using System;
using System.Collections.Generic;
using System.Globalization;
using System.Windows;
using System.Windows.Forms;
using JD.Collections.Extensions;
using JD.Kernel.Classes;
using JD.Kernel.StaticHelpers;
using JD.LogService;

namespace JD.MessageService
{
    /// <summary>
    /// Helper class used to display advanced Message Boxes and other forms of user interaction.
    /// </summary>
    /// <remarks>
    /// Do NOT use this class in command line mode. Although some methods will simply not do anything in command-line mode (ShowMessage, ShowWarning, ShowError),
    /// others will throw in command-line mode.
    /// </remarks>
    public static class MessageService
    {
        #region Inner Types

        /// <summary>
        /// Delegate that represents a method that shows a given error.
        /// </summary>
        /// <param name="ex">Thrown Exception</param>
        /// <param name="message">An optional message</param>
        internal delegate void ShowErrorDelegate(Exception ex, string message);

        /// <summary>
        /// Delegates that acts like a predicate for a string. Instead of returning true or false,
        /// it has to return null if the validation passes or an error message if it fails.
        /// </summary>
        /// <param name="candidate">Candidate to test.</param>
        /// <returns>Null if the validation passes, an error string to display otherwise.</returns>
        public delegate string ValidationPredicate(string candidate);

        #endregion

        #region Variables

        private const string DefaultMessageCaption = "Message";
        private const string DefaultWarningCaption = "Warning";
        private const string DefaultErrorCaption = "Error";
        
        private static ShowErrorDelegate m_customErrorReporter;
        private static IMessageService ms_instance;
        private static bool _isCommandLine;

        #endregion
        
        #region Properties

        public static bool IsCommandLine
        {
            get { return _isCommandLine; }
            set
            {
                _isCommandLine = value;
                ms_instance = null;
            }
        }

        public static IMessageService Instance
        {
            get
            {
                if (ms_instance == null)
                {
                    if (IsCommandLine)
                    {
                        ms_instance = new CommandlineMessageService();
                    }
                    else
                    {
                        ms_instance = new GuiMessageService();
                    }
                }

                return ms_instance;
            }
        }
        
        /// <summary>
        /// Gets/Sets the custom error reporter. If this property is null, the default
        /// messagebox is used (except for debug builds, where the
        /// message is only logged to the LogService).
        /// </summary>
        internal static ShowErrorDelegate CustomErrorReporter
        {
            get
            {
                return m_customErrorReporter;
            }
            set
            {
                m_customErrorReporter = value;
            }
        }
        
        #endregion

        #region Methods

        #region Lifetime

        public static void Initialize()
        {
            Instance.Initialize();
        }

        public static void Close()
        {
            DisposableHelper.SafeDispose(ms_instance as IDisposable);
        }

        #endregion

        #region Mock

        public static IDisposable Use(IMessageService messageService)
        {
            Throw.IfNull(messageService, "messageService");

            IMessageService old = ms_instance;

            ms_instance = messageService;

            return new DisposableHelper(delegate
            {
                ms_instance = old;
            });
        }

        #endregion

        #region ShowMessage

        /// <summary>
        /// Shows a message box.
        /// </summary>
        /// <param name="message"></param>
        /// <returns>Returns which button was clicked</returns>
        public static void ShowMessage(string message)
        {
            ShowMessage(message, DefaultMessageCaption);
        }
        
        /// <summary>
        /// <see cref="MessageService.ShowMessage(string)"/>
        /// </summary>
        /// <param name="message"></param>
        /// <param name="caption"></param>
        /// <returns>Returns which button was clicked</returns>
        public static void ShowMessage(string message, string caption)
        {
            LogService.LogService.LogMessage(message);

            Instance.Show(LogCategory.Message, message, caption);
        }

        #endregion

        #region ShowWarning

        /// <summary>
        /// <see cref="MessageService.ShowWarning(string, string)"/>
        /// </summary>
        /// <param name="message"></param>
        public static void ShowWarning(string message)
        {
            ShowWarning(message, DefaultWarningCaption);
        }
        
        /// <summary>
        /// Shows a warning to the user
        /// </summary>
        /// <param name="message"></param>
        /// <param name="caption"></param>
        public static void ShowWarning(string message, string caption)
        {
            LogService.LogService.LogWarning(message);

            Instance.Show(LogCategory.Warning, message, caption);
        }

        #endregion

        #region ShowError

        /// <summary>
        /// Shows an error to the user.
        /// </summary>
        /// <param name="ex"></param>
        /// <param name="message"></param>
        public static void ShowError(Exception ex, string message)
        {
            ShowError(ex, message, false);
        }

