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

namespace Tango.Logging
{
    /// <summary>
    /// Represents stand-alone visual console emulation logger.
    /// </summary>
    /// <seealso cref="Tango.Logging.ILogger" />
    public class ConsoleLogger : ILogger
    {
        private bool _consoleOpened;
        private String _consoleTitle;
        private ConsoleWindow console;

        /// <summary>
        /// Gets or sets a value indicating whether this <see cref="ILogger" /> is enabled.
        /// </summary>
        public bool Enabled { get; set; }

        /// <summary>
        /// Initializes a new instance of the <see cref="ConsoleLogger"/> class.
        /// </summary>
        public ConsoleLogger(String consoleTitle)
        {
            _consoleTitle = consoleTitle;
            Enabled = true;
        }

        /// <summary>
        /// Called when a new library trace is available.
        /// </summary>
        /// <param name="output">The output.</param>
        public void OnLog(LogItemBase output)
        {
            EnsureConsoleOpen(() =>
            {
                switch (output.Category)
                {
                    case LogCategory.Info:
                        console.SetColor(ConsoleColor.White);
                        break;
                    case LogCategory.Warning:
                        console.SetColor(ConsoleColor.Yellow);
                        break;
                    case LogCategory.Error:
                        console.SetColor(ConsoleColor.Red);
                        break;
                    case LogCategory.Critical:
                        console.SetColor(ConsoleColor.DarkRed);
                        break;
                    case LogCategory.Debug:
                        console.SetColor(ConsoleColor.Gray);
                        break;
                }

                console.WriteLine(output.ToString());
            });
        }

        /// <summary>
        /// Waits until user closes the console.
        /// </summary>
        /// <returns></returns>
        public async Task WaitForConsoleExit()
        {
            if (console != null)
            {
                await console.WaitForUserClose();
            }
        }

        /// <summary>
        /// Ensures the console is open.
        /// </summary>
        private void EnsureConsoleOpen(Action post)
        {
            if (!_consoleOpened)
            {
                Thread t = new Thread(() =>
                {
                    console = new ConsoleWindow();
                    console.Title += " - " + _consoleTitle;
                    _consoleOpened = true;
                    console.Show();
                    console.Closed += (sender2, e2) => console.Dispatcher.InvokeShutdown();
                    System.Windows.Threading.Dispatcher.Run();
                });

                t.IsBackground = true;
                t.SetApartmentState(ApartmentState.STA);
                t.Start();
            }

            while (!_consoleOpened)
            {
                Thread.Sleep(10);
            }

            post();
        }
    }
}