planetiler/openmaptiles/src/main/java/com/onthegomap/flatmap/openmaptiles/layers/Boundary.java

/*
Copyright (c) 2016, KlokanTech.com & OpenMapTiles contributors.
All rights reserved.

Code license: BSD 3-Clause License

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

* Neither the name of the copyright holder nor the names of its
  contributors may be used to endorse or promote products derived from
  this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Design license: CC-BY 4.0

See https://github.com/openmaptiles/openmaptiles/blob/master/LICENSE.md for details on usage
*/
package com.onthegomap.flatmap.openmaptiles.layers;

import static java.util.stream.Collectors.counting;
import static java.util.stream.Collectors.groupingBy;

import com.carrotsearch.hppc.LongObjectMap;
import com.graphhopper.coll.GHLongObjectHashMap;
import com.graphhopper.reader.ReaderElementUtils;
import com.graphhopper.reader.ReaderRelation;
import com.onthegomap.flatmap.Arguments;
import com.onthegomap.flatmap.FeatureCollector;
import com.onthegomap.flatmap.FeatureMerge;
import com.onthegomap.flatmap.MemoryEstimator;
import com.onthegomap.flatmap.Parse;
import com.onthegomap.flatmap.SourceFeature;
import com.onthegomap.flatmap.Translations;
import com.onthegomap.flatmap.VectorTileEncoder;
import com.onthegomap.flatmap.geo.GeoUtils;
import com.onthegomap.flatmap.geo.GeometryException;
import com.onthegomap.flatmap.monitoring.Stats;
import com.onthegomap.flatmap.openmaptiles.OpenMapTilesProfile;
import com.onthegomap.flatmap.openmaptiles.generated.OpenMapTilesSchema;
import com.onthegomap.flatmap.read.OpenStreetMapReader;
import com.onthegomap.flatmap.read.ReaderFeature;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.Consumer;
import java.util.function.Function;
import org.jetbrains.annotations.NotNull;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.LineString;
import org.locationtech.jts.geom.Point;
import org.locationtech.jts.geom.TopologyException;
import org.locationtech.jts.geom.prep.PreparedGeometry;
import org.locationtech.jts.geom.prep.PreparedGeometryFactory;
import org.locationtech.jts.operation.linemerge.LineMerger;
import org.locationtech.jts.operation.polygonize.Polygonizer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This class is ported to Java from https://github.com/openmaptiles/openmaptiles/tree/master/layers/boundary
 */
public class Boundary implements
  OpenMapTilesSchema.Boundary,
  OpenMapTilesProfile.NaturalEarthProcessor,
  OpenMapTilesProfile.OsmRelationPreprocessor,
  OpenMapTilesProfile.OsmAllProcessor,
  OpenMapTilesProfile.FeaturePostProcessor,
  OpenMapTilesProfile.FinishHandler {

  private static final Logger LOGGER = LoggerFactory.getLogger(Boundary.class);
  private static final double COUNTRY_TEST_OFFSET = GeoUtils.metersToPixelAtEquator(0, 100) / 256d;
  private final Map<Long, String> regionNames = new HashMap<>();
  private final Map<Long, List<Geometry>> regionGeometries = new HashMap<>();
  private final Map<CountryBoundaryComponent, List<Geometry>> boundariesToMerge = new HashMap<>();
  private final Stats stats;
  private final boolean addCountryNames;

  public Boundary(Translations translations, Arguments args, Stats stats) {
    this.addCountryNames = args.get(
      "boundary_country_names",
      "boundary layer: add left/right codes of neighboring countries",
      true
    );
    this.stats = stats;
  }

  private static boolean isDisputed(Map<String, Object> tags) {
    return Parse.bool(tags.get("disputed")) ||
      Parse.bool(tags.get("dispute")) ||
      "dispute".equals(tags.get("border_status")) ||
      tags.containsKey("disputed_by") ||
      tags.containsKey("claimed_by");
  }

  private static String editName(String name) {
    return name == null ? null : name.replace(" at ", "")
      .replaceAll("\\s+", "")
      .replace("Extentof", "");
  }

