// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.data.osm;

import static org.openstreetmap.josm.tools.I18n.tr;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.DoubleStream;
import java.util.stream.IntStream;

import org.openstreetmap.josm.data.coor.ILatLon;
import org.openstreetmap.josm.data.osm.visitor.OsmPrimitiveVisitor;
import org.openstreetmap.josm.data.osm.visitor.PrimitiveVisitor;
import org.openstreetmap.josm.spi.preferences.Config;
import org.openstreetmap.josm.tools.CopyList;
import org.openstreetmap.josm.tools.Geometry;
import org.openstreetmap.josm.tools.Pair;
import org.openstreetmap.josm.tools.Utils;

/**
 * One full way, consisting of a list of way {@link Node nodes}.
 *
 * @author imi
 * @since 64
 */
public final class Way extends OsmPrimitive implements IWay<Node> {

    static final UniqueIdGenerator idGenerator = new UniqueIdGenerator();
    private static final Node[] EMPTY_NODES = new Node[0];

    /**
     * All way nodes in this way
     */
    private Node[] nodes = EMPTY_NODES;
    private BBox bbox;

    @Override
    public List<Node> getNodes() {
        return new CopyList<>(nodes);
    }

    @Override
    public void setNodes(List<Node> nodes) {
        checkDatasetNotReadOnly();
        boolean locked = writeLock();
        try {
            for (Node node:this.nodes) {
                node.removeReferrer(this);
                node.clearCachedStyle();
            }

            if (Utils.isEmpty(nodes)) {
                this.nodes = EMPTY_NODES;
            } else {
                this.nodes = nodes.toArray(EMPTY_NODES);
            }
            for (Node node: this.nodes) {
                node.addReferrer(this);
                node.clearCachedStyle();
            }

            clearCachedStyle();
            fireNodesChanged();
        } finally {
            writeUnlock(locked);
        }
    }

    /**
     * Prevent directly following identical nodes in ways.
     * @param nodes list of nodes
     * @return {@code nodes} with consecutive identical nodes removed
     */
    private static List<Node> removeDouble(List<Node> nodes) {
        Node last = null;
        int count = nodes.size();
        for (int i = 0; i < count && count > 2;) {
            Node n = nodes.get(i);
            if (last == n) {
                nodes.remove(i);
                --count;
            } else {
                last = n;
                ++i;
            }
        }
        return nodes;
    }

    @Override
    public int getNodesCount() {
        return nodes.length;
    }

    @Override
    public Node getNode(int index) {
        return nodes[index];
    }

    @Override
    public long getNodeId(int idx) {
        return nodes[idx].getUniqueId();
    }

    @Override
    public List<Long> getNodeIds() {
        return Arrays.stream(nodes).map(Node::getId).collect(Collectors.toList());
    }

    /**
     * Replies true if this way contains the node <code>node</code>, false
     * otherwise. Replies false if  <code>node</code> is null.
     *
     * @param node the node. May be null.
     * @return true if this way contains the node <code>node</code>, false
     * otherwise
     * @since 1911
     */
    public boolean containsNode(Node node) {
        return node != null && Arrays.asList(nodes).contains(node);
    }

    /**
     * Return nodes adjacent to <code>node</code>
     *
     * @param node the node. May be null.
     * @return Set of nodes adjacent to <code>node</code>
     * @since 4671
     */
    public Set<Node> getNeighbours(Node node) {
        Set<Node> neigh = new HashSet<>();

        if (node == null) return neigh;

        for (int i = 0; i < nodes.length; i++) {
            if (nodes[i].equals(node)) {
                if (i > 0)
                    neigh.add(nodes[i-1]);
                if (i < nodes.length-1)
                    neigh.add(nodes[i+1]);
            }
        }
        return neigh;
    }

