#include <mbgl/text/placement.hpp>

#include <mbgl/layout/symbol_layout.hpp>
#include <mbgl/renderer/render_layer.hpp>
#include <mbgl/renderer/layers/render_layer_symbol_interface.hpp>
#include <mbgl/renderer/render_tile.hpp>
#include <mbgl/tile/geometry_tile.hpp>
#include <mbgl/renderer/buckets/symbol_bucket.hpp>
#include <mbgl/renderer/bucket.hpp>
#include <mbgl/util/math.hpp>
#include <utility>

namespace mbgl {

OpacityState::OpacityState(bool placed_, bool skipFade)
    : opacity((skipFade && placed_) ? 1 : 0)
    , placed(placed_)
{
}

OpacityState::OpacityState(const OpacityState& prevState, float increment, bool placed_) :
    opacity(::fmax(0, ::fmin(1, prevState.opacity + (prevState.placed ? increment : -increment)))),
    placed(placed_) {}

bool OpacityState::isHidden() const {
    return opacity == 0 && !placed;
}

JointOpacityState::JointOpacityState(bool placedText, bool placedIcon, bool skipFade) :
    icon(OpacityState(placedIcon, skipFade)),
    text(OpacityState(placedText, skipFade)) {}

JointOpacityState::JointOpacityState(const JointOpacityState& prevOpacityState, float increment, bool placedText, bool placedIcon) :
    icon(OpacityState(prevOpacityState.icon, increment, placedIcon)),
    text(OpacityState(prevOpacityState.text, increment, placedText)) {}

bool JointOpacityState::isHidden() const {
    return icon.isHidden() && text.isHidden();
}
    
const CollisionGroups::CollisionGroup& CollisionGroups::get(const std::string& sourceID) {
    // The predicate/groupID mechanism allows for arbitrary grouping,
    // but the current interface defines one source == one group when
    // crossSourceCollisions == true.
    if (!crossSourceCollisions) {
        if (collisionGroups.find(sourceID) == collisionGroups.end()) {
            uint16_t nextGroupID = ++maxGroupID;
            collisionGroups.emplace(sourceID, CollisionGroup(
                nextGroupID,
                optional<Predicate>([nextGroupID](const IndexedSubfeature& feature) -> bool {
                    return feature.collisionGroupId == nextGroupID;
                })
            ));
        }
        return collisionGroups[sourceID];
    } else {
        static CollisionGroup nullGroup{0, nullopt};
        return nullGroup;
    }
}

Placement::Placement(const TransformState& state_, MapMode mapMode_, style::TransitionOptions transitionOptions_, const bool crossSourceCollisions, std::unique_ptr<Placement> prevPlacement_)
    : collisionIndex(state_)
    , state(state_)
    , mapMode(mapMode_)
    , transitionOptions(std::move(transitionOptions_))
    , collisionGroups(crossSourceCollisions)
    , prevPlacement(std::move(prevPlacement_))
{
    if (prevPlacement) {
        prevPlacement->prevPlacement.reset(); // Only hold on to one placement back
    }
}

void Placement::placeLayer(const RenderLayerSymbolInterface& symbolInterface, const mat4& projMatrix, bool showCollisionBoxes) {

    std::unordered_set<uint32_t> seenCrossTileIDs;

    for (const RenderTile& renderTile : symbolInterface.getRenderTiles()) {
        if (!renderTile.tile.isRenderable()) {
            continue;
        }
        assert(renderTile.tile.kind == Tile::Kind::Geometry);
        auto& geometryTile = static_cast<GeometryTile&>(renderTile.tile);

        auto bucket = symbolInterface.getSymbolBucket(renderTile);
        if (!bucket) {
            continue;
        }
        SymbolBucket& symbolBucket = *bucket;

        if (symbolBucket.bucketLeaderID != symbolInterface.layerID()) {
            // Only place this layer if it's the "group leader" for the bucket
            continue;
        }

        auto& layout = symbolBucket.layout;

