using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace Neo.Afx.Services
{
    public class FileSystemServiceScheduler
    {
        List<ServiceTask> _serviceTasks;
        ServiceTaskScheduler _serviceTaskScheduler;
        readonly ServiceConfigurations _serviceConfigurations;

        #region FileSystemServiceScheduler

        public FileSystemServiceScheduler()
        {
            _serviceConfigurations = new ServiceConfigurations();
        }

        #endregion

        #region Start

        /// <summary>
        /// Starts the scheduler.
        /// </summary>
        public void Start()
        {
            var services = _serviceConfigurations.GetServices();
            if(services.Count() == 0)
            {
                UpdateRunStatus("Start", DateTime.Now, "No services configured in application configuration file.");
            }

            try
            {
                _serviceTasks = new List<ServiceTask>(
                    services.Select(
                        service => new ServiceTask(new ServiceSchedule((PollFrequencyEnum)service.PollFrequencyID, TimeSpan.Parse(service.PollTime)),
                                       service.ServiceID,
                                       service.ServiceName,
                                       (IExecutable)Worker.Create(service.ServiceTypeName, _serviceConfigurations.GetSystemUserID(), _serviceConfigurations.GetSystemUserEmail(), service.Settings))));

                _serviceTaskScheduler = new ServiceTaskScheduler(_serviceTasks);
                _serviceTaskScheduler.TaskBusy += OnServiceTaskBusy;
                _serviceTaskScheduler.TaskCompleted += OnServiceTaskCompleted;
                _serviceTaskScheduler.UnhandledError += OnUnhandledError;
                _serviceTaskScheduler.Start();
            }
            catch(Exception ex)
            {
                UpdateRunStatus("Start", DateTime.Now, (ex.Message.ToLower().IndexOf("inner excep") != -1 ? ex.InnerException.Message : ex.Message));
            }
        }

        #endregion

        #region Stop

        /// <summary>
        /// Stops the scheduler.
        /// </summary>
        public void Stop()
        {
            if(_serviceTaskScheduler != null)
            {
                _serviceTaskScheduler.TaskBusy -= OnServiceTaskBusy;
                _serviceTaskScheduler.TaskCompleted -= OnServiceTaskCompleted;
                _serviceTaskScheduler.UnhandledError -= OnUnhandledError;
                _serviceTaskScheduler = null;
            }

            if(_serviceTasks == null)
            {
                return;
            }

            _serviceTasks.Clear();
            _serviceTasks = null;
        }

        #endregion

        #region OnServiceTaskBusy/Completed

        void OnServiceTaskBusy(object sender, ServiceTaskEventArgs e)
        {
            UpdateRunStatus(e.ServiceTask.ServiceName, e.SignalTime, "Service is busy");
        }

        void OnServiceTaskCompleted(object sender, ServiceTaskEventArgs e)
        {
            if(e.ServiceTask.Exceptions != null)
            {
                foreach(var ex in e.ServiceTask.Exceptions)
                {
                    UpdateRunStatus(e.ServiceTask.ServiceName, e.ServiceTask.Schedule.LastRunTime, (ex.Message.ToLower().IndexOf("inner excep") != -1 ? ex.InnerException.Message : ex.Message));
                }
            }

            UpdateRunStatus(e.ServiceTask.ServiceName, e.ServiceTask.Schedule.LastRunTime, e.ServiceTask.TraceInfo);
        }

        #endregion

        #region OnUnhandledError

        void OnUnhandledError(object sender, ErrorEventArgs e)
        {
            var ex = e.GetException();
            UpdateRunStatus("Unhandled", DateTime.Now, (ex.Message.ToLower().IndexOf("inner excep") != -1 ? ex.InnerException.Message : ex.Message));
        }

        #endregion

        #region Update Audit/Trace Log

        public void UpdateRunStatus(string sourceName, DateTime runDate, string traceInfo)
        {
            _serviceConfigurations.UpdateRunStatus(sourceName, runDate, traceInfo);
        }

        #endregion
    }
}