    /**
     * Replies the ordered {@link List} of chunks of this way. Each chunk is replied as a {@link Pair} of {@link Node nodes}.
     * @param sort If true, the nodes of each pair are sorted as defined by {@link Pair#sort}.
     *             If false, Pair.a and Pair.b are in the way order
     *             (i.e for a given Pair(n), Pair(n-1).b == Pair(n).a, Pair(n).b == Pair(n+1).a, etc.)
     * @return The ordered list of chunks of this way.
     * @since 3348
     */
    public List<Pair<Node, Node>> getNodePairs(boolean sort) {
        // For a way of size n, there are n - 1 pairs (a -> b, b -> c, c -> d, etc., 4 nodes -> 3 pairs)
        List<Pair<Node, Node>> chunkSet = new ArrayList<>(Math.max(0, this.getNodesCount() - 1));
        if (isIncomplete()) return chunkSet;
        Node lastN = null;
        for (Node n : nodes) {
            if (lastN == null) {
                lastN = n;
                continue;
            }
            Pair<Node, Node> np = new Pair<>(lastN, n);
            if (sort) {
                Pair.sort(np);
            }
            chunkSet.add(np);
            lastN = n;
        }
        return chunkSet;
    }

    @Override public void accept(OsmPrimitiveVisitor visitor) {
        visitor.visit(this);
    }

    @Override public void accept(PrimitiveVisitor visitor) {
        visitor.visit(this);
    }

    Way(long id, boolean allowNegative) {
        super(id, allowNegative);
    }

    /**
     * Constructs a new {@code Way} with id 0.
     * @since 86
     */
    public Way() {
        super(0, false);
    }

    /**
     * Constructs a new {@code Way} from an existing {@code Way}.
     * This adds links from all way nodes to the clone. See #19885 for possible memory leaks.
     * @param original The original {@code Way} to be identically cloned. Must not be null
     * @param clearMetadata If {@code true}, clears the OSM id and other metadata as defined by {@link #clearOsmMetadata}.
     * If {@code false}, does nothing
     * @param copyNodes whether to copy nodes too
     * @since 16212
     */
    public Way(Way original, boolean clearMetadata, boolean copyNodes) {
        super(original.getUniqueId(), true);
        cloneFrom(original, copyNodes);
        if (clearMetadata) {
            clearOsmMetadata();
        }
    }

    /**
     * Constructs a new {@code Way} from an existing {@code Way}.
     * This adds links from all way nodes to the clone. See #19885 for possible memory leaks.
     * @param original The original {@code Way} to be identically cloned. Must not be null
     * @param clearMetadata If {@code true}, clears the OSM id and other metadata as defined by {@link #clearOsmMetadata}.
     * If {@code false}, does nothing
     * @since 2410
     */
    public Way(Way original, boolean clearMetadata) {
        this(original, clearMetadata, true);
    }

    /**
     * Constructs a new {@code Way} from an existing {@code Way} (including its id).
     * This adds links from all way nodes to the clone. See #19885 for possible memory leaks.
     * @param original The original {@code Way} to be identically cloned. Must not be null
     * @since 86
     */
    public Way(Way original) {
        this(original, false);
    }

    /**
     * Constructs a new {@code Way} for the given id. If the id &gt; 0, the way is marked
     * as incomplete. If id == 0 then way is marked as new
     *
     * @param id the id. &gt;= 0 required
     * @throws IllegalArgumentException if id &lt; 0
     * @since 343
     */
    public Way(long id) {
        super(id, false);
    }

    /**
     * Constructs a new {@code Way} with given id and version.
     * @param id the id. &gt;= 0 required
     * @param version the version
     * @throws IllegalArgumentException if id &lt; 0
     * @since 2620
     */
    public Way(long id, int version) {
        super(id, version, false);
    }

    @Override
    public void load(PrimitiveData data) {
        if (!(data instanceof WayData))
            throw new IllegalArgumentException("Not a way data: " + data);
        boolean locked = writeLock();
        try {
            super.load(data);

            List<Long> nodeIds = ((WayData) data).getNodeIds();

            if (!nodeIds.isEmpty() && getDataSet() == null) {
                throw new AssertionError("Data consistency problem - way without dataset detected");
            }

            List<Node> newNodes = new ArrayList<>(nodeIds.size());
            for (Long nodeId : nodeIds) {
                Node node = (Node) getDataSet().getPrimitiveById(nodeId, OsmPrimitiveType.NODE);
                if (node != null) {
                    newNodes.add(node);
                } else {
                    throw new AssertionError("Data consistency problem - way with missing node detected");
                }
            }
            setNodes(newNodes);
        } finally {
            writeUnlock(locked);
        }
    }

