// Copyright 2019 The Dawn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef INCLUDE_DAWN_PLATFORM_DAWNPLATFORM_H_
#define INCLUDE_DAWN_PLATFORM_DAWNPLATFORM_H_

#include <cstddef>
#include <cstdint>
#include <memory>

#include "dawn/platform/dawn_platform_export.h"
#include "dawn/webgpu.h"

namespace dawn::platform {

enum class TraceCategory {
    General,     // General trace events
    Validation,  // Dawn validation
    Recording,   // Native command recording
    GPUWork,     // Actual GPU work
};

class DAWN_PLATFORM_EXPORT CachingInterface {
  public:
    CachingInterface();
    virtual ~CachingInterface();

    // LoadData has two modes. The first mode is used to get a value which
    // corresponds to the |key|. The |valueOut| is a caller provided buffer
    // allocated to the size |valueSize| which is loaded with data of the
    // size returned. The second mode is used to query for the existence of
    // the |key| where |valueOut| is nullptr and |valueSize| must be 0.
    // The return size is non-zero if the |key| exists.
    virtual size_t LoadData(const WGPUDevice device,
                            const void* key,
                            size_t keySize,
                            void* valueOut,
                            size_t valueSize) = 0;

    // StoreData puts a |value| in the cache which corresponds to the |key|.
    virtual void StoreData(const WGPUDevice device,
                           const void* key,
                           size_t keySize,
                           const void* value,
                           size_t valueSize) = 0;

  private:
    CachingInterface(const CachingInterface&) = delete;
    CachingInterface& operator=(const CachingInterface&) = delete;
};

class DAWN_PLATFORM_EXPORT WaitableEvent {
  public:
    WaitableEvent() = default;
    virtual ~WaitableEvent() = default;
    virtual void Wait() = 0;        // Wait for completion
    virtual bool IsComplete() = 0;  // Non-blocking check if the event is complete
};

using PostWorkerTaskCallback = void (*)(void* userdata);

class DAWN_PLATFORM_EXPORT WorkerTaskPool {
  public:
    WorkerTaskPool() = default;
    virtual ~WorkerTaskPool() = default;
    virtual std::unique_ptr<WaitableEvent> PostWorkerTask(PostWorkerTaskCallback,
                                                          void* userdata) = 0;
};

class DAWN_PLATFORM_EXPORT Platform {
  public:
    Platform();
    virtual ~Platform();

    virtual const unsigned char* GetTraceCategoryEnabledFlag(TraceCategory category);

    virtual double MonotonicallyIncreasingTime();

    virtual uint64_t AddTraceEvent(char phase,
                                   const unsigned char* categoryGroupEnabled,
                                   const char* name,
                                   uint64_t id,
                                   double timestamp,
                                   int numArgs,
                                   const char** argNames,
                                   const unsigned char* argTypes,
                                   const uint64_t* argValues,
                                   unsigned char flags);

    // The |fingerprint| is provided by Dawn to inform the client to discard the Dawn caches
    // when the fingerprint changes. The returned CachingInterface is expected to outlive the
    // device which uses it to persistently cache objects.
    virtual CachingInterface* GetCachingInterface(const void* fingerprint, size_t fingerprintSize);
    virtual std::unique_ptr<WorkerTaskPool> CreateWorkerTaskPool();

  private:
    Platform(const Platform&) = delete;
    Platform& operator=(const Platform&) = delete;
};

}  // namespace dawn::platform

// TODO(dawn:824): Remove once the deprecation period is passed.
namespace dawn_platform = dawn::platform;

#endif  // INCLUDE_DAWN_PLATFORM_DAWNPLATFORM_H_