using System;
using System.Globalization;
using System.Threading;
using System.Threading.Tasks;

namespace Xylem.Common.Utils.ProcessExec
{
    /// <summary>
    /// Execution of process in separate task.
    /// Task execution uses an initialization-, an execution-, an event-
    /// and a finalization-routine.
    /// Process states are given to successful-, erroneous- ore break-execution as a array of objects to keep it
    /// anonymous.
    /// </summary>
    public class ProcessExec
    {
        /// <summary>
        /// Definition of void thread call back function
        /// </summary> 
        public delegate void VoidCallbackFunction();

        /// <summary>
        /// Definition of boolean thread call back function
        /// </summary> 
        public delegate Boolean BoolCallbackFunction();

        /// <summary>
        /// Definition of thread call back function
        /// </summary>
        /// <param name="success">execution of routine returned success</param>
        /// <param name="obj">objects to callback function</param>
        public delegate void ExitStateCallbackFunction(Boolean success, Object[] obj);

        /// <summary>
        /// Definition of thread call back function
        /// </summary> 
        private Object[] _exitObjects;

        /// <summary>
        /// Current task calling the init-, the cyclic execution and the final-function.
        /// The task adjusts the current culture.
        /// </summary>
        /// <param name="initFn">initial function executed in caller task</param>
        /// <param name="execFn">execution function executed in separated new task</param>
        /// <param name="finalFn">finalizing function</param>
        /// <param name="cultureInfo">language selection passing</param>
        /// <param name="exitObjects">exit objects</param>
        /// <remarks date="2020-Dec-12" author="Thomas Wiedebusch">
        /// - Initial.
        /// </remarks>
        public void NewProcess(VoidCallbackFunction initFn, BoolCallbackFunction execFn,
            ExitStateCallbackFunction finalFn, CultureInfo cultureInfo, Object[] exitObjects)
        {
            _exitObjects = new Object[exitObjects.Length];
            _exitObjects = exitObjects;
            var success = false;

            Thread.CurrentThread.CurrentUICulture = cultureInfo;
            Thread.CurrentThread.CurrentCulture = cultureInfo;

            initFn?.Invoke();
            Task.Factory.StartNew(() =>
            {
                Thread.CurrentThread.CurrentUICulture = cultureInfo;
                Thread.CurrentThread.CurrentCulture = cultureInfo;

                if (execFn == null) return;
                success = (Boolean)execFn.DynamicInvoke();

            }).ContinueWith(delegate { finalFn?.Invoke(success, _exitObjects); });
        }
    }
}