    @Override
    public WayData save() {
        WayData data = new WayData();
        saveCommonAttributes(data);
        for (Node node:nodes) {
            data.getNodeIds().add(node.getUniqueId());
        }
        return data;
    }

    @Override
    public void cloneFrom(OsmPrimitive osm, boolean copyNodes) {
        if (!(osm instanceof Way))
            throw new IllegalArgumentException("Not a way: " + osm);
        boolean locked = writeLock();
        try {
            super.cloneFrom(osm, copyNodes);
            if (copyNodes) {
                setNodes(((Way) osm).getNodes());
            }
        } finally {
            writeUnlock(locked);
        }
    }

    @Override
    public String toString() {
        String nodesDesc = isIncomplete() ? "(incomplete)" : ("nodes=" + Arrays.toString(nodes));
        return "{Way id=" + getUniqueId() + " version=" + getVersion()+ ' ' + getFlagsAsString() + ' ' + nodesDesc + '}';
    }

    @Override
    public boolean hasEqualSemanticAttributes(OsmPrimitive other, boolean testInterestingTagsOnly) {
        if (!(other instanceof Way))
            return false;
        Way w = (Way) other;
        if (getNodesCount() != w.getNodesCount()) return false;
        if (!super.hasEqualSemanticAttributes(other, testInterestingTagsOnly))
            return false;
        return IntStream.range(0, getNodesCount())
                .allMatch(i -> getNode(i).hasEqualSemanticAttributes(w.getNode(i)));
    }

    /**
     * Removes the given {@link Node} from this way. Ignored, if n is null.
     * @param n The node to remove. Ignored, if null
     * @since 1463
     */
    public void removeNode(Node n) {
        checkDatasetNotReadOnly();
        if (n == null || isIncomplete()) return;
        boolean locked = writeLock();
        try {
            boolean closed = lastNode() == n && firstNode() == n;
            int i;
            List<Node> copy = getNodes();
            while ((i = copy.indexOf(n)) >= 0) {
                copy.remove(i);
            }
            i = copy.size();
            if (closed && i > 2) {
                copy.add(copy.get(0));
            } else if (i >= 2 && i <= 3 && copy.get(0) == copy.get(i-1)) {
                copy.remove(i-1);
            }
            setNodes(removeDouble(copy));
            n.clearCachedStyle();
        } finally {
            writeUnlock(locked);
        }
    }

    /**
     * Removes the given set of {@link Node nodes} from this way. Ignored, if selection is null.
     * @param selection The selection of nodes to remove. Ignored, if null
     * @since 5408
     */
    public void removeNodes(Set<? extends Node> selection) {
        checkDatasetNotReadOnly();
        if (selection == null || isIncomplete()) return;
        boolean locked = writeLock();
        try {
            setNodes(calculateRemoveNodes(selection));
            for (Node n : selection) {
                n.clearCachedStyle();
            }
        } finally {
            writeUnlock(locked);
        }
    }

    /**
     * Calculate the remaining nodes after a removal of the given set of {@link Node nodes} from this way.
     * @param selection The selection of nodes to remove. Ignored, if null
     * @return result of the removal, can be empty
     * @since 17102
     */
    public List<Node> calculateRemoveNodes(Set<? extends Node> selection) {
        if (selection == null || isIncomplete())
            return getNodes();
        boolean closed = isClosed() && selection.contains(lastNode());
        List<Node> copy = Arrays.stream(nodes)
                .filter(n -> !selection.contains(n))
                .collect(Collectors.toList());

        int i = copy.size();
        if (closed && i > 2) {
            copy.add(copy.get(0));
        } else if (i >= 2 && i <= 3 && copy.get(0) == copy.get(i-1)) {
            copy.remove(i-1);
        }
        return removeDouble(copy);
    }