        /// <summary>
        /// Shows an error message to the user with a custom caption.
        /// </summary>
        /// <param name="ex"></param>
        /// <param name="message"></param>
        /// <param name="caption"></param>
        public static void ShowError(Exception ex, string message, string caption)
        {
            ShowError(ex, message, caption, false);
        }

        /// <summary>
        /// <see cref="MessageService.ShowError(Exception, string)"/>
        /// </summary>
        /// <param name="ex"></param>
        public static void ShowError(Exception ex)
        {
            ShowError(ex, null);
        }

        public static void ShowError(string message, LoggingContext context)
        {
            ShowLoggingErrorImpl(message, context.Errors);
        }

        /// <summary>
        /// <see cref="MessageService.ShowError(Exception, string)"/>
        /// </summary>
        /// <param name="message"></param>
        public static void ShowError(string message)
        {
            ShowError((Exception)null, message);
        }

        public static void ShowError(string message, string caption)
        {
            ShowError(null, message, caption);
        }

        /// <summary>
        /// <see cref="MessageService.ShowError(Exception, string)"/>
        /// </summary>
        /// <param name="format"></param>
        /// <param name="formatItems"></param>
        public static void ShowErrorFormatted(string format, params object[] formatItems)
        {
            ShowError((Exception)null, Format(format, formatItems));
        }
        
        /// <summary>
        /// <see cref="MessageService.ShowError(Exception, string)"/>
        /// </summary>
        /// <param name="ex"></param>
        /// <param name="message"></param>
        /// <param name="forceSilent"></param>
        public static void ShowError(Exception ex, string message, bool forceSilent /* = false */)
        {
            ShowErrorImpl(ex, message, DefaultErrorCaption, forceSilent, false);
        }

        /// <summary>
        /// <see cref="MessageService.ShowError(Exception, string)"/>
        /// </summary>
        /// <param name="ex"></param>
        /// <param name="message"></param>
        /// <param name="caption"></param>
        /// <param name="forceSilent"></param>
        public static void ShowError(Exception ex, string message, string caption, bool forceSilent /* = false */)
        {
            ShowErrorImpl(ex, message, caption, forceSilent, false);
        }

        /// <summary>
        /// Shows an error to the user.
        /// </summary>
        /// <param name="ex"></param>
        /// <param name="message"></param>
        /// <param name="caption"></param>
        /// <param name="forceSilent"></param>
        /// <param name="isUnhandled"></param>
        private static void ShowErrorImpl(Exception ex, string message, string caption, bool forceSilent /* = false */, bool isUnhandled)
        {
            if (ex != null)
            {
                LogService.LogService.LogError(message + ": " + ex);
                if (CustomErrorReporter != null && isUnhandled)
                {
                    CustomErrorReporter(ex, message);
                    return;
                }
            }
            else
            {
                LogService.LogService.LogError(message);
            }

            if (forceSilent)
            {
                return;
            }

            string msg = string.Empty;

            if (message != null)
            {
                msg += message;
            }

            if (message != null && ex != null)
            {
                msg += "\n\n";
            }


            if (ex != null)
            {
                msg += "Exception occurred: " + ex;
            }

            Instance.Show(LogCategory.Error, msg, caption);
        }

        private static void ShowLoggingErrorImpl(string message, IEnumerable<Error> errors)
        {
            ShowErrorFormatted("{0}\n{1}", message, errors.Join("\n", error => error.Message));
        }

        #endregion

        #region AskQuestion

        /// <summary>
        /// Asks a Yes/No question to the user.
        /// </summary>
        /// <param name="question"></param>
        /// <param name="caption"></param>
        /// <returns></returns>
        public static bool AskQuestion(string question, string caption)
        {
            return AskQuestion(question, caption, MessageBoxImage.Question);
        }

        /// <summary>
        /// Asks a Yes/No question to the user.
        /// </summary>
        /// <param name="question"></param>
        /// <param name="caption"></param>
        /// <param name="icon"></param>
        /// <returns></returns>
        public static bool AskQuestion(string question, string caption, MessageBoxImage icon)
        {
            return AskQuestion(question, caption, icon, true);
        }

        /// <summary>
        /// Asks a Yes/No question to the user.
        /// </summary>
        /// <param name="question"></param>
        /// <param name="caption"></param>
        /// <param name="icon"></param>
        /// <param name="defaultAnswer"></param>
        /// <returns></returns>
        public static bool AskQuestion(string question, string caption, MessageBoxImage icon, bool defaultAnswer)
        {
            return Instance.AskQuestion(question, caption, icon, MessageBoxButton.YesNo, defaultAnswer ? MessageBoxResult.Yes : MessageBoxResult.No) == MessageBoxResult.Yes;
        }

