using System;
using System.Collections.Generic;
using JD.Interfaces.Remoting;

namespace JD.Remoting.Details
{
    /// <summary>
    /// Allows to register a Query and to have a callback when the data is ready.
    /// </summary>
    public class QueryDictionary
    {
        private readonly List<PendingQuery> m_queries = new List<PendingQuery>();
        
        public bool Handle(IMessage message)
        {
            var query = DequeueQuery(message.CommandName);
            if (query != null)
            {
                query.HandleResultAction(message.Content.ConvertToRead());
                return true;
            }
            return false;
        }

        public void Register(string commandName, Action<IBlob> handleQuery)
        {
            m_queries.Add(new PendingQuery(commandName, handleQuery));
        }

        private PendingQuery DequeueQuery(string commandName)
        {
            lock (m_queries)
            {
                for (int i = 0; i < m_queries.Count; i++)
                {
                    if (m_queries[i].CommandName == commandName)
                    {
                        var query = m_queries[i];
                        m_queries.RemoveAt(i);
                        return query;
                    }
                }
            }
            return null;
        }

        private class PendingQuery
        {
            public string CommandName { get; private set; }
            public Action<IBlob> HandleResultAction { get; private set; }

            public PendingQuery(string commandName, Action<IBlob> handleResultAction)
            {
                CommandName = commandName;
                HandleResultAction = handleResultAction;
            }
        }
    }
}