// Copyright 2018 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.

#include "dawn_native/ComputePassEncoder.h"

#include "dawn_native/Buffer.h"
#include "dawn_native/CommandEncoder.h"
#include "dawn_native/CommandValidation.h"
#include "dawn_native/Commands.h"
#include "dawn_native/ComputePipeline.h"
#include "dawn_native/Device.h"
#include "dawn_native/PassResourceUsageTracker.h"
#include "dawn_native/QuerySet.h"

namespace dawn_native {

    namespace {

        MaybeError ValidatePerDimensionDispatchSizeLimit(uint32_t size) {
            if (size > kMaxComputePerDimensionDispatchSize) {
                return DAWN_VALIDATION_ERROR("Dispatch size exceeds defined limits");
            }

            return {};
        }

    }  // namespace

    ComputePassEncoder::ComputePassEncoder(DeviceBase* device,
                                           CommandEncoder* commandEncoder,
                                           EncodingContext* encodingContext)
        : ProgrammablePassEncoder(device, encodingContext), mCommandEncoder(commandEncoder) {
    }

    ComputePassEncoder::ComputePassEncoder(DeviceBase* device,
                                           CommandEncoder* commandEncoder,
                                           EncodingContext* encodingContext,
                                           ErrorTag errorTag)
        : ProgrammablePassEncoder(device, encodingContext, errorTag),
          mCommandEncoder(commandEncoder) {
    }

    ComputePassEncoder* ComputePassEncoder::MakeError(DeviceBase* device,
                                                      CommandEncoder* commandEncoder,
                                                      EncodingContext* encodingContext) {
        return new ComputePassEncoder(device, commandEncoder, encodingContext, ObjectBase::kError);
    }

    void ComputePassEncoder::APIEndPass() {
        if (mEncodingContext->TryEncode(this, [&](CommandAllocator* allocator) -> MaybeError {
                if (IsValidationEnabled()) {
                    DAWN_TRY(ValidateProgrammableEncoderEnd());
                }

                allocator->Allocate<EndComputePassCmd>(Command::EndComputePass);

                return {};
            })) {
            mEncodingContext->ExitComputePass(this, mUsageTracker.AcquireResourceUsage());
        }
    }

    void ComputePassEncoder::APIDispatch(uint32_t x, uint32_t y, uint32_t z) {
        mEncodingContext->TryEncode(this, [&](CommandAllocator* allocator) -> MaybeError {
            if (IsValidationEnabled()) {
                DAWN_TRY(mCommandBufferState.ValidateCanDispatch());
                DAWN_TRY(ValidatePerDimensionDispatchSizeLimit(x));
                DAWN_TRY(ValidatePerDimensionDispatchSizeLimit(y));
                DAWN_TRY(ValidatePerDimensionDispatchSizeLimit(z));
            }

            // Record the synchronization scope for Dispatch, which is just the current bindgroups.
            AddDispatchSyncScope();

            DispatchCmd* dispatch = allocator->Allocate<DispatchCmd>(Command::Dispatch);
            dispatch->x = x;
            dispatch->y = y;
            dispatch->z = z;

            return {};
        });
    }

    void ComputePassEncoder::APIDispatchIndirect(BufferBase* indirectBuffer,
                                                 uint64_t indirectOffset) {
        mEncodingContext->TryEncode(this, [&](CommandAllocator* allocator) -> MaybeError {
            if (IsValidationEnabled()) {
                DAWN_TRY(GetDevice()->ValidateObject(indirectBuffer));
                DAWN_TRY(ValidateCanUseAs(indirectBuffer, wgpu::BufferUsage::Indirect));
                DAWN_TRY(mCommandBufferState.ValidateCanDispatch());