  @Override
  public void release() {
    regionGeometries.clear();
    boundariesToMerge.clear();
    regionNames.clear();
  }

  @Override
  public void processNaturalEarth(String table, SourceFeature feature, FeatureCollector features) {
    boolean disputed = feature.getString("featurecla", "").startsWith("Disputed");
    record BoundaryInfo(int adminLevel, int minzoom, int maxzoom) {}
    BoundaryInfo info = switch (table) {
      case "ne_110m_admin_0_boundary_lines_land" -> new BoundaryInfo(2, 0, 0);
      case "ne_50m_admin_0_boundary_lines_land" -> new BoundaryInfo(2, 1, 3);
      case "ne_10m_admin_0_boundary_lines_land" -> feature.hasTag("featurecla", "Lease Limit") ? null
        : new BoundaryInfo(2, 4, 4);
      case "ne_10m_admin_1_states_provinces_lines" -> {
        Double minZoom = Parse.parseDoubleOrNull(feature.getTag("min_zoom"));
        yield minZoom != null && minZoom <= 7 ? new BoundaryInfo(4, 1, 4) : null;
      }
      default -> null;
    };
    if (info != null) {
      features.line(LAYER_NAME).setBufferPixels(BUFFER_SIZE)
        .setZoomRange(info.minzoom, info.maxzoom)
        .setMinPixelSizeAtAllZooms(0)
        .setAttr(Fields.ADMIN_LEVEL, info.adminLevel)
        .setAttr(Fields.MARITIME, 0)
        .setAttr(Fields.DISPUTED, disputed ? 1 : 0);
    }
  }

  @Override
  public List<OpenStreetMapReader.RelationInfo> preprocessOsmRelation(ReaderRelation relation) {
    if (relation.hasTag("type", "boundary") &&
      relation.hasTag("admin_level") &&
      relation.hasTag("boundary", "administrative")) {
      Integer adminLevelValue = Parse.parseIntSubstring(relation.getTag("admin_level"));
      String code = relation.getTag("ISO3166-1:alpha3");
      if (adminLevelValue != null && adminLevelValue >= 2 && adminLevelValue <= 10) {
        boolean disputed = isDisputed(ReaderElementUtils.getProperties(relation));
        if (code != null) {
          synchronized (regionNames) {
            regionNames.put(relation.getId(), code);
          }
        }
        return List.of(new BoundaryRelation(
          relation.getId(),
          adminLevelValue,
          disputed,
          relation.getTag("name"),
          disputed ? relation.getTag("claimed_by") : null,
          code
        ));
      }
    }
    return null;
  }

  @Override
  public void processAllOsm(SourceFeature feature, FeatureCollector features) {
    if (!feature.canBeLine()) {
      return;
    }
    var relationInfos = feature.relationInfo(BoundaryRelation.class);
    if (!relationInfos.isEmpty()) {
      int minAdminLevel = Integer.MAX_VALUE;
      String disputedName = null, claimedBy = null;
      Set<Long> regionIds = new HashSet<>();
      boolean disputed = false;
      for (var info : relationInfos) {
        BoundaryRelation rel = info.relation();
        disputed |= rel.disputed;
        if (rel.adminLevel < minAdminLevel) {
          minAdminLevel = rel.adminLevel;
        }
        if (rel.disputed) {
          disputedName = disputedName == null ? rel.name : disputedName;
          claimedBy = claimedBy == null ? rel.claimedBy : claimedBy;
        }
        if (minAdminLevel == 2 && regionNames.containsKey(info.relation().id)) {
          regionIds.add(info.relation().id);
        }
      }

