/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

#include "LayoutAnimationKeyFrameManager.h"

#include <algorithm>
#include <sstream>
#include <utility>

#include <react/debug/flags.h>
#include <react/debug/react_native_assert.h>

#include <react/renderer/animations/conversions.h>
#include <react/renderer/animations/utils.h>
#include <react/renderer/componentregistry/ComponentDescriptorFactory.h>
#include <react/renderer/components/image/ImageProps.h>
#include <react/renderer/components/view/ViewProps.h>
#include <react/renderer/core/ComponentDescriptor.h>
#include <react/renderer/core/LayoutMetrics.h>
#include <react/renderer/core/Props.h>
#include <react/renderer/core/PropsParserContext.h>
#include <react/renderer/core/RawValue.h>
#include <react/renderer/mounting/MountingCoordinator.h>
#include <react/renderer/mounting/ShadowView.h>
#include <react/renderer/mounting/ShadowViewMutation.h>

#include <glog/logging.h>

namespace facebook::react {

#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
static std::string GetMutationInstructionString(
    ShadowViewMutation const &mutation) {
  Tag tag = mutation.type == ShadowViewMutation::Type::Insert ||
          mutation.type == ShadowViewMutation::Type::Create
      ? mutation.newChildShadowView.tag
      : mutation.oldChildShadowView.tag;
  return getDebugName(mutation) + " [" + std::to_string(tag) + "]->[" +
      std::to_string(mutation.parentShadowView.tag) + "] @" +
      std::to_string(mutation.index);
}

void PrintMutationInstruction(
    std::string message,
    ShadowViewMutation const &mutation) {
  [&](std::ostream &stream) -> std::ostream & {
    stream << message
           << " Mutation: " << GetMutationInstructionString(mutation);
    if (mutation.oldChildShadowView.tag != 0) {
      stream << " old hash: ##"
             << std::hash<ShadowView>{}(mutation.oldChildShadowView);
    }
    if (mutation.newChildShadowView.tag != 0) {
      stream << " new hash: ##"
             << std::hash<ShadowView>{}(mutation.newChildShadowView);
    }
    return stream;
  }(LOG(ERROR));
}

void PrintMutationInstructionRelative(
    std::string message,
    ShadowViewMutation const &mutation,
    ShadowViewMutation const &relativeMutation) {
  LOG(ERROR) << message
             << " Mutation: " << GetMutationInstructionString(mutation)
             << " RelativeMutation: "
             << GetMutationInstructionString(relativeMutation);
}
#endif

static inline Float
interpolateFloats(Float coefficient, Float oldValue, Float newValue) {
  return oldValue + (newValue - oldValue) * coefficient;
}

#pragma mark -

LayoutAnimationKeyFrameManager::LayoutAnimationKeyFrameManager(
    RuntimeExecutor runtimeExecutor,
    ContextContainer::Shared &contextContainer,
    LayoutAnimationStatusDelegate *delegate)
    : runtimeExecutor_(std::move(runtimeExecutor)),
      contextContainer_(contextContainer),
      layoutAnimationStatusDelegate_(delegate),
      now_([]() {
        return std::chrono::duration_cast<std::chrono::milliseconds>(
                   std::chrono::high_resolution_clock::now().time_since_epoch())
            .count();
      }) {}

#pragma mark UIManagerAnimationDelegate methods

/**
 * Globally configure next LayoutAnimation.
 * This is guaranteed to be called only on the JS thread.
 */
void LayoutAnimationKeyFrameManager::uiManagerDidConfigureNextLayoutAnimation(
    jsi::Runtime &runtime,
    RawValue const &config,
    const jsi::Value &successCallbackValue,
    const jsi::Value &failureCallbackValue) const {
  bool hasSuccessCallback = successCallbackValue.isObject() &&
      successCallbackValue.getObject(runtime).isFunction(runtime);
  bool hasFailureCallback = failureCallbackValue.isObject() &&
      failureCallbackValue.getObject(runtime).isFunction(runtime);
  LayoutAnimationCallbackWrapper successCallback = hasSuccessCallback
      ? LayoutAnimationCallbackWrapper(
            successCallbackValue.getObject(runtime).getFunction(runtime))
      : LayoutAnimationCallbackWrapper();
  LayoutAnimationCallbackWrapper failureCallback = hasFailureCallback
      ? LayoutAnimationCallbackWrapper(
            failureCallbackValue.getObject(runtime).getFunction(runtime))
      : LayoutAnimationCallbackWrapper();

  auto layoutAnimationConfig =
      parseLayoutAnimationConfig((folly::dynamic)config);

  if (layoutAnimationConfig) {
    std::lock_guard<std::mutex> lock(currentAnimationMutex_);

    uiManagerDidConfigureNextLayoutAnimation(LayoutAnimation{
        -1,
        0,
        false,
        *layoutAnimationConfig,
        successCallback,
        failureCallback,
        {}});
  } else {
    LOG(ERROR) << "Parsing LayoutAnimationConfig failed: "
               << (folly::dynamic)config;

    callCallback(failureCallback);
  }
}

void LayoutAnimationKeyFrameManager::setComponentDescriptorRegistry(
    const SharedComponentDescriptorRegistry &componentDescriptorRegistry) {
  componentDescriptorRegistry_ = componentDescriptorRegistry;
}

void LayoutAnimationKeyFrameManager::setReduceDeleteCreateMutation(
    const bool reduceDeleteCreateMutation) {
  reduceDeleteCreateMutation_ = reduceDeleteCreateMutation;
}

bool LayoutAnimationKeyFrameManager::shouldAnimateFrame() const {
  std::lock_guard<std::mutex> lock(currentAnimationMutex_);
  return currentAnimation_ || !inflightAnimations_.empty();
}

void LayoutAnimationKeyFrameManager::stopSurface(SurfaceId surfaceId) {
  std::lock_guard<std::mutex> lock(surfaceIdsToStopMutex_);
  surfaceIdsToStop_.insert(surfaceId);
}

#pragma mark - MountingOverrideDelegate methods

bool LayoutAnimationKeyFrameManager::shouldOverridePullTransaction() const {
  return shouldAnimateFrame();
}

std::optional<MountingTransaction>
LayoutAnimationKeyFrameManager::pullTransaction(
    SurfaceId surfaceId,
    MountingTransaction::Number transactionNumber,
    TransactionTelemetry const &telemetry,
    ShadowViewMutationList mutations) const {
  // Current time in milliseconds
  uint64_t now = now_();

  bool inflightAnimationsExistInitially = !inflightAnimations_.empty();
  deleteAnimationsForStoppedSurfaces();

  if (!mutations.empty()) {
#ifdef RN_SHADOW_TREE_INTROSPECTION
    {
      std::stringstream ss(getDebugDescription(mutations, {}));
      std::string to;
      while (std::getline(ss, to, '\n')) {
        LOG(ERROR)
            << "LayoutAnimationKeyFrameManager.cpp: got mutation list: Line: "
            << to;
      }
    };
#endif

      // DEBUG ONLY: list existing inflight animations
#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
    LOG(ERROR) << "BEGINNING DISPLAYING ONGOING inflightAnimations_!";
    int i = 0;
    int j = 0;
    for (auto const &inflightAnimation : inflightAnimations_) {
      i++;
      j = 0;
      if (inflightAnimation.completed) {
        continue;
      }
      for (auto &keyframe : inflightAnimation.keyFrames) {
        j++;
        if (keyframe.invalidated) {
          continue;
        }
        for (const auto &finalMutationForKeyFrame :
             keyframe.finalMutationsForKeyFrame) {
          if (finalMutationForKeyFrame.mutatedViewIsVirtual()) {
            std::string msg = "Animation " + std::to_string(i) + " keyframe " +
                std::to_string(j) + ": Final Animation";
            PrintMutationInstruction(msg, finalMutationForKeyFrame);
          } else {
            LOG(ERROR) << "Animation " << i << " keyframe " << j
                       << ": on tag: [" << keyframe.viewStart.tag << "]";
          }
        }
      }
    }
    LOG(ERROR) << "BEGINNING DONE DISPLAYING ONGOING inflightAnimations_!";
#endif

    PropsParserContext propsParserContext{surfaceId, *contextContainer_};

