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

using System.IO;
using System.Net;

namespace System.Speech.Internal
{
    internal class ResourceLoader
    {
        #region Internal Methods

        /// <summary>
        /// Load a file either from a local network or from the Internet.
        /// </summary>
        internal Stream LoadFile(Uri uri, out string? mimeType, out Uri? baseUri, out string? localPath)
        {
            localPath = null;

            {
                Stream? stream = null;

                // Check for a local file
                if (!uri.IsAbsoluteUri || uri.IsFile)
                {
                    // Local file
                    string file = uri.IsAbsoluteUri ? uri.LocalPath : uri.OriginalString;
                    try
                    {
                        stream = new FileStream(file, FileMode.Open, FileAccess.Read, FileShare.Read);
                    }
                    catch
                    {
                        if (Directory.Exists(file))
                        {
                            throw new InvalidOperationException(SR.Get(SRID.CannotReadFromDirectory, file));
                        }
                        throw;
                    }
                    baseUri = null;
                }
                else
                {
                    try
                    {
                        // http:// Load the data from the web
                        stream = DownloadData(uri, out baseUri);
                    }
                    catch (WebException e)
                    {
                        throw new IOException(e.Message, e);
                    }
                }
                mimeType = null;
                return stream;
            }
        }

        /// <summary>
        /// Release a file from a cache if any
        /// </summary>
        internal void UnloadFile(string? localPath)
        {
        }

        internal Stream LoadFile(Uri uri, out string? localPath, out Uri? redirectedUri)
        {
            return LoadFile(uri, out _, out redirectedUri, out localPath);
        }

        #endregion

        #region Private Methods

        /// <summary>
        /// Download data from the web.
        /// Set the redirectUri as the location of the file could be redirected in ASP pages.
        /// </summary>
        private static MemoryStream DownloadData(Uri uri, out Uri redirectedUri)
        {
#pragma warning disable SYSLIB0014
            // Create a request for the URL.
            WebRequest request = WebRequest.Create(uri);

            // If required by the server, set the credentials.
            request.Credentials = CredentialCache.DefaultCredentials;

            // Get the response.
            using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
            {
                // Get the stream containing content returned by the server.
                using (Stream dataStream = response.GetResponseStream())
                {
                    redirectedUri = response.ResponseUri;

                    // http:// Load the data from the web
                    using (WebClient client = new())
                    {
                        client.UseDefaultCredentials = true;
                        return new MemoryStream(client.DownloadData(redirectedUri));
                    }
                }
            }
#pragma warning restore SYSLIB0014
        }

        #endregion

        #region Private Fields

        #endregion
    }
}