      if (minAdminLevel <= 10) {
        boolean wayIsDisputed = isDisputed(feature.properties());
        disputed |= wayIsDisputed;
        if (wayIsDisputed) {
          disputedName = disputedName == null ? feature.getString("name") : disputedName;
          claimedBy = claimedBy == null ? feature.getString("claimed_by") : claimedBy;
        }
        boolean maritime = feature.getBoolean("maritime") ||
          feature.hasTag("natural", "coastline") ||
          feature.hasTag("boundary_type", "maritime");
        int minzoom =
          (maritime && minAdminLevel == 2) ? 4 :
            minAdminLevel <= 4 ? 5 :
              minAdminLevel <= 6 ? 9 :
                minAdminLevel <= 8 ? 11 : 12;
        if (addCountryNames && !regionIds.isEmpty()) {
          // save for later
          try {
            CountryBoundaryComponent component = new CountryBoundaryComponent(
              minAdminLevel,
              disputed,
              maritime,
              minzoom,
              feature.line(),
              regionIds,
              claimedBy,
              disputedName
            );
            synchronized (regionGeometries) {
              boundariesToMerge.computeIfAbsent(component.groupingKey(), key -> new ArrayList<>()).add(component.line);
              for (var info : relationInfos) {
                var rel = info.relation();
                if (rel.adminLevel <= 2) {
                  regionGeometries.computeIfAbsent(rel.id, id -> new ArrayList<>()).add(component.line);
                }
              }
            }
          } catch (GeometryException e) {
            LOGGER.warn("Cannot extract boundary line from " + feature);
          }
        } else {
          features.line(LAYER_NAME).setBufferPixels(BUFFER_SIZE)
            .setAttr(Fields.ADMIN_LEVEL, minAdminLevel)
            .setAttr(Fields.DISPUTED, disputed ? 1 : 0)
            .setAttr(Fields.MARITIME, maritime ? 1 : 0)
            .setMinPixelSizeAtAllZooms(0)
            .setZoomRange(minzoom, 14)
            .setAttr(Fields.CLAIMED_BY, claimedBy)
            .setAttr(Fields.DISPUTED_NAME, editName(disputedName));
        }
      }
    }
  }

  @Override
  public void finish(String sourceName, FeatureCollector.Factory featureCollectors,
    Consumer<FeatureCollector.Feature> next) {
    if (OpenMapTilesProfile.OSM_SOURCE.equals(sourceName)) {
      var timer = stats.startTimer("boundaries");
      LongObjectMap<PreparedGeometry> countryBoundaries = prepareRegionPolygons();

      long number = 0;
      for (var entry : boundariesToMerge.entrySet()) {
        number++;
        CountryBoundaryComponent key = entry.getKey();
        LineMerger merger = new LineMerger();
        for (Geometry geom : entry.getValue()) {
          merger.add(geom);
        }
        entry.getValue().clear();
        for (Object merged : merger.getMergedLineStrings()) {
          if (merged instanceof LineString lineString) {
            BorderingRegions borderingRegions = getBorderingRegions(countryBoundaries, key.regions, lineString);

            var features = featureCollectors.get(new ReaderFeature(
              GeoUtils.worldToLatLonCoords(lineString),
              Map.of(),
              number
            ));
            features.line(LAYER_NAME).setBufferPixels(BUFFER_SIZE)
              .setAttr(Fields.ADMIN_LEVEL, key.adminLevel)
              .setAttr(Fields.DISPUTED, key.disputed ? 1 : 0)
              .setAttr(Fields.MARITIME, key.maritime ? 1 : 0)
              .setAttr(Fields.CLAIMED_BY, key.claimedBy)
              .setAttr(Fields.DISPUTED_NAME, key.disputed ? editName(key.name) : null)
              .setAttr(Fields.ADM0_L, regionNames.get(borderingRegions.left))
              .setAttr(Fields.ADM0_R, regionNames.get(borderingRegions.right))
              .setMinPixelSizeAtAllZooms(0)
              .setZoomRange(key.minzoom, 14);
            for (var feature : features) {
              next.accept(feature);
            }
          }
        }
      }
      timer.stop();
    }
  }

