using HPlusSports.Models;
using System;
using System.Linq;
using System.Web.Mvc;

namespace HPlusSports.Controllers
{
    [Authorize(Roles = UserRoles.Admin)]
    public class InventoryController : Controller
    {
        private HPlusSportsDbContext _context;

        public InventoryController()
          : this(new HPlusSportsDbContext())
        {
        }

        public InventoryController(HPlusSportsDbContext context)
        {
            _context = context;
        }

        public ActionResult Index()
        {
            var products =
              _context.Products
                .OrderBy(x => x.CategoryId)
                .ThenBy(x => x.Name);

            return View(products);
        }

        [HttpGet]
        public ActionResult Create()
        {
            return View();
        }

        [HttpPost]
        public ActionResult Create(Product product)
        {
            if (!ModelState.IsValid)
            {
                return View();
            }

            product.LastUpdated = DateTime.UtcNow;
            product.LastUpdatedUserId = GetUserId(this);

            _context.Products.Add(product);
            _context.SaveChanges();

            TempData["SuccessMessage"] =
              $"Successfully created \"{product.Name}\"";

            return RedirectToAction(nameof(Index));
        }

        [HttpGet]
        public ActionResult Update(long id)
        {
            var existing = _context.Products.Find(id);

            if (existing == null)
            {
                return ProductListError(
                  $"Couldn't update product #\"{id}\": product not found!"
                );
            }

            return View(existing);
        }

        [HttpPost]
        public ActionResult Update(long id, Product product)
        {
            if (!ModelState.IsValid)
            {
                return View();
            }

            var existing = _context.Products.Find(id);

            if (existing == null)
            {
                return ProductListError(
                  $"Couldn't update product #\"{id}\": product not found!"
                );
            }

            var hasPriceChanged = existing.Price != product.Price;

            existing.CategoryId = product.CategoryId;
            existing.Description = product.Description;
            existing.MSRP = product.MSRP;
            existing.Name = product.Name;
            existing.Price = product.Price;
            existing.SKU = product.SKU;
            existing.Summary = product.Summary;

            existing.LastUpdated = DateTime.UtcNow;
            existing.LastUpdatedUserId = GetUserId(this);

            _context.SaveChanges();

            if (hasPriceChanged)
            {
                var cartsToUpdate =
                  _context.ShoppingCarts
                    .Include("Items")
                    .Where(cart => cart.Items.Any(x => x.SKU == product.SKU));

                foreach (var cart in cartsToUpdate)
                {
                    foreach (var cartItem in cart.Items.Where(x => x.SKU == product.SKU))
                    {
                        cartItem.Price = product.Price;
                    }

                    cart.Recalculate();
                }
            }

            _context.SaveChanges();

            TempData["SuccessMessage"] =
              $"Successfully updated \"{product.Name}\"";

            return RedirectToAction(nameof(Index));
        }

        public ActionResult Delete(long id)
        {
            var product = _context.Products.Find(id);

            if (product == null)
            {
                return ProductListError(
                  $"Couldn't delete \"{product.Name}\": product not found!"
                );
            }

            _context.Products.Remove(product);
            _context.SaveChanges();

            TempData["SuccessMessage"] =
              $"Successfully deleted \"{product.Name}\"";

            return RedirectToAction(nameof(Index));
        }

        private ActionResult ProductListError(string error)
        {
            TempData["ErrorMessage"] = error;
            return RedirectToAction(nameof(Index));
        }

        protected override void OnResultExecuting(ResultExecutingContext filterContext)
        {
            ViewData["CategoryId"] =
              _context.Categories
                  .Select(x => new SelectListItem
                  {
                      Text = x.Name,
                      Value = x.Id.ToString(),
                  })
                  .ToArray();
        }

        // Overwriteable function for unit testing
        internal Func<Controller, string> GetUserId =
            (controller) => controller.User.Identity.Name;
    }
}