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package com.oracle.graal.python.nodes.generator;

import com.oracle.graal.python.PythonLanguage;
import com.oracle.graal.python.builtins.objects.function.PArguments;
import com.oracle.graal.python.builtins.objects.function.PFunction;
import com.oracle.graal.python.builtins.objects.function.Signature;
import com.oracle.graal.python.nodes.PClosureFunctionRootNode;
import com.oracle.graal.python.nodes.PRootNode;
import com.oracle.graal.python.parser.ExecutionCellSlots;
import com.oracle.graal.python.parser.GeneratorInfo;
import com.oracle.graal.python.runtime.object.PythonObjectFactory;
import com.oracle.graal.python.util.PythonUtils;
import com.oracle.truffle.api.CompilerAsserts;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
import com.oracle.truffle.api.RootCallTarget;
import com.oracle.truffle.api.frame.FrameDescriptor;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.nodes.NodeUtil;
import com.oracle.truffle.api.nodes.RootNode;
import com.oracle.truffle.api.source.SourceSection;

public class GeneratorFunctionRootNode extends PClosureFunctionRootNode {
    private final RootCallTarget callTarget;
    @CompilationFinal(dimensions = 1) private RootCallTarget[] callTargets;
    private final FrameDescriptor frameDescriptor;
    private final GeneratorInfo generatorInfo;
    private final ExecutionCellSlots cellSlots;
    private final String originalName;

    @Child private PythonObjectFactory factory = PythonObjectFactory.create();

    public GeneratorFunctionRootNode(PythonLanguage language, RootCallTarget callTarget, String originalName, FrameDescriptor frameDescriptor, ExecutionCellSlots executionCellSlots,
                    Signature signature, GeneratorInfo generatorInfo) {
        super(language, frameDescriptor, executionCellSlots, signature);
        this.callTarget = callTarget;
        this.originalName = originalName;
        this.frameDescriptor = frameDescriptor;
        this.cellSlots = executionCellSlots;
        this.generatorInfo = generatorInfo;
    }

    @Override
    public Object execute(VirtualFrame frame) {
        // TODO 'materialize' generator frame and create locals dict eagerly
        if (callTargets == null) {
            CompilerDirectives.transferToInterpreterAndInvalidate();
            callTargets = createYieldTargets(callTarget);
        }
        CompilerAsserts.partialEvaluationConstant(cellSlots);

        Object[] arguments = frame.getArguments();

        // This is passed from CallDispatch node
        PFunction generatorFunction = PArguments.getGeneratorFunction(arguments);

        return factory.createGenerator(generatorFunction.getName(), generatorFunction.getQualname(), callTargets, frameDescriptor, arguments, PArguments.getClosure(frame), cellSlots,
                        generatorInfo, null);
    }

    public static RootCallTarget[] createYieldTargets(RootCallTarget callTarget) {
        CompilerAsserts.neverPartOfCompilation();
        int numYields = NodeUtil.countNodes(callTarget.getRootNode(), (node) -> node instanceof AbstractYieldNode);
        RootCallTarget[] callTargets = new RootCallTarget[numYields + 1];
        callTargets[0] = callTarget;
        for (int i = 1; i < callTargets.length; i++) {
            callTargets[i] = PythonUtils.getOrCreateCallTarget(NodeUtil.cloneNode(callTarget.getRootNode()));
        }
        return callTargets;
    }

    public RootNode getFunctionRootNode() {
        return callTarget.getRootNode();
    }

    @Override
    public String getName() {
        return originalName;
    }

    @Override
    public String toString() {
        CompilerAsserts.neverPartOfCompilation();
        return "<generator function root" + originalName + ">";
    }

    @Override
    public void initializeFrame(VirtualFrame frame) {
        // nothing to do
    }

    @Override
    public boolean isPythonInternal() {
        RootNode rootNode = callTarget.getRootNode();
        return rootNode instanceof PRootNode && ((PRootNode) rootNode).isPythonInternal();
    }

    @Override
    public SourceSection getSourceSection() {
        return getFunctionRootNode().getSourceSection();
    }

}
