package dev.modzuozhi;

import dev.modzuozhi.core.compat.*;
import dev.modzuozhi.core.dimthread.*;
import net.minecraft.server.MinecraftServer;
import net.minecraft.resources.ResourceLocation;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import java.util.*;

public final class ReviewRegression {
    static final List<String> failures=new ArrayList<>();
    static void expect(boolean ok,String name){if(!ok){failures.add(name);ModZuozhi.LOGGER.error("REVIEW RED: {}",name);}}
    public static void run(MinecraftServer server) throws Exception {
        var manager=DimThreadCore.MANAGER;manager.setPaused(server,true);
        var player=new net.neoforged.neoforge.common.util.FakePlayer(server.overworld(),
            new com.mojang.authlib.GameProfile(UUID.randomUUID(),"ReviewTest"));
        var disconnects=new AtomicInteger();
        new net.minecraft.server.network.ServerGamePacketListenerImpl(server,
            new net.minecraft.network.Connection(net.minecraft.network.protocol.PacketFlow.SERVERBOUND),player,
            net.minecraft.server.network.CommonListenerCookie.createInitial(player.getGameProfile(),false)) {
                @Override public void disconnect(net.minecraft.network.chat.Component reason){disconnects.incrementAndGet();}
            };
        var ctx=new net.neoforged.neoforge.network.handling.ServerPayloadContext(player.connection,ResourceLocation.parse("dimensionalripper:review"));
        var result=new AtomicReference<CompletableFuture<Integer>>();
        Thread rejected=new Thread(() -> result.set(ctx.enqueueWork(() -> {throw new RejectedExecutionException("handler executor closed");})));
        rejected.start();rejected.join(5000);PayloadMainThreadDispatch.drain(server);PayloadMainThreadDispatch.drain(server);
        expect(disconnects.get()==0,"handler rejection must not disconnect player");
        try{expect(result.get().join()==null,"guard preserves handler rejection result");}
        catch(CompletionException e){expect(false,"guard preserves handler rejection result");}
        Thread cancelledHandler=new Thread(() -> result.set(ctx.enqueueWork(() -> {throw new CancellationException("handler cancelled its own computation");})));
        cancelledHandler.start();cancelledHandler.join(5000);PayloadMainThreadDispatch.drain(server);
        expect(result.get().join()==null,"guard preserves handler cancellation result");
        var overflow=new AtomicReference<CompletableFuture<Integer>>();
        Thread flood=new Thread(() -> {for(int i=0;i<257;i++)overflow.set(ctx.enqueueWork(() -> 1));});
        flood.start();flood.join(5000);
        expect(overflow.get().isCompletedExceptionally(),"capacity rejection remains exceptional");
        PayloadMainThreadDispatch.drain(server);
        expect(disconnects.get()==1,"genuine capacity rejection disconnects once");
        for(int i=0;i<10;i++)PayloadMainThreadDispatch.drain(server);
        String counters=PayloadDiagnostics.snapshot(server);
        expect(counters.contains("failed=2") && counters.contains("rejected=1"),
                "diagnostics distinguish handler failures from capacity rejection");

        var other=server.getLevel(net.minecraft.world.level.Level.NETHER);
        manager.removeLoop(other);
        manager.runMainThreadPhase(server,"review-new-loop",() -> manager.getLoop(other).scheduleIfNeeded());
        expect(manager.getLoop(other).isPaused(),"new loop inherits menu pause after phase exit");
        manager.setPaused(server,true);

        var loop=manager.getLoop(other);var entered=new CountDownLatch(1);var release=new CountDownLatch(1);
        var finished=new AtomicBoolean();
        loop.execute(() -> {
            server.execute(() -> manager.removeLoop(other));entered.countDown();
            while(release.getCount()!=0) try{release.await();}catch(InterruptedException ignored){}
            finished.set(true);
        });
        manager.setPaused(server,false);PayloadRegression.check(entered.await(5,TimeUnit.SECONDS),"retiring loop fixture start");
        Thread releaser=new Thread(() -> {try{Thread.sleep(250);}catch(InterruptedException ignored){}release.countDown();});
        releaser.start();
        try{manager.runMainThreadPhase(server,"review-retire",() -> expect(finished.get() && !loop.isTicking(),"retired loop must drain before exclusive phase"));}
        finally{release.countDown();releaser.join(5000);}
        manager.setPaused(server,true);

        var labelled=new CountDownLatch(1);var labelRelease=new CountDownLatch(1);
        var late=new AtomicReference<CompletableFuture<Integer>>();
        Thread submitter=new Thread(() -> {
            labelled.countDown();try{labelRelease.await(5,TimeUnit.SECONDS);}catch(InterruptedException e){throw new RuntimeException(e);}
            // Exact late-registration boundary after the submitter had obtained its queue.
            var ticket=PayloadDiagnostics.begin(server,"dimensionalripper:shutdown_race");
            PayloadDiagnostics.end(server,ticket,new CancellationException("stopped"));
            late.set(PayloadMainThreadDispatch.submit(player,ctx.payloadId(),() -> {throw new AssertionError("late action");}));
        });
        submitter.start();PayloadRegression.check(labelled.await(5,TimeUnit.SECONDS),"late submit fixture pause");
        PayloadMainThreadDispatch.stop(server);PayloadMainThreadDispatch.clear(server);labelRelease.countDown();submitter.join(5000);
        expect(late.get()!=null && late.get().isCompletedExceptionally(),"late future completed");
        expect(PayloadDiagnostics.snapshot(server).equals("payloads: pending=0 batches=0"),"late submission must not recreate diagnostics after clear");
        if(!failures.isEmpty())throw new AssertionError(String.join("; ",failures));
        ModZuozhi.LOGGER.info("PAYLOAD REVIEW PASS");
    }
}