using System.Linq;
using System.Windows.Forms;
using Tanshu.Accounts.Contracts;
using Tanshu.Accounts.Repository;
using Tanshu.Common;

namespace Tanshu.Accounts.PointOfSale.Sales
{
    public class BillHelperFunctions
    {
        private readonly OrderedDictionary<BillItemKey, BillInventory> bill;
        private readonly BindingSource _bindingSource;
        private readonly BillItemKey _newKey;

        public BillHelperFunctions(BindingSource bindingSource, OrderedDictionary<BillItemKey, BillInventory> bill,
                                   int productID)
        {
            this._bindingSource = bindingSource;
            this.bill = bill;
            _newKey = new BillItemKey(productID, 0);
        }

        public void SetDiscount(string name, decimal discount)
        {
            if (discount > 1 || discount < 0)
                return;
            decimal maxDiscount = VoucherBI.GetProductDiscountLimit(_newKey.ProductID);
            if (discount > maxDiscount)
                MessageBox.Show(string.Format("Maximum discount for {0} is {1:P}", name, maxDiscount),
                                "Excessive Discount", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            foreach (var item in bill)
            {
                if (item.Value.ProductID == _newKey.ProductID)
                    item.Value.Discount = discount;
            }
        }

        public void SetPrice(BillInventory product)
        {
            if (!Allowed(product, RoleConstants.CHANGE_RATE))
                return;
            decimal rate = product.Price;
            if (!GetInput("Price", ref rate))
                return;
            if (rate == 0 && !Session.IsAllowed(RoleConstants.ZERO_RATE))
                return;
            foreach (var item in bill)
            {
                if (item.Value.ProductID == _newKey.ProductID)
                    item.Value.Price = rate;
            }
        }

        private void InputBox_Validating(object sender, InputBoxValidatingArgs e)
        {
        }

        private bool Allowed(BillInventory item, RoleConstants role)
        {
            if (item == null)
                return false;
            if (!Session.IsAllowed(role))
                return false;
            return true;
        }

        private bool GetInput(string prompt, ref decimal amount)
        {
            InputBoxResult result = InputBox.Show(prompt, amount.ToString(), InputBox_Validating);
            if (!result.OK)
                return false;
            if (!decimal.TryParse(result.Text, out amount))
                return false;
            return true;
        }

        #region Add Product

        public BillInventory AddProduct()
        {
            BillInventory product;
            if (bill.ContainsKey(_newKey))
            {
                _bindingSource.CurrencyManager.Position = bill.IndexOfKey(_newKey);
                product = bill[_newKey];
                product.Quantity += 1;
            }
            else
            {
                //Has only old
                product = VoucherBI.GetDefaultSaleBillItem(_newKey.ProductID);
                foreach (var item in bill)
                {
                    if (item.Key.ProductID == _newKey.ProductID)
                    {
                        product.Discount = item.Value.Discount;
                        product.Price = item.Value.Price;
                    }
                }
                product = AddProduct(product);
            }
            return product;
        }

        private BillInventory AddProduct(BillInventory product)
        {
            bill.Add(new BillItemKey(product.ProductID, 0), product);
            _bindingSource.DataSource = bill.Values.ToList();
            _bindingSource.CurrencyManager.Position = _bindingSource.CurrencyManager.Count - 1;
            return product;
        }

        #endregion

        #region Quantity

        public void SetQuantity(BillInventory product, decimal quantity, bool prompt)
        {
            if (product.Printed)
                return;
            if (prompt && !GetInput("Price", ref quantity))
                return;

            if (!prompt)
                quantity += product.Quantity;
            SetQuantity(product, quantity);
        }

        private void SetQuantity(BillInventory product, decimal quantity)
        {
            if (quantity < 0 && !Session.IsAllowed(RoleConstants.EDIT_PRINTED_PRODUCT))
                return;
            var total = quantity + bill.Where(item => item.Value.ProductID == _newKey.ProductID).Sum(item => item.Value.Quantity);

            if (total < 0)
                quantity -= total;
            product.Quantity = quantity;
        }

        #endregion
    }
}