        const float pixelsToTileUnits = renderTile.id.pixelsToTileUnits(1, state.getZoom());

        const float scale = std::pow(2, state.getZoom() - geometryTile.id.overscaledZ);
        const float textPixelRatio = (util::tileSize * geometryTile.id.overscaleFactor()) / util::EXTENT;

        mat4 posMatrix;
        state.matrixFor(posMatrix, renderTile.id);
        matrix::multiply(posMatrix, projMatrix, posMatrix);

        mat4 textLabelPlaneMatrix = getLabelPlaneMatrix(posMatrix,
                layout.get<style::TextPitchAlignment>() == style::AlignmentType::Map,
                layout.get<style::TextRotationAlignment>() == style::AlignmentType::Map,
                state,
                pixelsToTileUnits);

        mat4 iconLabelPlaneMatrix = getLabelPlaneMatrix(posMatrix,
                layout.get<style::IconPitchAlignment>() == style::AlignmentType::Map,
                layout.get<style::IconRotationAlignment>() == style::AlignmentType::Map,
                state,
                pixelsToTileUnits);
        
        
        // As long as this placement lives, we have to hold onto this bucket's
        // matching FeatureIndex/data for querying purposes
        retainedQueryData.emplace(std::piecewise_construct,
                                  std::forward_as_tuple(symbolBucket.bucketInstanceId),
                                  std::forward_as_tuple(symbolBucket.bucketInstanceId, geometryTile.getFeatureIndex(), geometryTile.id));
        
        const auto collisionGroup = collisionGroups.get(geometryTile.sourceID);
        
        placeLayerBucket(symbolBucket, posMatrix, textLabelPlaneMatrix, iconLabelPlaneMatrix, scale, textPixelRatio, showCollisionBoxes, seenCrossTileIDs, renderTile.tile.holdForFade(), collisionGroup);
    }
}

namespace {
Point<float> calculateVariableLayoutOffset(style::SymbolAnchorType anchor, float width, float height, float radialOffset, float textBoxScale) {
    AnchorAlignment alignment = AnchorAlignment::getAnchorAlignment(anchor);
    float shiftX = -(alignment.horizontalAlign - 0.5f) * width;
    float shiftY = -(alignment.verticalAlign - 0.5f) * height;
    Point<float> offset = SymbolLayout::evaluateRadialOffset(anchor, radialOffset);
    return Point<float>(
        shiftX + offset.x * textBoxScale,
        shiftY + offset.y * textBoxScale
    );
}
} // namespace

void Placement::placeLayerBucket(
        SymbolBucket& bucket,
        const mat4& posMatrix,
        const mat4& textLabelPlaneMatrix,
        const mat4& iconLabelPlaneMatrix,
        const float scale,
        const float textPixelRatio,
        const bool showCollisionBoxes,
        std::unordered_set<uint32_t>& seenCrossTileIDs,
        const bool holdingForFade,
        const CollisionGroups::CollisionGroup& collisionGroup) {

    auto partiallyEvaluatedTextSize = bucket.textSizeBinder->evaluateForZoom(state.getZoom());
    auto partiallyEvaluatedIconSize = bucket.iconSizeBinder->evaluateForZoom(state.getZoom());

    optional<CollisionTileBoundaries> avoidEdges;
    if (mapMode == MapMode::Tile &&
        (bucket.layout.get<style::SymbolAvoidEdges>() ||
         bucket.layout.get<style::SymbolPlacement>() == style::SymbolPlacementType::Line)) {
        avoidEdges = collisionIndex.projectTileBoundaries(posMatrix);
    }
    
