/*
 **** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * License Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2005 Thomas E Enebo <enebo@acm.org>
 * Copyright (C) 2009 MenTaLguY <mental@rydia.net>
 * Copyright (C) 2010 Charles Oliver Nutter <headius@headius.com>
 * 
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
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 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the EPL, the GPL or the LGPL.
 ***** END LICENSE BLOCK *****/

package org.jruby.ext.jruby;

import org.jcodings.specific.ASCIIEncoding;
import org.jruby.*;
import org.jruby.anno.JRubyMethod;
import org.jruby.anno.JRubyModule;
import org.jruby.ast.Node;
import org.jruby.ast.RootNode;
import org.jruby.ast.util.ArgsUtil;
import org.jruby.ir.IRBuilder;
import org.jruby.ir.IRManager;
import org.jruby.ir.IRScriptBody;
import org.jruby.ir.targets.JVMVisitor;
import org.jruby.ir.targets.JVMVisitorMethodContext;
import org.jruby.javasupport.Java;
import org.jruby.javasupport.JavaUtil;
import org.jruby.runtime.*;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.runtime.load.Library;
import org.jruby.util.ByteList;

import java.io.ByteArrayInputStream;

Native part of require 'jruby', e.g. provides methods for swapping between the normal Ruby reference to an
object and the Java-integration-wrapped reference.
Parts of JRuby name-space are loaded even without require 'jruby', those live under JRuby::Util.
See Also:
JRubyUtilLibrary/**
 * Native part of require 'jruby', e.g. provides methods for swapping between the normal Ruby reference to an
 * object and the Java-integration-wrapped reference.
 *
 * Parts of JRuby name-space are loaded even without <code>require 'jruby'<code/>, those live under JRuby::Util.
 * @see JRubyUtilLibrary
 */
@JRubyModule(name="JRuby")
public class JRubyLibrary implements Library {
    public void load(Ruby runtime, boolean wrap) {
        // load Ruby parts of the 'jruby' library
        runtime.getLoadService().loadFromClassLoader(runtime.getJRubyClassLoader(), "jruby/jruby.rb", false);

        RubyModule JRuby = runtime.getOrCreateModule("JRuby");

        JRuby.defineAnnotatedMethods(JRubyLibrary.class);
        JRuby.defineAnnotatedMethods(JRubyUtilLibrary.class);

        JRuby.defineClassUnder("ThreadLocal", runtime.getObject(), JRubyThreadLocal.ALLOCATOR)
             .defineAnnotatedMethods(JRubyExecutionContextLocal.class);

        JRuby.defineClassUnder("FiberLocal", runtime.getObject(), JRubyFiberLocal.ALLOCATOR)
             .defineAnnotatedMethods(JRubyExecutionContextLocal.class);

        RubyModule CONFIG = JRuby.defineModuleUnder("CONFIG");
        CONFIG.getSingletonClass().defineAnnotatedMethods(JRubyConfig.class);
    }

    
JRuby::CONFIG
/**
     * JRuby::CONFIG
     */
    public static class JRubyConfig {
        @JRubyMethod(name = "rubygems_disabled?")
        public static IRubyObject rubygems_disabled_p(ThreadContext context, IRubyObject self) {
            return context.runtime.newBoolean(context.runtime.getInstanceConfig().isDisableGems());
        }

        @JRubyMethod(name = "did_you_mean_disabled?")
        public static IRubyObject did_you_mean_disabled_p(ThreadContext context, IRubyObject self) {
            return context.runtime.newBoolean(context.runtime.getInstanceConfig().isDisableDidYouMean());
        }
    }

    
Wrap the given object as in Java integration and return the wrapper. This
version uses ObjectProxyCache to guarantee the same wrapper is returned
as long as it is in use somewhere.
/**
     * Wrap the given object as in Java integration and return the wrapper. This
     * version uses ObjectProxyCache to guarantee the same wrapper is returned
     * as long as it is in use somewhere.
     */
    @JRubyMethod(module = true, name = {"reference", "ref"})
    public static IRubyObject reference(ThreadContext context, IRubyObject recv, IRubyObject obj) {
        return Java.getInstance(context.runtime, obj, false);
    }

    
Wrap the given object as in Java integration and return the wrapper.
This version does not use ObjectProxyCache.
/**
     * Wrap the given object as in Java integration and return the wrapper.
     * This version does not use ObjectProxyCache.
     */
    @JRubyMethod(module = true)
    public static IRubyObject reference0(ThreadContext context, IRubyObject recv, IRubyObject obj) {
        return Java.wrapJavaObject(context.runtime, obj);
    }

    @JRubyMethod(module = true)
    public static IRubyObject runtime(ThreadContext context, IRubyObject recv) {
        return Java.wrapJavaObject(context.runtime, context.runtime);
    }

