using System;
using System.Collections.Generic;

namespace PkmnLibSharp.Utilities
{
    /// <summary>
    /// Helper class to ensure an object is disposed when it goes out of scope.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class ScopedOwner<T> : IDisposable where T : PointerWrapper
    {
        public T? Value { get; private set; }
        
        public ScopedOwner(T value)
        {
            Value = value;
        }

        public T? TakeOwnership()
        {
            var val = Value;
            Value = null;
            return val;
        }

        ~ScopedOwner()
        {
            if (Value != null)
                Value.Dispose();
        }

        public static implicit operator T?(ScopedOwner<T> val) => val.Value;

        public override string ToString()
        {
            if (Value == null) return "null";
            return Value.ToString();
        }

        public void Dispose()
        {
            if (Value != null)
                Value.Dispose();
            Value = null;
        }

        protected bool Equals(ScopedOwner<T> other)
        {
            return EqualityComparer<T?>.Default.Equals(Value, other.Value);
        }

        public override bool Equals(object? obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            if (ReferenceEquals(this, obj)) return true;
            if (obj.GetType() != this.GetType()) return false;
            return Equals((ScopedOwner<T>) obj);
        }

        public override int GetHashCode()
        {
            return EqualityComparer<T?>.Default.GetHashCode(Value);
        }

        public static bool operator ==(ScopedOwner<T>? left, ScopedOwner<T>? right)
        {
            return Equals(left, right);
        }

        public static bool operator !=(ScopedOwner<T>? left, ScopedOwner<T>? right)
        {
            return !Equals(left, right);
        }
    }
}