/***** BEGIN LICENSE BLOCK *****
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 * except in compliance with the License. You may obtain a copy of
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 *
 * Software distributed under the License is distributed on an "AS
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 * Copyright (C) 2001-2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
 * Copyright (C) 2002 Benoit Cerrina <b.cerrina@wanadoo.fr>
 * Copyright (C) 2002-2004 Anders Bengtsson <ndrsbngtssn@yahoo.se>
 * Copyright (C) 2004 Thomas E Enebo <enebo@acm.org>
 * Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de>
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package org.jruby.javasupport;

import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.jruby.Ruby;
import org.jruby.util.ArraySupport;
import org.jruby.util.WeakIdentityHashMap;
import org.jruby.util.collections.ClassValue;
import org.jruby.javasupport.binding.AssignedName;
import org.jruby.javasupport.proxy.JavaProxyClass;

/**
 * Internal APIs of {@link JavaSupport}.
 */
public class JavaSupportImpl extends JavaSupport {

    private final ClassValue<Map<String, AssignedName>> staticAssignedNames =
            ClassValue.newInstance(JavaSupportImpl::newAssignedNames);
    private final ClassValue<Map<String, AssignedName>> instanceAssignedNames =
            ClassValue.newInstance(JavaSupportImpl::newAssignedNames);

    public JavaSupportImpl(final Ruby runtime) {
        super(runtime);
    }

    public void tearDown() {
        super.tearDown();
        staticAssignedNames.clear();
        instanceAssignedNames.clear();
    }

    private static Map<String, AssignedName> newAssignedNames(Class<?> klass) {
        return new HashMap<>(8, 1);
    }


    public ClassValue<Map<String, AssignedName>> getStaticAssignedNames() {
        return staticAssignedNames;
    }

    public ClassValue<Map<String, AssignedName>> getInstanceAssignedNames() {
        return instanceAssignedNames;
    }

    // cache of all JavaProxyClass objects created for this runtime
    private final Map<ProxyClassKey, JavaProxyClass> javaProxyClasses = new HashMap<>();

    /**
     * a replacement for {@link #getJavaProxyClassCache()} API
     */
    protected JavaProxyClass fetchJavaProxyClass(ProxyClassKey classKey) {
        synchronized (javaProxyClasses) {
            return javaProxyClasses.get(classKey);
        }
    }

    /**
     * a replacement for {@link #getJavaProxyClassCache()} API
     */
    protected JavaProxyClass saveJavaProxyClass(ProxyClassKey classKey, JavaProxyClass klass) {
        synchronized (javaProxyClasses) {
            JavaProxyClass existing = javaProxyClasses.get(classKey);
            if ( existing != null ) return existing;
            javaProxyClasses.put(classKey, klass);
        }
        return klass;
    }

    // internal helper to access non-public fetch method
    public static JavaProxyClass fetchJavaProxyClass(final Ruby runtime, ProxyClassKey classKey) {
        return ((JavaSupportImpl) runtime.getJavaSupport()).fetchJavaProxyClass(classKey);
    }

    // internal helper to access non-public save method
    public static JavaProxyClass saveJavaProxyClass(final Ruby runtime, ProxyClassKey classKey, JavaProxyClass klass) {
        return ((JavaSupportImpl) runtime.getJavaSupport()).saveJavaProxyClass(classKey, klass);
    }

    /**
     * <p>Note: Internal API - subject to change!</p>
     */
    public static final class ProxyClassKey {
        final Class superClass;
        final Class[] interfaces;
        final Set<String> names; // "usable" method names - assumed immutable

        private ProxyClassKey(Class superClass, Class[] interfaces, Set<String> names) {
            this.superClass = superClass;
            this.interfaces = interfaces;
            this.names = names;
        }

        public static ProxyClassKey getInstance(Class superClass, Class[] interfaces, Set<String> names) {
            return new ProxyClassKey(superClass, interfaces, names);
        }

        @Override
        public boolean equals(Object obj) {
            if ( obj instanceof ProxyClassKey ) {
                final ProxyClassKey that = (ProxyClassKey) obj;
                if (this.superClass != that.superClass) return false;

                if (this.names.size() != that.names.size()) return false;
                if ( ! this.names.equals(that.names) ) return false;

                final int len = this.interfaces.length;
                if (len != that.interfaces.length) return false;
                // order is not important :
                for ( int i = 0; i < len; i++ ) {
                    final Class iface = this.interfaces[i];
                    boolean ifaceFound = false;
                    for ( int j = 0; j < len; j++ ) {
                        if ( iface == that.interfaces[j] ) {
                            ifaceFound = true; break;
                        }
                    }
                    if ( ! ifaceFound ) return false;
                }
                return true;
            }
            return false;
        }

        private int hash;

        @Override
        public int hashCode() {
            int hash = this.hash;
            if (hash != 0) return hash;

            for ( int i = 0; i < interfaces.length; i++ ) {
                hash += interfaces[i].hashCode();
            }
            return this.hash = (hash * superClass.hashCode()) ^ this.names.hashCode();
        }
    }

}
