using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.Mvc;
using System.Web.Routing;
using Umbraco.Core;
using Umbraco.Core.Configuration;
using Umbraco.Core.Composing;
using Umbraco.Web.WebApi;

namespace Umbraco.Web.Mvc
{
    /// <summary>
    /// A custom area for controllers that are plugins
    /// </summary>
    internal class PluginControllerArea : AreaRegistration
    {
        private readonly IGlobalSettings _globalSettings;
        private readonly IEnumerable<PluginControllerMetadata> _surfaceControllers;
        private readonly IEnumerable<PluginControllerMetadata> _apiControllers;
        private readonly string _areaName;

        /// <summary>
        /// The constructor accepts all types of plugin controllers and will verify that ALL of them have the same areaName assigned to them
        /// based on their PluginControllerAttribute. If they are not the same an exception will be thrown.
        /// </summary>
        /// <param name="globalSettings"></param>
        /// <param name="pluginControllers"></param>
        public PluginControllerArea(IGlobalSettings globalSettings, IEnumerable<PluginControllerMetadata> pluginControllers)
        {
            _globalSettings = globalSettings;
            var controllers = pluginControllers.ToArray();

            if (controllers.Any(x => x.AreaName.IsNullOrWhiteSpace()))
            {
                throw new InvalidOperationException("Cannot create a PluginControllerArea unless all plugin controllers assigned have a PluginControllerAttribute assigned");
            }
            _areaName = controllers.First().AreaName;
            foreach(var c in controllers)
            {
                if (c.AreaName != _areaName)
                {
                    throw new InvalidOperationException("Cannot create a PluginControllerArea unless all plugin controllers assigned have the same AreaName. The first AreaName found was " + _areaName + " however, the controller of type " + c.GetType().FullName + " has an AreaName of " + c.AreaName);
                }
            }

            //get the controllers
            _surfaceControllers = controllers.Where(x => TypeHelper.IsTypeAssignableFrom<SurfaceController>(x.ControllerType));
            _apiControllers = controllers.Where(x => TypeHelper.IsTypeAssignableFrom<UmbracoApiController>(x.ControllerType));
        }

        public override void RegisterArea(AreaRegistrationContext context)
        {
            MapRouteSurfaceControllers(context.Routes, _surfaceControllers);
            MapRouteApiControllers(context.Routes, _apiControllers);
        }

        public override string AreaName
        {
            get { return _areaName; }
        }

        ///  <summary>
        ///  Registers all surface controller routes
        ///  </summary>
        /// <param name="routes"></param>
        ///  <param name="surfaceControllers"></param>
        ///  <remarks>
        ///  The routes will be:
        /// 
        ///  /Umbraco/[AreaName]/[ControllerName]/[Action]/[Id]
        ///  </remarks>
        private void MapRouteSurfaceControllers(RouteCollection routes, IEnumerable<PluginControllerMetadata> surfaceControllers)
        {
            foreach (var s in surfaceControllers)
            {
                var route = this.RouteControllerPlugin(_globalSettings, s.ControllerName, s.ControllerType, routes, "", "Index", UrlParameter.Optional, "surface");
                //set the route handler to our SurfaceRouteHandler
                route.RouteHandler = new SurfaceRouteHandler();
            }
        }

        /// <summary>
        /// Registers all api controller routes
        /// </summary>
        /// <param name="routes"></param>
        /// <param name="apiControllers"></param>
        private void MapRouteApiControllers(RouteCollection routes, IEnumerable<PluginControllerMetadata> apiControllers)
        {
            foreach (var s in apiControllers)
            {
                this.RouteControllerPlugin(_globalSettings, s.ControllerName, s.ControllerType, routes, "", "", UrlParameter.Optional, "api",
                    isMvc: false,
                    areaPathPrefix: s.IsBackOffice ? "backoffice" : null);
            }
        }
    }
}