drawPointSprites(const imvu::PointSpriteVector& sprites)
{
    if (innerDraws()) {
        inner_->drawPointSprites(sprites);
    }
    ++stats_.sprites;
    if (sprites.first == nullptr || sprites.last <= sprites.first) {
        return;
    }
    const auto count = static_cast<std::uint32_t>(sprites.last - sprites.first);
    if (std::byte* payload = recorder_->add(Op::DrawPointSprites, protocol::DrawPointSprites{count},
                                            std::size_t{count} * sizeof(imvu::PointSprite))) {
        std::memcpy(payload, sprites.first, std::size_t{count} * sizeof(imvu::PointSprite));
    }
}

void Engine::drawTrianglesFromMemory(std::uint32_t vertexCount, std::uint32_t indexCount,
                                     const std::uint16_t* indices,
                                     const imvu::VertexAttributeArray<imvu::Vec3f>& positions,
                                     const imvu::VertexAttributeArray<imvu::Vec3f>& normals,
                                     const imvu::VertexAttributeArray<imvu::Vec2f>& texCoords,
                                     const imvu::VertexAttributeArray<imvu::Color>& colors)
{
    if (innerDraws()) {
        inner_->drawTrianglesFromMemory(vertexCount, indexCount, indices, positions, normals, texCoords, colors);
    }
    ++(indices != nullptr ? stats_.indexed : stats_.unindexed);
    if (positions.data == nullptr || vertexCount == 0) {
        return;
    }
    // Without indices: the vertices in order, as a triangle list.
    std::vector<std::uint16_t> sequence;
    if (indices == nullptr) {
        if (vertexCount > 0xffff) {
            return;
        }
        sequence.resize(vertexCount - vertexCount % 3);
        for (std::size_t i = 0; i < sequence.size(); ++i) {
            sequence[i] = static_cast<std::uint16_t>(i);
        }
        indices = sequence.data();
        indexCount = static_cast<std::uint32_t>(sequence.size());
    }
    const bool hasNormals = normals.data != nullptr && normals.count >= vertexCount;
    const bool hasTexCoords = texCoords.data != nullptr && texCoords.count >= vertexCount;
    const bool hasColors = colors.data != nullptr && colors.count >= vertexCount;
    const std::size_t indexBytes = protocol::padded(std::size_t{indexCount} * 2);
    const std::size_t size = indexBytes + std::size_t{vertexCount} * (12 + (hasNormals ? 12 : 0) +
                                                                      (hasTexCoords ? 8 : 0) + (hasColors ? 4 : 0));
    std::byte* payload = recorder_->add(Op::DrawArrays,
                                        protocol::DrawArrays{vertexCount, indexCount, hasNormals, hasTexCoords,
                                                             hasColors},
                                        size);
    if (payload == nullptr) {
        return;
    }
    std::memcpy(payload, indices, std::size_t{indexCount} * 2);
    std::byte* next = payload + indexBytes;
    pack(next, positions.data, positions.stride, 12, vertexCount);
    next += std::size_t{vertexCount} * 12;
    if (hasNormals) {
        pack(next, normals.data, normals.stride, 12, vertexCount);
        next += std::size_t{vertexCount} * 12;
    }
    if (hasTexCoords) {
        pack(next, texCoords.data, texCoords.stride, 8, vertexCount);
        next += std::size_t{vertexCount} * 8;
    }
    if (hasColors) {
        pack(next, colors.data, colors.stride, 4, vertexCount);
    }
}

} // namespace t5de