#region License Information (GPL v3)

/*
    ShareX - A program that allows you to take screenshots and share any file type
    Copyright (c) 2007-2023 ShareX Team

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; either version 2
    of the License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

    Optionally you can also view the license at <http://www.gnu.org/licenses/>.
*/

#endregion License Information (GPL v3)

using System;
using System.IO;

namespace ShareX.HelpersLib
{
    internal sealed class MaxLengthStream : Stream
    {
        private readonly Stream stream;
        private long length = 0L;

        public MaxLengthStream(Stream stream, long maxLength)
        {
            this.stream = stream ?? throw new ArgumentNullException(nameof(stream));
            MaxLength = maxLength;
        }

        public long MaxLength { get; }

        public override bool CanRead => stream.CanRead;
        public override bool CanSeek => false;
        public override bool CanWrite => false;
        public override long Length => stream.Length;

        public override long Position
        {
            get => stream.Position;
            set => throw new NotSupportedException();
        }

        public override int Read(byte[] buffer, int offset, int count)
        {
            int result = stream.Read(buffer, offset, count);
            length += result;
            if (length > MaxLength)
            {
                throw new Exception("Stream is larger than the maximum allowed size.");
            }

            return result;
        }

        public override void Flush() => throw new NotSupportedException();
        public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
        public override void SetLength(long value) => throw new NotSupportedException();
        public override void Write(byte[] buffer, int offset, int count) => throw new NotSupportedException();

        protected override void Dispose(bool disposing)
        {
            stream.Dispose();
            base.Dispose(disposing);
        }
    }
}