#include <mbgl/style/source_impl.hpp>
#include <mbgl/style/source_observer.hpp>
#include <mbgl/map/transform.hpp>
#include <mbgl/renderer/render_tile.hpp>
#include <mbgl/renderer/painter.hpp>
#include <mbgl/style/update_parameters.hpp>
#include <mbgl/style/query_parameters.hpp>
#include <mbgl/text/placement_config.hpp>
#include <mbgl/platform/log.hpp>
#include <mbgl/math/clamp.hpp>
#include <mbgl/util/tile_cover.hpp>
#include <mbgl/util/enum.hpp>

#include <mbgl/algorithm/update_renderables.hpp>
#include <mbgl/algorithm/generate_clip_ids.hpp>
#include <mbgl/algorithm/generate_clip_ids_impl.hpp>

#include <mapbox/geometry/envelope.hpp>

#include <algorithm>

namespace mbgl {
namespace style {

static SourceObserver nullObserver;

Source::Impl::Impl(SourceType type_, std::string id_, Source& base_)
    : type(type_),
      id(std::move(id_)),
      base(base_),
      observer(&nullObserver) {
}

Source::Impl::~Impl() = default;

bool Source::Impl::isLoaded() const {
    if (!loaded) return false;

    for (const auto& pair : tiles) {
        if (!pair.second->isComplete()) {
            return false;
        }
    }

    return true;
}

void Source::Impl::invalidateTiles() {
    tiles.clear();
    renderTiles.clear();
    cache.clear();
}

void Source::Impl::startRender(algorithm::ClipIDGenerator& generator,
                         const mat4& projMatrix,
                         const TransformState& transform) {
    if (type == SourceType::Vector ||
        type == SourceType::GeoJSON ||
        type == SourceType::Annotations) {
        generator.update(renderTiles);
    }

    for (auto& pair : renderTiles) {
        auto& tile = pair.second;
        transform.matrixFor(tile.matrix, tile.id);
        matrix::multiply(tile.matrix, projMatrix, tile.matrix);
    }
}

void Source::Impl::finishRender(Painter& painter) {
    for (auto& pair : renderTiles) {
        auto& tile = pair.second;
        painter.renderTileDebug(tile);
    }
}

const std::map<UnwrappedTileID, RenderTile>& Source::Impl::getRenderTiles() const {
    return renderTiles;
}

void Source::Impl::updateTiles(const UpdateParameters& parameters) {
    if (!loaded) {
        return;
    }

    const uint16_t tileSize = getTileSize();
    const Range<uint8_t> zoomRange = getZoomRange();

    // Determine the overzooming/underzooming amounts and required tiles.
    int32_t overscaledZoom = util::coveringZoomLevel(parameters.transformState.getZoom(), type, tileSize);
    int32_t tileZoom = overscaledZoom;

    std::vector<UnwrappedTileID> idealTiles;
    if (overscaledZoom >= zoomRange.min) {
        int32_t idealZoom = std::min<int32_t>(zoomRange.max, overscaledZoom);

        // Make sure we're not reparsing overzoomed raster tiles.
        if (type == SourceType::Raster) {
            tileZoom = idealZoom;
        }

        idealTiles = util::tileCover(parameters.transformState, idealZoom);
    }

    // Stores a list of all the tiles that we're definitely going to retain. There are two
    // kinds of tiles we need: the ideal tiles determined by the tile cover. They may not yet be in
    // use because they're still loading. In addition to that, we also need to retain all tiles that
    // we're actively using, e.g. as a replacement for tile that aren't loaded yet.
    std::set<OverscaledTileID> retain;

    auto retainTileFn = [&retain](Tile& tile, Resource::Necessity necessity) -> void {
        retain.emplace(tile.id);
        tile.setNecessity(necessity);
    };
    auto getTileFn = [this](const OverscaledTileID& tileID) -> Tile* {
        auto it = tiles.find(tileID);
        return it == tiles.end() ? nullptr : it->second.get();
    };
    auto createTileFn = [this, &parameters](const OverscaledTileID& tileID) -> Tile* {
        std::unique_ptr<Tile> tile = cache.get(tileID);
        if (!tile) {
            tile = createTile(tileID, parameters);
            if (tile) {
                tile->setObserver(this);
            }
        }
        if (!tile) {
            return nullptr;
        }
        return tiles.emplace(tileID, std::move(tile)).first->second.get();
    };
    auto renderTileFn = [this](const UnwrappedTileID& tileID, Tile& tile) {
        renderTiles.emplace(tileID, RenderTile{ tileID, tile });
    };