        /// <summary>
        /// Asks a Yes/No/Cancel question to the user.
        /// </summary>
        public static MessageBoxResult AskQuestionYesNoCancel(string question, string caption, MessageBoxImage icon)
        {
            return AskQuestion(question, caption, icon, MessageBoxButton.YesNoCancel);
        }

        /// <summary>
        /// Asks a Yes/No/Cancel question to the user.
        /// </summary>
        public static MessageBoxResult AskQuestion(string question, string caption, MessageBoxImage icon, MessageBoxButton buttons)
        {
            return Instance.AskQuestion(question, caption, icon, buttons, MessageBoxResult.Cancel);
        }
        
        /// <summary>
        /// <see cref="MessageService.AskQuestion(string, string)"/>
        /// </summary>
        /// <param name="format"></param>
        /// <param name="formatItems"></param>
        /// <returns></returns>
        public static bool AskQuestionFormatted(string format, params object[] formatItems)
        {
            return AskQuestion(Format(format, formatItems));
        }

        /// <summary>
        /// <see cref="MessageService.AskQuestion(string, string)"/>
        /// </summary>
        /// <param name="question"></param>
        /// <returns></returns>
        public static bool AskQuestion(string question)
        {
            return AskQuestion(question, "Question");
        }

        #endregion

        #region ShowCustomDialog
        
        #endregion

        #region ShowBalloon

        /// <summary>
        /// Shows a balloon in tray icon closing after the timeout expired.
        /// </summary>
        /// <param name="timeout">The duration before the balloon closes and hides.</param>
        /// <param name="title">The bold title in the header.</param>
        /// <param name="text">The content of the balloon.</param>
        /// <param name="icon">Type of balloon.</param>
        public static IBalloon ShowBalloon(TimeSpan timeout, string title, string text, ToolTipIcon icon)
        {
            return Instance.ShowBalloon(timeout, title, text, icon, null);
        }

        /// <summary>
        /// Shows a balloon in tray icon closing after the timeout expired.
        /// </summary>
        /// <param name="timeout">The duration before the balloon closes and hides.</param>
        /// <param name="title">The bold title in the header.</param>
        /// <param name="text">The content of the balloon.</param>
        /// <param name="icon">Type of balloon.</param>
        /// <param name="clickHandler">An action to execute when clicking the balloon.</param>
        public static IBalloon ShowBalloon(TimeSpan timeout, string title, string text, ToolTipIcon icon, Action clickHandler)
        {
            return Instance.ShowBalloon(timeout, title, text, icon, clickHandler);
        }

        #endregion

        #region ShowInput
        
        /// <summary>
        /// <see cref="MessageService.ShowInputBox(string, string, string, ValidationPredicate)"/>
        /// </summary>
        /// <param name="question"></param>
        /// <param name="caption"></param>
        /// <returns></returns>
        public static string ShowInputBox(string question, string caption)
        {
            return ShowInputBox(question, caption, string.Empty, null);
        }

        /// <summary>
        /// <see cref="MessageService.ShowInputBox(string, string, string, ValidationPredicate)"/>
        /// </summary>
        /// <param name="question"></param>
        /// <param name="caption"></param>
        /// <param name="defaultValue"></param>
        /// <returns></returns>
        public static string ShowInputBox(string question, string caption, string defaultValue)
        {
            return ShowInputBox(question, caption, defaultValue, null);
        }
        
        /// <summary>
        /// Show a input box.
        /// </summary>
        /// <param name="question">Question asked.</param>
        /// <param name="caption">Title of the input box.</param>
        /// <param name="defaultValue">Default value in the input box.</param>
        /// <param name="validationPredicate">Predicate used to validate the user input.</param>
        /// <returns>Value enter by user.</returns>
        public static string ShowInputBox(string question, string caption, string defaultValue, ValidationPredicate validationPredicate)
        {
            ThrowIfCommandLineMode();
            return Instance.ShowInputBox(question, caption, defaultValue, validationPredicate);
        }

        #endregion

        #region Helper Methods

        private static string Format(string formatString, object[] formatItems)
        {
            return string.Format(CultureInfo.CurrentCulture, formatString, formatItems);
        }

        private static void ThrowIfCommandLineMode()
        {
            Throw.InvalidOperationIf(IsCommandLine, "Cannot use this method in command-line mode.");
        }

        #endregion

        #endregion
    }
}