using System;
using System.ComponentModel;
using System.Drawing;
using System.Reflection;
using System.Windows.Forms;
using JD.Kernel.Classes;

namespace JD.MessageService
{
    /// <summary>
    /// Used to show messages in the tray icon. 
    /// </summary>
    /// <remarks>This is a gui object and should be created in the Gui thread.</remarks>

    public class TrayBalloon : IDisposable
    {
        private const int MaxTitleLength = 63;

        #region Variables

        private readonly object m_lock = new object();
        private readonly Container m_components = new Container(); // Must be initialized on Main thread.
        private readonly NotifyIcon m_icon;

        // Use a custom timer instead of default timeout to hide the icon and to bypass the minimum timeout of NotifyIcon
        private readonly System.Timers.Timer m_timer;
        private Request m_currentRequest;

        #endregion

        #region Constructor

        public TrayBalloon()
        {
            m_icon = new NotifyIcon(m_components);
            m_icon.Visible = true;
            m_icon.Visible = false; // Necessary or the icon is erroneous if shown the first time from another thread than the main thread.
            m_icon.BalloonTipClicked += m_icon_Click;
            m_icon.MouseUp += m_icon_MouseUp;
            m_icon.Icon = ExtractApplicationIcon();
            m_timer = new System.Timers.Timer();
            m_timer.Elapsed += m_timer_Tick;
        }

        public void Dispose()
        {
            DisposableHelper.SafeDispose(m_timer);
            DisposableHelper.SafeDispose(m_components);
            DisposableHelper.SafeDispose(m_icon);
        }

        #endregion

        #region Methods

        /// <summary>
        /// Shows a balloon for the requested duration. If there was another balloon, the new call close the old one.
        /// </summary>
        public IBalloon Show(TimeSpan timeout, string title, string text, ToolTipIcon icon, Action clickHandler)
        {
            if (m_icon != null)
            {
                lock (m_lock)
                {
                    // Make sure the balloon does not flicker to infinite when prompting the same message a lot of times.
                    if (IsOnSameRequest(title, text))
                    {
                        return m_currentRequest;
                    }

                    m_currentRequest = new Request(this);

                    // No initialization on single line ...
                    m_currentRequest.Title = title;
                    m_currentRequest.Text = text;
                    m_currentRequest.ClickHandler = clickHandler;

                    m_icon.Visible = true;
                    m_timer.Stop();
                    m_timer.Interval = (int)timeout.TotalMilliseconds;
                    m_timer.Start();
                }

                m_icon.ShowBalloonTip((int)timeout.TotalMilliseconds, Truncate(title, MaxTitleLength), Truncate(text, 255), icon);
            }
            return m_currentRequest;
        }

        private bool IsOnSameRequest(string title, string text)
        {
            var request = m_currentRequest;
            return request != null && request.Title == title && request.Text == text;
        }

        private static string Truncate(string value, int length)
        {
            if (value == null)
            {
                return string.Empty;
            }

            return value.Substring(0, Math.Min(value.Length, length));
        }

        private static Icon ExtractApplicationIcon()
        {
            try
            {
                return Icon.ExtractAssociatedIcon(Assembly.GetEntryAssembly().Location);
            }
            catch
            {
                return null;
            }
        }

        public void Hide()
        {
            lock (m_lock)
            {
                m_timer.Stop();
                m_currentRequest = null;
                m_icon.Visible = false;
            }
        }

        #endregion

        #region Handlers

        void m_timer_Tick(object sender, EventArgs e)
        {
            Hide();
        }

        void m_icon_Click(object sender, EventArgs e)
        {
            var currentRequest = m_currentRequest;
            if (currentRequest != null)
            {
                currentRequest.OnClick();
            }
        }

        void m_icon_MouseUp(object sender, MouseEventArgs e)
        {
            var currentRequest = m_currentRequest;
            if (currentRequest != null)
            {
                currentRequest.OnIconMouseUp();
            }
        }

        #endregion

        #region Nested

        private class Request : IBalloon
        {
            private readonly TrayBalloon m_balloon;
            private string m_title;

            public Request(TrayBalloon balloon)
            {
                m_balloon = balloon;
            }

            public void Hide()
            {
                if (IsActiveRequest)
                {
                    m_balloon.Hide();
                }
            }

            private bool IsActiveRequest
            {
                get { return m_balloon.m_currentRequest == this; }
            }

            public string Title
            {
                get { return m_title; }
                set
                {
                    m_title = value;
                    if (IsActiveRequest)
                    {
                        m_balloon.m_icon.Text = Truncate(m_title, MaxTitleLength);
                    }
                }
            }

            public string Text
            {
                get; 
                set; 
            }

            public Action IconMouseUpHandler
            {
                get; 
                set; 
            }

            public void OnIconMouseUp()
            {
                var handler = IconMouseUpHandler;
                if (handler != null)
                {
                    IconMouseUpHandler = null;
                    handler();
                }
            }

            public Action ClickHandler
            {
                get;
                set;
            }

            public void OnClick()
            {
                var handler = ClickHandler;
                if (handler != null)
                {
                    ClickHandler = null;
                    handler();
                }
            }
        }

        #endregion
    }
}