// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;

namespace System.Buffers
{
    internal sealed class ReadOnlySequenceDebugView<T>
    {
        private readonly T[] _array;

        private readonly ReadOnlySequenceDebugViewSegments _segments;

        public ReadOnlySequenceDebugView(ReadOnlySequence<T> sequence)
        {
            _array = sequence.ToArray();

            var segmentCount = 0;
            foreach (var _ in sequence)
            {
                segmentCount++;
            }

            var segments = new ReadOnlyMemory<T>[segmentCount];
            int i = 0;
            foreach (ReadOnlyMemory<T> readOnlyMemory in sequence)
            {
                segments[i] = readOnlyMemory;
                i++;
            }
            _segments = new ReadOnlySequenceDebugViewSegments()
            {
                Segments = segments
            };
        }

        public ReadOnlySequenceDebugViewSegments BufferSegments => _segments;

        [DebuggerBrowsable(DebuggerBrowsableState.RootHidden)]
        public T[] Items => _array;

        [DebuggerDisplay("Count = {Segments.Length}", Name = "Segments")]
        public struct ReadOnlySequenceDebugViewSegments
        {
            [DebuggerBrowsable(DebuggerBrowsableState.RootHidden)]
            public ReadOnlyMemory<T>[] Segments { get; set; }
        }
    }
}