#include <mbgl/renderer/layers/render_circle_layer.hpp>
#include <mbgl/renderer/buckets/circle_bucket.hpp>
#include <mbgl/renderer/render_tile.hpp>
#include <mbgl/renderer/paint_parameters.hpp>
#include <mbgl/programs/programs.hpp>
#include <mbgl/programs/circle_program.hpp>
#include <mbgl/tile/tile.hpp>
#include <mbgl/style/layers/circle_layer_impl.hpp>
#include <mbgl/geometry/feature_index.hpp>
#include <mbgl/gfx/cull_face_mode.hpp>
#include <mbgl/gfx/shader_registry.hpp>
#include <mbgl/util/math.hpp>
#include <mbgl/util/intersection_tests.hpp>

namespace mbgl {

using namespace style;

namespace {

struct RenderableSegment {
    RenderableSegment(const Segment<CircleAttributes>& segment_,
                      const RenderTile& tile_,
                      const LayerRenderData* renderData_,
                      float sortKey_)
        : segment(segment_),
          tile(tile_),
          renderData(renderData_),
          sortKey(sortKey_) {}

    const Segment<CircleAttributes>& segment;
    const RenderTile& tile;
    const LayerRenderData* renderData;
    const float sortKey;

    friend bool operator<(const RenderableSegment& lhs, const RenderableSegment& rhs) {
        if (lhs.sortKey == rhs.sortKey) return lhs.tile.id < rhs.tile.id;
        return lhs.sortKey < rhs.sortKey;
    }
};

inline const style::CircleLayer::Impl& impl_cast(const Immutable<style::Layer::Impl>& impl) {
    assert(impl->getTypeInfo() == CircleLayer::Impl::staticTypeInfo());
    return static_cast<const style::CircleLayer::Impl&>(*impl);
}

} // namespace

RenderCircleLayer::RenderCircleLayer(Immutable<style::CircleLayer::Impl> _impl)
    : RenderLayer(makeMutable<CircleLayerProperties>(std::move(_impl))),
      unevaluated(impl_cast(baseImpl).paint.untransitioned()) {}

void RenderCircleLayer::transition(const TransitionParameters& parameters) {
    unevaluated = impl_cast(baseImpl).paint.transitioned(parameters, std::move(unevaluated));
}

void RenderCircleLayer::evaluate(const PropertyEvaluationParameters& parameters) {
    auto properties = makeMutable<CircleLayerProperties>(staticImmutableCast<CircleLayer::Impl>(baseImpl),
                                                         unevaluated.evaluate(parameters));
    const auto& evaluated = properties->evaluated;

    passes = ((evaluated.get<style::CircleRadius>().constantOr(1) > 0 ||
               evaluated.get<style::CircleStrokeWidth>().constantOr(1) > 0) &&
              (evaluated.get<style::CircleColor>().constantOr(Color::black()).a > 0 ||
               evaluated.get<style::CircleStrokeColor>().constantOr(Color::black()).a > 0) &&
              (evaluated.get<style::CircleOpacity>().constantOr(1) > 0 ||
               evaluated.get<style::CircleStrokeOpacity>().constantOr(1) > 0))
                 ? RenderPass::Translucent
                 : RenderPass::None;
    properties->renderPasses = mbgl::underlying_type(passes);
    evaluatedProperties = std::move(properties);
}

bool RenderCircleLayer::hasTransition() const {
    return unevaluated.hasTransition();
}

bool RenderCircleLayer::hasCrossfade() const {
    return false;
}

void RenderCircleLayer::render(PaintParameters& parameters) {
    assert(renderTiles);
    if (parameters.pass == RenderPass::Opaque) {
        return;
    }

    if (!parameters.shaders.populate(circleProgram)) return;

    const auto drawTile = [&](const RenderTile& tile, const LayerRenderData* data, const auto& segments) {
        auto& circleBucket = static_cast<CircleBucket&>(*data->bucket);
        const auto& evaluated = getEvaluated<CircleLayerProperties>(data->layerProperties);
        const bool scaleWithMap = evaluated.template get<CirclePitchScale>() == CirclePitchScaleType::Map;
        const bool pitchWithMap = evaluated.template get<CirclePitchAlignment>() == AlignmentType::Map;
        const auto& paintPropertyBinders = circleBucket.paintPropertyBinders.at(getID());

        using LayoutUniformValues = CircleProgram::LayoutUniformValues;
        const auto& allUniformValues = CircleProgram::computeAllUniformValues(
            LayoutUniformValues(
                uniforms::matrix::Value(tile.translatedMatrix(evaluated.template get<CircleTranslate>(),
                                                              evaluated.template get<CircleTranslateAnchor>(),
                                                              parameters.state)),
                uniforms::scale_with_map::Value(scaleWithMap),
                uniforms::extrude_scale::Value(
                    pitchWithMap ? std::array<float, 2>{{tile.id.pixelsToTileUnits(
                                                             1.0f, static_cast<float>(parameters.state.getZoom())),
                                                         tile.id.pixelsToTileUnits(
                                                             1.0f, static_cast<float>(parameters.state.getZoom()))}}
                                 : parameters.pixelsToGLUnits),
                uniforms::device_pixel_ratio::Value(parameters.pixelRatio),
                uniforms::camera_to_center_distance::Value(parameters.state.getCameraToCenterDistance()),
                uniforms::pitch_with_map::Value(pitchWithMap)),
            paintPropertyBinders,
            evaluated,
            static_cast<float>(parameters.state.getZoom()));
        const auto& allAttributeBindings = CircleProgram::computeAllAttributeBindings(
            *circleBucket.vertexBuffer, paintPropertyBinders, evaluated);