    const bool textAllowOverlap = bucket.layout.get<style::TextAllowOverlap>();
    const bool iconAllowOverlap = bucket.layout.get<style::IconAllowOverlap>();
    // This logic is similar to the "defaultOpacityState" logic below in updateBucketOpacities
    // If we know a symbol is always supposed to show, force it to be marked visible even if
    // it wasn't placed into the collision index (because some or all of it was outside the range
    // of the collision grid).
    // There is a subtle edge case here we're accepting:
    //  Symbol A has text-allow-overlap: true, icon-allow-overlap: true, icon-optional: false
    //  A's icon is outside the grid, so doesn't get placed
    //  A's text would be inside grid, but doesn't get placed because of icon-optional: false
    //  We still show A because of the allow-overlap settings.
    //  Symbol B has allow-overlap: false, and gets placed where A's text would be
    //  On panning in, there is a short period when Symbol B and Symbol A will overlap
    //  This is the reverse of our normal policy of "fade in on pan", but should look like any other
    //  collision and hopefully not be too noticeable.
    // See https://github.com/mapbox/mapbox-gl-native/issues/12683
    const bool alwaysShowText = textAllowOverlap && (iconAllowOverlap || !bucket.hasIconData() || bucket.layout.get<style::IconOptional>());
    const bool alwaysShowIcon = iconAllowOverlap && (textAllowOverlap || !bucket.hasTextData() || bucket.layout.get<style::TextOptional>());
    std::vector<style::TextVariableAnchorType> variableTextAnchors = bucket.layout.get<style::TextVariableAnchor>();
    const bool rotateWithMap = bucket.layout.get<style::TextRotationAlignment>() == style::AlignmentType::Map;
    const bool pitchWithMap = bucket.layout.get<style::TextPitchAlignment>() == style::AlignmentType::Map;
    
    for (SymbolInstance& symbolInstance : bucket.symbolInstances) {

        if (seenCrossTileIDs.count(symbolInstance.crossTileID) == 0) {
            if (holdingForFade) {
                // Mark all symbols from this tile as "not placed", but don't add to seenCrossTileIDs, because we don't
                // know yet if we have a duplicate in a parent tile that _should_ be placed.
                placements.emplace(symbolInstance.crossTileID, JointPlacement(false, false, false));
                continue;
            }

            bool placeText = false;
            bool placeIcon = false;
            bool offscreen = true;
            optional<size_t> horizontalTextIndex = symbolInstance.getDefaultHorizontalPlacedTextIndex();
            if (horizontalTextIndex) {
                CollisionFeature& textCollisionFeature = symbolInstance.textCollisionFeature;
                PlacedSymbol& placedSymbol = bucket.text.placedSymbols.at(*horizontalTextIndex);
                const float fontSize = evaluateSizeForFeature(partiallyEvaluatedTextSize, placedSymbol);
                if (variableTextAnchors.empty()) {
                    auto placed = collisionIndex.placeFeature(textCollisionFeature, {},
                            posMatrix, textLabelPlaneMatrix, textPixelRatio,
                            placedSymbol, scale, fontSize,
                            bucket.layout.get<style::TextAllowOverlap>(),
                            pitchWithMap,
                            showCollisionBoxes, avoidEdges, collisionGroup.second);
                    placeText = placed.first;
                    offscreen &= placed.second;
                } else if (!textCollisionFeature.alongLine && !textCollisionFeature.boxes.empty()) {
                    const CollisionBox& textBox = symbolInstance.textCollisionFeature.boxes[0];
                    const float width = textBox.x2 - textBox.x1;
                    const float height = textBox.y2 - textBox.y1;
                    const float textBoxScale = symbolInstance.textBoxScale;

                    // If this symbol was in the last placement, shift the previously used
                    // anchor to the front of the anchor list.
                    if (prevPlacement) {
                        auto prevOffset = prevPlacement->variableOffsets.find(symbolInstance.crossTileID);
                        if (prevOffset != prevPlacement->variableOffsets.end() &&
                            variableTextAnchors.front() != prevOffset->second.anchor) {
                            std::vector<style::TextVariableAnchorType> filtered;
                            filtered.reserve(variableTextAnchors.size());
                            filtered.push_back(prevOffset->second.anchor);
                            for (auto anchor : variableTextAnchors) {
                                if (anchor != prevOffset->second.anchor) {
                                    filtered.push_back(anchor);
                                }
                            }
                            variableTextAnchors = std::move(filtered);
                        }
                    }

                    for (auto anchor : variableTextAnchors) {
                        Point<float> shift = calculateVariableLayoutOffset(anchor, width, height, symbolInstance.radialTextOffset, textBoxScale);
                        if (rotateWithMap) {            
                            float angle = pitchWithMap ? state.getBearing() : -state.getBearing();
                            shift = util::rotate(shift, angle);
                        }