    // What to do if we detect a conflict? Get current value and make
    // that the baseline of the next animation. Scale the remaining time
    // in the animation
    // Types of conflicts and how we handle them:
    // Update -> update: remove the previous update, make it the baseline of the
    // next update (with current progress) Update -> remove: same, with final
    // mutation being a remove Insert -> update: treat as update->update Insert
    // -> remove: same, as update->remove Remove -> update/insert: not possible
    // We just collect pairs here of <Mutation, AnimationConfig> and delete them
    // from active animations. If another animation is queued up from the
    // current mutations then these deleted mutations will serve as the baseline
    // for the next animation. If not, the current mutations are executed
    // immediately without issues.
    std::vector<AnimationKeyFrame> conflictingAnimations{};
    getAndEraseConflictingAnimations(
        surfaceId, mutations, conflictingAnimations);

    // Are we animating this list of mutations?
    std::optional<LayoutAnimation> currentAnimation{};
    {
      std::lock_guard<std::mutex> lock(currentAnimationMutex_);
      if (currentAnimation_) {
        currentAnimation = std::move(currentAnimation_);
        currentAnimation_.reset();
      }
    }

    if (currentAnimation.has_value()) {
      LayoutAnimation animation = std::move(currentAnimation).value();
      animation.surfaceId = surfaceId;
      animation.startTime = now;

      // Pre-process list to:
      //   Catch remove+reinsert (reorders)
      //   Catch delete+create (reparenting) (this should be optimized away at
      //   the diffing level eventually?)
      // TODO: to prevent this step we could tag Remove/Insert mutations as
      // being moves on the Differ level, since we know that there? We could use
      // TinyMap here, but it's not exposed by Differentiator (yet).
      butter::set<Tag> insertedTags;
      butter::set<Tag> deletedTags;
      butter::set<Tag> reparentedTags; // tags that are deleted and recreated
      std::unordered_map<Tag, ShadowViewMutation> movedTags;
      for (const auto &mutation : mutations) {
        if (mutation.type == ShadowViewMutation::Type::Insert) {
          insertedTags.insert(mutation.newChildShadowView.tag);
        }
        if (mutation.type == ShadowViewMutation::Type::Delete) {
          deletedTags.insert(mutation.oldChildShadowView.tag);
        }
        if (mutation.type == ShadowViewMutation::Type::Create) {
          if (deletedTags.find(mutation.newChildShadowView.tag) !=
              deletedTags.end()) {
            reparentedTags.insert(mutation.newChildShadowView.tag);
          }
        }
      }

      // Process mutations list into operations that can be sent to platform
      // immediately, and those that need to be animated Deletions, removals,
      // updates are delayed and animated. Creations and insertions are sent to
      // platform and then "animated in" with opacity updates. Upon completion,
      // removals and deletions are sent to platform
      ShadowViewMutation::List immediateMutations;

      // Remove operations that are actually moves should be copied to
      // "immediate mutations". The corresponding "insert" will also be executed
      // immediately and animated as an update.
      std::vector<AnimationKeyFrame> keyFramesToAnimate;
      auto const layoutAnimationConfig = animation.layoutAnimationConfig;
      for (auto const &mutation : mutations) {
        if (mutation.type == ShadowViewMutation::Type::RemoveDeleteTree) {
          continue;
        }

        ShadowView baselineShadowView =
            (mutation.type == ShadowViewMutation::Type::Delete ||
                     mutation.type == ShadowViewMutation::Type::Remove ||
                     mutation.type == ShadowViewMutation::Type::Update
                 ? mutation.oldChildShadowView
                 : mutation.newChildShadowView);
        react_native_assert(baselineShadowView.tag > 0);
        bool haveComponentDescriptor =
            hasComponentDescriptorForShadowView(baselineShadowView);

        // Immediately execute any mutations on a root node
        if (baselineShadowView.traits.check(
                ShadowNodeTraits::Trait::RootNodeKind)) {
          immediateMutations.push_back(mutation);
          continue;
        }

        std::optional<ShadowViewMutation> executeMutationImmediately{};

        bool isRemoveReinserted =
            mutation.type == ShadowViewMutation::Type::Remove &&
            insertedTags.find(mutation.oldChildShadowView.tag) !=
                insertedTags.end();

        // Reparenting can result in a node being removed, inserted (moved) and
        // also deleted and created in the same frame, with the same props etc.
        // This should eventually be optimized out of the diffing algorithm, but
        // for now we detect reparenting and prevent the corresponding
        // Delete/Create instructions from being animated.
        bool isReparented =
            reparentedTags.find(baselineShadowView.tag) != reparentedTags.end();

        if (isRemoveReinserted) {
          movedTags.insert({mutation.oldChildShadowView.tag, mutation});
        }

        // Inserts that follow a "remove" of the same tag should be treated as
        // an update (move) animation.
        bool wasInsertedTagRemoved = false;
        auto movedIt = movedTags.end();
        if (mutation.type == ShadowViewMutation::Type::Insert) {
          // If this is a move, we actually don't want to copy this insert
          // instruction to animated instructions - we want to
          // generate an Update mutation for Remove+Insert pairs to animate
          // the layout.
          // The corresponding Remove and Insert instructions will instead
          // be treated as "immediate" instructions.
          movedIt = movedTags.find(mutation.newChildShadowView.tag);
          wasInsertedTagRemoved = movedIt != movedTags.end();
        }

        auto const &mutationConfig =
            (mutation.type == ShadowViewMutation::Type::Delete ||
                     (mutation.type == ShadowViewMutation::Type::Remove &&
                      !wasInsertedTagRemoved)
                 ? layoutAnimationConfig.deleteConfig
                 : (mutation.type == ShadowViewMutation::Type::Insert &&
                            !wasInsertedTagRemoved
                        ? layoutAnimationConfig.createConfig
                        : layoutAnimationConfig.updateConfig));
        bool haveConfiguration =
            mutationConfig.animationType != AnimationType::None;

        // Creates and inserts should also be executed immediately.
        // Mutations that would otherwise be animated, but have no
        // configuration, are also executed immediately.
        if (isRemoveReinserted || !haveConfiguration || isReparented ||
            mutation.type == ShadowViewMutation::Type::Create ||
            mutation.type == ShadowViewMutation::Type::Insert) {
          executeMutationImmediately = mutation;

          // It is possible, especially in the case of "moves", that we have a
          // sequence of operations like:
          // UPDATE X
          // REMOVE X
          // INSERT X
          // In these cases, we will have queued up an animation for the UPDATE
          // and delayed its execution; the REMOVE and INSERT will be executed
          // first; and then the UPDATE will be animating to/from ShadowViews
          // that are out-of-sync with what's on the mounting layer. Thus, for
          // any UPDATE animations already queued up for this tag, we adjust the
          // "previous" ShadowView.
          if (mutation.type == ShadowViewMutation::Type::Insert) {
            for (auto &keyframe : keyFramesToAnimate) {
              if (keyframe.tag == baselineShadowView.tag) {
                // If there's already an animation queued up, followed by this
                // Insert, it *must* be an Update mutation animation. Other
                // sequences should not be possible.
                react_native_assert(
                    keyframe.type == AnimationConfigurationType::Update);

                // The mutation is an "insert", so it must have a
                // "newChildShadowView"
                react_native_assert(mutation.newChildShadowView.tag > 0);

                // Those asserts don't run in prod. If there's some edge-case
                // that we haven't caught yet, we'd crash in debug; make sure we
                // don't mutate the prevView in prod.
                if (keyframe.type == AnimationConfigurationType::Update &&
                    mutation.newChildShadowView.tag > 0) {
                  keyframe.viewPrev = mutation.newChildShadowView;
                }
              }
            }
          } else if (mutation.type == ShadowViewMutation::Type::Remove) {
            for (auto &keyframe : keyFramesToAnimate) {
              if (keyframe.tag == baselineShadowView.tag) {
                // If there's already an animation queued up, followed by this
                // Insert, it *must* be an Update mutation animation. Other
                // sequences should not be possible.
                react_native_assert(
                    keyframe.type == AnimationConfigurationType::Update);

                // The mutation is a "remove", so it must have a
                // "oldChildShadowView"
                react_native_assert(mutation.oldChildShadowView.tag > 0);

