// Effect implementation

#include "gpu/effect.h"
#include "gpu/gpu.h"
#include "gpu/sequence.h"
#include "util/fatal_error.h"

Effect::Effect(const GpuContext& ctx, const std::vector<std::string>& inputs,
               const std::vector<std::string>& outputs, float start_time,
               float end_time)
    : ctx_(ctx), input_nodes_(inputs), output_nodes_(outputs),
      start_time_(start_time), end_time_(end_time) {
  FATAL_CHECK(!inputs.empty(), "Effect must have at least one input\n");
  FATAL_CHECK(!outputs.empty(), "Effect must have at least one output\n");
  FATAL_CHECK(start_time <= end_time, "Invalid time range: %f > %f\n",
              start_time, end_time);
  HEADLESS_RETURN_IF_NULL(ctx_.device);
}

void Effect::dispatch_render(WGPUCommandEncoder encoder,
                              const UniformsSequenceParams& params,
                              NodeRegistry& nodes) {
  // Check if effect is active at current time
  const bool active =
      (params.time >= start_time_ && params.time < end_time_);

  // Auto-passthrough for 1:1 input/output effects outside active range
  if (!active && input_nodes_.size() == 1 && output_nodes_.size() == 1) {
    blit_input_to_output(encoder, nodes);
  } else if (active) {
    render(encoder, params, nodes);
  }
  // Multi-output effects: output undefined when inactive (validated at compile time)
}

void Effect::blit_input_to_output(WGPUCommandEncoder encoder,
                                   NodeRegistry& nodes) {
  HEADLESS_RETURN_IF_NULL(encoder);

  WGPUTexture src = nodes.get_texture(input_nodes_[0]);
  WGPUTexture dst = nodes.get_texture(output_nodes_[0]);

  // Skip passthrough if textures are external (source/sink) or invalid
  if (!src || !dst) {
    return;
  }

  GpuTextureCopyInfo src_copy = {
      .texture = src, .mipLevel = 0, .origin = {0, 0, 0}};
  GpuTextureCopyInfo dst_copy = {
      .texture = dst, .mipLevel = 0, .origin = {0, 0, 0}};

  WGPUExtent3D extent = {(unsigned int)(width_),
                         (unsigned int)(height_), 1};

  wgpuCommandEncoderCopyTextureToTexture(encoder, &src_copy, &dst_copy,
                                         &extent);
}

void Effect::init_uniforms_buffer() {
  uniforms_buffer_.init(ctx_.device);
}

void Effect::create_linear_sampler() {
  sampler_ = gpu_create_linear_sampler(ctx_.device);
}

void Effect::create_nearest_sampler() {
  sampler_ = gpu_create_nearest_sampler(ctx_.device);
}

void Effect::create_dummy_scene_texture() {
  TextureWithView dummy = gpu_create_dummy_scene_texture(ctx_.device);
  dummy_texture_ = dummy.texture;
  dummy_texture_view_ = dummy.view;
}