                        auto placed = collisionIndex.placeFeature(textCollisionFeature, shift,
                                                                  posMatrix, mat4(), textPixelRatio,
                                                                  placedSymbol, scale, fontSize,
                                                                  bucket.layout.get<style::TextAllowOverlap>(),
                                                                  pitchWithMap,
                                                                  showCollisionBoxes, avoidEdges, collisionGroup.second);

                        if (placed.first) {
                            assert(symbolInstance.crossTileID != 0u);
                            optional<style::TextVariableAnchorType> prevAnchor;

                            // If this label was placed in the previous placement, record the anchor position
                            // to allow us to animate the transition
                            if (prevPlacement) {
                                auto prevOffset = prevPlacement->variableOffsets.find(symbolInstance.crossTileID);
                                auto prevPlacements = prevPlacement->placements.find(symbolInstance.crossTileID);
                                if (prevOffset != prevPlacement->variableOffsets.end() &&
                                    prevPlacements != prevPlacement->placements.end() &&
                                    prevPlacements->second.text) {
                                    prevAnchor = prevOffset->second.anchor;
                                }
                            }

                            variableOffsets.insert(std::make_pair(symbolInstance.crossTileID, VariableOffset{
                                symbolInstance.radialTextOffset,
                                width,
                                height,
                                anchor,
                                textBoxScale,
                                prevAnchor
                            }));
                            markUsedJustification(bucket, anchor, symbolInstance);

                            placeText = placed.first;
                            offscreen &= placed.second;
                            break;
                        }
                    }

                    // If we didn't get placed, we still need to copy our position from the last placement for
                    // fade animations
                    if (prevPlacement && variableOffsets.find(symbolInstance.crossTileID) == variableOffsets.end()) {
                        auto prevOffset = prevPlacement->variableOffsets.find(symbolInstance.crossTileID);
                        if (prevOffset != prevPlacement->variableOffsets.end()) {
                            variableOffsets[symbolInstance.crossTileID] = prevOffset->second;
                            markUsedJustification(bucket, prevOffset->second.anchor, symbolInstance);
                        }
                    }
                }
            }

            if (symbolInstance.placedIconIndex) {
                PlacedSymbol& placedSymbol = bucket.icon.placedSymbols.at(*symbolInstance.placedIconIndex);
                const float fontSize = evaluateSizeForFeature(partiallyEvaluatedIconSize, placedSymbol);

                auto placed = collisionIndex.placeFeature(symbolInstance.iconCollisionFeature, {},
                        posMatrix, iconLabelPlaneMatrix, textPixelRatio,
                        placedSymbol, scale, fontSize,
                        bucket.layout.get<style::IconAllowOverlap>(),
                        pitchWithMap,
                        showCollisionBoxes, avoidEdges, collisionGroup.second);
                placeIcon = placed.first;
                offscreen &= placed.second;
            }

            const bool iconWithoutText = !symbolInstance.hasText || bucket.layout.get<style::TextOptional>();
            const bool textWithoutIcon = !symbolInstance.hasIcon || bucket.layout.get<style::IconOptional>();

