/*
 * Copyright (c) 2013, 2016 Oracle and/or its affiliates. All rights reserved. This
 * code is released under a tri EPL/GPL/LGPL license. You can use it,
 * redistribute it and/or modify it under the terms of the:
 *
 * Eclipse Public License version 1.0
 * GNU General Public License version 2
 * GNU Lesser General Public License version 2.1
 */
package org.jruby.truffle.language;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.Truffle;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.FrameInstance;
import com.oracle.truffle.api.frame.FrameInstanceVisitor;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.nodes.IndirectCallNode;
import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.api.source.Source;
import org.jcodings.specific.UTF8Encoding;
import org.jruby.truffle.RubyContext;
import org.jruby.truffle.builtins.CoreClass;
import org.jruby.truffle.builtins.CoreMethod;
import org.jruby.truffle.builtins.CoreMethodArrayArgumentsNode;
import org.jruby.truffle.builtins.CoreMethodNode;
import org.jruby.truffle.core.string.StringOperations;
import org.jruby.truffle.language.control.JavaException;
import org.jruby.truffle.language.loader.CodeLoader;
import org.jruby.truffle.language.loader.SourceLoader;
import org.jruby.truffle.language.methods.DeclarationContext;
import org.jruby.truffle.parser.ParserContext;
import org.jruby.truffle.util.ByteListUtils;
import org.jruby.util.Memo;

import java.io.IOException;

@CoreClass("Truffle::Boot")
public abstract class TruffleBootNodes {

    @CoreMethod(names = "jruby_home_directory", onSingleton = true)
    public abstract static class JRubyHomeDirectoryNode extends CoreMethodNode {

        @TruffleBoundary
        @Specialization
        public DynamicObject jrubyHomeDirectory() {
            return createString(StringOperations.encodeRope(getContext().getJRubyInterop().getJRubyHome(), UTF8Encoding.INSTANCE));
        }

    }

    @CoreMethod(names = "jruby_home_directory_protocol", onSingleton = true)
    public abstract static class JRubyHomeDirectoryProtocolNode extends CoreMethodNode {

        @TruffleBoundary
        @Specialization
        public DynamicObject jrubyHomeDirectoryProtocol() {
            String home = getContext().getJRubyInterop().getJRubyHome();

            if (home.startsWith("uri:classloader:")) {
                home = home.substring("uri:classloader:".length());

                while (home.startsWith("/")) {
                    home = home.substring(1);
                }

                home = SourceLoader.JRUBY_SCHEME + "/" + home;
            }

            return createString(StringOperations.encodeRope(home, UTF8Encoding.INSTANCE));
        }

    }

    @CoreMethod(names = "context", onSingleton = true)
    public abstract static class ContextNode extends CoreMethodArrayArgumentsNode {

        @Specialization
        public RubyContext context() {
            return getContext();
        }
    }

    @CoreMethod(names = "run_jruby_root", onSingleton = true)
    public abstract static class RunJRubyRootNode extends CoreMethodArrayArgumentsNode {

        @Specialization
        public Object runJRubyRootNode(VirtualFrame frame, @Cached("create()") IndirectCallNode callNode) {
            String dollar0 = getContext().getJRubyInterop().getArg0();
            coreLibrary().getGlobalVariables().put("$0", StringOperations.createString(
                    getContext(), StringOperations.encodeRope(dollar0, UTF8Encoding.INSTANCE)));

            String inputFile = getContext().getJRubyInterop().getOriginalInputFile();

            final Source source;
            try {
                source = getContext().getSourceCache().getSource(inputFile);
            } catch (IOException e) {
                throw new JavaException(e);
            }

            final RubyRootNode rootNode = getContext().getCodeLoader().parse(
                    source,
                    UTF8Encoding.INSTANCE,
                    ParserContext.TOP_LEVEL_FIRST,
                    null,
                    true,
                    null);

            final CodeLoader.DeferredCall deferredCall = getContext().getCodeLoader().prepareExecute(
                    ParserContext.TOP_LEVEL,
                    DeclarationContext.TOP_LEVEL,
                    rootNode,
                    null,
                    coreLibrary().getMainObject());

            return deferredCall.call(frame, callNode);
        }
    }

    @CoreMethod(names = "original_argv", onSingleton = true)
    public abstract static class OriginalArgvNode extends CoreMethodNode {

        @TruffleBoundary
        @Specialization
        public DynamicObject originalArgv() {
            final String[] argv = getContext().getJRubyInterop().getArgv();
            final Object[] array = new Object[argv.length];

            for (int n = 0; n < array.length; n++) {
                array[n] = StringOperations.createString(getContext(), StringOperations.encodeRope(argv[n], UTF8Encoding.INSTANCE));
            }

            return createArray(array, array.length);
        }

    }

    @CoreMethod(names = "original_load_path", onSingleton = true)
    public abstract static class OriginalLoadPathNode extends CoreMethodNode {

        @TruffleBoundary
        @Specialization
        public DynamicObject originalLoadPath() {
            final String[] path = getContext().getJRubyInterop().getOriginalLoadPath();
            final Object[] array = new Object[path.length];

            for (int n = 0; n < array.length; n++) {
                array[n] = StringOperations.createString(getContext(), StringOperations.encodeRope(path[n], UTF8Encoding.INSTANCE));
            }

            return createArray(array, array.length);
        }

    }
    
    @CoreMethod(names = "source_of_caller", isModuleFunction = true)
    public abstract static class SourceOfCallerNode extends CoreMethodArrayArgumentsNode {

        @TruffleBoundary
        @Specialization
        public DynamicObject sourceOfCaller() {
            final Memo<Integer> frameCount = new Memo<>(0);

            final String source = Truffle.getRuntime().iterateFrames(new FrameInstanceVisitor<String>() {

                @Override
                public String visitFrame(FrameInstance frameInstance) {
                    if (frameCount.get() == 2) {
                        return frameInstance.getCallNode().getEncapsulatingSourceSection().getSource().getName();
                    } else {
                        frameCount.set(frameCount.get() + 1);
                        return null;
                    }
                }

            });

            if (source == null) {
                return nil();
            }

            return createString(StringOperations.encodeRope(source, UTF8Encoding.INSTANCE));
        }

    }

}
