using System;

namespace Core.Economy
{
    /// <summary>
    /// A basic model for in game currency
    /// </summary>
    public class Currency
    {
        /// <summary>
        /// How much currency there currently is
        /// </summary>
        public int currentCurrency { get; private set; }

        /// <summary>
        /// Occurs when currency changed.
        /// </summary>
        public event Action currencyChanged;

        /// <summary>
        /// Initializes a new instance of the <see cref="Core.Economy.Currency" /> class.
        /// </summary>
        public Currency(int startingCurrency)
        {
            ChangeCurrency(startingCurrency);
        }

        /// <summary>
        /// Adds the currency.
        /// </summary>
        /// <param name="increment">the change in currency</param>
        public void AddCurrency(int increment)
        {
            if (increment == 0) return;

            ChangeCurrency(increment);
        }

        /// <summary>
        /// Method for trying to purchase, returns false for insufficient funds
        /// </summary>
        /// <returns><c>true</c>, if purchase was successful i.e. enough currency <c>false</c> otherwise.</returns>
        public bool TryPurchase(int cost)
        {
            // Cannot afford this item
            if (!CanAfford(cost))
            {
                return false;
            }
            ChangeCurrency(-cost);
            return true;
        }

        /// <summary>
        /// Determines if the specified cost is affordable.
        /// </summary>
        /// <returns><c>true</c> if this cost is affordable; otherwise, <c>false</c>.</returns>
        public bool CanAfford(int cost)
        {
            return currentCurrency >= cost;
        }

        /// <summary>
        /// Changes the currency.
        /// </summary>
        /// <param name="increment">the change in currency</param>
        protected void ChangeCurrency(int increment)
        {
            if (increment != 0)
            {
                currentCurrency += increment;
                if (currencyChanged != null)
                {
                    currencyChanged();
                }
            }
        }
    }
}