            // combine placements for icon and text
            if (!iconWithoutText && !textWithoutIcon) {
                placeText = placeIcon = placeText && placeIcon;
            } else if (!textWithoutIcon) {
                placeText = placeText && placeIcon;
            } else if (!iconWithoutText) {
                placeIcon = placeText && placeIcon;
            }

            if (placeText) {
                collisionIndex.insertFeature(symbolInstance.textCollisionFeature, bucket.layout.get<style::TextIgnorePlacement>(), bucket.bucketInstanceId, collisionGroup.first);
            }

            if (placeIcon) {
                collisionIndex.insertFeature(symbolInstance.iconCollisionFeature, bucket.layout.get<style::IconIgnorePlacement>(), bucket.bucketInstanceId, collisionGroup.first);
            }

            assert(symbolInstance.crossTileID != 0);

            if (placements.find(symbolInstance.crossTileID) != placements.end()) {
                // If there's a previous placement with this ID, it comes from a tile that's fading out
                // Erase it so that the placement result from the non-fading tile supersedes it
                placements.erase(symbolInstance.crossTileID);
            }
            
            placements.emplace(symbolInstance.crossTileID, JointPlacement(placeText || alwaysShowText, placeIcon || alwaysShowIcon, offscreen || bucket.justReloaded));
            seenCrossTileIDs.insert(symbolInstance.crossTileID);
        }
    } 

    bucket.justReloaded = false;
}

void Placement::commit(TimePoint now) {
    assert(prevPlacement);
    commitTime = now;

    bool placementChanged = false;

    float increment = mapMode == MapMode::Continuous &&
                      transitionOptions.enablePlacementTransitions &&
                      transitionOptions.duration.value_or(util::DEFAULT_TRANSITION_DURATION) > Milliseconds(0) ?
        std::chrono::duration<float>(commitTime - prevPlacement->commitTime) / transitionOptions.duration.value_or(util::DEFAULT_TRANSITION_DURATION) :
        1.0;

    // add the opacities from the current placement, and copy their current values from the previous placement
    for (auto& jointPlacement : placements) {
        auto prevOpacity = prevPlacement->opacities.find(jointPlacement.first);
        if (prevOpacity != prevPlacement->opacities.end()) {
            opacities.emplace(jointPlacement.first, JointOpacityState(prevOpacity->second, increment, jointPlacement.second.text, jointPlacement.second.icon));
            placementChanged = placementChanged ||
                jointPlacement.second.icon != prevOpacity->second.icon.placed ||
                jointPlacement.second.text != prevOpacity->second.text.placed;
        } else {
            opacities.emplace(jointPlacement.first, JointOpacityState(jointPlacement.second.text, jointPlacement.second.icon, jointPlacement.second.skipFade));
            placementChanged = placementChanged || jointPlacement.second.icon || jointPlacement.second.text;
        }
    }

    // copy and update values from the previous placement that aren't in the current placement but haven't finished fading
    for (auto& prevOpacity : prevPlacement->opacities) {
        if (opacities.find(prevOpacity.first) == opacities.end()) {
            JointOpacityState jointOpacity(prevOpacity.second, increment, false, false);
            if (!jointOpacity.isHidden()) {
                opacities.emplace(prevOpacity.first, jointOpacity);
                placementChanged = placementChanged || prevOpacity.second.icon.placed || prevOpacity.second.text.placed;
            }
        }
    }

    for (auto& prevOffset : prevPlacement->variableOffsets) {
        const uint32_t crossTileID = prevOffset.first;
        auto foundOffset = variableOffsets.find(crossTileID);
        auto foundOpacity = opacities.find(crossTileID);
        if (foundOffset == variableOffsets.end() && foundOpacity != opacities.end() && !foundOpacity->second.isHidden()) {
            variableOffsets[prevOffset.first] = prevOffset.second;
        }
    }

    fadeStartTime = placementChanged ? commitTime : prevPlacement->fadeStartTime;
}

void Placement::updateLayerOpacities(const RenderLayerSymbolInterface& symbolInterface) {
    std::set<uint32_t> seenCrossTileIDs;
    for (const RenderTile& renderTile : symbolInterface.getRenderTiles()) {
        if (!renderTile.tile.isRenderable()) {
            continue;
        }

        auto bucket = symbolInterface.getSymbolBucket(renderTile);
        if (!bucket) {
            continue;
        }
        SymbolBucket& symbolBucket = *bucket;