    
Unwrap the given Java-integration-wrapped object, returning the unwrapped
object. If the wrapped object is not a Ruby object, an error will raise.
/**
     * Unwrap the given Java-integration-wrapped object, returning the unwrapped
     * object. If the wrapped object is not a Ruby object, an error will raise.
     */
    @JRubyMethod(module = true, name = {"dereference", "deref"})
    public static IRubyObject dereference(ThreadContext context, IRubyObject recv, IRubyObject obj) {
        Object unwrapped = JavaUtil.unwrapIfJavaObject(obj);
        if (unwrapped == obj) {
            throw context.runtime.newTypeError("got " + obj.inspect() + ", expected wrapped Java object");
        }
        if (!(unwrapped instanceof IRubyObject)) {
            throw context.runtime.newTypeError("got " + obj.inspect() + ", expected Java-wrapped Ruby object");
        }
        return (IRubyObject) unwrapped;
    }

    
Run the provided (required) block with the "global runtime" set to the current runtime,
for libraries that expect to operate against the global runtime.
/**
     * Run the provided (required) block with the "global runtime" set to the current runtime,
     * for libraries that expect to operate against the global runtime.
     */
    @JRubyMethod(module = true)
    public static IRubyObject with_current_runtime_as_global(ThreadContext context, IRubyObject recv, Block block) {
        final Ruby current = context.runtime;
        final Ruby global = Ruby.getGlobalRuntime();
        try {
            if (current != global) {
                current.useAsGlobalRuntime();
            }
            return block.yield(context, runtime(context, recv)); // previously yield (without an argument)
        }
        finally {
            if (Ruby.getGlobalRuntime() != global) {
                global.useAsGlobalRuntime();
            }
        }
    }

    @JRubyMethod(module = true, rest = true, optional = 1) // (loader = JRuby.runtime.jruby_class_loader)
    public static IRubyObject set_context_class_loader(ThreadContext context, IRubyObject recv, IRubyObject[] args) {
        final ClassLoader loader;
        if (args.length == 0 || args[0] == context.nil) {
            loader = context.runtime.getJRubyClassLoader();
        }
        else {
            loader = JavaUtil.unwrapJavaObject(args[0]);
        }
        java.lang.Thread.currentThread().setContextClassLoader(loader);
        return Java.wrapJavaObject(context.runtime, loader); // reference0
    }

    @JRubyMethod(name = "security_restricted?", module = true)
    public static RubyBoolean is_security_restricted(IRubyObject recv) {
        final Ruby runtime = recv.getRuntime();
        return RubyBoolean.newBoolean(runtime, Ruby.isSecurityRestricted());
    }

    // NOTE: its probably too late to set this when jruby library is booted (due the java library) ?
    @JRubyMethod(name = "security_restricted=", module = true)
    public static IRubyObject set_security_restricted(IRubyObject recv, IRubyObject arg) {
        Ruby.setSecurityRestricted(arg.isTrue());
        return is_security_restricted(recv);
    }

    
Provide the "identity" hash code that System.identityHashCode would produce.
Added here as an extension because calling System.identityHashCode (and other
Java-integration-related mechanisms) will cause some core types to coerce to
Java types, losing their proper identity.
/**
     * Provide the "identity" hash code that System.identityHashCode would produce.
     *
     * Added here as an extension because calling System.identityHashCode (and other
     * Java-integration-related mechanisms) will cause some core types to coerce to
     * Java types, losing their proper identity.
     */
    @JRubyMethod(module = true)
    public static IRubyObject identity_hash(ThreadContext context, IRubyObject recv, IRubyObject obj) {
        return context.runtime.newFixnum(System.identityHashCode(obj));
    }

    @JRubyMethod(module = true, name = "parse", alias = "ast_for", required = 1, optional = 3)
    public static IRubyObject parse(ThreadContext context, IRubyObject recv, IRubyObject[] args, Block block) {
        // def parse(content = nil, filename = DEFAULT_FILENAME, extra_position_info = false, lineno = 0, &block)
        return Java.wrapJavaObject(context.runtime, parseImpl(context, args, block));
    }

    private static Node parseImpl(ThreadContext context, IRubyObject[] args, Block block) {
        if (block.isGiven()) {
            throw context.runtime.newNotImplementedError("JRuby.parse with block returning AST no longer supported");
        }

        final RubyString content = args[0].convertToString();
        final String filename;
        boolean extra_position_info = false; int lineno = 0;

        switch (args.length) {
            case 1 :
                filename = "";
                break;
            case 2 :
                filename = args[1].convertToString().toString();
                break;
            case 3 :
                filename = args[1].convertToString().toString();
                extra_position_info = args[2].isTrue();
                break;
            case 4 :
                filename = args[1].convertToString().toString();
                extra_position_info = args[2].isTrue();
                lineno = args[3].convertToInteger().getIntValue();
                break;
            default :
                throw new AssertionError("unexpected arguments: " + java.util.Arrays.toString(args));
        }

        final ByteList bytes = content.getByteList();
        final DynamicScope scope = null;