    /**
     * Adds a node to the end of the list of nodes. Ignored, if n is null.
     *
     * @param n the node. Ignored, if null
     * @throws IllegalStateException if this way is marked as incomplete. We can't add a node
     * to an incomplete way
     * @since 1313
     */
    public void addNode(Node n) {
        checkDatasetNotReadOnly();
        if (n == null) return;

        boolean locked = writeLock();
        try {
            if (isIncomplete())
                throw new IllegalStateException(tr("Cannot add node {0} to incomplete way {1}.", n.getId(), getId()));
            clearCachedStyle();
            n.addReferrer(this);
            nodes = Utils.addInArrayCopy(nodes, n);
            n.clearCachedStyle();
            fireNodesChanged();
        } finally {
            writeUnlock(locked);
        }
    }

    /**
     * Adds a node at position offs.
     *
     * @param offs the offset
     * @param n the node. Ignored, if null.
     * @throws IllegalStateException if this way is marked as incomplete. We can't add a node
     * to an incomplete way
     * @throws IndexOutOfBoundsException if offs is out of bounds
     * @since 1313
     */
    public void addNode(int offs, Node n) {
        checkDatasetNotReadOnly();
        if (n == null) return;

        boolean locked = writeLock();
        try {
            if (isIncomplete())
                throw new IllegalStateException(tr("Cannot add node {0} to incomplete way {1}.", n.getId(), getId()));

            clearCachedStyle();
            n.addReferrer(this);
            Node[] newNodes = new Node[nodes.length + 1];
            System.arraycopy(nodes, 0, newNodes, 0, offs);
            System.arraycopy(nodes, offs, newNodes, offs + 1, nodes.length - offs);
            newNodes[offs] = n;
            nodes = newNodes;
            n.clearCachedStyle();
            fireNodesChanged();
        } finally {
            writeUnlock(locked);
        }
    }

    @Override
    public void setDeleted(boolean deleted) {
        boolean locked = writeLock();
        try {
            for (Node n:nodes) {
                if (deleted) {
                    n.removeReferrer(this);
                } else {
                    n.addReferrer(this);
                }
                n.clearCachedStyle();
            }
            fireNodesChanged();
            super.setDeleted(deleted);
        } finally {
            writeUnlock(locked);
        }
    }

    @Override
    public boolean isClosed() {
        if (isIncomplete()) return false;

        return nodes.length >= 3 && nodes[nodes.length-1] == nodes[0];
    }

    /**
     * Determines if this way denotes an area (closed way with at least three distinct nodes).
     * @return {@code true} if this way is closed and contains at least three distinct nodes
     * @see #isClosed
     * @since 5490
     */
    public boolean isArea() {
        if (this.nodes.length >= 4 && isClosed()) {
            Node distinctNode = null;
            for (int i = 1; i < nodes.length-1; i++) {
                if (distinctNode == null && nodes[i] != nodes[0]) {
                    distinctNode = nodes[i];
                } else if (distinctNode != null && nodes[i] != nodes[0] && nodes[i] != distinctNode) {
                    return true;
                }
            }
        }
        return false;
    }

    @Override
    public Node lastNode() {
        if (isIncomplete() || nodes.length == 0) return null;
        return nodes[nodes.length-1];
    }

    @Override
    public Node firstNode() {
        if (isIncomplete() || nodes.length == 0) return null;
        return nodes[0];
    }

    @Override
    public boolean isFirstLastNode(INode n) {
        if (isIncomplete() || nodes.length == 0) return false;
        return n == nodes[0] || n == nodes[nodes.length -1];
    }

    @Override
    public boolean isInnerNode(INode n) {
        if (isIncomplete() || nodes.length <= 2) return false;
        /* circular ways have only inner nodes, so return true for them! */
        if (n == nodes[0] && n == nodes[nodes.length-1]) return true;
        return IntStream.range(1, nodes.length - 1)
                .anyMatch(i -> nodes[i] == n);
    }

    @Override
    public OsmPrimitiveType getType() {
        return OsmPrimitiveType.WAY;
    }