        if (symbolBucket.bucketLeaderID != symbolInterface.layerID()) {
            // Only update opacities this layer if it's the "group leader" for the bucket
            continue;
        }
        updateBucketOpacities(symbolBucket, seenCrossTileIDs);
    }
}

void Placement::updateBucketOpacities(SymbolBucket& bucket, std::set<uint32_t>& seenCrossTileIDs) {
    if (bucket.hasTextData()) bucket.text.opacityVertices.clear();
    if (bucket.hasIconData()) bucket.icon.opacityVertices.clear();
    if (bucket.hasCollisionBoxData()) bucket.collisionBox.dynamicVertices.clear();
    if (bucket.hasCollisionCircleData()) bucket.collisionCircle.dynamicVertices.clear();

    JointOpacityState duplicateOpacityState(false, false, true);

    const bool textAllowOverlap = bucket.layout.get<style::TextAllowOverlap>();
    const bool iconAllowOverlap = bucket.layout.get<style::IconAllowOverlap>();
    const bool variablePlacement = !bucket.layout.get<style::TextVariableAnchor>().empty();
    const bool rotateWithMap = bucket.layout.get<style::TextRotationAlignment>() == style::AlignmentType::Map;
    const bool pitchWithMap = bucket.layout.get<style::TextPitchAlignment>() == style::AlignmentType::Map;

    // If allow-overlap is true, we can show symbols before placement runs on them
    // But we have to wait for placement if we potentially depend on a paired icon/text
    // with allow-overlap: false.
    // See https://github.com/mapbox/mapbox-gl-native/issues/12483
    JointOpacityState defaultOpacityState(
            textAllowOverlap && (iconAllowOverlap || !bucket.hasIconData() || bucket.layout.get<style::IconOptional>()),
            iconAllowOverlap && (textAllowOverlap || !bucket.hasTextData() || bucket.layout.get<style::TextOptional>()),
            true);

    for (SymbolInstance& symbolInstance : bucket.symbolInstances) {
        bool isDuplicate = seenCrossTileIDs.count(symbolInstance.crossTileID) > 0;

        auto it = opacities.find(symbolInstance.crossTileID);
        auto opacityState = defaultOpacityState;
        if (isDuplicate) {
            opacityState = duplicateOpacityState;
        } else if (it != opacities.end()) {
            opacityState = it->second;
        }

        if (it == opacities.end()) {
            opacities.emplace(symbolInstance.crossTileID, defaultOpacityState);
        }

        seenCrossTileIDs.insert(symbolInstance.crossTileID);

        if (symbolInstance.hasText) {
            auto opacityVertex = SymbolSDFTextProgram::opacityVertex(opacityState.text.placed, opacityState.text.opacity);
            if (symbolInstance.placedRightTextIndex) {
                for (size_t i = 0; i < symbolInstance.rightJustifiedGlyphQuads.size() * 4; i++) {
                    bucket.text.opacityVertices.emplace_back(opacityVertex);
                }
                PlacedSymbol& placed = bucket.text.placedSymbols[*symbolInstance.placedRightTextIndex];
                placed.hidden = opacityState.isHidden();
            }
            if (symbolInstance.placedCenterTextIndex && !symbolInstance.singleLine) {
                for (size_t i = 0; i < symbolInstance.centerJustifiedGlyphQuads.size() * 4; i++) {
                    bucket.text.opacityVertices.emplace_back(opacityVertex);
                }
                PlacedSymbol& placed = bucket.text.placedSymbols[*symbolInstance.placedCenterTextIndex];
                placed.hidden = opacityState.isHidden();
            }
            if (symbolInstance.placedLeftTextIndex && !symbolInstance.singleLine) {
                for (size_t i = 0; i < symbolInstance.leftJustifiedGlyphQuads.size() * 4; i++) {
                    bucket.text.opacityVertices.emplace_back(opacityVertex);
                }
                PlacedSymbol& placed = bucket.text.placedSymbols[*symbolInstance.placedLeftTextIndex];
                placed.hidden = opacityState.isHidden();
            }
            if (symbolInstance.placedVerticalTextIndex) {
                for (size_t i = 0; i < symbolInstance.verticalGlyphQuads.size() * 4; i++) {
                    bucket.text.opacityVertices.emplace_back(opacityVertex);
                }
                bucket.text.placedSymbols[*symbolInstance.placedVerticalTextIndex].hidden = opacityState.isHidden();
            }

