using System;
using System.Collections.Generic;
using System.Runtime.Serialization;

namespace WingServerCommon.Config.Parameters
{ /// <summary>
  /// Enum parameter base type
  /// </summary>
  /// <typeparam name="T"></typeparam>
    [DataContract]
    public abstract class EnumParameterBase<T> : IParameter
    {
        private T _initialValue;

        private T _value;

        /// <summary>
        /// parameter value
        /// </summary>
        [DataMember]
        public IList<T> Source { get; set; }
        
        public T InitialValue => _initialValue;

        /// <summary>
        /// parameter value
        /// </summary>
        [DataMember]
        public T Value
        {
            get => _value;
            set
            {
                if (!Equals(_value, value))
                {
                    _value = value;
                    OnValueChanged();
                }
            }
        }

        /// <summary>
        /// parameter name
        /// </summary>
        public string Name { get; set; }

        /// <summary>
        /// parameter section
        /// </summary>
        public string Section { get; set; }

        /// <summary>
        /// parameter value changed state
        /// </summary>
        public bool IsChanged => !Equals(_initialValue, Value);

        /// <summary>
        /// value changed event
        /// </summary>
        public event EventHandler ValueChanged;

        /// <summary>
        /// notify value changed
        /// </summary>
        private void OnValueChanged()
        {
            ValueChanged?.Invoke(this, EventArgs.Empty);
        }

        /// <summary>
        /// change initial value
        /// </summary>
        public void ChangeInitialValue()
        {
            _initialValue = Value;            
        }
        

        /// <summary>
        /// Set user value;
        /// </summary>
        /// <param name="value">User setting value.</param>
        public abstract void ChangeParameterValue(object value);
    }    
}