        final Node parseResult;
        if (content.getEncoding() == ASCIIEncoding.INSTANCE) {
            // binary content, parse as though from a stream
            ByteArrayInputStream stream = new ByteArrayInputStream(bytes.getUnsafeBytes(), bytes.getBegin(), bytes.getRealSize());
            parseResult = context.runtime.parseFile(stream, filename, scope, lineno);
        }
        else {
            parseResult = context.runtime.parse(bytes, filename, scope, lineno, extra_position_info);
        }

        return parseResult;
    }

    @JRubyMethod(module = true, name = "compile_ir", required = 1, optional = 3)
    public static IRubyObject compile_ir(ThreadContext context, IRubyObject recv, IRubyObject[] args, Block block) {
        // def compile_ir(content = nil, filename = DEFAULT_FILENAME, extra_position_info = false, &block)
        return Java.wrapJavaObject(context.runtime, compileIR(context, args, block));
    }

    private static IRScriptBody compileIR(ThreadContext context, IRubyObject[] args, Block block) {
        RootNode node = (RootNode) parseImpl(context, args, block);
        IRManager manager = new IRManager(context.runtime, context.runtime.getInstanceConfig());
        manager.setDryRun(true);
        IRScriptBody scope = (IRScriptBody) IRBuilder.buildRoot(manager, node).getScope();
        scope.setScriptDynamicScope(node.getScope());
        return scope;
    }

    @JRubyMethod(module = true, name = "compile", required = 1, optional = 3)
    public static IRubyObject compile(ThreadContext context, IRubyObject recv, IRubyObject[] args, Block block) {
        // def compile(content = nil, filename = DEFAULT_FILENAME, extra_position_info = false, &block)
        final Ruby runtime = context.runtime;

        final RubyString content = args[0].convertToString();
        args[0] = content;
        final RubyString filename = args.length > 1 ? args[1].convertToString() : RubyString.newEmptyString(runtime);

        IRScriptBody scope = compileIR(context, args, block);

        JVMVisitor visitor = new JVMVisitor(runtime);
        JVMVisitorMethodContext methodContext = new JVMVisitorMethodContext();
        byte[] bytes = visitor.compileToBytecode(scope, methodContext);

        scope.getStaticScope().setModule( runtime.getTopSelf().getMetaClass() );

        RubyClass CompiledScript = (RubyClass) runtime.getModule("JRuby").getConstantAt("CompiledScript");
        // JRuby::CompiledScript#initialize(filename, class_name, content, bytes)
        return CompiledScript.newInstance(context, new IRubyObject[] {
                filename,
                runtime.newSymbol(scope.getId()),
                content,
                Java.getInstance(runtime, bytes)
        }, Block.NULL_BLOCK);
    }

    @Deprecated // @JRubyMethod(meta = true, visibility = Visibility.PRIVATE)
    public static IRubyObject load_string_ext(ThreadContext context, IRubyObject recv) {
        CoreExt.loadStringExtensions(context.runtime);
        return context.nil;
    }

    @JRubyMethod(module = true)
    public static IRubyObject subclasses(ThreadContext context, IRubyObject recv, IRubyObject arg) {
        return subclasses(context, recv, arg instanceof RubyClass ? (RubyClass) arg : arg.getMetaClass(), false);
    }

    @JRubyMethod(module = true)
    public static IRubyObject subclasses(ThreadContext context, IRubyObject recv, IRubyObject arg, IRubyObject opts) {
        boolean recurseAll = false;
        opts = ArgsUtil.getOptionsArg(context.runtime, opts);
        if (opts != context.nil) {
            IRubyObject all = ((RubyHash) opts).fastARef(context.runtime.newSymbol("all"));
            if (all != null) recurseAll = all.isTrue();
        }
        return subclasses(context, recv, arg instanceof RubyClass ? (RubyClass) arg : arg.getMetaClass(), recurseAll);
    }

    private static RubyArray subclasses(ThreadContext context, final IRubyObject recv,
                                        final RubyClass klass, final boolean recurseAll) {

        final RubyArray subclasses = RubyArray.newArray(context.runtime);

        RubyClass singletonClass = klass.getSingletonClass();
        RubyObjectSpace.each_objectInternal(context, recv, new IRubyObject[] { singletonClass },
                new Block(new JavaInternalBlockBody(context.runtime, Signature.ONE_ARGUMENT) {

                    @Override
                    public IRubyObject yield(ThreadContext context, IRubyObject[] args) {
                        return doYield(context, null, args[0]);
                    }

                    @Override
                    protected IRubyObject doYield(ThreadContext context, Block block, IRubyObject value) {
                        if (klass != value) {
                            if (recurseAll) {
                                return subclasses.append(value);
                            }
                            if (((RubyClass) value).superclass(context) == klass) {
                                return subclasses.append(value);
                            }
                        }
                        return context.nil;
                    }

                })
        );
        return subclasses;
    }

}