                // Those asserts don't run in prod. If there's some edge-case
                // that we haven't caught yet, we'd crash in debug; make sure we
                // don't mutate the prevView in prod.
                // Since normally the UPDATE would have been executed first and
                // now it's deferred, we need to change the `oldChildShadowView`
                // that is being referenced by the REMOVE mutation.
                if (keyframe.type == AnimationConfigurationType::Update &&
                    mutation.oldChildShadowView.tag > 0) {
                  executeMutationImmediately =
                      ShadowViewMutation::RemoveMutation(
                          mutation.parentShadowView,
                          keyframe.viewPrev,
                          mutation.index);
                }
              }
            }
          }
        }

        // Deletes, non-move inserts, updates get animated
        if (!wasInsertedTagRemoved && !isRemoveReinserted && !isReparented &&
            haveConfiguration &&
            mutation.type != ShadowViewMutation::Type::Create) {
          ShadowView viewStart = ShadowView(
              mutation.type == ShadowViewMutation::Type::Insert
                  ? mutation.newChildShadowView
                  : mutation.oldChildShadowView);
          react_native_assert(viewStart.tag > 0);
          ShadowView viewFinal = ShadowView(
              mutation.type == ShadowViewMutation::Type::Update
                  ? mutation.newChildShadowView
                  : viewStart);
          react_native_assert(viewFinal.tag > 0);
          ShadowView parent = mutation.parentShadowView;
          react_native_assert(
              parent.tag > 0 ||
              mutation.type == ShadowViewMutation::Type::Update ||
              mutation.type == ShadowViewMutation::Type::Delete);
          Tag tag = viewStart.tag;

          AnimationKeyFrame keyFrame{};
          if (mutation.type == ShadowViewMutation::Type::Insert) {
            if (mutationConfig.animationProperty ==
                    AnimationProperty::Opacity &&
                haveComponentDescriptor) {
              auto props =
                  getComponentDescriptorForShadowView(baselineShadowView)
                      .cloneProps(propsParserContext, viewStart.props, {});

              if (baselineShadowView.traits.check(
                      ShadowNodeTraits::Trait::ViewKind)) {
                auto const &viewProps =
                    *std::static_pointer_cast<ViewProps const>(props);
                const_cast<ViewProps &>(viewProps).opacity = 0;
              }

              react_native_assert(props != nullptr);
              if (props != nullptr) {
                viewStart.props = props;
              }
            }
            bool isScaleX =
                mutationConfig.animationProperty == AnimationProperty::ScaleX ||
                mutationConfig.animationProperty == AnimationProperty::ScaleXY;
            bool isScaleY =
                mutationConfig.animationProperty == AnimationProperty::ScaleY ||
                mutationConfig.animationProperty == AnimationProperty::ScaleXY;
            if ((isScaleX || isScaleY) && haveComponentDescriptor) {
              auto props =
                  getComponentDescriptorForShadowView(baselineShadowView)
                      .cloneProps(propsParserContext, viewStart.props, {});
              if (baselineShadowView.traits.check(
                      ShadowNodeTraits::Trait::ViewKind)) {
                auto const &viewProps =
                    *std::static_pointer_cast<ViewProps const>(props);
                const_cast<ViewProps &>(viewProps).transform =
                    Transform::Scale(isScaleX ? 0 : 1, isScaleY ? 0 : 1, 1);
              }

              react_native_assert(props != nullptr);
              if (props != nullptr) {
                viewStart.props = props;
              }
            }

            PrintMutationInstruction(
                "Setting up animation KeyFrame for INSERT mutation (Create animation)",
                mutation);

            keyFrame = AnimationKeyFrame{
                /* .finalMutationsForKeyFrame = */ {},
                /* .type = */ AnimationConfigurationType::Create,
                /* .tag = */ tag,
                /* .parentView = */ parent,
                /* .viewStart = */ viewStart,
                /* .viewEnd = */ viewFinal,
                /* .viewPrev = */ baselineShadowView,
                /* .initialProgress = */ 0};
          } else if (mutation.type == ShadowViewMutation::Type::Delete) {
// This is just for assertion purposes.
// The NDEBUG check here is to satisfy the compiler in certain environments
// complaining about correspondingRemoveIt being unused.
#ifdef REACT_NATIVE_DEBUG
#ifndef NDEBUG
// This block is temporarily disabled to fix some internal builds.
// In some build configurations, we get a compiler error that
// `correspondingRemoveIt` is unused.
/*            Tag deleteTag = mutation.oldChildShadowView.tag;
            auto correspondingRemoveIt = std::find_if(
                mutations.begin(),
                mutations.end(),
                [&deleteTag](auto &mutation) {
                  return mutation.type == ShadowViewMutation::Type::Remove &&
                      mutation.oldChildShadowView.tag == deleteTag;
                });
            react_native_assert(correspondingRemoveIt != mutations.end());
*/
#endif
#endif
            continue;
          } else if (mutation.type == ShadowViewMutation::Type::Update) {
            viewFinal = ShadowView(mutation.newChildShadowView);

            PrintMutationInstruction(
                "Setting up animation KeyFrame for UPDATE mutation (Update animation)",
                mutation);

            keyFrame = AnimationKeyFrame{
                /* .finalMutationsForKeyFrame = */ {mutation},
                /* .type = */ AnimationConfigurationType::Update,
                /* .tag = */ tag,
                /* .parentView = */ parent,
                /* .viewStart = */ viewStart,
                /* .viewEnd = */ viewFinal,
                /* .viewPrev = */ baselineShadowView,
                /* .initialProgress = */ 0};
          } else {
            // This should just be "Remove" instructions that are not animated
            // (either this is a "move", or there's a corresponding "Delete"
            // that is animated).
            react_native_assert(
                mutation.type == ShadowViewMutation::Type::Remove);

            Tag removeTag = mutation.oldChildShadowView.tag;
            auto correspondingInsertIt = std::find_if(
                mutations.begin(),
                mutations.end(),
                [&removeTag](auto &mutation) {
                  return mutation.type == ShadowViewMutation::Type::Insert &&
                      mutation.newChildShadowView.tag == removeTag;
                });
            if (correspondingInsertIt == mutations.end()) {
              // This is a REMOVE not paired with an INSERT (move), so it must
              // be paired with a DELETE.
              auto correspondingDeleteIt = std::find_if(
                  mutations.begin(),
                  mutations.end(),
                  [&removeTag](auto &mutation) {
                    return mutation.type == ShadowViewMutation::Type::Delete &&
                        mutation.oldChildShadowView.tag == removeTag;
                  });
              react_native_assert(correspondingDeleteIt != mutations.end());

              auto deleteMutation = *correspondingDeleteIt;

              if (mutationConfig.animationProperty ==
                      AnimationProperty::Opacity &&
                  haveComponentDescriptor) {
                auto props =
                    getComponentDescriptorForShadowView(baselineShadowView)
                        .cloneProps(propsParserContext, viewFinal.props, {});

                if (baselineShadowView.traits.check(
                        ShadowNodeTraits::Trait::ViewKind)) {
                  auto const &viewProps =
                      *std::static_pointer_cast<ViewProps const>(props);
                  const_cast<ViewProps &>(viewProps).opacity = 0;
                }

                react_native_assert(props != nullptr);
                if (props != nullptr) {
                  viewFinal.props = props;
                }
              }
              bool isScaleX = mutationConfig.animationProperty ==
                      AnimationProperty::ScaleX ||
                  mutationConfig.animationProperty ==
                      AnimationProperty::ScaleXY;
              bool isScaleY = mutationConfig.animationProperty ==
                      AnimationProperty::ScaleY ||
                  mutationConfig.animationProperty ==
                      AnimationProperty::ScaleXY;
              if ((isScaleX || isScaleY) && haveComponentDescriptor) {
                auto props =
                    getComponentDescriptorForShadowView(baselineShadowView)
                        .cloneProps(propsParserContext, viewFinal.props, {});

                if (baselineShadowView.traits.check(
                        ShadowNodeTraits::Trait::ViewKind)) {
                  auto const &viewProps =
                      *std::static_pointer_cast<ViewProps const>(props);
                  const_cast<ViewProps &>(viewProps).transform =
                      Transform::Scale(isScaleX ? 0 : 1, isScaleY ? 0 : 1, 1);
                }

                react_native_assert(props != nullptr);
                if (props != nullptr) {
                  viewFinal.props = props;
                }
              }

