using System;
using System.Data.Entity.Core.Objects;
using System.Linq;
using Neo.Afx.ComponentModel;
using System.Threading;

namespace Neo.Afx.WinService.Workflows
{
    public class WorkflowServiceDatabase : Database<WorkflowServiceContext>
    {
        public WorkflowServiceDatabase(string connectionString)
            : base(new WorkflowServiceContext(connectionString))
        {
        }

        #region GetHandlers

        public IQueryable<WorkflowTaskHandler> GetHandlers()
        {
            return from q in Context.WorkflowTaskHandlers.Include("WorkflowTaskHandlerSettings")
                   where !q.IsCancelled
                   select q;
        }

        #endregion

        #region GetTasks

        public IQueryable<WorkflowInstanceTask> GetTasks()
        {
            return from q in Context.WorkflowInstanceTasks.Include("WorkflowTemplateStep")
                   orderby q.CreatedDate
                   where q.WorkflowInstanceTaskStatusID == (short)WorkflowInstanceTaskStatusEnum.Outstanding
                         && q.WorkflowTemplateStep.WorkflowTemplateStepTypeID == (short)WorkflowTemplateStepTypeEnum.Automated
                   select q;
        }

        #endregion
       
        #region UpdateTaskStatus

        public bool UpdateTaskStatus(long workflowInstanceTaskID, short workflowInstanceTaskStatusID, string completedByUserName, string comments, out string error)
        {
            var errorMessage = new ObjectParameter("ErrorMessage", typeof(string));
            var tryActionCount = 0;

            TryAction:
            try
            {
                Context.Pr_WorkflowInstanceTaskAction(workflowInstanceTaskID, workflowInstanceTaskStatusID, completedByUserName, -1, comments, errorMessage);
                error = errorMessage.Value.ToStringSafe();
            }
            catch (Exception ex)
            {
                var message = GetInnermostMessage(ex);

                error = message;

                if (!String.IsNullOrEmpty(message) && message.ToLower().Contains("deadlock") && tryActionCount < 5)
                {
                    Random rnd = new Random();
                    Thread.Sleep(rnd.Next(2000, 4000));
                    tryActionCount++;
                    goto TryAction;
                }
                else {
                    throw ex;
                }
            }
            
            return string.IsNullOrEmpty(error);
        }

        #endregion

        #region UpdateTaskStatusFailover

        public void UpdateTaskStatusFailover(long workflowInstanceTaskID, string error, long updatedByID)
        {
            Context.Pr_WorkflowInstanceTaskActionFailover(workflowInstanceTaskID, error, updatedByID);
        }

        #endregion

        #region RaiseException
        public bool RaiseException(long workflowInstanceTaskID, string completedByUserName, string comments, out string error)
        {
            var errorMessage = new ObjectParameter("ErrorMessage", typeof(string));
            var tryActionCount = 0;

            TryAction:
            try
            {
                Context.Pr_WorkflowInstanceRaiseException(workflowInstanceTaskID, completedByUserName, comments, errorMessage);
                error = errorMessage.Value.ToStringSafe();
            }
            catch (Exception ex)
            {
                var message = GetInnermostMessage(ex);

                error = message;

                if (!String.IsNullOrEmpty(message) && message.ToLower().Contains("deadlock") && tryActionCount < 5)
                {
                    Random rnd = new Random();
                    Thread.Sleep(rnd.Next(2000, 4000));
                    tryActionCount++;
                    goto TryAction;
                }
                else
                {
                    throw ex;
                }
            }

            return string.IsNullOrEmpty(error);
        }
        #endregion

        #region GetInnermostMessage
        public string GetInnermostMessage(Exception ex)
        {
            if (ex.InnerException == null)
            {
                return ex.Message;
            }
            else
            {
                return GetInnermostMessage(ex.InnerException);
            }
        }
        #endregion
    }
}