    renderTiles.clear();
    algorithm::updateRenderables(getTileFn, createTileFn, retainTileFn, renderTileFn,
                                 idealTiles, zoomRange, tileZoom);

    if (type != SourceType::Raster && type != SourceType::Annotations && cache.getSize() == 0) {
        size_t conservativeCacheSize =
            ((float)parameters.transformState.getWidth() / util::tileSize) *
            ((float)parameters.transformState.getHeight() / util::tileSize) *
            (parameters.transformState.getMaxZoom() - parameters.transformState.getMinZoom() + 1) *
            0.5;
        cache.setSize(conservativeCacheSize);
    }

    removeStaleTiles(retain);

    const PlacementConfig config { parameters.transformState.getAngle(),
                                   parameters.transformState.getPitch(),
                                   parameters.debugOptions & MapDebugOptions::Collision };

    for (auto& pair : tiles) {
        pair.second->setPlacementConfig(config);
    }
}

// Moves all tiles to the cache except for those specified in the retain set.
void Source::Impl::removeStaleTiles(const std::set<OverscaledTileID>& retain) {
    // Remove stale tiles. This goes through the (sorted!) tiles map and retain set in lockstep
    // and removes items from tiles that don't have the corresponding key in the retain set.
    auto tilesIt = tiles.begin();
    auto retainIt = retain.begin();
    while (tilesIt != tiles.end()) {
        if (retainIt == retain.end() || tilesIt->first < *retainIt) {
            tilesIt->second->setNecessity(Tile::Necessity::Optional);
            cache.add(tilesIt->first, std::move(tilesIt->second));
            tiles.erase(tilesIt++);
        } else {
            if (!(*retainIt < tilesIt->first)) {
                ++tilesIt;
            }
            ++retainIt;
        }
    }
}

void Source::Impl::removeTiles() {
    renderTiles.clear();
    if (!tiles.empty()) {
        removeStaleTiles({});
    }
}

void Source::Impl::reloadTiles() {
    cache.clear();

    for (auto& pair : tiles) {
        pair.second->redoLayout();
    }
}

std::unordered_map<std::string, std::vector<Feature>> Source::Impl::queryRenderedFeatures(const QueryParameters& parameters) const {
    std::unordered_map<std::string, std::vector<Feature>> result;
    if (renderTiles.empty() || parameters.geometry.empty()) {
        return result;
    }

    LineString<double> queryGeometry;

    for (const auto& p : parameters.geometry) {
        queryGeometry.push_back(TileCoordinate::fromScreenCoordinate(
            parameters.transformState, 0, { p.x, parameters.transformState.getHeight() - p.y }).p);
    }

    mapbox::geometry::box<double> box = mapbox::geometry::envelope(queryGeometry);

    for (const auto& tilePtr : renderTiles) {
        const RenderTile& renderTile = tilePtr.second;
        GeometryCoordinate tileSpaceBoundsMin = TileCoordinate::toGeometryCoordinate(renderTile.id, box.min);
        if (tileSpaceBoundsMin.x >= util::EXTENT || tileSpaceBoundsMin.y >= util::EXTENT) {
            continue;
        }

        GeometryCoordinate tileSpaceBoundsMax = TileCoordinate::toGeometryCoordinate(renderTile.id, box.max);
        if (tileSpaceBoundsMax.x < 0 || tileSpaceBoundsMax.y < 0) {
            continue;
        }

        GeometryCoordinates tileSpaceQueryGeometry;
        tileSpaceQueryGeometry.reserve(queryGeometry.size());
        for (const auto& c : queryGeometry) {
            tileSpaceQueryGeometry.push_back(TileCoordinate::toGeometryCoordinate(renderTile.id, c));
        }

        renderTile.tile.queryRenderedFeatures(result,
                                              tileSpaceQueryGeometry,
                                              parameters.transformState,
                                              parameters.layerIDs);
    }

    return result;
}

void Source::Impl::setCacheSize(size_t size) {
    cache.setSize(size);
}

void Source::Impl::onLowMemory() {
    cache.clear();
}

void Source::Impl::setObserver(SourceObserver* observer_) {
    observer = observer_;
}

void Source::Impl::onTileChanged(Tile& tile) {
    observer->onTileChanged(base, tile.id);
}

void Source::Impl::onTileError(Tile& tile, std::exception_ptr error) {
    observer->onTileError(base, tile.id, error);
}

void Source::Impl::dumpDebugLogs() const {
    Log::Info(Event::General, "Source::id: %s", base.getID().c_str());
    Log::Info(Event::General, "Source::loaded: %d", loaded);

    for (const auto& pair : tiles) {
        pair.second->dumpDebugLogs();
    }
}

} // namespace style
} // namespace mbgl