// CNN post-processing effect implementation
// Neural network-based stylization with modular WGSL

#include "gpu/effects/cnn_effect.h"
#include "gpu/effects/post_process_helper.h"
#include "gpu/effects/shaders.h"
#include "gpu/effects/shader_composer.h"
#include "gpu/effect.h"
#include "gpu/bind_group_builder.h"
#include "gpu/sampler_cache.h"
#include "gpu/pipeline_builder.h"

// Create custom pipeline with 5 bindings (includes original texture)
static WGPURenderPipeline create_cnn_pipeline(WGPUDevice device,
                                               WGPUTextureFormat format,
                                               const char* shader_code) {
  WGPUBindGroupLayout bgl = BindGroupLayoutBuilder()
    .sampler(0, WGPUShaderStage_Fragment)
    .texture(1, WGPUShaderStage_Fragment)
    .uniform(2, WGPUShaderStage_Vertex | WGPUShaderStage_Fragment)
    .uniform(3, WGPUShaderStage_Fragment)
    .texture(4, WGPUShaderStage_Fragment)
    .build(device);

  WGPURenderPipeline pipeline = RenderPipelineBuilder(device)
    .shader(shader_code)
    .bind_group_layout(bgl)
    .format(format)
    .build();

  wgpuBindGroupLayoutRelease(bgl);
  return pipeline;
}

CNNEffect::CNNEffect(const GpuContext& ctx)
    : PostProcessEffect(ctx), layer_index_(0), total_layers_(1),
      blend_amount_(1.0f), input_view_(nullptr), original_view_(nullptr),
      bind_group_(nullptr) {
  pipeline_ = create_cnn_pipeline(ctx_.device, ctx_.format,
                                  cnn_layer_shader_wgsl);
}

CNNEffect::CNNEffect(const GpuContext& ctx, const CNNEffectParams& params)
    : PostProcessEffect(ctx), layer_index_(params.layer_index),
      total_layers_(params.total_layers), blend_amount_(params.blend_amount),
      input_view_(nullptr), original_view_(nullptr), bind_group_(nullptr) {
  pipeline_ = create_cnn_pipeline(ctx_.device, ctx_.format,
                                  cnn_layer_shader_wgsl);
}

void CNNEffect::init(MainSequence* demo) {
  PostProcessEffect::init(demo);
  demo_ = demo;
  params_buffer_.init(ctx_.device);

  // Register captured_frame texture (used by all layers for original input)
  if (layer_index_ == 0) {
    demo_->register_auxiliary_texture("captured_frame", width_, height_);
  }

  CNNLayerParams params = {layer_index_, blend_amount_, {0.0f, 0.0f}};
  params_buffer_.update(ctx_.queue, params);
}

void CNNEffect::render(WGPURenderPassEncoder pass, float time, float beat,
                      float intensity, float aspect_ratio) {
  if (!bind_group_) {
    fprintf(stderr, "CNN render: no bind_group\n");
    return;
  }

  wgpuRenderPassEncoderSetPipeline(pass, pipeline_);
  wgpuRenderPassEncoderSetBindGroup(pass, 0, bind_group_, 0, nullptr);
  wgpuRenderPassEncoderDraw(pass, 3, 1, 0, 0);
}

void CNNEffect::update_bind_group(WGPUTextureView input_view) {
  input_view_ = input_view;

  // Update common uniforms (CRITICAL for UV calculation!)
  const CommonPostProcessUniforms u = {
      .resolution = {(float)width_, (float)height_},
      .aspect_ratio = (float)width_ / (float)height_,
      .time = 0.0f,
      .beat = 0.0f,
      .audio_intensity = 0.0f,
  };
  uniforms_.update(ctx_.queue, u);

  // All layers: get captured frame (original input from layer 0)
  if (demo_) {
    original_view_ = demo_->get_auxiliary_view("captured_frame");
  }

  // Create bind group with original texture
  if (bind_group_)
    wgpuBindGroupRelease(bind_group_);

  WGPUBindGroupLayout bgl = wgpuRenderPipelineGetBindGroupLayout(pipeline_, 0);
  WGPUSampler sampler = SamplerCache::Get().get_or_create(ctx_.device, SamplerCache::linear());

  bind_group_ = BindGroupBuilder()
    .sampler(0, sampler)
    .texture(1, input_view_)
    .buffer(2, uniforms_.get().buffer, uniforms_.get().size)
    .buffer(3, params_buffer_.get().buffer, params_buffer_.get().size)
    .texture(4, original_view_ ? original_view_ : input_view_)
    .build(ctx_.device, bgl);
}