using System.Collections.Generic;
using System.Linq;
using Microsoft.AspNet.Authorization;
using Microsoft.AspNet.Mvc;
using Microsoft.AspNet.Mvc.Rendering;
using Microsoft.Data.Entity;
using Microsoft.Extensions.Localization;
using Yavsc.Models;

namespace Yavsc.Controllers
{
    [ServiceFilter(typeof(LanguageActionFilter)), Authorize("AdministratorOnly")]
    public class ActivityController : Controller
    {
        private ApplicationDbContext _context;
        IStringLocalizer<Yavsc.Resources.YavscLocalisation> SR;

        public ActivityController(ApplicationDbContext context, IStringLocalizer<Yavsc.Resources.YavscLocalisation> SR)
        {
            _context = context;
            this.SR = SR;
        }

        // GET: Activity
        public IActionResult Index()
        {
            return View(_context.Activities.ToList());
        }

        private List<SelectListItem> GetEligibleParent(string code)
        {
            // eligibles are those
            // who are not in descendants

            //
            var acts = _context.Activities.Where(
                a=> a.Code != code
            ).Select(a => new SelectListItem
            {
                Text = a.Name,
                Value = a.Code
            }).ToList();
            acts.Add(new SelectListItem { Text=SR["aucun"], Value=null } );
            if (code == null) return acts;
            var existing = _context.Activities.Include(a => a.Children).FirstOrDefault(a => a.Code == code);
            if (existing == null) return acts;
            var pi =  acts.FirstOrDefault(i=>i.Value==existing.ParentCode);
            // Assert(pi!=null)
            pi.Selected=true;
            RecFilterChild(acts, existing);
            return acts;
        }

        /// <summary>
        /// Filters a activity selection list
        /// in order to exculde any descendant 
        /// from the eligible list at the <c>Parent</c> property.
        /// WARN! results in a infinite loop when
        /// data is corrupted and there is a circularity
        /// in the activity hierarchy graph (Parent/Children)
        /// </summary>
        /// <param name="list"></param>
        /// <param name="activity"></param>
        private static void RecFilterChild(List<SelectListItem> list, Activity activity)
        {
            if (activity == null) return;
            if (activity.Children == null) return;
            if (list.Count==0) return;
            foreach (var child in activity.Children)
            {
                RecFilterChild(list, child);
                var rem = list.FirstOrDefault(i => i.Value == child.Code);
                if (rem != null) list.Remove(rem);
            }
        }

        // GET: Activity/Details/5
        public IActionResult Details(string id)
        {
            if (id == null)
            {
                return HttpNotFound();
            }

            Activity activity = _context.Activities.Single(m => m.Code == id);
            if (activity == null)
            {
                return HttpNotFound();
            }

            return View(activity);
        }

        // GET: Activity/Create
        public IActionResult Create()
        {
            ViewBag.ParentCode = GetEligibleParent(null);
            return View();
        }

        // POST: Activity/Create
        [HttpPost]
        [ValidateAntiForgeryToken]
        public IActionResult Create(Activity activity)
        {
            if (ModelState.IsValid)
            {
                _context.Activities.Add(activity);
                _context.SaveChanges();
                return RedirectToAction("Index");
            }
            return View(activity);
        }

        // GET: Activity/Edit/5
        public IActionResult Edit(string id)
        {
            if (id == null)
            {
                return HttpNotFound();
            }

            Activity activity = _context.Activities.Single(m => m.Code == id);
            if (activity == null)
            {
                return HttpNotFound();
            }
            ViewBag.ParentCode = GetEligibleParent(id);
            return View(activity);
        }

        // POST: Activity/Edit/5
        [HttpPost]
        [ValidateAntiForgeryToken]
        public IActionResult Edit(Activity activity)
        {
            if (ModelState.IsValid)
            {
                _context.Update(activity);
                _context.SaveChanges();
                return RedirectToAction("Index");
            }
            return View(activity);
        }

        // GET: Activity/Delete/5
        [ActionName("Delete")]
        public IActionResult Delete(string id)
        {
            if (id == null)
            {
                return HttpNotFound();
            }

            Activity activity = _context.Activities.Single(m => m.Code == id);
            if (activity == null)
            {
                return HttpNotFound();
            }

            return View(activity);
        }

        // POST: Activity/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public IActionResult DeleteConfirmed(string id)
        {
            Activity activity = _context.Activities.Single(m => m.Code == id);
            _context.Activities.Remove(activity);
            _context.SaveChanges();
            return RedirectToAction("Index");
        }
    }
}