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package com.oracle.graal.python.builtins.modules;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Map;

import com.oracle.graal.python.builtins.Builtin;
import com.oracle.graal.python.builtins.CoreFunctions;
import com.oracle.graal.python.builtins.Python3Core;
import com.oracle.graal.python.builtins.PythonBuiltinClassType;
import com.oracle.graal.python.builtins.PythonBuiltins;
import com.oracle.graal.python.builtins.objects.PNone;
import com.oracle.graal.python.builtins.objects.function.PKeyword;
import com.oracle.graal.python.builtins.objects.list.PList;
import com.oracle.graal.python.builtins.objects.object.PythonBuiltinObject;
import com.oracle.graal.python.builtins.objects.tuple.PTuple;
import com.oracle.graal.python.builtins.objects.tuple.StructSequence;
import com.oracle.graal.python.nodes.SpecialMethodNames;
import com.oracle.graal.python.nodes.function.PythonBuiltinBaseNode;
import com.oracle.graal.python.nodes.function.PythonBuiltinNode;
import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.InstrumentInfo;
import com.oracle.truffle.api.TruffleContext;
import com.oracle.truffle.api.TruffleLanguage.Env;
import com.oracle.truffle.api.dsl.GenerateNodeFactory;
import com.oracle.truffle.api.dsl.NodeFactory;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.instrumentation.SourceSectionFilter;
import com.oracle.truffle.api.object.Shape;
import com.oracle.truffle.api.source.SourceSection;
import com.oracle.truffle.tools.profiler.CPUSampler;
import com.oracle.truffle.tools.profiler.CPUSampler.Payload;
import com.oracle.truffle.tools.profiler.CPUSamplerData;
import com.oracle.truffle.tools.profiler.ProfilerNode;
import com.oracle.truffle.tools.profiler.impl.CPUSamplerInstrument;

@CoreFunctions(defineModule = "_lsprof")
public class LsprofModuleBuiltins extends PythonBuiltins {

    static final StructSequence.BuiltinTypeDescriptor PROFILER_ENTRY_DESC = new StructSequence.BuiltinTypeDescriptor(
                    PythonBuiltinClassType.PProfilerEntry,
                    null,
                    6,
                    new String[]{
                                    "code", "callcount", "reccallcount", "totaltime", "inlinetime", "calls"
                    },
                    new String[]{
                                    "code object or built-in function name",
                                    "how many times this was called",
                                    "how many times called recursively",
                                    "total time in this entry",
                                    "inline time in this entry (not in subcalls)",
                                    "details of the calls"
                    });

    static final StructSequence.BuiltinTypeDescriptor PROFILER_SUBENTRY_DESC = new StructSequence.BuiltinTypeDescriptor(
                    PythonBuiltinClassType.PProfilerSubentry,
                    null,
                    5,
                    new String[]{
                                    "code", "callcount", "reccallcount", "totaltime", "inlinetime"
                    },
                    new String[]{
                                    "called code object or built-in function name",
                                    "how many times this is called",
                                    "how many times this is called recursively",
                                    "total time spent in this call",
                                    "inline time (not in further subcalls)"
                    });

    @Override
    protected List<? extends NodeFactory<? extends PythonBuiltinBaseNode>> getNodeFactories() {
        return LsprofModuleBuiltinsFactory.getFactories();
    }

    @Override
    public void initialize(Python3Core core) {
        super.initialize(core);
        StructSequence.initType(core, PROFILER_ENTRY_DESC);
        StructSequence.initType(core, PROFILER_SUBENTRY_DESC);
    }

    public static PythonBuiltins newProfilerBuiltins() {
        return new ProfilerBuiltins();
    }

