using System;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;

namespace Jellyfin.Server.Middleware
{
    /// <summary>
    /// Redirect requests to robots.txt to web/robots.txt.
    /// </summary>
    public class RobotsRedirectionMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly ILogger<RobotsRedirectionMiddleware> _logger;

        /// <summary>
        /// Initializes a new instance of the <see cref="RobotsRedirectionMiddleware"/> class.
        /// </summary>
        /// <param name="next">The next delegate in the pipeline.</param>
        /// <param name="logger">The logger.</param>
        public RobotsRedirectionMiddleware(
            RequestDelegate next,
            ILogger<RobotsRedirectionMiddleware> logger)
        {
            _next = next;
            _logger = logger;
        }

        /// <summary>
        /// Executes the middleware action.
        /// </summary>
        /// <param name="httpContext">The current HTTP context.</param>
        /// <returns>The async task.</returns>
        public async Task Invoke(HttpContext httpContext)
        {
            var localPath = httpContext.Request.Path.ToString();
            if (string.Equals(localPath, "/robots.txt", StringComparison.OrdinalIgnoreCase))
            {
                _logger.LogDebug("Redirecting robots.txt request to web/robots.txt");
                httpContext.Response.Redirect("web/robots.txt");
                return;
            }

            await _next(httpContext).ConfigureAwait(false);
        }
    }
}