using System;
using System.Collections;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace StgSharp.Collections
{
    public interface IBidirectionalDictionary<TFirst, TSecond> : 
        IDictionary<TFirst, TSecond>
    {
#pragma warning disable CA1033 
        ICollection<TFirst> IDictionary<TFirst, TSecond>.Keys => FirstIndex;
        ICollection<TSecond> IDictionary<TFirst, TSecond>.Values => SecondIndex;
        bool IDictionary<TFirst, TSecond>.ContainsKey(TFirst key) => Contains(key);
#pragma warning restore CA1033 

        public IReadOnlyDictionary<TFirst, TSecond> Forward { get; }
        public IReadOnlyDictionary<TSecond, TFirst> Reverse { get; }

        public ICollection<TFirst> FirstIndex { get;}

        public ICollection<TSecond> SecondIndex { get; }

        public TFirst this[TSecond key] { get;set; }

        /// <summary>
        /// Determines whether the <see cref="IBidirectionalDictionary{TFirst, TSecond}" /> contains the
        /// specified key.
        /// </summary>
        /// <param name="key"> The value to locate in the <see cref="IBidirectionalDictionary{TFirst, TSecond}" />. </param>
        /// <returns>
        /// true if the <see cref="IBidirectionalDictionary{TFirst, TSecond}" /> contains an element with the
        /// specified key; otherwise, false.
        /// </returns>
        public bool Contains(TSecond key);

        /// <summary>
        /// Determines whether the <see cref="IBidirectionalDictionary{TFirst, TSecond}" /> contains the
        /// specified key.
        /// </summary>
        /// <param name="key"> The value to locate in the <see cref="IBidirectionalDictionary{TFirst, TSecond}" />. </param>
        /// <returns>
        /// true if the <see cref="IBidirectionalDictionary{TFirst, TSecond}"/> contains an element with the
        /// specified key; otherwise, false.
        /// </returns>
        public bool Contains(TFirst key);

        public bool TryGetValue(TSecond key, out TFirst value);
    }
}