using System;
using System.Collections.Generic;
using System.Linq;
using Sarand.Net.Standard.Base.App;
using Sarand.Net.Standard.Base.Core;
using Sarand.Net.Standard.Base.Utils;

namespace Sarand.Net.Standard.Base.Procs
{
	//=======================================================================
	public interface ISacsProcessNotifier
	{
		void OnStartProcess ();
		void SetProgressInfo (List<String> progressInfo);
		void OnEndProcess ();
	}

	//=======================================================================
	public abstract class SaProcess_Base : SacsDisposable
	{
		//-------------------------------------------------------------------
		// Process options and groups - for configuration of process to run.
		// See Sarand.Win.Forms.Utility.SaForm_SelectOptions.
		public class OptionData
		{
			public OptionData (TypeCodeDesc option)
			{
				Option = option;
			}
			public TypeCodeDesc Option { get; set; }
			public String Notes { get; set; } = "";
			public bool Selected { get; set; } = false;
		}
		public class GroupData
		{
			public GroupData (TypeCodeDesc optionGroup)
			{
				OptionGroup = optionGroup;
			}
			public TypeCodeDesc OptionGroup { get; set; }
			public List<OptionData> Options { get; } = new List<OptionData>();
			public bool ExclusiveOptions { get; set; } = false;
			public bool Selected { get; set; } = false;
		}

		//-------------------------------------------------------------------
		// Configuration.
		public enum ProcessType
		{
			Unknown = 0,
			ImportData,
			ExportData,
			ImportExportData,
			Other,
		}
		public class Config
		{
			protected Config ()
			{
			}
			/// <summary>Identifies the type of process.</summary>
			public ProcessType ProcessType { get; set; } = ProcessType.Unknown;
			/// <summary>Is the process to be run in 'Test' mode.</summary>
			public bool TestProcess{ get; set; } = SacsSystem.DebugMode;
			/// <summary>Process imports data.</summary>
			public bool Import { get { return ProcessType == ProcessType.ImportData || ProcessType == ProcessType.ImportExportData; } }
			/// <summary>Process exports data.</summary>
			public bool Export { get { return ProcessType == ProcessType.ExportData || ProcessType == ProcessType.ImportExportData; } }
			/// <summary>Can the process be interrupted?</summary>
			public bool AllowInterruption { get; set; } = true;
			/// <summary>Confirm when interruption is requested.</summary>
			public bool ConfirmInterruption { get; set; } = true;
			/// <summary>Automated processes must not display desktop coponents - popup messages etc.</summary>
			public bool Automated { get; set; } = false;
		}

		//-------------------------------------------------------------------
		// Data members.
		private Config config;
		private String processError = "";

		//-------------------------------------------------------------------
		// Construction.
		protected SaProcess_Base (Config config)
		{
			this.config = config;
		}
		protected override void Dispose (bool disposing)
		{
			if (disposing)
			{
			}
		}

		//-------------------------------------------------------------------
		// Properties.
		public bool DebugMode { get { return SacsSystem.DebugMode; } }
		public ISacsProcessNotifier ProcessNotifier { get; set; } = null;
		public bool Processing { get; protected set; } = false;
		public bool ProcessEnded { get; protected set; } = false;
		public DateTime StartedAt { get; private set; } = DateTime.MinValue;
		public DateTime FinishedAt { get; private set; } = DateTime.MinValue;
		public int ElapsedSecs
		{
			get
			{
				if (DateUtil.IsValid(StartedAt))
					return (int)((DateUtil.IsValid(FinishedAt) ? FinishedAt : DateTime.Now) - StartedAt).TotalSeconds;
				return 0;
			}
		}

		//-------------------------------------------------------------------
		// Properties.
		/// <summary>Process caption.</summary>
		public abstract String ProcessDescription { get; }
		/// <summary>Process comments - to be displayed with process selection.</summary>
		public virtual List<String> ProcessComments { get { return new List<String>(); } }
		/// <summary>Processing statistics.</summary>
		public virtual List<StringPair> ProcessingStatistics { get { return new List<StringPair>(); } }

		//-------------------------------------------------------------------
		// Run process inline.
		public bool RunProcess ()
		{
			String fn = GetType().Name+".RunProcess";
			if (ProcessNotifier == null)
				throw new NotSupportedException("Process Notifier must be specified");
			// Prepare process.
			bool runProcess = false;
			Reset();
			Processing = true;
			StartedAt = DateTime.Now;
			try
			{
				// Notify start of process and log/ignore exceptions.
				ProcessNotifier.OnStartProcess();
			}
			catch (Exception exc)
			{
				SaLogger.Error(fn + " OnStartProcess: " + GetProcessError() + exc.GetStackEntries(6).Concat("", "\n\tat "), true);
			}
			try
			{
				// Run process.
				OnProcessStarting();
				runProcess = Run();
				OnProcessEnding();
			}
			catch (Exception exc)
			{
				SetProcessError(exc.GetType().Name + ": " + exc.Message);
				SaLogger.Error(fn + " " + GetProcessError() + exc.GetStackEntries(6).Concat("", "\n\tat "), true);
			}
			// Processing completed.
			FinishedAt = DateTime.Now;
			Processing = false;
			ProcessEnded = true;
			try
			{
				// Notify end of process and log/ignore exceptions.
				ProcessNotifier.OnEndProcess();
			}
			catch (Exception exc)
			{
				SaLogger.Error(fn + " OnEndProcess: " + GetProcessError() + exc.GetStackEntries(6).Concat("", "\n\tat "), true);
			}
			return runProcess;
		}
		protected abstract bool Run ();
		protected virtual void OnProcessStarting () { }
		protected virtual void OnProcessEnding () { }

		//-------------------------------------------------------------------
		// Process control.
		public bool OK
		{
			get
			{
				if (HasProcessError()) return false;
				if (isInterrupted) return false;
				return true;
			}
		}
		private void Reset ()
		{
			ClearProcessError();
			isInterrupted = false;
			ProcessEnded = false;
			StartedAt = DateTime.MinValue;
			FinishedAt = DateTime.MinValue;
		}

		//-------------------------------------------------------------------
		// Progress information.
		protected void SetProgressInfo (String progressInfo)
		{
			SetProgressInfo(StringListUtil.CreateList(progressInfo));
		}
		protected void SetProgressInfo (List<String> progressInfo)
		{
			if (ProcessNotifier != null)
				ProcessNotifier.SetProgressInfo(progressInfo);
		}

		//-------------------------------------------------------------------
		// Error handling.
		public bool HasProcessError () { return !StringUtil.IsEmpty(processError); }
		public String GetProcessError () { return StringUtil.EmptyOnNull(processError); }
		public void ClearProcessError () { processError = ""; }
		/// <summary>Record the processing error - always returns false.</summary>
		public bool SetProcessError (String error)
		{
			processError = StringUtil.EmptyOnNull(error);
			return false;
		}

		//-------------------------------------------------------------------
		// Interruption.
		private bool isInterrupted = false;
		public bool IsInterrupted
		{
			get { return isInterrupted; }
		}
		public bool Interrupt ()
		{
			if (!config.AllowInterruption)
			{
				SaLogger.Warn("SacsProcess.Interrupt() Interruptions not allowed in " + this.GetType().Name);
				return false;
			}
			if (config.ConfirmInterruption && !IsInterruptionConfirmed()) return false;
			isInterrupted = true;
			return true;
		}
		protected virtual bool IsInterruptionConfirmed ()
		{
			return true;
		}

		//-------------------------------------------------------------------
	}
	//=======================================================================
}