              PrintMutationInstruction(
                  "Setting up animation KeyFrame for REMOVE mutation (Delete animation)",
                  mutation);

              keyFrame = AnimationKeyFrame{
                  /* .finalMutationsForKeyFrame */ {mutation, deleteMutation},
                  /* .type */ AnimationConfigurationType::Delete,
                  /* .tag */ tag,
                  /* .parentView */ parent,
                  /* .viewStart */ viewStart,
                  /* .viewEnd */ viewFinal,
                  /* .viewPrev */ baselineShadowView,
                  /* .initialProgress */ 0};
            } else {
              PrintMutationInstruction(
                  "Executing Remove Immediately, due to reordering operation",
                  mutation);
              immediateMutations.push_back(mutation);
              continue;
            }
          }

          // Handle conflicting animations
          for (auto &conflictingKeyFrame : conflictingAnimations) {
            auto const &conflictingMutationBaselineShadowView =
                conflictingKeyFrame.viewStart;

            // We've found a conflict.
            if (conflictingMutationBaselineShadowView.tag == tag) {
              conflictingKeyFrame.generateFinalSyntheticMutations = false;

              // Do NOT update viewStart for a CREATE animation.
              if (keyFrame.type == AnimationConfigurationType::Create) {
                break;
              }

#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
              LOG(ERROR)
                  << "Due to conflict, replacing 'viewStart' of animated keyframe: ["
                  << conflictingKeyFrame.viewPrev.tag << "] with ##"
                  << std::hash<ShadowView>{}(conflictingKeyFrame.viewPrev);
#endif
              // Pick a Prop or layout property, depending on the current
              // animation configuration. Figure out how much progress we've
              // already made in the current animation, and start the animation
              // from this point.
              keyFrame.viewPrev = conflictingKeyFrame.viewPrev;
              keyFrame.viewStart = conflictingKeyFrame.viewPrev;
              react_native_assert(keyFrame.viewStart.tag > 0);
              keyFrame.initialProgress = 0;

              // We're guaranteed that a tag only has one animation associated
              // with it, so we can break here. If we support multiple
              // animations and animation curves over the same tag in the
              // future, this will need to be modified to support that.
              break;
            }
          }

#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
          LOG(ERROR) << "Checking validity of keyframe: ["
                     << keyFrame.viewStart.tag << "] [" << keyFrame.viewEnd.tag
                     << "] [" << keyFrame.viewPrev.tag
                     << "] animation type: " << (int)keyFrame.type;
#endif
          react_native_assert(keyFrame.viewStart.tag > 0);
          react_native_assert(keyFrame.viewEnd.tag > 0);
          react_native_assert(keyFrame.viewPrev.tag > 0);
          keyFramesToAnimate.push_back(keyFrame);
        }

        if (executeMutationImmediately.has_value()) {
          PrintMutationInstruction(
              "Queue Up For Immediate Execution", *executeMutationImmediately);
          immediateMutations.push_back(*executeMutationImmediately);
        }
      }

#ifdef RN_SHADOW_TREE_INTROSPECTION
#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
      {
        int idx = 0;
        for (auto &mutation : immediateMutations) {
          PrintMutationInstruction(
              std::string("IMMEDIATE list: ") + std::to_string(idx) + "/" +
                  std::to_string(immediateMutations.size()),
              mutation);
          idx++;
        }
      }

      {
        int idx = 0;
        for (const auto &keyframe : keyFramesToAnimate) {
          for (const auto &finalMutationForKeyFrame :
               keyframe.finalMutationsForKeyFrame) {
            PrintMutationInstruction(
                std::string("FINAL list: ") + std::to_string(idx) + "/" +
                    std::to_string(keyFramesToAnimate.size()),
                finalMutationForKeyFrame);
          }
          idx++;
        }
      }
#endif
#endif

      auto finalConflictingMutations = ShadowViewMutationList{};
      for (auto &keyFrame : conflictingAnimations) {
        // Special-case: if the next conflicting animation contain "delete",
        // while the final mutation has the same tag with "create", we should
        // remove both the delete and create as they have no effect when
        // combined in the same frame. The Fabric mount layer assumes no such
        // combinations in the final mutations either.
        if (reduceDeleteCreateMutation_) {
          for (auto itMutation = immediateMutations.begin();
               itMutation != immediateMutations.end();) {
            auto &mutation = *itMutation;
            bool hasCreateMutationDeletedWithSameTag = false;
            if (mutation.newChildShadowView.tag == keyFrame.tag &&
                mutation.type == ShadowViewMutation::Create) {
              for (auto itKeyFrame = keyFrame.finalMutationsForKeyFrame.begin();
                   itKeyFrame != keyFrame.finalMutationsForKeyFrame.end();) {
                auto &conflictFinalMutation = *itKeyFrame;
                if (conflictFinalMutation.type == ShadowViewMutation::Delete) {
                  itKeyFrame =
                      keyFrame.finalMutationsForKeyFrame.erase(itKeyFrame);
                  hasCreateMutationDeletedWithSameTag = true;
                  break;
                } else {
                  itKeyFrame++;
                }
              }
            }

            if (hasCreateMutationDeletedWithSameTag) {
              itMutation = immediateMutations.erase(itMutation);
            } else {
              itMutation++;
            }
          }
        }

        // Special-case: if we have some (1) ongoing UPDATE animation,
        // (2) it conflicted with a new MOVE operation (REMOVE+INSERT)
        // without another corresponding UPDATE, we should re-queue the
        // keyframe so that its position/props don't suddenly "jump".
        if (keyFrame.type == AnimationConfigurationType::Update) {
          auto movedIt = movedTags.find(keyFrame.tag);
          if (movedIt != movedTags.end()) {
            auto newKeyFrameForUpdate = std::find_if(
                keyFramesToAnimate.begin(),
                keyFramesToAnimate.end(),
                [&](auto const &newKeyFrame) {
                  return newKeyFrame.type ==
                      AnimationConfigurationType::Update &&
                      newKeyFrame.tag == keyFrame.tag;
                });
            if (newKeyFrameForUpdate == keyFramesToAnimate.end()) {
              keyFrame.invalidated = false;

              // The animation will continue from the current position - we
              // restart viewStart to make sure there are no sudden jumps
              keyFrame.viewStart = keyFrame.viewPrev;

              // Find the insert mutation that conflicted with this update
              for (auto &mutation : immediateMutations) {
                if (mutation.newChildShadowView.tag == keyFrame.tag &&
                    (mutation.type == ShadowViewMutation::Insert ||
                     mutation.type == ShadowViewMutation::Create)) {
                  keyFrame.viewPrev = mutation.newChildShadowView;
                  keyFrame.viewEnd = mutation.newChildShadowView;
                }
              }
              keyFramesToAnimate.push_back(keyFrame);
              continue;
            }
          }
        }

        // If the "final" mutation is already accounted for, by previously
        // setting the correct "viewPrev" of the next conflicting animation, we
        // don't want to queue up any final UPDATE mutations here.
        bool shouldGenerateSyntheticMutations =
            keyFrame.generateFinalSyntheticMutations;
        auto numFinalMutations = keyFrame.finalMutationsForKeyFrame.size();
        bool onlyMutationIsUpdate =
            (numFinalMutations == 1 &&
             keyFrame.finalMutationsForKeyFrame[0].type ==
                 ShadowViewMutation::Update);
        if (!shouldGenerateSyntheticMutations &&
            (numFinalMutations == 0 || onlyMutationIsUpdate)) {
          continue;
        }

        queueFinalMutationsForCompletedKeyFrame(
            keyFrame,
            finalConflictingMutations,
            true,
            "KeyFrameManager: Finished Conflicting Keyframe");
      }

      // Make sure that all operations execute in the proper order, since
      // conflicting animations are not sorted in any reasonable way.
      std::stable_sort(
          finalConflictingMutations.begin(),
          finalConflictingMutations.end(),
          &shouldFirstComeBeforeSecondMutation);

      std::stable_sort(
          immediateMutations.begin(),
          immediateMutations.end(),
          &shouldFirstComeBeforeSecondRemovesOnly);

      animation.keyFrames = keyFramesToAnimate;
      inflightAnimations_.push_back(std::move(animation));

