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

namespace StardewModdingAPI.Web.Framework.RedirectRules
{
    /// <summary>Redirect matching requests to a URL.</summary>
    internal abstract class RedirectMatchRule : IRule
    {
        /*********
        ** Fields
        *********/
        /// <summary>The status code to use for redirects.</summary>
        protected HttpStatusCode StatusCode { get; set; } = HttpStatusCode.Redirect;


        /*********
        ** Public methods
        *********/
        /// <summary>Applies the rule. Implementations of ApplyRule should set the value for <see cref="RewriteContext.Result" /> (defaults to RuleResult.ContinueRules).</summary>
        /// <param name="context">The rewrite context.</param>
        public void ApplyRule(RewriteContext context)
        {
            string? newUrl = this.GetNewUrl(context);
            if (newUrl == null)
                return;

            HttpResponse response = context.HttpContext.Response;
            response.StatusCode = (int)HttpStatusCode.Redirect;
            response.Headers["Location"] = newUrl;
            context.Result = RuleResult.EndResponse;
        }


        /*********
        ** 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 abstract string? GetNewUrl(RewriteContext context);

        /// <summary>Get the full request URL.</summary>
        /// <param name="request">The request.</param>
        protected UriBuilder GetUrl(HttpRequest request)
        {
            return new UriBuilder
            {
                Scheme = request.Scheme,
                Host = request.Host.Host,
                Port = request.Host.Port ?? -1,
                Path = request.PathBase + request.Path,
                Query = request.QueryString.Value
            };
        }
    }
}