// 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.

#include <array>

#include "common/Assert.h"
#include "common/BitSetIterator.h"
#include "dawn_native/Toggles.h"

namespace dawn_native {
    namespace {

        struct ToggleEnumAndInfo {
            Toggle toggle;
            ToggleInfo info;
        };

        using ToggleEnumAndInfoList =
            std::array<ToggleEnumAndInfo, static_cast<size_t>(Toggle::EnumCount)>;

        static constexpr ToggleEnumAndInfoList kToggleNameAndInfoList = {
            {{Toggle::EmulateStoreAndMSAAResolve,
              {"emulate_store_and_msaa_resolve",
               "Emulate storing into multisampled color attachments and doing MSAA resolve "
               "simultaneously. This workaround is enabled by default on the Metal drivers that do "
               "not support MTLStoreActionStoreAndMultisampleResolve. To support StoreOp::Store on "
               "those platforms, we should do MSAA resolve in another render pass after ending the "
               "previous one.",
               "https://bugs.chromium.org/p/dawn/issues/detail?id=56"}},
             {Toggle::NonzeroClearResourcesOnCreationForTesting,
              {"nonzero_clear_resources_on_creation_for_testing",
               "Clears texture to full 1 bits as soon as they are created, but doesn't update "
               "the tracking state of the texture. This way we can test the logic of clearing "
               "textures that use recycled memory.",
               "https://bugs.chromium.org/p/dawn/issues/detail?id=145"}},
             {Toggle::AlwaysResolveIntoZeroLevelAndLayer,
              {"always_resolve_into_zero_level_and_layer",
               "When the resolve target is a texture view that is created on the non-zero level or "
               "layer of a texture, we first resolve into a temporarily 2D texture with only one "
               "mipmap level and one array layer, and copy the result of MSAA resolve into the "
               "true resolve target. This workaround is enabled by default on the Metal drivers "
               "that have bugs when setting non-zero resolveLevel or resolveSlice.",
               "https://bugs.chromium.org/p/dawn/issues/detail?id=56"}},
             {Toggle::LazyClearResourceOnFirstUse,
              {"lazy_clear_resource_on_first_use",
               "Clears resource to zero on first usage. This initializes the resource "
               "so that no dirty bits from recycled memory is present in the new resource.",
               "https://bugs.chromium.org/p/dawn/issues/detail?id=145"}}}};

    }  // anonymous namespace

    void TogglesSet::SetToggle(Toggle toggle, bool enabled) {
        ASSERT(toggle != Toggle::InvalidEnum);
        const size_t toggleIndex = static_cast<size_t>(toggle);
        toggleBitset.set(toggleIndex, enabled);
    }

    bool TogglesSet::IsEnabled(Toggle toggle) const {
        ASSERT(toggle != Toggle::InvalidEnum);
        const size_t toggleIndex = static_cast<size_t>(toggle);
        return toggleBitset.test(toggleIndex);
    }

    std::vector<const char*> TogglesSet::GetEnabledToggleNames() const {
        std::vector<const char*> togglesNameInUse(toggleBitset.count());

        uint32_t index = 0;
        for (uint32_t i : IterateBitSet(toggleBitset)) {
            const char* toggleName = ToggleEnumToName(static_cast<Toggle>(i));
            togglesNameInUse[index] = toggleName;
            ++index;
        }

        return togglesNameInUse;
    }

    const char* ToggleEnumToName(Toggle toggle) {
        ASSERT(toggle != Toggle::InvalidEnum);

        const ToggleEnumAndInfo& toggleNameAndInfo =
            kToggleNameAndInfoList[static_cast<size_t>(toggle)];
        ASSERT(toggleNameAndInfo.toggle == toggle);
        return toggleNameAndInfo.info.name;
    }

    const ToggleInfo* TogglesInfo::GetToggleInfo(const char* toggleName) {
        ASSERT(toggleName);

        EnsureToggleNameToEnumMapInitialized();

        const auto& iter = mToggleNameToEnumMap.find(toggleName);
        if (iter != mToggleNameToEnumMap.cend()) {
            return &kToggleNameAndInfoList[static_cast<size_t>(iter->second)].info;
        }
        return nullptr;
    }

    Toggle TogglesInfo::ToggleNameToEnum(const char* toggleName) {
        ASSERT(toggleName);

        EnsureToggleNameToEnumMapInitialized();

        const auto& iter = mToggleNameToEnumMap.find(toggleName);
        if (iter != mToggleNameToEnumMap.cend()) {
            return kToggleNameAndInfoList[static_cast<size_t>(iter->second)].toggle;
        }
        return Toggle::InvalidEnum;
    }

    void TogglesInfo::EnsureToggleNameToEnumMapInitialized() {
        if (mToggleNameToEnumMapInitialized) {
            return;
        }

        for (size_t index = 0; index < kToggleNameAndInfoList.size(); ++index) {
            const ToggleEnumAndInfo& toggleNameAndInfo = kToggleNameAndInfoList[index];
            ASSERT(index == static_cast<size_t>(toggleNameAndInfo.toggle));
            mToggleNameToEnumMap[toggleNameAndInfo.info.name] = toggleNameAndInfo.toggle;
        }

        mToggleNameToEnumMapInitialized = true;
    }

}  // namespace dawn_native