      // At this point, we have the following information and knowledge graph:
      // Knowledge Graph:
      // [ImmediateMutations] -> assumes [FinalConflicting], [FrameDelayed],
      // [Delayed] already executed [FrameDelayed] -> assumes
      // [FinalConflicting], [Delayed] already executed [FinalConflicting] ->
      // is adjusted based on [Delayed], no dependency on [FinalConflicting],
      // [FrameDelayed] [Delayed] -> assumes [FinalConflicting],
      // [ImmediateMutations] not executed yet

      // Adjust [Delayed] based on [FinalConflicting]
      // Knowledge Graph:
      // [ImmediateMutations] -> assumes [FinalConflicting], [FrameDelayed],
      // [Delayed] already executed [FrameDelayed] -> assumes
      // [FinalConflicting], [Delayed] already executed [FinalConflicting] ->
      // is adjusted based on [Delayed], no dependency on [FinalConflicting],
      // [FrameDelayed] [Delayed] -> adjusted for [FinalConflicting]; assumes
      // [ImmediateMutations] not executed yet
#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
      LOG(ERROR) << "Adjust [Delayed] based on [FinalConflicting]";
#endif
      for (auto &mutation : finalConflictingMutations) {
        if (mutation.type == ShadowViewMutation::Type::Insert ||
            mutation.type == ShadowViewMutation::Type::Remove) {
          adjustDelayedMutationIndicesForMutation(surfaceId, mutation, true);
        }
      }

      // Adjust [FrameDelayed] based on [Delayed]
      // Knowledge Graph:
      // [ImmediateExecutions] -> assumes [FinalConflicting], [Delayed],
      // [FrameDelayed] already executed [FrameDelayed] -> adjusted for
      // [Delayed]; assumes [FinalConflicting] already executed
      // [FinalConflicting] -> is adjusted based on [Delayed], no dependency
      // on [FinalConflicting], [FrameDelayed] [Delayed] -> adjusted for
      // [FinalConflicting]; assumes [ImmediateExecutions] not executed yet
#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
      LOG(ERROR) << "Adjust [FrameDelayed] based on [Delayed]";
#endif
      for (auto &keyframe : inflightAnimations_.back().keyFrames) {
        for (auto &finalMutation : keyframe.finalMutationsForKeyFrame) {
          if (finalMutation.type == ShadowViewMutation::Type::Insert ||
              finalMutation.type == ShadowViewMutation::Type::Remove) {
            // When adjusting, skip adjusting against last animation - because
            // all `mutation`s here come from the last animation, so we can't
            // adjust a batch against itself.
            adjustImmediateMutationIndicesForDelayedMutations(
                surfaceId, finalMutation, true);
          }
        }
      }

      // Adjust [ImmediateExecutions] based on [Delayed]
      // Knowledge Graph:
      // [ImmediateExecutions] -> adjusted for [FrameDelayed], [Delayed];
      // assumes [FinalConflicting] already executed [FrameDelayed] ->
      // adjusted for [Delayed]; assumes [FinalConflicting] already executed
      // [FinalConflicting] -> is adjusted based on [Delayed], no dependency
      // on [FinalConflicting], [FrameDelayed] [Delayed] -> adjusted for
      // [FinalConflicting]; assumes [ImmediateExecutions] not executed yet
      //
      // THEN,
      // Adjust [Delayed] based on [ImmediateExecutions] and
      // [FinalConflicting] Knowledge Graph: [ImmediateExecutions] -> adjusted
      // for [FrameDelayed], [Delayed]; assumes [FinalConflicting] already
      // executed [FrameDelayed] -> adjusted for [Delayed]; assumes
      // [FinalConflicting] already executed [FinalConflicting] -> is adjusted
      // based on [Delayed], no dependency on [FinalConflicting],
      // [FrameDelayed] [Delayed] -> adjusted for [FinalConflicting],
      // [ImmediateExecutions]
      //
      // We do these in the same loop because each immediate execution is
      // impacted by each delayed mutation, and also can impact each delayed
      // mutation, and these effects compound.
#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
      LOG(ERROR)
          << "Adjust each [ImmediateExecution] based on [Delayed] and [Delayed] based on each [ImmediateExecution]";
#endif
      for (auto &mutation : immediateMutations) {
        // Note: when adjusting [ImmediateExecutions] based on [FrameDelayed],
        // we need only adjust Inserts. Since inserts are executed
        // highest-index-first, lower indices being delayed does not impact
        // the higher-index removals; and conversely, higher indices being
        // delayed cannot impact lower index removal, regardless of order.
        if (mutation.type == ShadowViewMutation::Type::Insert ||
            mutation.type == ShadowViewMutation::Type::Remove) {
          adjustImmediateMutationIndicesForDelayedMutations(
              surfaceId,
              mutation,
              mutation.type == ShadowViewMutation::Type::Remove);
          // Here we need to adjust both Delayed and FrameDelayed mutations.
          // Delayed Removes can be impacted by non-delayed Inserts from the
          // same frame.
          adjustDelayedMutationIndicesForMutation(surfaceId, mutation);
        }
      }

      // If the knowledge graph progression above is correct, it is now safe
      // to execute finalConflictingMutations and immediateMutations in that
      // order, and to queue the delayed animations from this frame.
      //
      // Execute the conflicting, delayed operations immediately. Any UPDATE
      // operations that smoothly transition into another animation will be
      // overridden by generated UPDATE operations at the end of the list, and
      // we want any REMOVE or DELETE operations to execute immediately.
      // Additionally, this should allow us to avoid performing index
      // adjustment between this list of conflicting animations and the batch
      // we're about to execute.
      finalConflictingMutations.insert(
          finalConflictingMutations.end(),
          immediateMutations.begin(),
          immediateMutations.end());
      mutations = finalConflictingMutations;
    } /* if (currentAnimation) */
    else {
      // If there's no "next" animation, make sure we queue up "final"
      // operations from all ongoing, conflicting animations.
#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
      LOG(ERROR) << "No Animation: Queue up final conflicting animations";
#endif
      ShadowViewMutationList finalMutationsForConflictingAnimations{};
      for (auto const &keyFrame : conflictingAnimations) {
        queueFinalMutationsForCompletedKeyFrame(
            keyFrame,
            finalMutationsForConflictingAnimations,
            true,
            "Conflict with non-animated mutation");
      }

      // Make sure that all operations execute in the proper order.
      // REMOVE operations with highest indices must operate first.
      std::stable_sort(
          finalMutationsForConflictingAnimations.begin(),
          finalMutationsForConflictingAnimations.end(),
          &shouldFirstComeBeforeSecondMutation);

#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
      LOG(ERROR)
          << "No Animation: Adjust delayed mutations based on all finalMutationsForConflictingAnimations";
#endif
      for (auto const &mutation : finalMutationsForConflictingAnimations) {
        if (mutation.type == ShadowViewMutation::Type::Remove ||
            mutation.type == ShadowViewMutation::Type::Insert) {
          adjustDelayedMutationIndicesForMutation(surfaceId, mutation);
        }
      }

      // The ShadowTree layer doesn't realize that certain operations have
      // been delayed, so we must adjust all Remove and Insert operations
      // based on what else has been deferred, whether we are executing this
      // immediately or later.
#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
      LOG(ERROR)
          << "No Animation: Adjust mutations based on remaining delayed mutations / adjust delayed, based on each";
#endif
      for (auto &mutation : mutations) {
        if (mutation.type == ShadowViewMutation::Type::Remove ||
            mutation.type == ShadowViewMutation::Type::Insert) {
          adjustImmediateMutationIndicesForDelayedMutations(
              surfaceId, mutation);
          adjustDelayedMutationIndicesForMutation(surfaceId, mutation);
        }
      }

      // Append mutations to this list and swap - so that the final
      // conflicting mutations happen before any other mutations
      finalMutationsForConflictingAnimations.insert(
          finalMutationsForConflictingAnimations.end(),
          mutations.begin(),
          mutations.end());
      mutations = finalMutationsForConflictingAnimations;
    }
  } // if (mutations)

