#include "recorder.hpp"

#include <cstring>

#include "log.hpp"
#include "pixmap.hpp"

namespace t5de {

namespace {

// Between frames, recorded commands (mostly textures and buffers being loaded) are sent once they reach this size.
constexpr std::size_t flushSize = 4 * 1024 * 1024;

} // namespace

void pack(std::byte* destination, const void* source, std::uint32_t stride, std::uint32_t elementSize,
          std::uint32_t count)
{
    const auto* from = static_cast<const std::byte*>(source);
    if (stride == 0 || stride == elementSize) {
        std::memcpy(destination, from, std::size_t{elementSize} * count);
        return;
    }
    for (std::uint32_t i = 0; i < count; ++i) {
        std::memcpy(destination + std::size_t{i} * elementSize, from + std::size_t{i} * stride, elementSize);
    }
}

Recorder::Recorder(std::unique_ptr<RendererProcess> process) : process_(std::move(process)) {}

void Recorder::flush(bool endsFrame)
{
    if (!active()) {
        writer_.clear();
        return;
    }
    process_->send(writer_.bytes(), endsFrame);
    writer_.clear();
}

void Recorder::flushIfLarge()
{
    if (writer_.size() >= flushSize) {
        flush(false);
    }
}

void Recorder::addPixels(protocol::Op op, std::uint32_t id, const imvu::Pixmap& pixmap, std::uint32_t flags)
{
    const auto pixels = pixmap_pixels(pixmap);
    if (!pixels || pixels->pixels == nullptr) {
        return;
    }
    const std::size_t rowSize = std::size_t{pixels->width} * 4;
    std::byte* payload = nullptr;
    if (op == protocol::Op::CreateTexture) {
        payload = add(op, protocol::CreateTexture{id, pixels->width, pixels->height, flags}, rowSize * pixels->height);
    } else {
        payload = add(op, protocol::UpdateTexture{id, pixels->width, pixels->height}, rowSize * pixels->height);
    }
    if (payload == nullptr) {
        return;
    }
    const auto* rows = reinterpret_cast<const std::byte*>(pixels->pixels);
    for (std::uint32_t y = 0; y < pixels->height; ++y) {
        std::memcpy(payload + y * rowSize, rows + std::size_t{y} * pixels->rowBytes, rowSize);
    }
    flushIfLarge();
}

std::uint32_t Recorder::createRenderTarget(std::uint32_t width, std::uint32_t height)
{
    const std::uint32_t id = nextId_++;
    add(protocol::Op::CreateRenderTarget, protocol::CreateRenderTarget{id, width, height});
    return id;
}

std::span<const std::byte> Recorder::readBack()
{
    return active() ? process_->readBack() : std::span<const std::byte>{};
}

std::uint32_t Recorder::createTexture(const imvu::Pixmap& pixmap, std::uint32_t flags)
{
    const std::uint32_t id = nextId_++;
    addPixels(protocol::Op::CreateTexture, id, pixmap, flags);
    return id;
}

void Recorder::updateTexture(std::uint32_t id, const imvu::Pixmap& pixmap)
{
    addPixels(protocol::Op::UpdateTexture, id, pixmap, 0);
}

void Recorder::destroyTexture(std::uint32_t id) { add(protocol::Op::DestroyTexture, protocol::DestroyTexture{id}); }

std::uint32_t Recorder::createBuffer(protocol::BufferKind kind, const void* data, std::uint32_t stride,
                                     std::uint32_t elementSize, std::uint32_t count)
{
    const std::uint32_t id = nextId_++;
    const std::size_t size = data != nullptr ? std::size_t{elementSize} * count : 0;
    if (std::byte* payload = add(protocol::Op::CreateBuffer, protocol::CreateBuffer{id, kind, elementSize, count}, size);
        payload != nullptr && size != 0) {
        pack(payload, data, stride, elementSize, count);
    }
    flushIfLarge();
    return id;
}

void Recorder::updateBuffer(std::uint32_t id, const void* data, std::uint32_t stride, std::uint32_t elementSize,
                            std::uint32_t count)
{
    const std::size_t size = std::size_t{elementSize} * count;
    if (std::byte* payload = add(protocol::Op::UpdateBuffer, protocol::UpdateBuffer{id, elementSize, count}, size);
        payload != nullptr && data != nullptr) {
        pack(payload, data, stride, elementSize, count);
    }
}

void Recorder::destroyBuffer(std::uint32_t id) { add(protocol::Op::DestroyBuffer, protocol::DestroyBuffer{id}); }

} // namespace t5de