    @Builtin(name = "Profiler", minNumOfPositionalArgs = 1, takesVarArgs = true, takesVarKeywordArgs = true, constructsClass = PythonBuiltinClassType.LsprofProfiler)
    @GenerateNodeFactory
    abstract static class LsprofNew extends PythonBuiltinNode {
        @Specialization
        @TruffleBoundary
        Profiler doit(Object cls, @SuppressWarnings("unused") Object[] args, @SuppressWarnings("unused") PKeyword[] kwargs) {
            Env env = getContext().getEnv();
            Map<String, InstrumentInfo> instruments = env.getInstruments();
            InstrumentInfo instrumentInfo = instruments.get(CPUSamplerInstrument.ID);
            if (instrumentInfo != null) {
                CPUSampler sampler = env.lookup(instrumentInfo, CPUSampler.class);
                if (sampler != null) {
                    return factory().trace(new Profiler(cls, factory().getShape(cls), sampler));
                }
            }
            throw raise(PythonBuiltinClassType.NotImplementedError, "coverage tracker not available");
        }
    }
}

class Profiler extends PythonBuiltinObject {
    boolean subcalls;
    boolean builtins;
    double timeunit;
    Object externalTimer;
    double time;
    final CPUSampler sampler;

    public Profiler(Object cls, Shape instanceShape, CPUSampler sampler) {
        super(cls, instanceShape);
        this.sampler = sampler;
        this.sampler.setFilter(SourceSectionFilter.newBuilder().includeInternal(true).build());
        this.sampler.setPeriod(1);
    }
}

@CoreFunctions(extendClasses = PythonBuiltinClassType.LsprofProfiler)
class ProfilerBuiltins extends PythonBuiltins {
    @Override
    protected List<? extends NodeFactory<? extends PythonBuiltinBaseNode>> getNodeFactories() {
        return ProfilerBuiltinsFactory.getFactories();
    }

    @Builtin(name = SpecialMethodNames.__INIT__, minNumOfPositionalArgs = 1, parameterNames = {"$self", "timer", "timeunit", "subcalls", "builtins"})
    @GenerateNodeFactory
    abstract static class Init extends PythonBuiltinNode {
        @Specialization
        PNone doit(Profiler self, Object timer, double timeunit, long subcalls, long builtins) {
            self.subcalls = subcalls > 0;
            self.builtins = builtins > 0;
            self.timeunit = timeunit;
            self.externalTimer = timer;
            return PNone.NONE;
        }

        @Specialization
        @SuppressWarnings("unused")
        PNone doit(Profiler self, Object timer, PNone timeunit, PNone subcalls, PNone builtins) {
            self.subcalls = true;
            self.builtins = true;
            self.timeunit = -1;
            self.externalTimer = timer;
            return PNone.NONE;
        }
    }

    @Builtin(name = "enable", minNumOfPositionalArgs = 1, parameterNames = {"$self", "subcalls", "builtins"})
    @GenerateNodeFactory
    abstract static class Enable extends PythonBuiltinNode {
        @Specialization
        @TruffleBoundary
        PNone doit(Profiler self, long subcalls, long builtins) {
            self.subcalls = subcalls > 0;
            self.builtins = builtins > 0;
            // TODO: deal with any arguments
            self.time = System.currentTimeMillis();
            self.sampler.setCollecting(true);
            return PNone.NONE;
        }

        @Specialization
        PNone doit(Profiler self, long subcalls, @SuppressWarnings("unused") PNone builtins) {
            return doit(self, subcalls, self.builtins ? 1 : 0);
        }

        @Specialization
        PNone doit(Profiler self, @SuppressWarnings("unused") PNone subcalls, long builtins) {
            return doit(self, self.subcalls ? 1 : 0, builtins);
        }

        @Specialization
        PNone doit(Profiler self, @SuppressWarnings("unused") PNone subcalls, @SuppressWarnings("unused") PNone builtins) {
            return doit(self, self.subcalls ? 1 : 0, self.builtins ? 1 : 0);
        }
    }

    @Builtin(name = "disable", minNumOfPositionalArgs = 1)
    @GenerateNodeFactory
    abstract static class Disable extends PythonBuiltinNode {
        @Specialization
        @TruffleBoundary
        PNone doit(Profiler self) {
            self.sampler.setCollecting(false);
            self.time = (System.currentTimeMillis() - self.time) / 1000D;
            return PNone.NONE;
        }
    }