                // Indexed dispatches need a compute-shader based validation to check that the
                // dispatch sizes aren't too big. Disallow them as unsafe until the validation is
                // implemented.
                if (GetDevice()->IsToggleEnabled(Toggle::DisallowUnsafeAPIs)) {
                    return DAWN_VALIDATION_ERROR(
                        "DispatchIndirect is disallowed because it doesn't validate that the "
                        "dispatch "
                        "size is valid yet.");
                }

                if (indirectOffset % 4 != 0) {
                    return DAWN_VALIDATION_ERROR("Indirect offset must be a multiple of 4");
                }

                if (indirectOffset >= indirectBuffer->GetSize() ||
                    indirectOffset + kDispatchIndirectSize > indirectBuffer->GetSize()) {
                    return DAWN_VALIDATION_ERROR("Indirect offset out of bounds");
                }
            }

            // Record the synchronization scope for Dispatch, both the bindgroups and the indirect
            // buffer.
            SyncScopeUsageTracker scope;
            scope.BufferUsedAs(indirectBuffer, wgpu::BufferUsage::Indirect);
            mUsageTracker.AddReferencedBuffer(indirectBuffer);
            AddDispatchSyncScope(std::move(scope));

            DispatchIndirectCmd* dispatch =
                allocator->Allocate<DispatchIndirectCmd>(Command::DispatchIndirect);
            dispatch->indirectBuffer = indirectBuffer;
            dispatch->indirectOffset = indirectOffset;

            return {};
        });
    }

    void ComputePassEncoder::APISetPipeline(ComputePipelineBase* pipeline) {
        mEncodingContext->TryEncode(this, [&](CommandAllocator* allocator) -> MaybeError {
            if (IsValidationEnabled()) {
                DAWN_TRY(GetDevice()->ValidateObject(pipeline));
            }

            mCommandBufferState.SetComputePipeline(pipeline);

            SetComputePipelineCmd* cmd =
                allocator->Allocate<SetComputePipelineCmd>(Command::SetComputePipeline);
            cmd->pipeline = pipeline;

            return {};
        });
    }

    void ComputePassEncoder::APISetBindGroup(uint32_t groupIndexIn,
                                             BindGroupBase* group,
                                             uint32_t dynamicOffsetCount,
                                             const uint32_t* dynamicOffsets) {
        mEncodingContext->TryEncode(this, [&](CommandAllocator* allocator) -> MaybeError {
            BindGroupIndex groupIndex(groupIndexIn);

            if (IsValidationEnabled()) {
                DAWN_TRY(
                    ValidateSetBindGroup(groupIndex, group, dynamicOffsetCount, dynamicOffsets));
            }

            mUsageTracker.AddResourcesReferencedByBindGroup(group);

            RecordSetBindGroup(allocator, groupIndex, group, dynamicOffsetCount, dynamicOffsets);
            mCommandBufferState.SetBindGroup(groupIndex, group);

            return {};
        });
    }

    void ComputePassEncoder::APIWriteTimestamp(QuerySetBase* querySet, uint32_t queryIndex) {
        mEncodingContext->TryEncode(this, [&](CommandAllocator* allocator) -> MaybeError {
            if (IsValidationEnabled()) {
                DAWN_TRY(GetDevice()->ValidateObject(querySet));
                DAWN_TRY(ValidateTimestampQuery(querySet, queryIndex));
            }

            mCommandEncoder->TrackQueryAvailability(querySet, queryIndex);

            WriteTimestampCmd* cmd =
                allocator->Allocate<WriteTimestampCmd>(Command::WriteTimestamp);
            cmd->querySet = querySet;
            cmd->queryIndex = queryIndex;

            return {};
        });
    }

    void ComputePassEncoder::AddDispatchSyncScope(SyncScopeUsageTracker scope) {
        PipelineLayoutBase* layout = mCommandBufferState.GetPipelineLayout();
        for (BindGroupIndex i : IterateBitSet(layout->GetBindGroupLayoutsMask())) {
            scope.AddBindGroup(mCommandBufferState.GetBindGroup(i));
        }
        mUsageTracker.AddDispatch(scope.AcquireSyncScopeUsage());
    }

}  // namespace dawn_native