/*

 * Copyright (c) 2014, 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.Collections;

import java.util.Formatter;

import java.util.List;

import java.util.Map;

import java.util.ServiceLoader;

import java.util.Set;

import java.util.SortedMap;

import java.util.TreeMap;

/**

 * This class contains methods for parsing Graal options and matching them against a set of

 * {@link OptionDescriptors}. The {@link OptionDescriptors} are loaded via a {@link ServiceLoader}.

 */

public class OptionsParser {

    public interface OptionConsumer {

        void set(OptionDescriptor desc, Object value);

    }

    /**

     * Parses a map representing assignments of values to options.

     *

     * @param optionSettings option settings (i.e., assignments of values to options)

     * @param setter the object to notify of the parsed option and value

     * @param loader the loader for {@linkplain #lookup(ServiceLoader, String) looking} up

     *            {@link OptionDescriptor}s

     * @throws IllegalArgumentException if there's a problem parsing {@code option}

     */

    public static void parseOptions(Map<String, String> optionSettings, OptionConsumer setter, ServiceLoader<OptionDescriptors> loader) {

        if (optionSettings != null && !optionSettings.isEmpty()) {

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

                parseOption(e.getKey(), e.getValue(), setter, loader);

            }

        }

    }

    /**

     * Parses a given option setting string to a map of settings.

     *

     * @param optionSetting a string matching the pattern {@code <name>=<value>}

     */

    public static void parseOptionSettingTo(String optionSetting, Map<String, String> dst) {

        int eqIndex = optionSetting.indexOf('=');

        if (eqIndex == -1) {

            throw new InternalError("Option setting has does not match the pattern <name>=<value>: " + optionSetting);

        }

        dst.put(optionSetting.substring(0, eqIndex), optionSetting.substring(eqIndex + 1));

    }

    /**

     * Looks up an {@link OptionDescriptor} based on a given name.

     *

     * @param loader provides the available {@link OptionDescriptor}s

     * @param name the name of the option to look up

     * @return the {@link OptionDescriptor} whose name equals {@code name} or null if not such

     *         descriptor is available

     */

    private static OptionDescriptor lookup(ServiceLoader<OptionDescriptors> loader, String name) {

        for (OptionDescriptors optionDescriptors : loader) {

            OptionDescriptor desc = optionDescriptors.get(name);

            if (desc != null) {

                return desc;

            }

        }

        return null;

    }

    /**

     * Parses a given option name and value.

     *

     * @param name the option name

     * @param valueString the option value as a string

     * @param setter the object to notify of the parsed option and value

     * @param loader the loader for {@linkplain #lookup(ServiceLoader, String) looking} up

     *            {@link OptionDescriptor}s

     * @throws IllegalArgumentException if there's a problem parsing {@code option}

     */

    private static void parseOption(String name, String valueString, OptionConsumer setter, ServiceLoader<OptionDescriptors> loader) {

        OptionDescriptor desc = lookup(loader, name);

        if (desc == null) {

            List<OptionDescriptor> matches = fuzzyMatch(loader, name);

            Formatter msg = new Formatter();

            msg.format("Could not find option %s", name);

            if (!matches.isEmpty()) {

                msg.format("%nDid you mean one of the following?");

                for (OptionDescriptor match : matches) {

                    msg.format("%n    %s=<value>", match.getName());

                }

            }

            throw new IllegalArgumentException(msg.toString());

        }

        Class<?> optionType = desc.getType();

        Object value;

        if (optionType == Boolean.class) {

            if ("true".equals(valueString)) {

                value = Boolean.TRUE;

            } else if ("false".equals(valueString)) {

                value = Boolean.FALSE;

            } else {

                throw new IllegalArgumentException("Boolean option '" + name + "' must have value \"true\" or \"false\", not \"" + valueString + "\"");

            }

        } else if (optionType == String.class || Enum.class.isAssignableFrom(optionType)) {

            value = valueString;

        } else {

            if (valueString.isEmpty()) {

                throw new IllegalArgumentException("Non empty value required for option '" + name + "'");

            }

            try {

                if (optionType == Float.class) {

                    value = Float.parseFloat(valueString);

                } else if (optionType == Double.class) {

                    value = Double.parseDouble(valueString);

                } else if (optionType == Integer.class) {

                    value = Integer.valueOf((int) parseLong(valueString));

