using System;
using System.Text.RegularExpressions;
using System.Collections.Generic;
using System.Text;
using System.Linq;
namespace ln.http.router
{
    public class SimpleRouter : IHttpRouter
    {
        List<SimpleRoute> routes = new List<SimpleRoute>();
        public SimpleRoute[] Routes => routes.ToArray();

        public SimpleRouter()
        {
        }

        public void AddSimpleRoute(string simpleRoute, Func<HttpRoutingContext, HttpRequest, HttpResponse> target) => AddSimpleRoute(simpleRoute, new RouterTarget(target));
        public void AddSimpleRoute(string simpleRoute, Func<string, HttpRequest, HttpResponse> target) => AddSimpleRoute(simpleRoute, new RouterTarget(target));
        public void AddSimpleRoute(string simpleRoute, Func<HttpRequest, HttpResponse> target) => AddSimpleRoute(simpleRoute, new RouterTarget(target));
        public void AddSimpleRoute(string simpleRoute, IHttpRouter target) => AddSimpleRoute(simpleRoute, target, simpleRoute.Split('/').Length);
        public void AddSimpleRoute(string simpleRoute, IHttpRouter target, int priority)
        {
            string[] parts = simpleRoute.Split(new char[] { '/' });
            string[] reparts = parts.Select((part) =>
            {
                if (part.StartsWith(":", StringComparison.InvariantCulture))
                    if (part.EndsWith("*", StringComparison.InvariantCulture))
                        return string.Format("(?<{0}>[^/]+)(?<_>/.*)?", part.Substring(1, part.Length - 2));
                    else
                        return string.Format("(?<{0}>[^/]+)", part.Substring(1));
                else if (part.Equals("*"))
                    return string.Format("(?<_>.*)");
                else
                    return string.Format("{0}", part);
            }).ToArray();

            string reroute = string.Join("/", reparts);

            AddRoute(reroute, target, priority);
        }

        public void AddRoute(String route, IHttpRouter target) => AddRoute(route, target, 0);
        public void AddRoute(String route, IHttpRouter target,int priority)
        {
            lock (this)
            {
                routes.Add(new SimpleRoute(route, target, priority));
                routes.Sort((SimpleRoute a, SimpleRoute b) => b.Priority - a.Priority);
            }
        }
        public void Remove(SimpleRoute simpleRoute) => routes.Remove(simpleRoute);

        public HttpResponse Route(HttpRoutingContext routingContext, HttpRequest httpRequest)
        {
            foreach (SimpleRoute simpleRoute in routes.ToArray())
            {
                Match match = simpleRoute.Route.Match(routingContext.Path);
                if (match.Success)
                {
                    string residual = "";

                    foreach (Group group in match.Groups)
                    {
                        httpRequest?.SetParameter(group.Name, group.Value);
                        if (group.Name.Equals("_"))
                            if (group.Value.StartsWith("/", StringComparison.InvariantCulture))
                                residual = group.Value;
                            else
                                residual = "/" + group.Value;
                    }

                    HttpResponse response = simpleRoute.Target.Route(routingContext.Routed(residual), httpRequest);
                    if (response != null)
                        return response;
                }
            }
            return null;
        }
    

        public class SimpleRoute
        {
            public int Priority { get; }

            public Regex Route { get; }
            public IHttpRouter Target { get; }

            public SimpleRoute(string regex, IHttpRouter target) : this(regex, target, 0) { }
            public SimpleRoute(string regex, IHttpRouter target,int priority)
            {
                Route = new Regex(regex);
                Target = target;
                Priority = priority;
            }
        }
    }
}