using System;
using System.Threading;
using TraceSource = System.Diagnostics.TraceSource;

namespace Implab.Diagnostics {
    /// <summary>
    /// This class is used to provide a single <see cref="TraceSourceChannel"/> 
    /// instance for the specified class in <typeparamref name="T"/> parameter.
    /// </summary>
    /// <typeparam name="T">
    /// The class for which <see cref="TraceSourceChannel"/> is required.
    /// </typeparam>
    /// <remarks>
    /// The <see cref="TraceSourceChannel"/> instance will be created on demand
    /// and automatically registered in <see cref="TraceRegistry.Global"/>.
    /// </remarks>
    public static class TraceSourceChannel<T> {
        static Lazy<TraceSourceChannel> _traceSource = new Lazy<TraceSourceChannel>(CreateChannel, LazyThreadSafetyMode.ExecutionAndPublication);

        /// <summary>
        /// The default <see cref="TraceSourceChannel"/> instance.
        /// </summary>
        public static TraceSourceChannel Default { get { return _traceSource.Value; } }

        static TraceSourceChannel CreateChannel() {
            var channel = new TraceSourceChannel(typeof(T), typeof(T).FullName);

            TraceRegistry.Global.Register(channel);

            return channel;
        }
    }
}