        checkRenderability(parameters, CircleProgram::activeBindingCount(allAttributeBindings));

        circleProgram->draw(parameters.context,
                            *parameters.renderPass,
                            gfx::Triangles(),
                            parameters.depthModeForSublayer(0, gfx::DepthMaskType::ReadOnly),
                            gfx::StencilMode::disabled(),
                            parameters.colorModeForRenderPass(),
                            gfx::CullFaceMode::disabled(),
                            *circleBucket.indexBuffer,
                            segments,
                            allUniformValues,
                            allAttributeBindings,
                            CircleProgram::TextureBindings{},
                            getID());
    };

    const bool sortFeaturesByKey = !impl_cast(baseImpl).layout.get<CircleSortKey>().isUndefined();
    std::multiset<RenderableSegment> renderableSegments;

    for (const RenderTile& renderTile : *renderTiles) {
        const LayerRenderData* renderData = getRenderDataForPass(renderTile, parameters.pass);
        if (!renderData) {
            continue;
        }
        auto& bucket = static_cast<CircleBucket&>(*renderData->bucket);
        if (!sortFeaturesByKey) {
            drawTile(renderTile, renderData, bucket.segments);
            continue;
        }
        for (auto& segment : bucket.segments) {
            renderableSegments.emplace(segment, renderTile, renderData, segment.sortKey);
        }
    }

    if (sortFeaturesByKey) {
        for (const auto& renderable : renderableSegments) {
            drawTile(renderable.tile, renderable.renderData, renderable.segment);
        }
    }
}

GeometryCoordinate projectPoint(const GeometryCoordinate& p, const mat4& posMatrix, const Size& size) {
    vec4 pos = {{static_cast<double>(p.x), static_cast<double>(p.y), 0, 1}};
    matrix::transformMat4(pos, pos, posMatrix);
    return {static_cast<int16_t>((static_cast<float>(pos[0] / pos[3]) + 1) * size.width * 0.5),
            static_cast<int16_t>((static_cast<float>(pos[1] / pos[3]) + 1) * size.height * 0.5)};
}

GeometryCoordinates projectQueryGeometry(const GeometryCoordinates& queryGeometry,
                                         const mat4& posMatrix,
                                         const Size& size) {
    GeometryCoordinates projectedGeometry;
    for (auto& p : queryGeometry) {
        projectedGeometry.push_back(projectPoint(p, posMatrix, size));
    }
    return projectedGeometry;
}

bool RenderCircleLayer::queryIntersectsFeature(const GeometryCoordinates& queryGeometry,
                                               const GeometryTileFeature& feature,
                                               const float zoom,
                                               const TransformState& transformState,
                                               const float pixelsToTileUnits,
                                               const mat4& posMatrix,
                                               const FeatureState& featureState) const {
    const auto& evaluated = static_cast<const CircleLayerProperties&>(*evaluatedProperties).evaluated;
    // Translate query geometry
    const GeometryCoordinates& translatedQueryGeometry = FeatureIndex::translateQueryGeometry(
                                                             queryGeometry,
                                                             evaluated.get<style::CircleTranslate>(),
                                                             evaluated.get<style::CircleTranslateAnchor>(),
                                                             static_cast<float>(transformState.getBearing()),
                                                             pixelsToTileUnits)
                                                             .value_or(queryGeometry);

    // Evaluate functions
    auto radius = evaluated.evaluate<style::CircleRadius>(zoom, feature, featureState);
    auto stroke = evaluated.evaluate<style::CircleStrokeWidth>(zoom, feature, featureState);
    auto size = radius + stroke;

    // For pitch-alignment: map, compare feature geometry to query geometry in the plane of the tile
    // Otherwise, compare geometry in the plane of the viewport
    // A circle with fixed scaling relative to the viewport gets larger in tile space as it moves into the distance
    // A circle with fixed scaling relative to the map gets smaller in viewport space as it moves into the distance
    bool alignWithMap = evaluated.evaluate<style::CirclePitchAlignment>(zoom, feature) == AlignmentType::Map;
    const GeometryCoordinates& transformedQueryGeometry = alignWithMap ? translatedQueryGeometry
                                                                       : projectQueryGeometry(translatedQueryGeometry,
                                                                                              posMatrix,
                                                                                              transformState.getSize());
    auto transformedSize = alignWithMap ? size * pixelsToTileUnits : size;

    const auto& geometry = feature.getGeometries();
    for (auto& ring : geometry) {
        for (auto& point : ring) {
            const GeometryCoordinate& transformedPoint = alignWithMap
                                                             ? point
                                                             : projectPoint(point, posMatrix, transformState.getSize());

            float adjustedSize = transformedSize;
            vec4 center = {{static_cast<double>(point.x), static_cast<double>(point.y), 0, 1}};
            matrix::transformMat4(center, center, posMatrix);
            auto pitchScale = evaluated.evaluate<style::CirclePitchScale>(zoom, feature);
            auto pitchAlignment = evaluated.evaluate<style::CirclePitchAlignment>(zoom, feature);
            if (pitchScale == CirclePitchScaleType::Viewport && pitchAlignment == AlignmentType::Map) {
                adjustedSize *= static_cast<float>(center[3] / transformState.getCameraToCenterDistance());
            } else if (pitchScale == CirclePitchScaleType::Map && pitchAlignment == AlignmentType::Viewport) {
                adjustedSize *= static_cast<float>(transformState.getCameraToCenterDistance() / center[3]);
            }

            if (util::polygonIntersectsBufferedPoint(transformedQueryGeometry, transformedPoint, adjustedSize))
                return true;
        }
    }

    return false;
}

} // namespace mbgl
