// This file is part of the 64k demo project.
// It implements the Sequence management logic.

#include "effect.h"
#include <algorithm>
#include <cstdio>

// --- Sequence Implementation ---

void Sequence::init(MainSequence *demo) {
  for (auto &item : items_) {
    if (!item.effect->is_initialized) {
      item.effect->init(demo);
      item.effect->is_initialized = true;
    }
  }
}

void Sequence::add_effect(std::shared_ptr<Effect> effect, float start_time,
                          float end_time, int priority) {
  items_.push_back({effect, start_time, end_time, priority, false});
  is_sorted_ = false;
}

void Sequence::sort_items() {
  if (is_sorted_) return;
  // Sort by priority ascending (0 draws first, 100 draws on top)
  std::sort(items_.begin(), items_.end(),
            [](const SequenceItem &a, const SequenceItem &b) {
              return a.priority < b.priority;
            });
  is_sorted_ = true;
}

void Sequence::update_active_list(float seq_time) {
  for (auto &item : items_) {
    bool should_be_active =
        (seq_time >= item.start_time && seq_time < item.end_time);

    if (should_be_active) {
      if (!item.active) {
        item.effect->start();
        item.active = true;
      }
    } else {
      if (item.active) {
        item.effect->end();
        item.active = false;
      }
    }
  }
}

void Sequence::dispatch_compute(WGPUCommandEncoder encoder, float seq_time,
                                float beat, float intensity,
                                float aspect_ratio) {
  sort_items();
  for (auto &item : items_) {
    if (item.active) {
      item.effect->compute(encoder, seq_time - item.start_time, beat, intensity,
                           aspect_ratio);
    }
  }
}

void Sequence::dispatch_render(WGPURenderPassEncoder pass, float seq_time,
                               float beat, float intensity,
                               float aspect_ratio) {
  sort_items(); // Should be sorted already but safe to check
  for (auto &item : items_) {
    if (item.active) {
      item.effect->render(pass, seq_time - item.start_time, beat, intensity,
                          aspect_ratio);
    }
  }
}

void Sequence::reset() {
  for (auto &item : items_) {
    if (item.active) {
      item.effect->end();
      item.active = false;
    }
  }
}

// --- MainSequence Implementation ---

void MainSequence::init(WGPUDevice d, WGPUQueue q, WGPUTextureFormat f) {
  device = d;
  queue = q;
  format = f;
  
  for (auto &entry : sequences_) {
    entry.seq->init(this);
  }
}

void MainSequence::add_sequence(std::shared_ptr<Sequence> seq, float start_time, int priority) {
  sequences_.push_back({seq, start_time, priority});
  // Sort sequences by priority
  std::sort(sequences_.begin(), sequences_.end(),
            [](const ActiveSequence &a, const ActiveSequence &b) {
              return a.priority < b.priority;
            });
}

void MainSequence::render_frame(float global_time, float beat, float peak,
                                float aspect_ratio, WGPUSurface surface) {
  WGPUSurfaceTexture surface_texture;
  wgpuSurfaceGetCurrentTexture(surface, &surface_texture);
  
#if defined(DEMO_CROSS_COMPILE_WIN32)
  #define STATUS_OPTIMAL WGPUSurfaceGetCurrentTextureStatus_Success
  #define STATUS_SUBOPTIMAL WGPUSurfaceGetCurrentTextureStatus_Success
#else
  #define STATUS_OPTIMAL WGPUSurfaceGetCurrentTextureStatus_SuccessOptimal
  #define STATUS_SUBOPTIMAL WGPUSurfaceGetCurrentTextureStatus_SuccessSuboptimal
#endif

  if (surface_texture.status != STATUS_OPTIMAL &&
      surface_texture.status != STATUS_SUBOPTIMAL) {
    return;
  }

  WGPUTextureView view = wgpuTextureCreateView(surface_texture.texture, nullptr);

  WGPUCommandEncoderDescriptor encoder_desc = {};
  WGPUCommandEncoder encoder = wgpuDeviceCreateCommandEncoder(device, &encoder_desc);

  // 1. Update & Compute Phase
  for (auto &entry : sequences_) {
    // Check if sequence is active (start_time <= global_time)
    // We assume sequences run until end of demo or have internal end? 
    // User said "Sequence ... overlap". Implicitly they might have duration but here we just check start.
    // Let's assume they are active if time >= start.
    // Effects inside sequence handle duration.
    if (global_time >= entry.start_time) {
        float seq_time = global_time - entry.start_time;
        entry.seq->update_active_list(seq_time);
        
        // Pass generic aspect ratio 16:9 for compute? 
        // Or wait for render. Particles compute uses it.
        // We can get it from surface texture size if we want?
        // Let's pass 1.777f for now or fetch.
        // gpu_draw used to pass it. We need it here.
        // Wait, render_frame doesn't take aspect_ratio. gpu_draw did.
        // I should add aspect_ratio to render_frame or calculate it from surface.
    }
  }
  
  for (auto &entry : sequences_) {
    if (global_time >= entry.start_time) {
        entry.seq->dispatch_compute(encoder, global_time - entry.start_time, beat, peak, aspect_ratio);
    }
  }

  // 2. Render Phase
  {
    WGPURenderPassColorAttachment color_attachment = {};
    color_attachment.view = view;
    color_attachment.loadOp = WGPULoadOp_Clear;
    color_attachment.storeOp = WGPUStoreOp_Store;
    
    // Clear color logic could be dynamic or part of a "BackgroundEffect"?
    // For now hardcode.
    float flash = peak * 0.2f;
    color_attachment.clearValue = {0.05 + flash, 0.1 + flash, 0.2 + flash, 1.0};
    
#if !defined(DEMO_CROSS_COMPILE_WIN32)
    color_attachment.depthSlice = WGPU_DEPTH_SLICE_UNDEFINED;
#endif

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

    WGPURenderPassEncoder pass = wgpuCommandEncoderBeginRenderPass(encoder, &render_pass_desc);

    for (auto &entry : sequences_) {
        if (global_time >= entry.start_time) {
            entry.seq->dispatch_render(pass, global_time - entry.start_time, beat, peak, aspect_ratio);
        }
    }

    wgpuRenderPassEncoderEnd(pass);
  }

  WGPUCommandBufferDescriptor cmd_desc = {};
  WGPUCommandBuffer commands = wgpuCommandEncoderFinish(encoder, &cmd_desc);
  wgpuQueueSubmit(queue, 1, &commands);
  wgpuSurfacePresent(surface);

  wgpuTextureViewRelease(view);
  wgpuTextureRelease(surface_texture.texture);
}

void MainSequence::shutdown() {
    for (auto &entry : sequences_) {
        entry.seq->reset();
    }
    sequences_.clear();
}