/*

 * Copyright (c) 2011, 2011, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package org.graalvm.compiler.graph;

import java.util.AbstractMap.SimpleEntry;

import java.util.Arrays;

import java.util.Iterator;

import java.util.Map.Entry;

public class NodeMap<T> extends NodeIdAccessor {

    private static final int MIN_REALLOC_SIZE = 16;

    protected Object[] values;

    public NodeMap(Graph graph) {

        super(graph);

        this.values = new Object[graph.nodeIdCount()];

    }

    public NodeMap(NodeMap<T> copyFrom) {

        super(copyFrom.graph);

        this.values = Arrays.copyOf(copyFrom.values, copyFrom.values.length);

    }

    @SuppressWarnings("unchecked")

    public T get(Node node) {

        assert check(node);

        return (T) values[getNodeId(node)];

    }

    @SuppressWarnings("unchecked")

    public T getAndGrow(Node node) {

        checkAndGrow(node);

        return (T) values[getNodeId(node)];

    }

    private void checkAndGrow(Node node) {

        if (isNew(node)) {

            this.values = Arrays.copyOf(values, Math.max(MIN_REALLOC_SIZE, graph.nodeIdCount() * 3 / 2));

        }

        assert check(node);

    }

    public boolean isEmpty() {

        return !entries().iterator().hasNext();

    }

    public boolean containsKey(Object key) {

        if (key instanceof Node) {

            Node node = (Node) key;

            if (node.graph() == graph()) {

                return get(node) != null;

            }

        }

        return false;

    }

    public boolean containsValue(Object value) {

        for (Object o : values) {

            if (o == value) {

                return true;

            }

        }

        return false;

    }

    public Graph graph() {

        return graph;

    }

    public void set(Node node, T value) {

        assert check(node);

        values[getNodeId(node)] = value;

    }

    public void setAndGrow(Node node, T value) {

        checkAndGrow(node);

        values[getNodeId(node)] = value;

    }

    /**

     * @param i

     * @return Return the key for the entry at index {@code i}

     */

    protected Node getKey(int i) {

        return graph.getNode(i);

    }

    public int size() {

        return values.length;

    }

    public boolean isNew(Node node) {

        return getNodeId(node) >= size();

    }

    private boolean check(Node node) {

        assert node.graph() == graph : String.format("%s is not part of the graph", node);

        assert !isNew(node) : "this node was added to the graph after creating the node map : " + node;

        return true;

    }

    public void clear() {

        Arrays.fill(values, null);

    }

    public Iterable<Entry<Node, T>> entries() {

        return new Iterable<Entry<Node, T>>() {

            @Override

            public Iterator<Entry<Node, T>> iterator() {

                return new Iterator<Entry<Node, T>>() {

                    int i = 0;

                    @Override

                    public boolean hasNext() {

                        forward();

                        return i < NodeMap.this.values.length;

                    }

                    @SuppressWarnings("unchecked")

                    @Override

                    public Entry<Node, T> next() {

                        final int pos = i;

                        Node key = NodeMap.this.getKey(pos);

                        T value = (T) NodeMap.this.values[pos];

                        i++;

                        forward();

                        return new SimpleEntry<Node, T>(key, value) {

                            private static final long serialVersionUID = 7813842391085737738L;

                            @Override

                            public T setValue(T v) {

                                T oldv = super.setValue(v);

                                NodeMap.this.values[pos] = v;

                                return oldv;

                            }

                        };

                    }

                    @Override

                    public void remove() {

                        throw new UnsupportedOperationException();

                    }

                    private void forward() {

                        while (i < NodeMap.this.values.length && (NodeMap.this.getKey(i) == null || NodeMap.this.values[i] == null)) {

                            i++;

                        }

                    }

                };

            }

        };

    }

    @Override

    public String toString() {

        Iterator<Entry<Node, T>> i = entries().iterator();

        if (!i.hasNext()) {

            return "{}";

        }

        StringBuilder sb = new StringBuilder();

        sb.append('{');

        while (true) {

            Entry<Node, T> e = i.next();

            Node key = e.getKey();

            T value = e.getValue();

            sb.append(key);

            sb.append('=');

            sb.append(value);

            if (!i.hasNext()) {

                return sb.append('}').toString();

            }

            sb.append(',').append(' ');

        }

    }

}