  // We never commit a different root or modify anything -
  // we just send additional mutations to the mounting layer until the
  // animations are finished and the mounting layer (view) represents exactly
  // what is in the most recent shadow tree
  // Add animation mutations to the end of our existing mutations list in this
  // function.
  ShadowViewMutationList mutationsForAnimation{};
  animationMutationsForFrame(surfaceId, mutationsForAnimation, now);

  // If any delayed removes were executed, update remaining delayed keyframes
#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
  LOG(ERROR)
      << "Adjust all delayed mutations based on final mutations generated by animation driver";
#endif
  for (auto const &mutation : mutationsForAnimation) {
    if (mutation.type == ShadowViewMutation::Type::Remove) {
      adjustDelayedMutationIndicesForMutation(surfaceId, mutation);
    }
  }

  mutations.insert(
      mutations.end(),
      mutationsForAnimation.begin(),
      mutationsForAnimation.end());

  // DEBUG ONLY: list existing inflight animations
#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
  LOG(ERROR) << "FINISHING DISPLAYING ONGOING inflightAnimations_!";
  int i = 0;
  int j = 0;
  for (auto const &inflightAnimation : inflightAnimations_) {
    i++;
    j = 0;
    if (inflightAnimation.completed) {
      continue;
    }
    for (auto &keyframe : inflightAnimation.keyFrames) {
      j++;
      if (keyframe.invalidated) {
        continue;
      }
      for (auto const &finalMutation : keyframe.finalMutationsForKeyFrame) {
        if (!finalMutation.mutatedViewIsVirtual()) {
          std::string msg = "Animation " + std::to_string(i) + " keyframe " +
              std::to_string(j) + ": Final Animation";
          PrintMutationInstruction(msg, finalMutation);
        }
      }
    }
  }
  LOG(ERROR) << "FINISHING DONE DISPLAYING ONGOING inflightAnimations_!";
#endif

  // Signal to delegate if all animations are complete, or if we were not
  // animating anything and now some animation exists.
  if (inflightAnimationsExistInitially && inflightAnimations_.empty()) {
    std::lock_guard<std::mutex> lock(layoutAnimationStatusDelegateMutex_);
    if (layoutAnimationStatusDelegate_ != nullptr) {
      layoutAnimationStatusDelegate_->onAllAnimationsComplete();
    }
  } else if (
      !inflightAnimationsExistInitially && !inflightAnimations_.empty()) {
    std::lock_guard<std::mutex> lock(layoutAnimationStatusDelegateMutex_);
    if (layoutAnimationStatusDelegate_ != nullptr) {
      layoutAnimationStatusDelegate_->onAnimationStarted();
    }
  }

  return MountingTransaction{
      surfaceId, transactionNumber, std::move(mutations), telemetry};
}

void LayoutAnimationKeyFrameManager::uiManagerDidConfigureNextLayoutAnimation(
    LayoutAnimation layoutAnimation) const {
  currentAnimation_ = std::optional<LayoutAnimation>{layoutAnimation};
}

void LayoutAnimationKeyFrameManager::setLayoutAnimationStatusDelegate(
    LayoutAnimationStatusDelegate *delegate) const {
  std::lock_guard<std::mutex> lock(layoutAnimationStatusDelegateMutex_);
  layoutAnimationStatusDelegate_ = delegate;
}

void LayoutAnimationKeyFrameManager::setClockNow(
    std::function<uint64_t()> now) {
  now_ = std::move(now);
}

#pragma mark - Protected

bool LayoutAnimationKeyFrameManager::hasComponentDescriptorForShadowView(
    ShadowView const &shadowView) const {
  return componentDescriptorRegistry_->hasComponentDescriptorAt(
      shadowView.componentHandle);
}

ComponentDescriptor const &
LayoutAnimationKeyFrameManager::getComponentDescriptorForShadowView(
    ShadowView const &shadowView) const {
  return componentDescriptorRegistry_->at(shadowView.componentHandle);
}

ShadowView LayoutAnimationKeyFrameManager::createInterpolatedShadowView(
    Float progress,
    ShadowView const &startingView,
    ShadowView const &finalView) const {
  react_native_assert(startingView.tag > 0);
  react_native_assert(finalView.tag > 0);
  if (!hasComponentDescriptorForShadowView(startingView)) {
    LOG(ERROR) << "No ComponentDescriptor for ShadowView being animated: ["
               << startingView.tag << "]";
    react_native_assert(false);
    return finalView;
  }

  ComponentDescriptor const &componentDescriptor =
      getComponentDescriptorForShadowView(startingView);

  // Base the mutated view on the finalView, so that the following stay
  // consistent:
  // - state
  // - eventEmitter
  // For now, we do not allow interpolation of state. And we probably never
  // will, so make sure we always keep the mounting layer consistent with the
  // "final" state.
  auto mutatedShadowView = ShadowView(finalView);
  react_native_assert(mutatedShadowView.tag > 0);

  react_native_assert(startingView.props != nullptr);
  react_native_assert(finalView.props != nullptr);
  if (startingView.props == nullptr || finalView.props == nullptr) {
    return finalView;
  }

  // Animate opacity or scale/transform
  PropsParserContext propsParserContext{
      finalView.surfaceId, *contextContainer_};
  mutatedShadowView.props = componentDescriptor.interpolateProps(
      propsParserContext, progress, startingView.props, finalView.props);
  react_native_assert(mutatedShadowView.props != nullptr);
  if (mutatedShadowView.props == nullptr) {
    return finalView;
  }

  // Interpolate LayoutMetrics
  LayoutMetrics const &finalLayoutMetrics = finalView.layoutMetrics;
  LayoutMetrics const &baselineLayoutMetrics = startingView.layoutMetrics;
  LayoutMetrics interpolatedLayoutMetrics = finalLayoutMetrics;
  interpolatedLayoutMetrics.frame.origin.x = interpolateFloats(
      progress,
      baselineLayoutMetrics.frame.origin.x,
      finalLayoutMetrics.frame.origin.x);
  interpolatedLayoutMetrics.frame.origin.y = interpolateFloats(
      progress,
      baselineLayoutMetrics.frame.origin.y,
      finalLayoutMetrics.frame.origin.y);
  interpolatedLayoutMetrics.frame.size.width = interpolateFloats(
      progress,
      baselineLayoutMetrics.frame.size.width,
      finalLayoutMetrics.frame.size.width);
  interpolatedLayoutMetrics.frame.size.height = interpolateFloats(
      progress,
      baselineLayoutMetrics.frame.size.height,
      finalLayoutMetrics.frame.size.height);
  mutatedShadowView.layoutMetrics = interpolatedLayoutMetrics;

  return mutatedShadowView;
}

void LayoutAnimationKeyFrameManager::callCallback(
    LayoutAnimationCallbackWrapper const &callback) const {
  runtimeExecutor_(
      [callback](jsi::Runtime &runtime) { callback.call(runtime); });
}

