//
// Copyright (c) 2008-2011, Kenneth Bell
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//

namespace DiscUtils
{
    using System.Collections.Generic;
    using System.IO;

    /// <summary>
    /// Base class for objects that can dynamically construct a stream.
    /// </summary>
    public abstract class StreamBuilder
    {
        /// <summary>
        /// Builds a new stream.
        /// </summary>
        /// <returns>The stream created by the StreamBuilder instance.</returns>
        public virtual SparseStream Build()
        {
            long totalLength;
            List<BuilderExtent> extents = FixExtents(out totalLength);
            return new BuiltStream(totalLength, extents);
        }

        /// <summary>
        /// Writes the stream contents to an existing stream.
        /// </summary>
        /// <param name="output">The stream to write to.</param>
        public void Build(Stream output)
        {
            using (Stream src = Build())
            {
                byte[] buffer = new byte[64 * 1024];
                int numRead = src.Read(buffer, 0, buffer.Length);
                while (numRead != 0)
                {
                    output.Write(buffer, 0, numRead);
                    numRead = src.Read(buffer, 0, buffer.Length);
                }
            }
        }

        /// <summary>
        /// Writes the stream contents to a file.
        /// </summary>
        /// <param name="outputFile">The file to write to.</param>
        public void Build(string outputFile)
        {
            using (FileStream destStream = new FileStream(outputFile, FileMode.Create, FileAccess.Write))
            {
                Build(destStream);
            }
        }

        internal abstract List<BuilderExtent> FixExtents(out long totalLength);
    }
}
