using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using UIWidgets;

namespace UIWidgetsSamples.Shops {
	/// <summary>
	/// On items change.
	/// </summary>
	public delegate void OnItemsChange();

	/// <summary>
	/// On money change.
	/// </summary>
	public delegate void OnMoneyChange();

	/// <summary>
	/// Trader.
	/// </summary>
	public class Trader {
		int money;

		/// <summary>
		/// Gets or sets the trader money. -1 to infinity money
		/// </summary>
		/// <value>The money.</value>
		public int Money {
			get {
				return money;
			}
			set {
				if (money==-1)
				{
					MoneyChanged();
					return ;
				}
				money = value;
				MoneyChanged();
			}
		}

		ObservableList<Item> inventory = new ObservableList<Item>();

		/// <summary>
		/// Gets or sets the inventory.
		/// </summary>
		/// <value>The inventory.</value>
		public ObservableList<Item> Inventory {
			get {
				return inventory;
			}
			set {
				if (inventory!=null)
				{
					inventory.OnChange -= ItemsChanged;
				}
				inventory = value;
				if (inventory!=null)
				{
					inventory.OnChange += ItemsChanged;
				}
				ItemsChanged();
			}
		}

		/// <summary>
		/// The price factor.
		/// </summary>
		public float PriceFactor = 1;

		/// <summary>
		/// The delete items if Item.count = 0.
		/// </summary>
		public bool DeleteIfEmpty = true;

		/// <summary>
		/// Occurs when data changed.
		/// </summary>
		public event OnItemsChange OnItemsChange;

		/// <summary>
		/// Occurs when money changed.
		/// </summary>
		public event OnMoneyChange OnMoneyChange;

		/// <summary>
		/// Initializes a new instance of the <see cref="UIWidgetsSamples.Shops.Trader"/> class.
		/// </summary>
		/// <param name="deleteIfEmpty">If set to <c>true</c> delete if empty.</param>
		public Trader(bool deleteIfEmpty = true)
		{
			DeleteIfEmpty = deleteIfEmpty;
			inventory.OnChange += ItemsChanged;
		}

		void ItemsChanged()
		{
			if (OnItemsChange!=null)
			{
				OnItemsChange();
			}
		}

		void MoneyChanged()
		{
			if (OnMoneyChange!=null)
			{
				OnMoneyChange();
			}
		}

		/// <summary>
		/// Sell the specified order.
		/// </summary>
		/// <param name="order">Order.</param>
		public void Sell(IOrder order)
		{
			if (order.OrderLinesCount()==0)
			{
				return ;
			}

			Inventory.BeginUpdate();
			order.GetOrderLines().ForEach(SellItem);
			Inventory.EndUpdate();

			Money += order.Total();
		}

		/// <summary>
		/// Sells the item.
		/// </summary>
		/// <param name="orderLine">Order line.</param>
		void SellItem(IOrderLine orderLine)
		{
			var count = orderLine.Count;

			// decrease items count
			orderLine.Item.Count -= count;

			// remove item from inventory if zero count
			if (DeleteIfEmpty && (orderLine.Item.Count==0))
			{
				Inventory.Remove(orderLine.Item);
			}
		}

		/// <summary>
		/// Buy the specified order.
		/// </summary>
		/// <param name="order">Order.</param>
		public void Buy(IOrder order)
		{
			if (order.OrderLinesCount()==0)
			{
				return ;
			}

			Inventory.BeginUpdate();
			order.GetOrderLines().ForEach(BuyItem);
			Inventory.EndUpdate();

			Money -= order.Total();
		}

		/// <summary>
		/// Buy the item.
		/// </summary>
		/// <param name="orderLine">Order line.</param>
		void BuyItem(IOrderLine orderLine)
		{
			// find item in inventory
			var item = Inventory.Find(x => x.Name==orderLine.Item.Name);

			var count = orderLine.Count;
			// if not found add new item to inventory
			if (item==null)
			{
				Inventory.Add(new Item(orderLine.Item.Name, count));
			}
			// if found increase count
			else
			{
				item.Count += count;
			}
		}

		/// <summary>
		/// Determines whether this instance can buy the specified order.
		/// </summary>
		/// <returns><c>true</c> if this instance can buy the specified order; otherwise, <c>false</c>.</returns>
		/// <param name="order">Order.</param>
		public bool CanBuy(IOrder order)
		{
			return Money==-1 || Money>=order.Total();
		}
	}
}