void LayoutAnimationKeyFrameManager::queueFinalMutationsForCompletedKeyFrame(
    AnimationKeyFrame const &keyframe,
    ShadowViewMutation::List &mutationsList,
    bool interrupted,
    const std::string & /*logPrefix*/) const {
  if (!keyframe.finalMutationsForKeyFrame.empty()) {
    // TODO: modularize this segment, it is repeated 2x in KeyFrameManager
    // as well.
    ShadowView prev = keyframe.viewPrev;
    for (auto const &finalMutation : keyframe.finalMutationsForKeyFrame) {
      PrintMutationInstruction(
          logPrefix + ": Queuing up Final Mutation:", finalMutation);
      // Copy so that if something else mutates the inflight animations,
      // it won't change this mutation after this point.
      switch (finalMutation.type) {
          // For CREATE/INSERT this will contain CREATE, INSERT in that order.
          // For REMOVE/DELETE, same.
        case ShadowViewMutation::Type::Create:
          mutationsList.push_back(ShadowViewMutation::CreateMutation(
              finalMutation.newChildShadowView));
          break;
        case ShadowViewMutation::Type::Delete:
          mutationsList.push_back(ShadowViewMutation::DeleteMutation(prev));
          break;
        case ShadowViewMutation::Type::Insert:
          mutationsList.push_back(ShadowViewMutation::InsertMutation(
              finalMutation.parentShadowView,
              finalMutation.newChildShadowView,
              finalMutation.index));
          break;
        case ShadowViewMutation::Type::Remove:
          mutationsList.push_back(ShadowViewMutation::RemoveMutation(
              finalMutation.parentShadowView, prev, finalMutation.index));
          break;
        case ShadowViewMutation::Type::RemoveDeleteTree:
          // Note: Currently, there is a guarantee that if RemoveDeleteTree
          // operations are generated, we /also/ generate corresponding
          // Remove/Delete operations that are marked as "redundant".
          // LayoutAnimations will process the redundant operations here, and
          // ignore this mega-op. In the future for perf reasons it would be
          // nice to remove the redundant operations entirely but we would need
          // to find a way to make the RemoveDeleteTree operation work with
          // LayoutAnimations (that might not be possible).
          break;
        case ShadowViewMutation::Type::Update:
          mutationsList.push_back(ShadowViewMutation::UpdateMutation(
              prev,
              finalMutation.newChildShadowView,
              finalMutation.parentShadowView));
          break;
      }
      if (finalMutation.newChildShadowView.tag > 0) {
        prev = finalMutation.newChildShadowView;
      }
    }
  } else {
    // If there's no final mutation associated, create a mutation that
    // corresponds to the animation being 100% complete. This is
    // important for, for example, INSERT mutations being animated from
    // opacity 0 to 1. If the animation is interrupted we must force the
    // View to be at opacity 1. For Android - since it passes along only
    // deltas, not an entire bag of props - generate an "animation"
    // frame corresponding to a final update for this view. Only then,
    // generate an update that will cause the ShadowTree to be
    // consistent with the Mounting layer by passing viewEnd,
    // unmodified, to the mounting layer. This helps with, for example,
    // opacity animations.
    // This is necessary for INSERT (create) and UPDATE (update) mutations, but
    // not REMOVE/DELETE mutations ("delete" animations).
    if (interrupted) {
      auto mutatedShadowView =
          createInterpolatedShadowView(1, keyframe.viewStart, keyframe.viewEnd);
      auto generatedPenultimateMutation = ShadowViewMutation::UpdateMutation(
          keyframe.viewPrev, mutatedShadowView, keyframe.parentView);
      react_native_assert(
          generatedPenultimateMutation.oldChildShadowView.tag > 0);
      react_native_assert(
          generatedPenultimateMutation.newChildShadowView.tag > 0);
      PrintMutationInstruction(
          "Queueing up penultimate mutation instruction - synthetic",
          generatedPenultimateMutation);
      mutationsList.push_back(generatedPenultimateMutation);

      auto generatedMutation = ShadowViewMutation::UpdateMutation(
          mutatedShadowView, keyframe.viewEnd, keyframe.parentView);
      react_native_assert(generatedMutation.oldChildShadowView.tag > 0);
      react_native_assert(generatedMutation.newChildShadowView.tag > 0);
      PrintMutationInstruction(
          "Queueing up final mutation instruction - synthetic",
          generatedMutation);
      mutationsList.push_back(generatedMutation);
    } else {
      auto mutation = ShadowViewMutation::UpdateMutation(
          keyframe.viewPrev, keyframe.viewEnd, keyframe.parentView);
      PrintMutationInstruction(
          logPrefix +
              "Animation Complete: Queuing up Final Synthetic Mutation:",
          mutation);
      react_native_assert(mutation.oldChildShadowView.tag > 0);
      react_native_assert(mutation.newChildShadowView.tag > 0);
      mutationsList.push_back(std::move(mutation));
    }
  }
}

#pragma mark - Private

void LayoutAnimationKeyFrameManager::
    adjustImmediateMutationIndicesForDelayedMutations(
        SurfaceId surfaceId,
        ShadowViewMutation &mutation,
        bool skipLastAnimation,
        bool lastAnimationOnly) const {
  bool isRemoveMutation = mutation.type == ShadowViewMutation::Type::Remove;
  react_native_assert(
      isRemoveMutation || mutation.type == ShadowViewMutation::Type::Insert);

  // TODO: turn all of this into a lambda and share code?
  if (mutation.mutatedViewIsVirtual()) {
    PrintMutationInstruction(
        "[IndexAdjustment] Not calling adjustImmediateMutationIndicesForDelayedMutations, is virtual, for:",
        mutation);
    return;
  }

  PrintMutationInstruction(
      "[IndexAdjustment] Calling adjustImmediateMutationIndicesForDelayedMutations for:",
      mutation);

  // First, collect all final mutations that could impact this immediate
  // mutation.
  std::vector<ShadowViewMutation const *> candidateMutations{};

  for (auto inflightAnimationIt =
           inflightAnimations_.rbegin() + (skipLastAnimation ? 1 : 0);
       inflightAnimationIt != inflightAnimations_.rend();
       inflightAnimationIt++) {
    auto &inflightAnimation = *inflightAnimationIt;
    if (inflightAnimation.surfaceId != surfaceId) {
      continue;
    }
    if (inflightAnimation.completed) {
      continue;
    }

    for (auto const &animatedKeyFrame : inflightAnimation.keyFrames) {
      if (animatedKeyFrame.invalidated) {
        continue;
      }

      // Detect if they're in the same view hierarchy, but not equivalent
      // We've already detected direct conflicts and removed them.
      if (animatedKeyFrame.parentView.tag != mutation.parentShadowView.tag) {
        continue;
      }

      for (auto const &delayedMutation :
           animatedKeyFrame.finalMutationsForKeyFrame) {
        if (delayedMutation.type != ShadowViewMutation::Type::Remove) {
          continue;
        }
        if (delayedMutation.mutatedViewIsVirtual()) {
          continue;
        }
        if (delayedMutation.oldChildShadowView.tag ==
            (isRemoveMutation ? mutation.oldChildShadowView.tag
                              : mutation.newChildShadowView.tag)) {
          continue;
        }

        PrintMutationInstructionRelative(
            "[IndexAdjustment] adjustImmediateMutationIndicesForDelayedMutations CANDIDATE for:",
            mutation,
            delayedMutation);
        candidateMutations.push_back(&delayedMutation);
      }
    }

    if (lastAnimationOnly) {
      break;
    }
  }

  // While the mutation keeps being affected, keep checking. We use the vector
  // so we only perform one adjustment per delayed mutation. See comments at
  // bottom of adjustDelayedMutationIndicesForMutation for further explanation.
  bool changed = true;
  int adjustedDelta = 0;
  while (changed) {
    changed = false;
    candidateMutations.erase(
        std::remove_if(
            candidateMutations.begin(),
            candidateMutations.end(),
            [&changed, &mutation, &adjustedDelta, &isRemoveMutation](
                ShadowViewMutation const *candidateMutation) {
              bool indexConflicts =
                  (candidateMutation->index < mutation.index ||
                   (isRemoveMutation &&
                    candidateMutation->index == mutation.index));
              if (indexConflicts) {
                mutation.index++;
                adjustedDelta++;
                changed = true;
                PrintMutationInstructionRelative(
                    "[IndexAdjustment] adjustImmediateMutationIndicesForDelayedMutations: Adjusting mutation UPWARD",
                    mutation,
                    *candidateMutation);
                return true;
              }
              return false;
            }),
        candidateMutations.end());
  }
}

void LayoutAnimationKeyFrameManager::adjustDelayedMutationIndicesForMutation(
    SurfaceId surfaceId,
    ShadowViewMutation const &mutation,
    bool skipLastAnimation) const {
  bool isRemoveMutation = mutation.type == ShadowViewMutation::Type::Remove;
  bool isInsertMutation = mutation.type == ShadowViewMutation::Type::Insert;
  auto tag = isRemoveMutation ? mutation.oldChildShadowView.tag
                              : mutation.newChildShadowView.tag;
  react_native_assert(isRemoveMutation || isInsertMutation);

  if (mutation.mutatedViewIsVirtual()) {
    PrintMutationInstruction(
        "[IndexAdjustment] Not calling adjustDelayedMutationIndicesForMutation, is virtual, for:",
        mutation);
    return;
  }

