/*

* Copyright (c) 2014-2015, Facebook, Inc.

* All rights reserved.

*

* This source code is licensed under the BSD-style license found in the

* LICENSE file in the root directory of this source tree. An additional grant

* of patent rights can be found in the PATENTS file in the same directory.

*/

using System.Web;

namespace React.Web

{

/// <summary>

/// ASP.NET handler that transforms JSX into JavaScript.

/// </summary>

public class JsxHandler : IJsxHandler

{

private readonly IReactEnvironment _environment;

private readonly IFileSystem _fileSystem;

private readonly HttpRequestBase _request;

private readonly HttpResponseBase _response;

/// <summary>

/// Initializes a new instance of the <see cref="JsxHandler"/> class.

/// </summary>

/// <param name="environment">The environment.</param>

/// <param name="fileSystem">File system</param>

/// <param name="request">HTTP request</param>

/// <param name="response">HTTP response</param>

public JsxHandler(

IReactEnvironment environment,

IFileSystem fileSystem,

HttpRequestBase request,

HttpResponseBase response

)

{

_environment = environment;

_fileSystem = fileSystem;

_request = request;

_response = response;

}

/// <summary>

/// Executes the handler. Outputs JavaScript to the response.

/// </summary>

public void Execute()

{

if (_request.QueryString["map"] != null)

{

RenderSourceMap();

}

else

{

RenderJsxFile();

}

}

/// <summary>

/// Renders the JSX file converted to regular JavaScript.

/// </summary>

private void RenderJsxFile()

{

var relativePath = _request.Url.LocalPath;

var result = _environment.JsxTransformer.TransformJsxFileWithSourceMap(relativePath);

var sourceMapUri = GetSourceMapUri(relativePath, result.Hash);

ConfigureCaching();

_response.ContentType = "text/javascript";

// The sourcemap spec says to use SourceMap, but Firefox only accepts X-SourceMap

_response.AddHeader("SourceMap", sourceMapUri);

_response.AddHeader("X-SourceMap", sourceMapUri);

_response.Write(result.Code);

}

/// <summary>

/// Renders the source map for this JSX file.

/// </summary>

private void RenderSourceMap()

{

var relativePath = _request.Url.LocalPath;

var result = _environment.JsxTransformer.TransformJsxFileWithSourceMap(relativePath, forceGenerateSourceMap: true);

if (result.SourceMap == null)

{

_response.StatusCode = 500;

_response.StatusDescription = "Unable to generate source map";

return;

}

var sourceMap = result.SourceMap.ToJson();

ConfigureCaching();

_response.ContentType = "application/json";

//_response.Write(")]}\n"); // Recommended by the spec but Firefox doesn't support it

_response.Write(sourceMap);

}

/// <summary>

/// Send headers to cache the response. Only caches on the server-side for now

/// </summary>

private void ConfigureCaching()

{

_response.AddFileDependency(_fileSystem.MapPath(_request.Url.LocalPath));

_response.Cache.SetCacheability(HttpCacheability.Server);

_response.Cache.SetLastModifiedFromFileDependencies();

_response.Cache.SetETagFromFileDependencies();

}

/// <summary>

/// Gets the URI to the source map of the specified file

/// </summary>

/// <param name="relativePath">Relative path to the JavaScript file</param>

/// <param name="hash">Hash of the file</param>

/// <returns>URI to the file</returns>

private static string GetSourceMapUri(string relativePath, string hash)

{

return string.Format("{0}?map={1}", relativePath, hash);

}

}

}