                } else if (optionType == Long.class) {

                    value = Long.valueOf(parseLong(valueString));

                } else {

                    throw new IllegalArgumentException("Wrong value for option '" + name + "'");

                }

            } catch (NumberFormatException nfe) {

                throw new IllegalArgumentException("Value for option '" + name + "' has invalid number format: " + valueString);

            }

        }

        if (setter == null) {

            desc.getOptionValue().setValue(value);

        } else {

            setter.set(desc, value);

        }

    }

    private static long parseLong(String v) {

        String valueString = v.toLowerCase();

        long scale = 1;

        if (valueString.endsWith("k")) {

            scale = 1024L;

        } else if (valueString.endsWith("m")) {

            scale = 1024L * 1024L;

        } else if (valueString.endsWith("g")) {

            scale = 1024L * 1024L * 1024L;

        } else if (valueString.endsWith("t")) {

            scale = 1024L * 1024L * 1024L * 1024L;

        }

        if (scale != 1) {

            /* Remove trailing scale character. */

            valueString = valueString.substring(0, valueString.length() - 1);

        }

        return Long.parseLong(valueString) * scale;

    }

    /**

     * 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 = Collections.singletonList(text);

        if (text.length() > width) {

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

            lines = new ArrayList<>();

            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(' ');

                }

                String[] embeddedLines = chunk.split("%n", -2);

                if (embeddedLines.length == 1) {

                    line.append(chunk);

                } else {

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

                        line.append(embeddedLines[i]);

                        if (i < embeddedLines.length - 1) {

                            lines.add(line.toString());

                            line.setLength(0);

                        }

                    }

                }

            }

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

                lines.add(line.toString());

            }

        }

        return lines;

    }

    private static final int PROPERTY_LINE_WIDTH = 80;

    private static final int PROPERTY_HELP_INDENT = 10;

    public static void printFlags(ServiceLoader<OptionDescriptors> loader, PrintStream out, Set<String> explicitlyAssigned, 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 : "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.getOptionValue().getValue();

            if (value instanceof String) {

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

            }

            String help = desc.getHelp();

            if (desc.getOptionValue() instanceof EnumOptionValue) {

                EnumOptionValue<?> eoption = (EnumOptionValue<?>) desc.getOptionValue();

                String evalues = eoption.getOptionValues().toString();

                if (help.length() > 0 && !help.endsWith(".")) {

                    help += ".";

                }

                help += " Valid values are: " + evalues.substring(1, evalues.length() - 1);

            }

            String name = namePrefix + e.getKey();

            String assign = explicitlyAssigned.contains(name) ? ":=" : "=";

            String typeName = desc.getOptionValue() instanceof EnumOptionValue ? "String" : desc.getType().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);

            }

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

                List<String> helpLines = wrap(help, PROPERTY_LINE_WIDTH - PROPERTY_HELP_INDENT);

                for (int i = 0; i < helpLines.size(); i++) {

                    out.printf("%" + PROPERTY_HELP_INDENT + "s%s%n", "", helpLines.get(i));

                }

            }

        }

    }

    /**

     * Compute string similarity based on Dice's coefficient.

     *

     * Ported from str_similar() in globals.cpp.

     */

    static float stringSimiliarity(String str1, String str2) {

        int hit = 0;

        for (int i = 0; i < str1.length() - 1; ++i) {

            for (int j = 0; j < str2.length() - 1; ++j) {

                if ((str1.charAt(i) == str2.charAt(j)) && (str1.charAt(i + 1) == str2.charAt(j + 1))) {

                    ++hit;

                    break;

                }

            }

        }

        return 2.0f * hit / (str1.length() + str2.length());

    }

    private static final float FUZZY_MATCH_THRESHOLD = 0.7F;

    /**

     * Returns the set of options that fuzzy match a given option name.

     */

    private static List<OptionDescriptor> fuzzyMatch(ServiceLoader<OptionDescriptors> loader, String optionName) {

        List<OptionDescriptor> matches = new ArrayList<>();

        for (OptionDescriptors options : loader) {

            for (OptionDescriptor option : options) {

                float score = stringSimiliarity(option.getName(), optionName);

                if (score >= FUZZY_MATCH_THRESHOLD) {

                    matches.add(option);

                }

            }

        }

        return matches;

    }

}