using System.Collections.Generic;

namespace TBL.CSharp.Serialization.Marshal.Context
{
    /// <summary>
    /// Marshal 风格的序列化上下文基础实现
    /// </summary>
    public class MarshalContextBasic : IMarshalContext
    {
        /// <summary>
        /// 已链接的符号
        /// </summary>
        private readonly IDictionary<int, string> _linkedSymbols =
            new Dictionary<int, string>();

        /// <summary>
        /// 已链接的对象
        /// </summary>
        private readonly IDictionary<int, object> _linkedObjects =
            new Dictionary<int, object>();

        /// <summary>
        /// 已链接的符号 Id
        /// </summary>
        private readonly IDictionary<string, int> _linkedSymbolIds = 
            new Dictionary<string, int>();

        /// <summary>
        /// 已链接的对象 Id
        /// </summary>
        private readonly IDictionary<object, int> _linkedObjectIds = 
            new Dictionary<object, int>();

        public void Clear()
        {
            _linkedSymbols.Clear();
            _linkedSymbolIds.Clear();
            _linkedObjects.Clear();
        }

        public string GetLinkableSymbol(int index) => _linkedSymbols[index];

        public string AddLinkableSymbol(string symbol)
        {
            var id = _linkedSymbols.Count + 1;
            _linkedSymbols.Add(id, symbol);
            _linkedSymbolIds.Add(symbol, id);
            return symbol;
        }

        public bool FindLinkableSymbol(string symbol, out int index) =>
            _linkedSymbolIds.TryGetValue(symbol, out index);

        public object GetLinkableObject(int index) => _linkedObjects[index];

        public T AddLinkableObject<T>(T element)
        {
            var id = _linkedObjects.Count + 1;
            _linkedObjects.Add(id, element);
            _linkedObjectIds.Add(element, id);
            return element;
        }

        public bool FindLinkableObject(object element, out int index) =>
            _linkedObjectIds.TryGetValue(element, out index);
    }
}