            auto prevOffset = variableOffsets.find(symbolInstance.crossTileID);
            if (prevOffset != variableOffsets.end()) {
                markUsedJustification(bucket, prevOffset->second.anchor, symbolInstance);
            }
        }
        if (symbolInstance.hasIcon) {
            auto opacityVertex = SymbolIconProgram::opacityVertex(opacityState.icon.placed, opacityState.icon.opacity);
            if (symbolInstance.iconQuad) {
                bucket.icon.opacityVertices.emplace_back(opacityVertex);
                bucket.icon.opacityVertices.emplace_back(opacityVertex);
                bucket.icon.opacityVertices.emplace_back(opacityVertex);
                bucket.icon.opacityVertices.emplace_back(opacityVertex);
            }
            if (symbolInstance.placedIconIndex) {
                bucket.icon.placedSymbols[*symbolInstance.placedIconIndex].hidden = opacityState.isHidden();
            }
        }
        
        auto updateCollisionBox = [&](const auto& feature, const bool placed) {
            if (feature.alongLine) {
                return;
            }
            auto dynamicVertex = CollisionBoxProgram::dynamicVertex(placed, false, {});
            for (size_t i = 0; i < feature.boxes.size() * 4; i++) {
                bucket.collisionBox.dynamicVertices.emplace_back(dynamicVertex);
            }
        };

        auto updateCollisionTextBox = [this, &bucket, &symbolInstance, variablePlacement, rotateWithMap, pitchWithMap](const auto& feature, const bool placed) {
            if (feature.alongLine) {
                return;
            }
            Point<float> shift;
            bool used = true;
            if (variablePlacement) {
                auto foundOffset = variableOffsets.find(symbolInstance.crossTileID);
                if (foundOffset != variableOffsets.end()) {
                    const VariableOffset& variableOffset = foundOffset->second;
                    // This will show either the currently placed position or the last
                    // successfully placed position (so you can visualize what collision
                    // just made the symbol disappear, and the most likely place for the
                    // symbol to come back)
                    shift = calculateVariableLayoutOffset(variableOffset.anchor,
                                                          variableOffset.width,
                                                          variableOffset.height,
                                                          variableOffset.radialOffset,
                                                          variableOffset.textBoxScale);
                    if (rotateWithMap) {
                        shift = util::rotate(shift, pitchWithMap ? state.getBearing() : -state.getBearing());
                    }
                } else {
                    // No offset -> this symbol hasn't been placed since coming on-screen
                    // No single box is particularly meaningful and all of them would be too noisy
                    // Use the center box just to show something's there, but mark it "not used"
                    used = false;
                }
            }
            auto dynamicVertex = CollisionBoxProgram::dynamicVertex(placed, !used, shift);
            for (size_t i = 0; i < feature.boxes.size() * 4; i++) {
                bucket.collisionBox.dynamicVertices.emplace_back(dynamicVertex);
            }
        };
        
        auto updateCollisionCircles = [&](const auto& feature, const bool placed) {
            if (!feature.alongLine) {
                return;
            }
            for (const CollisionBox& box : feature.boxes) {
                auto dynamicVertex = CollisionBoxProgram::dynamicVertex(placed, !box.used, {});
                bucket.collisionCircle.dynamicVertices.emplace_back(dynamicVertex);
                bucket.collisionCircle.dynamicVertices.emplace_back(dynamicVertex);
                bucket.collisionCircle.dynamicVertices.emplace_back(dynamicVertex);
                bucket.collisionCircle.dynamicVertices.emplace_back(dynamicVertex);
            }
        };
        
