// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef GPU_COMMAND_BUFFER_CLIENT_WEBGPU_IMPLEMENTATION_H_
#define GPU_COMMAND_BUFFER_CLIENT_WEBGPU_IMPLEMENTATION_H_

#include <dawn/webgpu.h>
#include <dawn/wire/WireClient.h>

#include <memory>
#include <optional>
#include <utility>
#include <vector>

#include "base/memory/raw_ptr.h"
#include "base/task/sequenced_task_runner.h"
#include "gpu/command_buffer/client/dawn_client_memory_transfer_service.h"
#include "gpu/command_buffer/client/dawn_client_serializer.h"
#include "gpu/command_buffer/client/dawn_wire_client.h"
#include "gpu/command_buffer/client/gpu_control_client.h"
#include "gpu/command_buffer/client/implementation_base.h"
#include "gpu/command_buffer/client/logging.h"
#include "gpu/command_buffer/client/transfer_buffer.h"
#include "gpu/command_buffer/client/webgpu_cmd_helper.h"
#include "gpu/command_buffer/client/webgpu_export.h"
#include "gpu/command_buffer/client/webgpu_interface.h"
#include "ui/gl/buildflags.h"

namespace gpu {
namespace webgpu {

#if BUILDFLAG(USE_DAWN)
class DawnWireServices : public APIChannel {
 private:
  friend class base::RefCounted<DawnWireServices>;
  ~DawnWireServices() override;

 public:
  DawnWireServices(WebGPUImplementation* webgpu_implementation,
                   WebGPUCmdHelper* helper,
                   MappedMemoryManager* mapped_memory,
                   std::unique_ptr<TransferBuffer> transfer_buffer,
                   bool support_locking = false);

  base::WeakPtr<DawnWireServices> AsWeakPtr();

  WGPUInstance GetWGPUInstance() const override;

  void Disconnect() override;

  void HandleCommands(uint64_t trace_id,
                      base::span<const volatile uint8_t> commands);
  void ProcessEvents();
  dawn::wire::ReservedBuffer ReserveBuffer(WGPUDevice device,
                                           const WGPUBufferDescriptor* desc);
  dawn::wire::ReservedTexture ReserveTexture(WGPUDevice device,
                                             const WGPUTextureDescriptor* desc);

  void Commit();
  bool EnsureAwaitingFlush();
  void SetAwaitingFlush(bool awaiting_flush);

  void FreeMappedResources(WebGPUCmdHelper* helper);

 private:
  // Lock to access internal Dawn wire related state.
  mutable std::optional<base::Lock> lock_ = std::nullopt;

  bool disconnected_ = false;
  DawnClientMemoryTransferService memory_transfer_service_;
  DawnClientSerializer serializer_;
  DawnWireClient wire_client_;
  WGPUInstance wgpu_instance_;
  base::WeakPtrFactory<DawnWireServices> weak_ptr_factory_{this};
};
#endif

class WEBGPU_EXPORT WebGPUImplementation final : public WebGPUInterface,
                                                 public ImplementationBase {
 public:
  explicit WebGPUImplementation(WebGPUCmdHelper* helper,
                                TransferBufferInterface* transfer_buffer,
                                GpuControl* gpu_control,
                                bool support_locking = false);

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

  ~WebGPUImplementation() override;

  gpu::ContextResult Initialize(const SharedMemoryLimits& limits);

// Include the auto-generated part of this class. We split this because
// it means we can easily edit the non-auto generated parts right here in
// this file instead of having to edit some template or the code generator.
#include "gpu/command_buffer/client/webgpu_implementation_autogen.h"

  void AssociateMailbox(GLuint device_id,
                        GLuint device_generation,
                        GLuint id,
                        GLuint generation,
                        uint64_t usage,
                        uint64_t internal_usage,
                        const WGPUTextureFormat* view_formats,
                        GLuint view_format_count,
                        MailboxFlags flags,
                        const Mailbox& mailbox) override;

  void AssociateMailboxForBuffer(GLuint device_id,
                                 GLuint device_generation,
                                 GLuint id,
                                 GLuint generation,
                                 uint64_t usage,
                                 const Mailbox& mailbox) override;

  // ContextSupport implementation.
  void SetAggressivelyFreeResources(bool aggressively_free_resources) override;
  void SetErrorMessageCallback(
      base::RepeatingCallback<void(const char*, int32_t)> callback) override;
  base::span<uint8_t> MapTransferCacheEntry(uint32_t serialized_size) override;
  void UnmapAndCreateTransferCacheEntry(uint32_t type, uint32_t id) override;
  bool ThreadsafeLockTransferCacheEntry(uint32_t type, uint32_t id) override;
  void UnlockTransferCacheEntries(
      const std::vector<std::pair<uint32_t, uint32_t>>& entries) override;
  void DeleteTransferCacheEntry(uint32_t type, uint32_t id) override;
  unsigned int GetTransferBufferFreeSize() const override;

  // InterfaceBase implementation.
  void GenSyncTokenCHROMIUM(GLbyte* sync_token) override;
  void GenUnverifiedSyncTokenCHROMIUM(GLbyte* sync_token) override;
  void VerifySyncTokensCHROMIUM(GLbyte** sync_tokens, GLsizei count) override;
  void WaitSyncTokenCHROMIUM(const GLbyte* sync_token) override;
  void ShallowFlushCHROMIUM() override;

  // ImplementationBase implementation.
  void IssueShallowFlush() override;
  void SetGLError(GLenum error,
                  const char* function_name,
                  const char* msg) override;

  // GpuControlClient implementation.
  void OnGpuControlLostContext() final;
  void OnGpuControlLostContextMaybeReentrant() final;
  void OnGpuControlErrorMessage(const char* message, int32_t id) final;
  void OnGpuControlReturnData(base::span<const uint8_t> data) final;

  // WebGPUInterface implementation
  void FlushCommands() override;
  bool EnsureAwaitingFlush() override;
  void FlushAwaitingCommands() override;
  scoped_refptr<APIChannel> GetAPIChannel() const override;
  ReservedBuffer ReserveBuffer(
      WGPUDevice device,
      const WGPUBufferDescriptor* optionalDesc) override;
  ReservedTexture ReserveTexture(
      WGPUDevice device,
      const WGPUTextureDescriptor* optionalDesc = nullptr) override;
  WGPUDevice DeprecatedEnsureDefaultDeviceSync() override;

 private:
  const char* GetLogPrefix() const { return "webgpu"; }
  void CheckGLError() {}
  void LoseContext();

  raw_ptr<WebGPUCmdHelper> helper_;

  // If set, this is the task runner that any ProcessEvent calls should be
  // proxied to. Otherwise, the default behaviour does not call ProcessEvent's
  // at all since the callbacks are expected to be AllowSpontaneous in that
  // case.
  scoped_refptr<base::SequencedTaskRunner> main_task_runner_;

#if BUILDFLAG(USE_DAWN)
  scoped_refptr<DawnWireServices> dawn_wire_;
#endif

  LogSettings log_settings_;

  std::atomic_bool lost_{false};
};

}  // namespace webgpu
}  // namespace gpu

#endif  // GPU_COMMAND_BUFFER_CLIENT_WEBGPU_IMPLEMENTATION_H_