// This file is part of the 64k demo project.
// It implements the Renderer3D class.

#include "3d/renderer.h"
#include "generated/assets.h"
#include "gpu/effects/shader_composer.h"
#include "util/asset_manager.h"
#include <algorithm>
#include <cassert>
#include <cstring>
#include <iostream>

#if !defined(STRIP_ALL)
bool Renderer3D::s_debug_enabled_ = false;
#endif

void Renderer3D::init(WGPUDevice device, WGPUQueue queue,
                      WGPUTextureFormat format) {
  device_ = device;
  queue_ = queue;
  format_ = format;

  WGPUSamplerDescriptor sampler_desc = {};
  sampler_desc.addressModeU = WGPUAddressMode_Repeat;
  sampler_desc.addressModeV = WGPUAddressMode_Repeat;
  sampler_desc.magFilter = WGPUFilterMode_Linear;
  sampler_desc.minFilter = WGPUFilterMode_Linear;
  sampler_desc.maxAnisotropy = 1;
  default_sampler_ = wgpuDeviceCreateSampler(device_, &sampler_desc);

  create_default_resources();
  create_pipeline();

#if !defined(STRIP_ALL)
  visual_debug_.init(device_, format_);
#endif
}

void Renderer3D::shutdown() {
#if !defined(STRIP_ALL)
  visual_debug_.shutdown();
#endif

  if (default_sampler_)
    wgpuSamplerRelease(default_sampler_);
  if (pipeline_)
    wgpuRenderPipelineRelease(pipeline_);
  if (bind_group_)
    wgpuBindGroupRelease(bind_group_);
  if (global_uniform_buffer_)
    wgpuBufferRelease(global_uniform_buffer_);
  if (object_storage_buffer_)
    wgpuBufferRelease(object_storage_buffer_);
  if (depth_view_)
    wgpuTextureViewRelease(depth_view_);
  if (depth_texture_)
    wgpuTextureRelease(depth_texture_);
}

void Renderer3D::resize(int width, int height) {
  if (width == width_ && height == height_)
    return;
  width_ = width;
  height_ = height;

  if (depth_view_)
    wgpuTextureViewRelease(depth_view_);
  if (depth_texture_)
    wgpuTextureRelease(depth_texture_);

  WGPUTextureDescriptor desc = {};
  desc.usage = WGPUTextureUsage_RenderAttachment;
  desc.dimension = WGPUTextureDimension_2D;
  desc.size = {(uint32_t)width, (uint32_t)height, 1};
  desc.format = WGPUTextureFormat_Depth24Plus;
  desc.mipLevelCount = 1;
  desc.sampleCount = 1;
  depth_texture_ = wgpuDeviceCreateTexture(device_, &desc);

  WGPUTextureViewDescriptor view_desc = {};
  view_desc.format = WGPUTextureFormat_Depth24Plus;
  view_desc.dimension = WGPUTextureViewDimension_2D;
  view_desc.aspect = WGPUTextureAspect_DepthOnly;
  view_desc.arrayLayerCount = 1;
  view_desc.mipLevelCount = 1;
  depth_view_ = wgpuTextureCreateView(depth_texture_, &view_desc);
}

void Renderer3D::create_default_resources() {
  global_uniform_buffer_ =
      gpu_create_buffer(device_, sizeof(GlobalUniforms),
                        WGPUBufferUsage_Uniform | WGPUBufferUsage_CopyDst,
                        nullptr)
          .buffer;
  object_storage_buffer_ =
      gpu_create_buffer(device_, sizeof(ObjectData) * kMaxObjects,
                        WGPUBufferUsage_Storage | WGPUBufferUsage_CopyDst,
                        nullptr)
          .buffer;
}

void Renderer3D::set_noise_texture(WGPUTextureView noise_view) {
  noise_texture_view_ = noise_view;
  // Note: Bind group needs recreation if texture changes, but we'll do it in
  // render for simplicity or just once at init if it's static. For this demo,
  // let's recreate in render if changed.
}

void Renderer3D::create_pipeline() {
  WGPUBindGroupLayoutEntry entries[4] = {};
  entries[0].binding = 0;
  entries[0].visibility = WGPUShaderStage_Vertex | WGPUShaderStage_Fragment;
  entries[0].buffer.type = WGPUBufferBindingType_Uniform;
  entries[0].buffer.minBindingSize = sizeof(GlobalUniforms);

  entries[1].binding = 1;
  entries[1].visibility = WGPUShaderStage_Vertex | WGPUShaderStage_Fragment;
  entries[1].buffer.type = WGPUBufferBindingType_ReadOnlyStorage;
  entries[1].buffer.minBindingSize = sizeof(ObjectData) * kMaxObjects;

  entries[2].binding = 2;
  entries[2].visibility = WGPUShaderStage_Fragment;
  entries[2].texture.sampleType = WGPUTextureSampleType_Float;
  entries[2].texture.viewDimension = WGPUTextureViewDimension_2D;

  entries[3].binding = 3;
  entries[3].visibility = WGPUShaderStage_Fragment;
  entries[3].sampler.type = WGPUSamplerBindingType_Filtering;

