// Frame-source trait (PLAN.md locked decision 6): content producers behind
// one interface — capture / remote-stream / test-pattern. v1 implements
// desktop capture (DXGI duplication, M3); the trait is the streaming-bridge
// and PipeWire seam.
//
// Contract: the source owns its producer thread and a small ring of
// textures living on the RENDER device in COMMON state. A buffer index is
// published only after the producer's GPU work is CPU-confirmed complete,
// so consumers may sample a published texture with no cross-API sync —
// just COMMON <-> PIXEL_SHADER_RESOURCE barriers around use. A published
// buffer is never rewritten until two newer publishes have happened
// (ring of 3); proper fence pacing is M4.

#pragma once

#include <d3d12.h>

#include <cstdint>

namespace sauna {

class FrameSource {
 public:
  virtual ~FrameSource() = default;

  // Spawns the producer. renderDev outlives the source.
  virtual bool start(ID3D12Device* renderDev) = 0;
  virtual void stop() = 0;

  // Park the producer pipeline (zero GPU work) without tearing it down —
  // SteamVR coexistence: while another runtime owns the headset our
  // capture would only contend with its compositor. Resume republishes
  // the latest content. Thread-safe; default no-op for sources with no
  // meaningful GPU cost (test card).
  virtual void setPaused(bool) {}

  // Texture-set description for the CURRENT generation. Valid after
  // start() succeeds; changes only when generation() bumps.
  virtual uint32_t width() const = 0;
  virtual uint32_t height() const = 0;
  virtual uint32_t mipLevels() const = 0;
  virtual uint32_t textureCount() const = 0;
  virtual ID3D12Resource* texture(uint32_t i) const = 0;

  // Latest published buffer index, or -1 if none yet this generation.
  // *gen bumps whenever the texture set was recreated (e.g. display mode
  // change) — consumers must rebuild SRVs when it changes.
  virtual int latest(uint32_t* gen) const = 0;
};

}  // namespace sauna