/*

 * 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

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 */

package org.graalvm.compiler.options;

import static jdk.vm.ci.services.Services.IS_BUILDING_NATIVE_IMAGE;

import static jdk.vm.ci.services.Services.IS_IN_NATIVE_IMAGE;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Formatter;

import java.util.List;

import java.util.ServiceLoader;

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

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

/**

 * 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 {

    private static volatile List<OptionDescriptors> cachedOptionDescriptors;

    /**

     * Gets an iterable of available {@link OptionDescriptors}.

     */

    public static Iterable<OptionDescriptors> getOptionsLoader() {

        if (IS_IN_NATIVE_IMAGE || cachedOptionDescriptors != null) {

            return cachedOptionDescriptors;

        }

        ClassLoader loader;

        if (java8OrEarlier) {

            // On JDK 8, Graal and its extensions are loaded by same class loader.

            loader = OptionDescriptors.class.getClassLoader();

        } else {

            /*

             * The Graal module (i.e., jdk.internal.vm.compiler) is loaded by the platform class

             * loader as of JDK 9. Modules that depend on and extend Graal are loaded by the app

             * class loader. As such, we need to start the provider search at the app class loader

             * instead of the platform class loader.

             */

            loader = ClassLoader.getSystemClassLoader();

        }

        Iterable<OptionDescriptors> result = ServiceLoader.load(OptionDescriptors.class, loader);

        if (IS_BUILDING_NATIVE_IMAGE) {

            ArrayList<OptionDescriptors> optionDescriptors = new ArrayList<>();

            for (OptionDescriptors descriptors : result) {

                optionDescriptors.add(descriptors);

            }

            OptionsParser.cachedOptionDescriptors = optionDescriptors;

        }

        return result;

    }

    /**

     * Parses a map representing assignments of values to options.

     *

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

     * @param values the object in which to store the parsed values

     * @param loader source of the available {@link OptionDescriptors}

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

     */

    public static void parseOptions(EconomicMap<String, String> optionSettings, EconomicMap<OptionKey<?>, Object> values, Iterable<OptionDescriptors> loader) {

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

            MapCursor<String, String> cursor = optionSettings.getEntries();

            while (cursor.advance()) {

                parseOption(cursor.getKey(), cursor.getValue(), values, loader);

            }

        }

    }

    /**

     * Parses a given option setting string and adds the parsed key and value {@code dst}.

     *

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

     */

    public static void parseOptionSettingTo(String optionSetting, EconomicMap<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 source of the available {@link OptionDescriptors}

     * @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(Iterable<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 uncheckedValue the unchecked value for the option

     * @param values the object in which to store the parsed option and value

     * @param loader source of the available {@link OptionDescriptors}

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

     */

    public static void parseOption(String name, Object uncheckedValue, EconomicMap<OptionKey<?>, Object> values, Iterable<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.getOptionValueType();

        Object value;

        if (!(uncheckedValue instanceof String)) {

            if (optionType != uncheckedValue.getClass()) {

                String type = optionType.getSimpleName();

                throw new IllegalArgumentException(type + " option '" + name + "' must have " + type + " value, not " + uncheckedValue.getClass() + " [toString: " + uncheckedValue + "]");

            }

            value = uncheckedValue;

        } else {

            String valueString = (String) uncheckedValue;

            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 \"" + uncheckedValue + "\"");

                }

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

                value = valueString;

            } else if (Enum.class.isAssignableFrom(optionType)) {

                value = ((EnumOptionKey<?>) desc.getOptionKey()).valueOf(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);

                }

            }

        }

        desc.getOptionKey().update(values, 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;

    }

    /**

     * 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(Iterable<OptionDescriptors> loader, String optionName) {

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

        for (OptionDescriptors options : loader) {

            collectFuzzyMatches(options, optionName, matches);

        }

        return matches;

    }

    /**

     * Collects the set of options that fuzzy match a given option name. String similarity for fuzzy

     * matching is based on Dice's coefficient.

     *

     * @param toSearch the set of option descriptors to search

     * @param name the option name to search for

     * @param matches the collection to which fuzzy matches of {@code name} will be added

     * @return whether any fuzzy matches were found

     */

    public static boolean collectFuzzyMatches(Iterable<OptionDescriptor> toSearch, String name, Collection<OptionDescriptor> matches) {

        boolean found = false;

        for (OptionDescriptor option : toSearch) {

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

            if (score >= FUZZY_MATCH_THRESHOLD) {

                found = true;

                matches.add(option);

            }

        }

        return found;

    }

}