  WGPUBindGroupLayoutDescriptor bgl_desc = {};
  bgl_desc.entryCount = 4;
  bgl_desc.entries = entries;
  WGPUBindGroupLayout bgl = wgpuDeviceCreateBindGroupLayout(device_, &bgl_desc);

  WGPUPipelineLayoutDescriptor pl_desc = {};
  pl_desc.bindGroupLayoutCount = 1;
  pl_desc.bindGroupLayouts = &bgl;
  WGPUPipelineLayout pipeline_layout =
      wgpuDeviceCreatePipelineLayout(device_, &pl_desc);

  std::string main_code =
      (const char*)GetAsset(AssetId::ASSET_SHADER_RENDERER_3D);
  std::string shader_source = ShaderComposer::Get().Compose(
      {"common_uniforms", "sdf_primitives", "lighting", "ray_box"}, main_code);

#if defined(DEMO_CROSS_COMPILE_WIN32)
  WGPUShaderModuleWGSLDescriptor wgsl_desc = {};
  wgsl_desc.chain.sType = WGPUSType_ShaderModuleWGSLDescriptor;
  wgsl_desc.code = shader_source.c_str();
  WGPUShaderModuleDescriptor shader_desc = {};
  shader_desc.nextInChain = (const WGPUChainedStruct*)&wgsl_desc.chain;
#else
  WGPUShaderSourceWGSL wgsl_desc = {};
  wgsl_desc.chain.sType = WGPUSType_ShaderSourceWGSL;
  wgsl_desc.code = {shader_source.c_str(), shader_source.length()};
  WGPUShaderModuleDescriptor shader_desc = {};
  shader_desc.nextInChain = (const WGPUChainedStruct*)&wgsl_desc.chain;
#endif
  WGPUShaderModule shader_module =
      wgpuDeviceCreateShaderModule(device_, &shader_desc);

  WGPUDepthStencilState depth_stencil = {};
  depth_stencil.format = WGPUTextureFormat_Depth24Plus;
  depth_stencil.depthWriteEnabled = WGPUOptionalBool_True;
  depth_stencil.depthCompare = WGPUCompareFunction_Less;

  WGPURenderPipelineDescriptor desc = {};
  desc.layout = pipeline_layout;
  desc.vertex.module = shader_module;
#if defined(DEMO_CROSS_COMPILE_WIN32)
  desc.vertex.entryPoint = "vs_main";
#else
  desc.vertex.entryPoint = {"vs_main", 7};
#endif
  WGPUColorTargetState color_target = {};
  color_target.format = format_;
  color_target.writeMask = WGPUColorWriteMask_All;
  WGPUFragmentState fragment = {};
  fragment.module = shader_module;
#if defined(DEMO_CROSS_COMPILE_WIN32)
  fragment.entryPoint = "fs_main";
#else
  fragment.entryPoint = {"fs_main", 7};
#endif
  fragment.targetCount = 1;
  fragment.targets = &color_target;
  desc.fragment = &fragment;
  desc.primitive.topology = WGPUPrimitiveTopology_TriangleList;
  desc.primitive.cullMode = WGPUCullMode_Back;
  desc.primitive.frontFace = WGPUFrontFace_CCW;
  desc.depthStencil = &depth_stencil;
  desc.multisample.count = 1;
  desc.multisample.mask = 0xFFFFFFFF;

  pipeline_ = wgpuDeviceCreateRenderPipeline(device_, &desc);
  wgpuBindGroupLayoutRelease(bgl);
  wgpuPipelineLayoutRelease(pipeline_layout);
  wgpuShaderModuleRelease(shader_module);
}

void Renderer3D::update_uniforms(const Scene& scene, const Camera& camera,
                                 float time) {
  GlobalUniforms globals;
  globals.view_proj = camera.get_projection_matrix() * camera.get_view_matrix();
  globals.camera_pos_time =
      vec4(camera.position.x, camera.position.y, camera.position.z, time);
  globals.params =
      vec4((float)std::min((size_t)kMaxObjects, scene.objects.size()), 0.0f,
           0.0f, 0.0f);

  wgpuQueueWriteBuffer(queue_, global_uniform_buffer_, 0, &globals,
                       sizeof(GlobalUniforms));

  std::vector<ObjectData> obj_data;
  for (const auto& obj : scene.objects) {
    ObjectData data;
    data.model = obj.get_model_matrix();

