using System;

namespace UniRx.Operators
{
    internal class RepeatObservable<T> : OperatorObservableBase<T>
    {
        private readonly int? repeatCount;
        private readonly IScheduler scheduler;
        private readonly T value;

        public RepeatObservable(T value, int? repeatCount, IScheduler scheduler)
            : base(scheduler == Scheduler.CurrentThread)
        {
            this.value = value;
            this.repeatCount = repeatCount;
            this.scheduler = scheduler;
        }

        protected override IDisposable SubscribeCore(IObserver<T> observer, IDisposable cancel)
        {
            observer = new Repeat(observer, cancel);

            if (repeatCount == null)
                return scheduler.Schedule(self =>
                {
                    observer.OnNext(value);
                    self();
                });

            if (scheduler == Scheduler.Immediate)
            {
                var count = repeatCount.Value;
                for (var i = 0; i < count; i++) observer.OnNext(value);
                observer.OnCompleted();
                return Disposable.Empty;
            }

            var currentCount = repeatCount.Value;
            return scheduler.Schedule(self =>
            {
                if (currentCount > 0)
                {
                    observer.OnNext(value);
                    currentCount--;
                }

                if (currentCount == 0)
                {
                    observer.OnCompleted();
                    return;
                }

                self();
            });
        }

        private class Repeat : OperatorObserverBase<T, T>
        {
            public Repeat(IObserver<T> observer, IDisposable cancel)
                : base(observer, cancel)
            {
            }

            public override void OnNext(T value)
            {
                try
                {
                    observer.OnNext(value);
                }
                catch
                {
                    Dispose();
                    throw;
                }
            }

            public override void OnError(Exception error)
            {
                try
                {
                    observer.OnError(error);
                }
                finally
                {
                    Dispose();
                }
            }

            public override void OnCompleted()
            {
                try
                {
                    observer.OnCompleted();
                }
                finally
                {
                    Dispose();
                }
            }
        }
    }
}