using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using Neo.Afx.ComponentModel;
using Neo.Afx.Services;

namespace Neo.Afx.WinService.Workflows
{
    public class WorkflowTaskProcessor : Worker, IExecutable
    {
        #region Handlers

        Dictionary<long, WorkflowTask> _handlers;
        public Dictionary<long, WorkflowTask> Handlers
        {
            get
            {
                lock(PropertyLock)
                {
                    return _handlers;
                }
            }
            set
            {
                lock(PropertyLock)
                {
                    _handlers = value;
                }
            }
        }

        #endregion

        #region Run

        public void Run()
        {
            TraceInfo = string.Empty;
            var trace = new StringBuilder();

            using (var database = new WorkflowServiceDatabase(Settings["ConnectionString"]))
            {
                if (Handlers == null)
                {
                    Handlers = new Dictionary<long, WorkflowTask>();

                    #region Initialize handlers from database

                    foreach (var handler in database.GetHandlers())
                    {
                        try
                        {
                            Handlers.Add(
                                handler.WorkflowTaskHandlerID,
                                new WorkflowTask(handler.HandlerTypeName, handler.MethodName, UserID, UserEmail, handler.Settings));
                        }
                        catch (Exception ex)
                        {
                            trace.AppendFormat("Error creating WorkflowTaskHandler ID={0} --> {1} ", handler.WorkflowTaskHandlerID, ex.ToStringComplete());
                            trace.AppendLine();
                        }
                    }

                    #endregion
                }

                if (Handlers.Count == 0)
                {
                    TraceInfo = trace.ToString();
                    return;
                }

                var tasks = database.GetTasks().ToList();
                if (tasks.Count == 0)
                {
                    return;
                }

                foreach (var task in tasks)
                {
                    if (!task.WorkflowTemplateStep.WorkflowTaskHandlerID.HasValue)
                    {
                        continue;
                    }

                    var handlerID = task.WorkflowTemplateStep.WorkflowTaskHandlerID.Value;
                    var workflowTask = Handlers[handlerID];
                    short workflowInstanceTaskStatusID;
                    string errorMessage = null;
                    string stackTrace = null;
                    try
                    {
                        workflowInstanceTaskStatusID = (short)workflowTask.Run(task.WorkflowInstanceTaskID);
                    }
                    catch (TargetInvocationException tiex)
                    {
                        workflowInstanceTaskStatusID = (short)WorkflowInstanceTaskStatusEnum.Error;
                        errorMessage = tiex.InnerException.Message;
                        stackTrace = tiex.InnerException.ToStringComplete();
                    }
                    catch (Exception ex)
                    {
                        workflowInstanceTaskStatusID = (short)WorkflowInstanceTaskStatusEnum.Error;
                        errorMessage = ex.Message;
                        stackTrace = ex.ToStringComplete();
                    }

                    if (!string.IsNullOrEmpty(workflowTask.TraceInfo))
                    {
                        trace.AppendLine(string.Format("TASK[{0}]: {1}", task.WorkflowInstanceTaskID, workflowTask.TraceInfo));
                    }
                    if (!string.IsNullOrEmpty(stackTrace))
                    {
                        trace.AppendLine(string.Format("TASK[{0}] ERROR: {1}", task.WorkflowInstanceTaskID, stackTrace));
                    }

                    // Don't update task if status is zero
                    if (workflowInstanceTaskStatusID <= 0)
                    {
                        continue;
                    }

                    var comments = string.IsNullOrEmpty(errorMessage) ? null : string.Format("ERROR: {0}", errorMessage);
                    string error;
                    try
                    {
                        if (workflowInstanceTaskStatusID != (short)WorkflowInstanceTaskStatusEnum.Error)
                        {
                            if (!database.UpdateTaskStatus(task.WorkflowInstanceTaskID, workflowInstanceTaskStatusID, UserEmail, comments, out error))
                            {
                                // Something horrible happened so stop the workflow...
                                error = string.Format("Update Workflow Task Status[ WorkflowInstanceTaskID={0}, Status={1}, UserEmail={2} ] ERROR --> {3}",
                                    task.WorkflowInstanceTaskID, workflowInstanceTaskStatusID, UserEmail, error);

                                trace.AppendLine(error);
                                database.UpdateTaskStatusFailover(task.WorkflowInstanceTaskID, error, UserID);
                            }
                        }
                        else
                        {
                            if (!database.RaiseException(task.WorkflowInstanceTaskID, UserEmail, comments, out error))
                            {
                                // Something horrible happened so stop the workflow...
                                error = string.Format("Update Workflow Task Status[ WorkflowInstanceTaskID={0}, Status={1}, UserEmail={2} ] ERROR --> {3}",
                                    task.WorkflowInstanceTaskID, workflowInstanceTaskStatusID, UserEmail, error);

                                trace.AppendLine(error);
                                database.UpdateTaskStatusFailover(task.WorkflowInstanceTaskID, error, UserID);
                            }
                        }
                    }
                    catch (Exception ex)
                    {
                        trace.AppendLine(ex.Message);
                        database.UpdateTaskStatusFailover(task.WorkflowInstanceTaskID, ex.Message, UserID);
                    }
                }
            }

            // This will be added to the service trace table
            TraceInfo = trace.ToString();
        }

        #endregion
    }
}