// SPDX-License-Identifier: GPL-3.0-or-later

#pragma once

#if defined(MKW_ENABLE_OPENXR) && defined(__ANDROID__)

#include "vr/openxr_backend.h"
#include "vr/openxr_runtime.h"

#include <cstdint>
#include <memory>
#include <string>

namespace mkw::vr {

struct OpenXRVulkanGraphicsRequirements {
    // XR_MAKE_VERSION-encoded bounds reported by xrGetVulkanGraphicsRequirements2KHR.
    XrVersion min_api_version = 0;
    XrVersion max_api_version = 0;
    // Which binding extension was negotiated: XR_KHR_vulkan_enable2 when the
    // runtime offers it, otherwise the original XR_KHR_vulkan_enable.
    bool uses_enable2 = false;
};

// Two-device Dawn/OpenXR Vulkan backend for Android (Meta Quest).
//
// Method surface and threading rules are identical to OpenXRD3D12Backend so the
// pacing thread in openxr_integration.cpp is shared. The difference is behind
// BindAurora: instead of binding Dawn's device to the session, this backend
// creates its own VkInstance/VkDevice through the OpenXR runtime, owns a small
// ring of AHardwareBuffers per eye, and hands them to Aurora's Vulkan stereo
// bridge (aurora/vulkan_interop.h). When Aurora reports a completed copy, the
// backend copies the buffer into the acquired XrSwapchain image on the
// session's queue, so the compositor sees ordinary same-queue rendering.
//
// QueryGraphicsRequirements() runs after OpenXRRuntime::Initialize() and before
// aurora_initialize(); BindAurora() runs afterwards, while Aurora's frame worker
// is idle. Everything from BeginFrame() through FinishFrame() belongs to one XR
// pacing thread; the Aurora callback only records a small copy on this
// backend's private queue and publishes a token.
class OpenXRVulkanBackend final {
public:
    explicit OpenXRVulkanBackend(OpenXRLogCallback logger = {});
    ~OpenXRVulkanBackend();

    OpenXRVulkanBackend(const OpenXRVulkanBackend&) = delete;
    OpenXRVulkanBackend& operator=(const OpenXRVulkanBackend&) = delete;
    OpenXRVulkanBackend(OpenXRVulkanBackend&&) = delete;
    OpenXRVulkanBackend& operator=(OpenXRVulkanBackend&&) = delete;

    bool QueryGraphicsRequirements(OpenXRRuntime& runtime);
    bool BindAurora(OpenXRRuntime& runtime);

    OpenXRBeginStatus BeginFrame(const OpenXRPresentation& presentation, OpenXRBackendFrame& frame);
    OpenXRSubmissionStatus WaitForSubmission(const OpenXRBackendFrame& frame,
                                             uint32_t timeout_ms = UINT32_MAX);
    bool TryCancelPendingFrame(OpenXRBackendFrame& frame);
    bool RepeatFrame(const OpenXRBackendFrame& frame);
    bool FinishFrame(OpenXRBackendFrame& frame, bool submit_layer);

    // Drains this backend's own queue before tearing down. Returns false only
    // when the private device could not be waited on, in which case the caller
    // retains the backend and runtime for the process lifetime.
    bool Shutdown();

    bool IsBound() const;
    const OpenXRVulkanGraphicsRequirements& GraphicsRequirements() const;
    int64_t SwapchainFormat() const;
    const std::string& LastError() const;

private:
    class Impl;
    std::unique_ptr<Impl> m_impl;
};

} // namespace mkw::vr

#endif // defined(MKW_ENABLE_OPENXR) && defined(__ANDROID__)