using Bridge.Html5;
using System;
using System.Collections.Generic;

namespace FrontendRouting
{
    public static class FeRoutingManager
    {
        public static event EventHandler Navigated;

        private static readonly Dictionary<string, FeRoutingView> Routes = new Dictionary<string, FeRoutingView>();
        private static FeRoutingView _currentView;
        private static string _basePath;

        private static FeRoutingView _pageNoFoundView = new DefaultPageNoFoundView();
        private static Node _parentNode = Window.Document.Body;

        public static FeRoutingView PageNoFoundView
        {
            get => _pageNoFoundView;
            set => _pageNoFoundView = value ?? throw new ArgumentNullException(nameof(value));
        }

        public static Node ParentNode
        {
            get => _parentNode;
            set
            {
                _currentView?.Leave();
                _parentNode = value ?? throw new ArgumentNullException(nameof(value));
                _currentView?.Enter(_parentNode);
            }
        }

        public static void Register(string path, FeRoutingView view)
        {
            if (false == path.StartsWith("/")) throw new ArgumentException($"{nameof(path)} must starts with /", nameof(path));
            if (Routes.ContainsKey(path)) throw new ArgumentException($"Route path `{path}' already registed", nameof(path));
            Routes.Add(path, view);
        }

        public static void UnRegister(string path)
        {
            Routes.Remove(path);
        }

        public static void Run(string basePath = "/")
        {
            if (null != _basePath) throw new InvalidOperationException("Already running");
            if (false == basePath.StartsWith("/")) throw new ArgumentException($"{nameof(basePath)} must starts with /", nameof(basePath));

            _basePath = basePath;
            Go(null);

            Window.AddEventListener(EventType.PopState, Window_PopState);
        }

        private static void Window_PopState(Event arg)
        {
            if (Go(null)) return;
            arg.PreventDefault();
            Window.History.Go(1);
        }

        public static bool Go(string path, bool replace = false)
        {
            if (null != _currentView) return _currentView.BeforeLeave(() => GoInternal(path, replace));
            return GoInternal(path, replace);
        }

        private static bool GoInternal(string path, bool replace)
        {
            if (null != path)
            {
                if (replace) Window.History.ReplaceState(null, null, path);
                else Window.History.PushState(null, null, path);
            }

            var routeKey = Window.Location.PathName;
            if (routeKey.StartsWith(_basePath)) routeKey = routeKey.Substring(_basePath.Length - 1);

            var targetView = Routes.TryGetValue(routeKey, out var controller)
                ? controller
                : PageNoFoundView;

            if (targetView.BeforeEnter(_currentView))
            {
                _currentView?.Leave();
                _currentView = targetView;
                _currentView.Enter(_parentNode);
                OnNavigated();
                return true;
            }
            return false;
        }

        private static void OnNavigated()
        {
            Navigated?.Invoke(null, EventArgs.Empty);
        }
    }
}