  @Override
  public List<VectorTileEncoder.Feature> postProcess(int zoom, List<VectorTileEncoder.Feature> items)
    throws GeometryException {
    double tolerance = zoom >= 14 ? 256d / 4096d : 0.1;
    return FeatureMerge.mergeLineStrings(items, 1, tolerance, BUFFER_SIZE);
  }

  @NotNull
  private BorderingRegions getBorderingRegions(
    LongObjectMap<PreparedGeometry> countryBoundaries,
    Set<Long> regions,
    LineString lineString
  ) {
    Long rightCountry = null, leftCountry = null;
    List<Long> rights = new ArrayList<>();
    List<Long> lefts = new ArrayList<>();
    int steps = 10;
    for (int i = 0; i < steps; i++) {
      double ratio = (double) (i + 1) / (steps + 2);
      Point right = GeoUtils.pointAlongOffset(lineString, ratio, COUNTRY_TEST_OFFSET);
      Point left = GeoUtils.pointAlongOffset(lineString, ratio, -COUNTRY_TEST_OFFSET);
      for (Long regionId : regions) {
        PreparedGeometry geom = countryBoundaries.get(regionId);
        if (geom != null) {
          if (geom.contains(right)) {
            rights.add(regionId);
          } else if (geom.contains(left)) {
            lefts.add(regionId);
          }
        }
      }
    }

    var right = mode(rights);
    if (right != null) {
      rightCountry = right.getKey();
      lefts.removeAll(List.of(rightCountry));
    }
    var left = mode(lefts);
    if (left != null) {
      leftCountry = left.getKey();
    }

    if (leftCountry == null && rightCountry == null) {
      LOGGER.warn("[boundaries] no left or right country for border between country relations: " + regions);
    }

    return new BorderingRegions(leftCountry, rightCountry);
  }

  @NotNull
  private LongObjectMap<PreparedGeometry> prepareRegionPolygons() {
    LOGGER.info("[boundaries] Creating polygons for " + regionGeometries.size() + " boundaries");
    LongObjectMap<PreparedGeometry> countryBoundaries = new GHLongObjectHashMap<>();
    for (var entry : regionGeometries.entrySet()) {
      Long regionId = entry.getKey();
      Polygonizer polygonizer = new Polygonizer();
      polygonizer.add(entry.getValue());
      try {
        Geometry combined = polygonizer.getGeometry().union();
        if (combined.isEmpty()) {
          LOGGER.warn("[boundaries] No valid polygons found for " + regionId);
        } else {
          countryBoundaries.put(regionId, PreparedGeometryFactory.prepare(combined));
        }
      } catch (TopologyException e) {
        LOGGER.warn("[boundaries] Unable to build boundary polygon for " + regionId + ": " + e.getMessage());
      }
    }
    LOGGER.info("[boundaries] Finished creating " + countryBoundaries.size() + " country polygons");
    return countryBoundaries;
  }

  private Map.Entry<Long, Long> mode(List<Long> rights) {
    return rights.stream()
      .collect(groupingBy(Function.identity(), counting())).entrySet().stream()
      .max(Map.Entry.comparingByValue())
      .orElse(null);
  }

  private static record BorderingRegions(Long left, Long right) {}

  private static record BoundaryRelation(
    long id,
    int adminLevel,
    boolean disputed,
    String name,
    String claimedBy,
    String iso3166alpha3
  ) implements OpenStreetMapReader.RelationInfo {

    @Override
    public long estimateMemoryUsageBytes() {
      return 29 + 8 + MemoryEstimator.size(name)
        + 8 + MemoryEstimator.size(claimedBy)
        + 8 + MemoryEstimator.size(iso3166alpha3);
    }
  }

  private static record CountryBoundaryComponent(
    int adminLevel,
    boolean disputed,
    boolean maritime,
    int minzoom,
    Geometry line,
    Set<Long> regions,
    String claimedBy,
    String name
  ) {

    CountryBoundaryComponent groupingKey() {
      return new CountryBoundaryComponent(adminLevel, disputed, maritime, minzoom, null, regions, claimedBy, name);
    }

  }
}