// Copyright (c) The LEGO Group. All rights reserved.

namespace LEGO.AsyncAPI.Readers

{

using System.IO;

using System.Threading;

using System.Threading.Tasks;

using LEGO.AsyncAPI.Models;

using LEGO.AsyncAPI.Models.Interfaces;

using LEGO.AsyncAPI.Readers.Interface;

/// <summary>

/// Service class for converting streams into AsyncApiDocument instances.

/// </summary>

public class AsyncApiStreamReader : IAsyncApiReader<Stream, AsyncApiDiagnostic>

{

private readonly AsyncApiReaderSettings settings;

/// <summary>

/// Create stream reader with custom settings if desired.

/// </summary>

/// <param name="settings"></param>

public AsyncApiStreamReader(AsyncApiReaderSettings settings = null)

{

this.settings = settings ?? new AsyncApiReaderSettings();

}

/// <summary>

/// Reads the stream input and parses it into an AsyncApi document.

/// </summary>

/// <param name="input">Stream containing AsyncApi description to parse.</param>

/// <param name="diagnostic">Returns diagnostic object containing errors detected during parsing.</param>

/// <returns>Instance of newly created AsyncApiDocument.</returns>

public AsyncApiDocument Read(Stream input, out AsyncApiDiagnostic diagnostic)

{

var reader = new StreamReader(input);

var result = new AsyncApiTextReader(this.settings).Read(reader, out diagnostic);

if (!this.settings.LeaveStreamOpen)

{

reader.Dispose();

}

return result;

}

/// <summary>

/// Reads the stream input and parses it into an AsyncApi document.

/// </summary>

/// <param name="input">Stream containing AsyncApi description to parse.</param>

/// <param name="cancellationToken">The cancellation token.</param>

/// <returns>

/// Instance result containing newly created AsyncApiDocument and diagnostics object from the process.

/// </returns>

public async Task<ReadResult> ReadAsync(Stream input, CancellationToken cancellationToken)

{

MemoryStream bufferedStream;

if (input is MemoryStream)

{

bufferedStream = (MemoryStream)input;

}

else

{

// Buffer stream so that AsyncApiTextReaderReader can process it synchronously

// YamlDocument doesn't support async reading.

bufferedStream = new MemoryStream();

await input.CopyToAsync(bufferedStream);

bufferedStream.Position = 0;

}

var reader = new StreamReader(bufferedStream);

return await new AsyncApiTextReader(this.settings).ReadAsync(reader, cancellationToken);

}

/// <summary>

/// Reads the stream input and parses the fragment of an AsyncApi description into an AsyncApi Element.

/// </summary>

/// <param name="input">Stream containing AsyncApi description to parse.</param>

/// <param name="version">Version of the AsyncApi specification that the fragment conforms to.</param>

/// <param name="diagnostic">Returns diagnostic object containing errors detected during parsing.</param>

/// <returns>Instance of newly created AsyncApiDocument.</returns>

public T ReadFragment<T>(Stream input, AsyncApiVersion version, out AsyncApiDiagnostic diagnostic)

where T : IAsyncApiReferenceable

{

using (var reader = new StreamReader(input))

{

return new AsyncApiTextReader(this.settings).ReadFragment<T>(reader, version, out diagnostic);

}

}

}

}