using System.Runtime.ExceptionServices;

namespace Source.MaterialSystem;

public sealed class MatQueueJob(MatQueueJob.JobKind kind, MatQueuedRenderContext? context = null)

{

public enum JobKind

{

AcquireThreadOwnership,

ReleaseThreadOwnership,

ExecuteQueuedContext

}

public readonly JobKind Kind = kind;

public readonly MatQueuedRenderContext? Context = context;

readonly ManualResetEventSlim Done = new(false);

ExceptionDispatchInfo? Exception;

public bool IsFinished() => Done.IsSet;

public void Reset() {

Exception = null;

Done.Reset();

}

internal void Complete(Exception? exception) {

if (exception != null)

Exception = ExceptionDispatchInfo.Capture(exception);

Done.Set();

}

public void WaitForFinish() {

Done.Wait();

ExceptionDispatchInfo? exception = Exception;

if (exception != null) {

Exception = null;

exception.Throw();

}

}

}

public sealed class MatQueueThread

{

readonly MaterialSystem Materials;

readonly Thread Thread;

readonly Queue<MatQueueJob> Jobs = new();

readonly object Sync = new();

bool Stopping;

public MatQueueThread(MaterialSystem materials) {

Materials = materials;

Thread = new Thread(Run) {

Name = "MatQueue",

IsBackground = true

};

Thread.Start();

}

public void AddJob(MatQueueJob job) {

lock (Sync) {

Jobs.Enqueue(job);

Monitor.Pulse(Sync);

}

}

public void Stop() {

lock (Sync) {

Stopping = true;

Monitor.Pulse(Sync);

}

Thread.Join();

}

void Run() {

while (true) {

MatQueueJob job;

lock (Sync) {

while (Jobs.Count == 0 && !Stopping)

Monitor.Wait(Sync);

if (Jobs.Count == 0)

return;

job = Jobs.Dequeue();

}

Exception? exception = null;

try {

Materials.ExecuteJob(job);

}

catch (Exception e) {

Warning($"MatQueue job {job.Kind} failed: {e}\n");

exception = e;

}

job.Complete(exception);

}

}

}