    @Override
    public OsmPrimitiveType getDisplayType() {
        return isClosed() ? OsmPrimitiveType.CLOSEDWAY : OsmPrimitiveType.WAY;
    }

    private void checkNodes() {
        DataSet dataSet = getDataSet();
        if (dataSet != null) {
            for (Node n: nodes) {
                if (n.getDataSet() != dataSet)
                    throw new DataIntegrityProblemException("Nodes in way must be in the same dataset",
                            tr("Nodes in way must be in the same dataset"));
                if (n.isDeleted())
                    throw new DataIntegrityProblemException("Deleted node referenced: " + toString(),
                            "<html>" + tr("Deleted node referenced by {0}",
                                    DefaultNameFormatter.getInstance().formatAsHtmlUnorderedList(this)) + "</html>",
                            this, n);
            }
            if (Config.getPref().getBoolean("debug.checkNullCoor", true)) {
                for (Node n: nodes) {
                    if (n.isVisible() && !n.isIncomplete() && !n.isLatLonKnown())
                        throw new DataIntegrityProblemException("Complete visible node with null coordinates: " + toString(),
                                "<html>" + tr("Complete node {0} with null coordinates in way {1}",
                                        DefaultNameFormatter.getInstance().formatAsHtmlUnorderedList(n),
                                        DefaultNameFormatter.getInstance().formatAsHtmlUnorderedList(this)) + "</html>",
                                this, n);
                }
            }
        }
    }

    private void fireNodesChanged() {
        checkNodes();
        if (getDataSet() != null) {
            getDataSet().fireWayNodesChanged(this);
        }
    }

    @Override
    void setDataset(DataSet dataSet) {
        super.setDataset(dataSet);
        checkNodes();
    }

    @Override
    public BBox getBBox() {
        if (getDataSet() == null)
            return new BBox(this);
        if (bbox == null) {
            setBBox(new BBox(this));
        }
        return bbox;
    }

    @Override
    protected void addToBBox(BBox box, Set<PrimitiveId> visited) {
        box.add(getBBox());
    }

    private void setBBox(BBox bbox) {
        this.bbox = bbox == null ? null : bbox.toImmutable();
    }

    @Override
    public void updatePosition() {
        setBBox(new BBox(this));
        clearCachedStyle();
    }

    @Override
    public boolean hasIncompleteNodes() {
        /*
         * Ideally, we would store this as a flag, but a node may become
         * incomplete under some circumstances without being able to notify the
         * way to recalculate the flag.
         *
         * When profiling #20716 on Mesa County, CO (overpass download), the
         * Arrays.stream method was fairly expensive. When switching to the for
         * loop, the CPU samples for hasIncompleteNodes went from ~150k samples
         * to ~8.5k samples (94% improvement) and the memory allocations for
         * hasIncompleteNodes went from ~15.6 GB to 0.
         */
        for (Node node : nodes) {
            if (node.isIncomplete()) {
                return true;
            }
        }
        return false;
    }

    /**
     * Replies true if all nodes of the way have known lat/lon, false otherwise.
     * @return true if all nodes of the way have known lat/lon, false otherwise
     * @since 13033
     */
    public boolean hasOnlyLocatableNodes() {
        // This is used in various places, some of which are on the UI thread.
        // If this is called many times, the memory allocations can become prohibitive, if
        // we use Java streams.
        // This can be easily tested by loading a large amount of ways into JOSM, and then
        // selecting everything.
        for (Node node : nodes) {
            if (!node.isLatLonKnown()) {
                return false;
            }
        }
        return true;
    }

    @Override
    public boolean isUsable() {
        return super.isUsable() && !hasIncompleteNodes();
    }

    @Override
    public boolean isDrawable() {
        return super.isDrawable() && hasOnlyLocatableNodes();
    }

    /**
     * Replies the length of the way, in metres, as computed by {@link ILatLon#greatCircleDistance}.
     * @return The length of the way, in metres
     * @since 4138
     */
    public double getLength() {
        double length = 0;
        Node lastN = null;
        for (Node n:nodes) {
            if (lastN != null && lastN.isLatLonKnown() && n.isLatLonKnown()) {
                length += n.greatCircleDistance(lastN);
            }
            lastN = n;
        }
        return length;
    }

