using System;
using System.Net;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Rewrite;

namespace StardewModdingAPI.Web.Framework.RedirectRules
{
    /// <summary>Redirect requests to HTTPS.</summary>
    internal class RedirectToHttpsRule : RedirectMatchRule
    {
        /*********
        ** Fields
        *********/
        /// <summary>Matches requests which should be ignored.</summary>
        private readonly Func<HttpRequest, bool> Except;


        /*********
        ** Public methods
        *********/
        /// <summary>Construct an instance.</summary>
        /// <param name="except">Matches requests which should be ignored.</param>
        public RedirectToHttpsRule(Func<HttpRequest, bool>? except = null)
        {
            this.Except = except ?? (_ => false);
            this.StatusCode = HttpStatusCode.RedirectKeepVerb;
        }


        /*********
        ** Protected methods
        *********/
        /// <summary>Get the new redirect URL.</summary>
        /// <param name="context">The rewrite context.</param>
        /// <returns>Returns the redirect URL, or <c>null</c> if the redirect doesn't apply.</returns>
        protected override string? GetNewUrl(RewriteContext context)
        {
            HttpRequest request = context.HttpContext.Request;
            if (request.IsHttps || this.Except(request))
                return null;

            UriBuilder uri = this.GetUrl(request);
            uri.Scheme = "https";
            return uri.ToString();
        }
    }
}