    @Builtin(name = "clear", minNumOfPositionalArgs = 1)
    @GenerateNodeFactory
    abstract static class Clear extends PythonBuiltinNode {
        @Specialization
        @TruffleBoundary
        PNone doit(Profiler self) {
            self.sampler.clearData();
            return PNone.NONE;
        }
    }

    @Builtin(name = "getstats", minNumOfPositionalArgs = 1, doc = "" +
                    "getstats() -> list of profiler_entry objects\n" +
                    "\n" +
                    "Return all information collected by the profiler.\n" +
                    "Each profiler_entry is a tuple-like object with the\n" +
                    "following attributes:\n" +
                    "\n" +
                    "    code          code object or functionname\n" +
                    "    callcount     how many times this was called\n" +
                    "    reccallcount  how many times called recursively\n" +
                    "    totaltime     total time in this entry\n" +
                    "    inlinetime    inline time in this entry (not in subcalls)\n" +
                    "    calls         details of the calls\n" +
                    "\n" +
                    "The calls attribute is either None or a list of\n" +
                    "profiler_subentry objects:\n" +
                    "\n" +
                    "    code          called code object\n" +
                    "    callcount     how many times this is called\n" +
                    "    reccallcount  how many times this is called recursively\n" +
                    "    totaltime     total time spent in this call\n" +
                    "    inlinetime    inline time (not in further subcalls)\n")
    @GenerateNodeFactory
    abstract static class GetStats extends PythonBuiltinNode {
        @Specialization
        @TruffleBoundary
        PList doit(Profiler self) {
            double avgSampleSeconds = self.sampler.getPeriod() / 1000D;
            List<PTuple> entries = new ArrayList<>();
            Map<TruffleContext, CPUSamplerData> data = self.sampler.getData();
            for (TruffleContext context : data.keySet()) {
                Map<Thread, Collection<ProfilerNode<Payload>>> threads = data.get(context).getThreadData();
                for (Thread thread : threads.keySet()) {
                    for (ProfilerNode<Payload> node : threads.get(thread)) {
                        countNode(entries, node, avgSampleSeconds);
                    }
                }
            }

            self.sampler.close();
            return factory().createList(entries.toArray());
        }

        private void countNode(List<PTuple> entries, ProfilerNode<Payload> node, double avgSampleTime) {
            Collection<ProfilerNode<Payload>> children = node.getChildren();
            Object[] profilerEntry = getProfilerEntry(node, avgSampleTime);
            Object[] calls = new Object[children.size()];
            int callIdx = 0;
            for (ProfilerNode<Payload> childNode : children) {
                countNode(entries, childNode, avgSampleTime);
                calls[callIdx++] = factory().createStructSeq(LsprofModuleBuiltins.PROFILER_SUBENTRY_DESC, getProfilerEntry(childNode, avgSampleTime));
            }
            assert callIdx == calls.length;
            profilerEntry = Arrays.copyOf(profilerEntry, 6);
            profilerEntry[profilerEntry.length - 1] = factory().createList(calls);
            entries.add(factory().createStructSeq(LsprofModuleBuiltins.PROFILER_ENTRY_DESC, profilerEntry));
        }

        private static Object[] getProfilerEntry(ProfilerNode<Payload> node, double avgSampleTime) {
            SourceSection sec = node.getSourceSection();
            String rootName;
            if (sec == null) {
                rootName = node.getRootName();
            } else {
                rootName = sec.getSource().getName() + ":" + sec.getStartLine() + "(" + node.getRootName() + ")";
            }
            if (rootName == null) {
                rootName = "<unknown root>";
            }
            int otherHitCount = node.getPayload().getHitCount();
            int selfHitCount = node.getPayload().getSelfHitCount();
            long hitCount = (long) otherHitCount + selfHitCount;
            Object[] profilerEntry = new Object[]{
                            rootName,
                            hitCount,
                            0,
                            otherHitCount * avgSampleTime,
                            selfHitCount * avgSampleTime
            };
            return profilerEntry;
        }
    }
}
