/*

 * Copyright (c) 2013, 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.options;

import java.io.PrintStream;

import java.util.ArrayList;

import java.util.Comparator;

import java.util.List;

import java.util.Map;

import java.util.SortedMap;

import java.util.TreeMap;

import jdk.internal.vm.compiler.collections.EconomicMap;

import jdk.internal.vm.compiler.collections.Equivalence;

import jdk.internal.vm.compiler.collections.UnmodifiableEconomicMap;

import jdk.internal.vm.compiler.collections.UnmodifiableMapCursor;

/**

 * A context for obtaining values for {@link OptionKey}s.

 */

public class OptionValues {

    private final UnmodifiableEconomicMap<OptionKey<?>, Object> values;

    protected boolean containsKey(OptionKey<?> key) {

        return values.containsKey(key);

    }

    public OptionValues(OptionValues initialValues, UnmodifiableEconomicMap<OptionKey<?>, Object> extraPairs) {

        EconomicMap<OptionKey<?>, Object> map = newOptionMap();

        if (initialValues != null) {

            map.putAll(initialValues.getMap());

        }

        initMap(map, extraPairs);

        this.values = map;

    }

    public OptionValues(OptionValues initialValues, OptionKey<?> key1, Object value1, Object... extraPairs) {

        this(initialValues, asMap(key1, value1, extraPairs));

    }

    /**

     * Creates a new map suitable for using {@link OptionKey}s as keys.

     */

    public static EconomicMap<OptionKey<?>, Object> newOptionMap() {

        return EconomicMap.create(Equivalence.IDENTITY);

    }

    /**

     * Gets an immutable view of the key/value pairs in this object. Values read from this view

     * should be {@linkplain #decodeNull(Object) decoded} before being used.

     */

    public UnmodifiableEconomicMap<OptionKey<?>, Object> getMap() {

        return values;

    }

    /**

     * @param key1 first key in map

     * @param value1 first value in map

     * @param extraPairs key/value pairs of the form {@code [key1, value1, key2, value2, ...]}

     * @return a map containing the key/value pairs as entries

     */

    public static EconomicMap<OptionKey<?>, Object> asMap(OptionKey<?> key1, Object value1, Object... extraPairs) {

        EconomicMap<OptionKey<?>, Object> map = newOptionMap();

        map.put(key1, value1);

        for (int i = 0; i < extraPairs.length; i += 2) {

            OptionKey<?> key = (OptionKey<?>) extraPairs[i];

            Object value = extraPairs[i + 1];

            map.put(key, value);

        }

        return map;

    }

    public OptionValues(UnmodifiableEconomicMap<OptionKey<?>, Object> values) {

        EconomicMap<OptionKey<?>, Object> map = newOptionMap();

        initMap(map, values);

        this.values = map;

    }

    protected static void initMap(EconomicMap<OptionKey<?>, Object> map, UnmodifiableEconomicMap<OptionKey<?>, Object> values) {

        UnmodifiableMapCursor<OptionKey<?>, Object> cursor = values.getEntries();

        while (cursor.advance()) {

            map.put(cursor.getKey(), encodeNull(cursor.getValue()));

        }

    }

    protected <T> T get(OptionKey<T> key) {

        return get(values, key);

    }

    @SuppressWarnings("unchecked")

    protected static <T> T get(UnmodifiableEconomicMap<OptionKey<?>, Object> values, OptionKey<T> key) {

        Object value = values.get(key);

        if (value == null) {

            return key.getDefaultValue();

        }

        return (T) decodeNull(value);

    }

    private static final Object NULL = new Object();

    protected static Object encodeNull(Object value) {

        return value == null ? NULL : value;

    }

    /**

     * Decodes a value that may be the sentinel value for {@code null} in a map.