    /**
     * Replies the segment lengths of the way as computed by {@link ILatLon#greatCircleDistance}.
     *
     * @return The segment lengths of a way in metres, following way direction
     * @since 18553
     */
    public double[] getSegmentLengths() {
        return this.segmentLengths().toArray();
    }

    /**
     * Replies the length of the longest segment of the way, in metres, as computed by {@link ILatLon#greatCircleDistance}.
     * @return The length of the segment, in metres
     * @since 8320
     */
    public double getLongestSegmentLength() {
        return this.segmentLengths().max().orElse(0);
    }

    /**
     * Get the segment lengths as a stream
     * @return The stream of segment lengths (ordered)
     */
    private DoubleStream segmentLengths() {
        DoubleStream.Builder builder = DoubleStream.builder();
        Node lastN = null;
        for (Node n : nodes) {
            if (lastN != null && n.isLatLonKnown() && lastN.isLatLonKnown()) {
                double distance = n.greatCircleDistance(lastN);
                builder.accept(distance);
            }
            lastN = n;
        }
        return builder.build();
    }

    /**
     * Tests if this way is a oneway.
     * @return {@code 1} if the way is a oneway,
     *         {@code -1} if the way is a reversed oneway,
     *         {@code 0} otherwise.
     * @since 5199
     */
    public int isOneway() {
        String oneway = get("oneway");
        if (oneway != null) {
            if ("-1".equals(oneway)) {
                return -1;
            } else {
                Boolean isOneway = OsmUtils.getOsmBoolean(oneway);
                if (isOneway != null && isOneway) {
                    return 1;
                }
            }
        }
        return 0;
    }

    /**
     * Replies the first node of this way, respecting or not its oneway state.
     * @param respectOneway If true and if this way is a reversed oneway, replies the last node. Otherwise, replies the first node.
     * @return the first node of this way, according to {@code respectOneway} and its oneway state.
     * @since 5199
     */
    public Node firstNode(boolean respectOneway) {
        return !respectOneway || isOneway() != -1 ? firstNode() : lastNode();
    }

    /**
     * Replies the last node of this way, respecting or not its oneway state.
     * @param respectOneway If true and if this way is a reversed oneway, replies the first node. Otherwise, replies the last node.
     * @return the last node of this way, according to {@code respectOneway} and its oneway state.
     * @since 5199
     */
    public Node lastNode(boolean respectOneway) {
        return !respectOneway || isOneway() != -1 ? lastNode() : firstNode();
    }

    @Override
    public boolean concernsArea() {
        return hasAreaTags();
    }

    @Override
    public boolean isOutsideDownloadArea() {
        return Arrays.stream(nodes).anyMatch(Node::isOutsideDownloadArea);
    }

    @Override
    protected void keysChangedImpl(Map<String, String> originalKeys) {
        super.keysChangedImpl(originalKeys);
        clearCachedNodeStyles();
    }

    /**
     * Clears all cached styles for all nodes of this way. This should not be called from outside.
     * @see Node#clearCachedStyle()
     */
    public void clearCachedNodeStyles() {
        for (final Node n : nodes) {
            n.clearCachedStyle();
        }
    }

    /**
     * Returns angles of vertices.
     * @return angles of the way
     * @since 13670
     */
    public synchronized List<Pair<Double, Node>> getAngles() {
        List<Pair<Double, Node>> angles = new ArrayList<>();

        for (int i = 1; i < nodes.length - 1; i++) {
            Node n0 = nodes[i - 1];
            Node n1 = nodes[i];
            Node n2 = nodes[i + 1];

            double angle = Geometry.getNormalizedAngleInDegrees(Geometry.getCornerAngle(
                    n0.getEastNorth(), n1.getEastNorth(), n2.getEastNorth()));
            angles.add(new Pair<>(angle, n1));
        }

        angles.add(new Pair<>(Geometry.getNormalizedAngleInDegrees(Geometry.getCornerAngle(
                nodes[nodes.length - 2].getEastNorth(),
                nodes[0].getEastNorth(),
                nodes[1].getEastNorth())), nodes[0]));

        return angles;
    }

    @Override
    public UniqueIdGenerator getIdGenerator() {
        return idGenerator;
    }
}