// Peak meter overlay for audio debugging

#include "effects/peak_meter_effect.h"
#include "gpu/post_process_helper.h"
#include "gpu/shader_composer.h"
#include "util/fatal_error.h"

PeakMeter::PeakMeter(const GpuContext& ctx,
                     const std::vector<std::string>& inputs,
                     const std::vector<std::string>& outputs)
    : Effect(ctx, inputs, outputs), pipeline_(nullptr), bind_group_(nullptr) {
  HEADLESS_RETURN_IF_NULL(ctx_.device);

  uniforms_buffer_.init(ctx_.device);

  const char* shader_main = R"(
    struct VertexOutput {
      @builtin(position) position: vec4<f32>,
      @location(0) uv: vec2<f32>,
    };

    @group(0) @binding(0) var inputSampler: sampler;
    @group(0) @binding(1) var inputTexture: texture_2d<f32>;
    @group(0) @binding(2) var<uniform> uniforms: CommonUniforms;

    @vertex
    fn vs_main(@builtin(vertex_index) vertexIndex: u32) -> VertexOutput {
      var output: VertexOutput;
      var pos = array<vec2<f32>, 3>(
        vec2<f32>(-1.0, -1.0),
        vec2<f32>(3.0, -1.0),
        vec2<f32>(-1.0, 3.0)
      );
      output.position = vec4<f32>(pos[vertexIndex], 0.0, 1.0);
      output.uv = pos[vertexIndex] * 0.5 + 0.5;
      return output;
    }

    @fragment
    fn fs_main(input: VertexOutput) -> @location(0) vec4<f32> {
      let bar_y_min = 0.005;
      let bar_y_max = 0.015;
      let bar_x_min = 0.015;
      let bar_x_max = 0.250;
      let in_bar_y = input.uv.y >= bar_y_min && input.uv.y <= bar_y_max;
      let in_bar_x = input.uv.x >= bar_x_min && input.uv.x <= bar_x_max;

      if (in_bar_y && in_bar_x) {
        let uv_x = (input.uv.x - bar_x_min) / (bar_x_max - bar_x_min);
        let factor = step(uv_x, uniforms.audio_intensity);
        return mix(vec4<f32>(0.0, 0.0, 0.0, 1.0), vec4<f32>(1.0, 0.0, 0.0, 1.0), factor);
      }

      return textureSample(inputTexture, inputSampler, input.uv);
    }
  )";

  std::string shader_code =
      ShaderComposer::Get().Compose({"common_uniforms"}, shader_main);

  pipeline_ = create_post_process_pipeline(
      ctx_.device, WGPUTextureFormat_RGBA8Unorm, shader_code.c_str());
}

PeakMeter::~PeakMeter() {
  if (bind_group_)
    wgpuBindGroupRelease(bind_group_);
  if (pipeline_)
    wgpuRenderPipelineRelease(pipeline_);
}

void PeakMeter::render(WGPUCommandEncoder encoder,
                       const UniformsSequenceParams& params,
                       NodeRegistry& nodes) {
  WGPUTextureView input_view = nodes.get_view(input_nodes_[0]);
  WGPUTextureView output_view = nodes.get_view(output_nodes_[0]);

  uniforms_buffer_.update(ctx_.queue, params);
  pp_update_bind_group(ctx_.device, pipeline_, &bind_group_, input_view,
                       uniforms_buffer_.get(), {nullptr, 0});

  WGPURenderPassColorAttachment color_attachment = {};
  color_attachment.view = output_view;
  color_attachment.depthSlice = WGPU_DEPTH_SLICE_UNDEFINED;
  color_attachment.loadOp = WGPULoadOp_Load;
  color_attachment.storeOp = WGPUStoreOp_Store;
  color_attachment.clearValue = {0.0, 0.0, 0.0, 1.0};

  WGPURenderPassDescriptor pass_desc = {};
  pass_desc.colorAttachmentCount = 1;
  pass_desc.colorAttachments = &color_attachment;

  WGPURenderPassEncoder pass =
      wgpuCommandEncoderBeginRenderPass(encoder, &pass_desc);
  wgpuRenderPassEncoderSetPipeline(pass, pipeline_);
  wgpuRenderPassEncoderSetBindGroup(pass, 0, bind_group_, 0, nullptr);
  wgpuRenderPassEncoderDraw(pass, 3, 1, 0, 0);
  wgpuRenderPassEncoderEnd(pass);
  wgpuRenderPassEncoderRelease(pass);
}