     */

    public static Object decodeNull(Object value) {

        return value == NULL ? null : value;

    }

    @Override

    public String toString() {

        return toString(getMap());

    }

    public static String toString(UnmodifiableEconomicMap<OptionKey<?>, Object> values) {

        Comparator<OptionKey<?>> comparator = new Comparator<OptionKey<?>>() {

            @Override

            public int compare(OptionKey<?> o1, OptionKey<?> o2) {

                return o1.getName().compareTo(o2.getName());

            }

        };

        SortedMap<OptionKey<?>, Object> sorted = new TreeMap<>(comparator);

        UnmodifiableMapCursor<OptionKey<?>, Object> cursor = values.getEntries();

        while (cursor.advance()) {

            sorted.put(cursor.getKey(), decodeNull(cursor.getValue()));

        }

        return sorted.toString();

    }

    private static final int PROPERTY_LINE_WIDTH = 80;

    private static final int PROPERTY_HELP_INDENT = 10;

    /**

     * Wraps some given text to one or more lines of a given maximum width.

     *

     * @param text text to wrap

     * @param width maximum width of an output line, exception for words in {@code text} longer than

     *            this value

     * @return {@code text} broken into lines

     */

    private static List<String> wrap(String text, int width) {

        List<String> lines = new ArrayList<>();

        if (text.length() > width) {

            String[] chunks = text.split("\\s+");

            StringBuilder line = new StringBuilder();

            for (String chunk : chunks) {

                if (line.length() + chunk.length() > width) {

                    lines.add(line.toString());

                    line.setLength(0);

                }

                if (line.length() != 0) {

                    line.append(' ');

                }

                line.append(chunk);

            }

            if (line.length() != 0) {

                lines.add(line.toString());

            }

        } else {

            lines.add(text);

        }

        return lines;

    }

    /**

     * Prints a help message to {@code out} describing all options available via {@code loader}. The

     * key/value for each option is separated by {@code :=} if the option has an entry in this

     * object otherwise {@code =} is used as the separator.

     *

     * @param loader

     * @param out

     * @param namePrefix

     */

    public void printHelp(Iterable<OptionDescriptors> loader, PrintStream out, String namePrefix) {

        SortedMap<String, OptionDescriptor> sortedOptions = new TreeMap<>();

        for (OptionDescriptors opts : loader) {

            for (OptionDescriptor desc : opts) {

                String name = desc.getName();

                OptionDescriptor existing = sortedOptions.put(name, desc);

                assert existing == null || existing == desc : "Option named \"" + name + "\" has multiple definitions: " + existing.getLocation() + " and " + desc.getLocation();

            }

        }

        for (Map.Entry<String, OptionDescriptor> e : sortedOptions.entrySet()) {

            OptionDescriptor desc = e.getValue();

            Object value = desc.getOptionKey().getValue(this);

            if (value instanceof String) {

                value = '"' + String.valueOf(value) + '"';

            }

            String name = namePrefix + e.getKey();

            String assign = containsKey(desc.optionKey) ? ":=" : "=";

            String typeName = desc.getOptionKey() instanceof EnumOptionKey ? "String" : desc.getOptionValueType().getSimpleName();

            String linePrefix = String.format("%s %s %s ", name, assign, value);

            int typeStartPos = PROPERTY_LINE_WIDTH - typeName.length();

            int linePad = typeStartPos - linePrefix.length();

            if (linePad > 0) {

                out.printf("%s%-" + linePad + "s[%s]%n", linePrefix, "", typeName);

            } else {

                out.printf("%s[%s]%n", linePrefix, typeName);

            }

            List<String> helpLines;

            String help = desc.getHelp();

            if (help.length() != 0) {

                helpLines = wrap(help, PROPERTY_LINE_WIDTH - PROPERTY_HELP_INDENT);

                helpLines.addAll(desc.getExtraHelp());

            } else {

                helpLines = desc.getExtraHelp();

            }

            for (String line : helpLines) {

                out.printf("%" + PROPERTY_HELP_INDENT + "s%s%n", "", line);

            }

        }

    }

}