        if (bucket.hasCollisionBoxData()) {
            updateCollisionTextBox(symbolInstance.textCollisionFeature, opacityState.text.placed);
            updateCollisionBox(symbolInstance.iconCollisionFeature, opacityState.icon.placed);
        }
        if (bucket.hasCollisionCircleData()) {
            updateCollisionCircles(symbolInstance.textCollisionFeature, opacityState.text.placed);
            updateCollisionCircles(symbolInstance.iconCollisionFeature, opacityState.icon.placed);
        }
    }

    bucket.updateOpacity();
    bucket.sortFeatures(state.getBearing());
    auto retainedData = retainedQueryData.find(bucket.bucketInstanceId);
    if (retainedData != retainedQueryData.end()) {
        retainedData->second.featureSortOrder = bucket.featureSortOrder;
    }
}

void Placement::markUsedJustification(SymbolBucket& bucket, style::TextVariableAnchorType placedAnchor, SymbolInstance& symbolInstance) {
    std::map<style::TextJustifyType, optional<size_t>> justificationToIndex {
                {style::TextJustifyType::Right, symbolInstance.placedRightTextIndex},
                {style::TextJustifyType::Center, symbolInstance.placedCenterTextIndex},
                {style::TextJustifyType::Left, symbolInstance.placedLeftTextIndex},
            };
    style::TextJustifyType justify = getAnchorJustification(placedAnchor);
    assert(justify == style::TextJustifyType::Right || justify == style::TextJustifyType::Center || justify == style::TextJustifyType::Left);
    const optional<size_t> autoIndex = justificationToIndex[justify];

    for (auto& pair : justificationToIndex) {
        const optional<size_t> index = pair.second;
        if (index) {
            assert(bucket.text.placedSymbols.size() > *index);
            if (autoIndex && *index != *autoIndex) {
                // There are multiple justifications and this one isn't it: shift offscreen
                bucket.text.placedSymbols.at(*index).crossTileID = 0u;
            } else {
                // Either this is the chosen justification or the justification is hardwired: use this one
                bucket.text.placedSymbols.at(*index).crossTileID = symbolInstance.crossTileID;
            }
        }
    }
}

float Placement::symbolFadeChange(TimePoint now) const {
    if (mapMode == MapMode::Continuous && transitionOptions.enablePlacementTransitions &&
        transitionOptions.duration.value_or(util::DEFAULT_TRANSITION_DURATION) > Milliseconds(0)) {
        return std::chrono::duration<float>(now - commitTime) / transitionOptions.duration.value_or(util::DEFAULT_TRANSITION_DURATION);
    } else {
        return 1.0;
    }
}

bool Placement::hasTransitions(TimePoint now) const {
    if (mapMode == MapMode::Continuous && transitionOptions.enablePlacementTransitions) {
        return stale || std::chrono::duration<float>(now - fadeStartTime) < transitionOptions.duration.value_or(util::DEFAULT_TRANSITION_DURATION);
    } else {
        return false;
    }
}

bool Placement::stillRecent(TimePoint now) const {
    // Even if transitionOptions.duration is set to a value < 300ms, we still wait for this default transition duration
    // before attempting another placement operation.
    return mapMode == MapMode::Continuous &&
        transitionOptions.enablePlacementTransitions &&
        commitTime + std::max(util::DEFAULT_TRANSITION_DURATION, transitionOptions.duration.value_or(util::DEFAULT_TRANSITION_DURATION)) > now;
}

void Placement::setStale() {
    stale = true;
}

const CollisionIndex& Placement::getCollisionIndex() const {
    return collisionIndex;
}
    
const RetainedQueryData& Placement::getQueryData(uint32_t bucketInstanceId) const {
    auto it = retainedQueryData.find(bucketInstanceId);
    if (it == retainedQueryData.end()) {
        throw std::runtime_error("Placement::getQueryData with unrecognized bucketInstanceId");
    }
    return it->second;
}

} // namespace mbgl