    // Calculate Inverse for point transformation
    data.inv_model = data.model.inverse();

    data.color = obj.color;
    float type_id = 0.0f;
    if (obj.type == ObjectType::SPHERE)
      type_id = 1.0f;
    else if (obj.type == ObjectType::BOX)
      type_id = 2.0f;
    else if (obj.type == ObjectType::TORUS)
      type_id = 3.0f;
    else if (obj.type == ObjectType::PLANE)
      type_id = 4.0f;
    data.params = vec4(type_id, 0, 0, 0);
    obj_data.push_back(data);
    if (obj_data.size() >= kMaxObjects)
      break;
  }
  if (!obj_data.empty()) {
    wgpuQueueWriteBuffer(queue_, object_storage_buffer_, 0, obj_data.data(),
                         obj_data.size() * sizeof(ObjectData));
  }
}

void Renderer3D::draw(WGPURenderPassEncoder pass, const Scene& scene,
                      const Camera& camera, float time) {
  update_uniforms(scene, camera, time);

  // Lazy Bind Group creation

  if (bind_group_)
    wgpuBindGroupRelease(bind_group_);

  WGPUBindGroupEntry bg_entries[4] = {};

  bg_entries[0].binding = 0;

  bg_entries[0].buffer = global_uniform_buffer_;

  bg_entries[0].size = sizeof(GlobalUniforms);

  bg_entries[1].binding = 1;

  bg_entries[1].buffer = object_storage_buffer_;

  bg_entries[1].size = sizeof(ObjectData) * kMaxObjects;

  bg_entries[2].binding = 2;

  bg_entries[2].textureView = noise_texture_view_;

  bg_entries[3].binding = 3;

  bg_entries[3].sampler = default_sampler_;

  WGPUBindGroupDescriptor bg_desc = {};

  bg_desc.layout = wgpuRenderPipelineGetBindGroupLayout(pipeline_, 0);

  bg_desc.entryCount = 4;

  bg_desc.entries = bg_entries;

  bind_group_ = wgpuDeviceCreateBindGroup(device_, &bg_desc);

  wgpuBindGroupLayoutRelease(bg_desc.layout);

  wgpuRenderPassEncoderSetPipeline(pass, pipeline_);

  wgpuRenderPassEncoderSetBindGroup(pass, 0, bind_group_, 0, nullptr);

  uint32_t instance_count =
      (uint32_t)std::min((size_t)kMaxObjects, scene.objects.size());

  if (instance_count > 0) {
    wgpuRenderPassEncoderDraw(pass, 36, instance_count, 0, 0);
  }

#if !defined(STRIP_ALL)
  if (s_debug_enabled_) {
    for (const auto& obj : scene.objects) {
      vec3 extent(1.0f, 1.0f, 1.0f);
      if (obj.type == ObjectType::TORUS) {
        extent = vec3(1.5f, 0.5f, 1.5f);
      }
      visual_debug_.add_box(obj.get_model_matrix(), extent,
                            vec3(1.0f, 1.0f, 0.0f)); // Yellow boxes
    }

    // Calculate ViewProj matrix for the debug renderer
    mat4 view_proj = camera.get_projection_matrix() * camera.get_view_matrix();
    visual_debug_.render(pass, view_proj);
  }
#endif
}

void Renderer3D::render(const Scene& scene, const Camera& camera, float time,

                        WGPUTextureView target_view,
                        WGPUTextureView depth_view_opt) {
  WGPUTextureView depth_view = depth_view_opt ? depth_view_opt : depth_view_;

  if (!depth_view)
    return;

  WGPURenderPassColorAttachment color_attachment = {};

  gpu_init_color_attachment(color_attachment, target_view);

  color_attachment.clearValue = {0.05, 0.05, 0.1, 1.0};

  WGPURenderPassDepthStencilAttachment depth_attachment = {};

  depth_attachment.view = depth_view;

  depth_attachment.depthLoadOp = WGPULoadOp_Clear;

  depth_attachment.depthStoreOp = WGPUStoreOp_Store;

  depth_attachment.depthClearValue = 1.0f;

  WGPURenderPassDescriptor pass_desc = {};

  pass_desc.colorAttachmentCount = 1;

  pass_desc.colorAttachments = &color_attachment;

  pass_desc.depthStencilAttachment = &depth_attachment;

  WGPUCommandEncoder encoder = wgpuDeviceCreateCommandEncoder(device_, nullptr);

  WGPURenderPassEncoder pass =
      wgpuCommandEncoderBeginRenderPass(encoder, &pass_desc);

  wgpuRenderPassEncoderSetViewport(pass, 0.0f, 0.0f, (float)width_,
                                   (float)height_, 0.0f, 1.0f);

  draw(pass, scene, camera, time);

  wgpuRenderPassEncoderEnd(pass);

  WGPUCommandBuffer commands = wgpuCommandEncoderFinish(encoder, nullptr);

  wgpuQueueSubmit(queue_, 1, &commands);

  wgpuRenderPassEncoderRelease(pass);

  wgpuCommandBufferRelease(commands);

  wgpuCommandEncoderRelease(encoder);
}