  // First, collect all final mutations that could impact this immediate
  // mutation.
  std::vector<ShadowViewMutation *> candidateMutations{};

  for (auto inflightAnimationIt =
           inflightAnimations_.rbegin() + (skipLastAnimation ? 1 : 0);
       inflightAnimationIt != inflightAnimations_.rend();
       inflightAnimationIt++) {
    auto &inflightAnimation = *inflightAnimationIt;

    if (inflightAnimation.surfaceId != surfaceId) {
      continue;
    }
    if (inflightAnimation.completed) {
      continue;
    }

    for (auto &animatedKeyFrame : inflightAnimation.keyFrames) {
      if (animatedKeyFrame.invalidated) {
        continue;
      }

      // Detect if they're in the same view hierarchy, but not equivalent
      // (We've already detected direct conflicts and handled them above)
      if (animatedKeyFrame.parentView.tag != mutation.parentShadowView.tag) {
        continue;
      }

      for (auto &finalAnimationMutation :
           animatedKeyFrame.finalMutationsForKeyFrame) {
        if (finalAnimationMutation.oldChildShadowView.tag == tag) {
          continue;
        }

        if (finalAnimationMutation.type != ShadowViewMutation::Type::Remove) {
          continue;
        }
        if (finalAnimationMutation.mutatedViewIsVirtual()) {
          continue;
        }

        PrintMutationInstructionRelative(
            "[IndexAdjustment] adjustDelayedMutationIndicesForMutation: CANDIDATE:",
            mutation,
            finalAnimationMutation);
        candidateMutations.push_back(&finalAnimationMutation);
      }
    }
  }

  // Because the finalAnimations are not sorted in any way, it is possible to
  // have some sequence like:
  // * DELAYED REMOVE 10 from {TAG}
  // * DELAYED REMOVE 9 from {TAG}
  // * ...
  // * DELAYED REMOVE 5 from {TAG}
  // with mutation: INSERT 6/REMOVE 6. This would cause the first few mutations
  // to *not* be adjusted, even though they would be impacted by mutation or
  // vice-versa after later adjustments are applied. Therefore, we just keep
  // recursing while there are any changes. This isn't great, but is good enough
  // for now until we change these data-structures.
  bool changed = true;
  while (changed) {
    changed = false;
    candidateMutations.erase(
        std::remove_if(
            candidateMutations.begin(),
            candidateMutations.end(),
            [&mutation, &isRemoveMutation, &isInsertMutation, &changed](
                ShadowViewMutation *candidateMutation) {
              if (isRemoveMutation &&
                  mutation.index <= candidateMutation->index) {
                candidateMutation->index--;
                changed = true;
                PrintMutationInstructionRelative(
                    "[IndexAdjustment] adjustDelayedMutationIndicesForMutation: Adjusting mutation DOWNWARD",
                    mutation,
                    *candidateMutation);
                return true;
              } else if (
                  isInsertMutation &&
                  mutation.index <= candidateMutation->index) {
                candidateMutation->index++;
                changed = true;
                PrintMutationInstructionRelative(
                    "[IndexAdjustment] adjustDelayedMutationIndicesForMutation: Adjusting mutation UPWARD",
                    mutation,
                    *candidateMutation);
                return true;
              }
              return false;
            }),
        candidateMutations.end());
  }
}

void LayoutAnimationKeyFrameManager::getAndEraseConflictingAnimations(
    SurfaceId surfaceId,
    ShadowViewMutationList const &mutations,
    std::vector<AnimationKeyFrame> &conflictingAnimations) const {
  ShadowViewMutationList localConflictingMutations{};
  for (auto const &mutation : mutations) {
    if (mutation.type == ShadowViewMutation::Type::RemoveDeleteTree) {
      continue;
    }

    bool mutationIsCreateOrDelete =
        mutation.type == ShadowViewMutation::Type::Create ||
        mutation.type == ShadowViewMutation::Type::Delete;
    auto const &baselineShadowView =
        (mutation.type == ShadowViewMutation::Type::Insert ||
         mutation.type == ShadowViewMutation::Type::Create)
        ? mutation.newChildShadowView
        : mutation.oldChildShadowView;
    auto baselineTag = baselineShadowView.tag;

    for (auto &inflightAnimation : inflightAnimations_) {
      if (inflightAnimation.surfaceId != surfaceId) {
        continue;
      }
      if (inflightAnimation.completed) {
        continue;
      }

      for (auto it = inflightAnimation.keyFrames.begin();
           it != inflightAnimation.keyFrames.end();) {
        auto &animatedKeyFrame = *it;

        if (animatedKeyFrame.invalidated) {
          continue;
        }

        // A conflict is when either: the animated node itself is mutated
        // directly; or, the parent of the node is created or deleted. In cases
        // of reparenting - say, the parent is deleted but the node was moved to
        // a different parent first - the reparenting (remove/insert) conflict
        // will be detected before we process the parent DELETE.
        // Parent deletion is important because deleting a parent recursively
        // deletes all children. If we previously deferred deletion of a child,
        // we need to force deletion/removal to happen immediately.
        bool conflicting = animatedKeyFrame.tag == baselineTag ||
            (mutationIsCreateOrDelete &&
             animatedKeyFrame.parentView.tag == baselineTag &&
             animatedKeyFrame.parentView.tag != 0);

        // Conflicting animation detected: if we're mutating a tag under
        // animation, or deleting the parent of a tag under animation, or
        // reparenting.
        if (conflicting) {
          animatedKeyFrame.invalidated = true;

          // We construct a list of all conflicting animations, whether or not
          // they have a "final mutation" to execute. This is important with,
          // for example, "insert" mutations where the final update needs to set
          // opacity to "1", even if there's no final ShadowNode update.
          // TODO: don't animate virtual views in the first place?
          bool isVirtual = false;
          for (const auto &finalMutationForKeyFrame :
               animatedKeyFrame.finalMutationsForKeyFrame) {
            isVirtual =
                isVirtual || finalMutationForKeyFrame.mutatedViewIsVirtual();

#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
            PrintMutationInstructionRelative(
                "Found mutation that conflicts with existing in-flight animation:",
                mutation,
                finalMutationForKeyFrame);
#endif
          }

          conflictingAnimations.push_back(animatedKeyFrame);
          for (const auto &finalMutationForKeyFrame :
               animatedKeyFrame.finalMutationsForKeyFrame) {
            if (!isVirtual ||
                finalMutationForKeyFrame.type ==
                    ShadowViewMutation::Type::Delete) {
              localConflictingMutations.push_back(finalMutationForKeyFrame);
            }
          }

          // Delete from existing animation
          it = inflightAnimation.keyFrames.erase(it);
        } else {
          it++;
        }
      }
    }
  }

  // Recurse, in case conflicting mutations conflict with other existing
  // animations
  if (!localConflictingMutations.empty()) {
    getAndEraseConflictingAnimations(
        surfaceId, localConflictingMutations, conflictingAnimations);
  }
}

void LayoutAnimationKeyFrameManager::deleteAnimationsForStoppedSurfaces()
    const {
  bool inflightAnimationsExistInitially = !inflightAnimations_.empty();

  // Execute stopSurface on any ongoing animations
  if (inflightAnimationsExistInitially) {
    butter::set<SurfaceId> surfaceIdsToStop{};
    {
      std::lock_guard<std::mutex> lock(surfaceIdsToStopMutex_);
      surfaceIdsToStop = surfaceIdsToStop_;
      surfaceIdsToStop_.clear();
    }

#ifdef LAYOUT_ANIMATION_VERBOSE_LOGGING
    std::ostringstream surfaceIdsStr;
    std::copy(
        surfaceIdsToStop.begin(),
        surfaceIdsToStop.end(),
        std::ostream_iterator<SurfaceId>(surfaceIdsStr, ", "));
    LOG(ERROR) << "LayoutAnimations: stopping animations due to stopSurface on "
               << surfaceIdsStr.str();
#endif

    for (auto it = inflightAnimations_.begin();
         it != inflightAnimations_.end();) {
      const auto &animation = *it;
      if (surfaceIdsToStop.find(animation.surfaceId) !=
          surfaceIdsToStop.end()) {
        it = inflightAnimations_.erase(it);
      } else {
        it++;
      }
    }
  }
}

} // namespace facebook::react