/*

 * Copyright (c) 2015, 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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 jdk.nashorn.tools.jjs;

import java.io.IOException;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.List;

import java.util.WeakHashMap;

import java.util.regex.Pattern;

import java.util.stream.Collectors;

import jdk.nashorn.internal.runtime.Context;

import jdk.nashorn.internal.runtime.JSType;

import jdk.nashorn.internal.runtime.NativeJavaPackage;

import jdk.nashorn.internal.runtime.PropertyMap;

import jdk.nashorn.internal.runtime.ScriptObject;

import jdk.nashorn.internal.runtime.ScriptRuntime;

import jdk.nashorn.internal.objects.NativeJava;

/*

 * A helper class to get properties of a given object for source code completion.

 */

final class PropertiesHelper {

    // Java package properties helper, may be null

    private PackagesHelper pkgsHelper;

    // cached properties list

    private final WeakHashMap<Object, List<String>> propsCache = new WeakHashMap<>();

    /**

     * Construct a new PropertiesHelper.

     *

     * @param context the current nashorn Context

     */

    PropertiesHelper(final Context context) {

        try {

            this.pkgsHelper = PackagesHelper.create(context);

        } catch (final IOException exp) {

            if (Main.DEBUG) {

                exp.printStackTrace();

            }

            this.pkgsHelper = null;

        }

    }

    void close() throws Exception {

        propsCache.clear();

        pkgsHelper.close();

    }

    /**

     * returns the list of properties of the given object.

     *

     * @param obj object whose property list is returned

     * @return the list of properties of the given object

     */

    List<String> getProperties(final Object obj) {

        assert obj != null && obj != ScriptRuntime.UNDEFINED;

        // wrap JS primitives as objects before gettting properties

        if (JSType.isPrimitive(obj)) {

            return getProperties(JSType.toScriptObject(obj));

        }

        // Handle Java package prefix case first. Should do it before checking

        // for its super class ScriptObject!

        if (obj instanceof NativeJavaPackage) {

            if (pkgsHelper != null) {

                return pkgsHelper.getPackageProperties(((NativeJavaPackage)obj).getName());

            } else {

                return Collections.<String>emptyList();

            }

        }

        // script object - all inherited and non-enumerable, non-index properties

        if (obj instanceof ScriptObject) {

            final ScriptObject sobj = (ScriptObject)obj;

            final PropertyMap pmap = sobj.getMap();

            if (propsCache.containsKey(pmap)) {

                return propsCache.get(pmap);

            }

            final String[] keys = sobj.getAllKeys();

            List<String> props = Arrays.asList(keys);

            props = props.stream()

                         .filter(s -> Character.isJavaIdentifierStart(s.charAt(0)))

                         .collect(Collectors.toList());

            Collections.sort(props);

            // cache properties against the PropertyMap

            propsCache.put(pmap, props);

            return props;

        }

        // java class case - don't refer to StaticClass directly

        if (NativeJava.isType(ScriptRuntime.UNDEFINED, obj)) {

            if (propsCache.containsKey(obj)) {

                return propsCache.get(obj);

            }

            final List<String> props = NativeJava.getProperties(obj);

            Collections.sort(props);

            // cache properties against the StaticClass representing the class

            propsCache.put(obj, props);

            return props;

        }

        // any other Java object

        final Class<?> clazz = obj.getClass();

        if (propsCache.containsKey(clazz)) {

            return propsCache.get(clazz);

        }

        final List<String> props = NativeJava.getProperties(obj);

        Collections.sort(props);

        // cache properties against the Class object

        propsCache.put(clazz, props);

        return props;

    }

    // This method creates a regex Pattern to use to do CamelCase

    // matching. The pattern is derived from user supplied string

    // containing one or more upper case characters in it.

    private static Pattern makeCamelCasePattern(final String str) {

        assert !str.isEmpty();

        final char[] chars = str.toCharArray();

        final StringBuilder buf = new StringBuilder();

        boolean seenUpperCase = false;

        // Skip first char for case check. Even if it is upper case,

        // we do not want to put lower case matching pattern before

        // the first letter!

        buf.append(chars[0]);

        for (int idx = 1; idx < chars.length; idx++) {

            final char ch = chars[idx];

            if (ch >= 'A' && ch <= 'Z') {

                seenUpperCase = true;

                buf.append("[^A-Z]*");

            }

            buf.append(ch);

        }

        if (seenUpperCase) {

            // match anything at the end!

            buf.append(".*");

            try {

                return Pattern.compile(buf.toString());

            } catch (Exception exp) {

            }

        }

        return null;

    }

    /**

     * Returns the list of properties of the given object that start with the given prefix.

     *

     * @param obj object whose property list is returned

     * @param prefix property prefix to be matched

     * @return the list of properties of the given object

     */

    List<String> getProperties(final Object obj, final String prefix) {

        assert prefix != null && !prefix.isEmpty();

        List<String> allProps = getProperties(obj);

        List<String> props = allProps.stream()

                   .filter(s -> s.startsWith(prefix))

                   .collect(Collectors.toList());

        // If no match, try CamelCase completion..

        if (props.isEmpty()) {

            final Pattern pat = makeCamelCasePattern(prefix);

            if (pat != null) {

                return allProps.stream()

                    .filter(s -> pat.matcher(s).matches())

                    .collect(Collectors.toList());

            }

        }

        return props;

    }

}