Public Class Scheduler

Public Shared _TaskQueue As New ArrayList()

Public Sub StartTask()
Try
TaskWorker.BeginInvoke(Nothing, Nothing)
Catch ex As Exception
Dim Message As New OurSettingsTableAdapters.MessagesTableAdapter
Message.Insert("Task Error", 1, ex.Message, False, Now.AddHours(Classes.TimeOffset), "Task Error", 0, 0, 0, 0)
Message.Dispose()
End Try
End Sub

Private Delegate Sub GetXMLDelegate()
Dim TaskWorker As New GetXMLDelegate(AddressOf ExecuteQueuedTasks)

Public Sub LoadTasks()
Dim Adaptor As New OurTasksTableAdapters.TasksTableAdapter
Dim Table As New OurTasks.TasksDataTable

Adaptor.FillNextTasks(Table, Now.AddHours(Classes.TimeOffset))

If Table.Rows.Count = 0 Then
Return
End If

For Each row As OurTasks.TasksRow In Table
Dim Task As New Task
Task.Load(row.TaskID, row.Task, row.Frequency, row.RunNext, row.Priority, row.AccountID, row.Comments)
_TaskQueue.Add(Task)
Next row
End Sub

Public Sub ExecuteQueuedTasks()
Dim Tasks As New ArrayList()

If _TaskQueue.Count = 0 Then
LoadTasks()
End If

' Collect which jobs are overdue
For Each Task As Task In _TaskQueue
If Task.RunNext <= DateTime.Now.AddHours(xtraparking.Classes.TimeOffset) Then
Tasks.Add(Task)
End If
Next Task

' Execute the jobs that are overdue
For Each Task As Task In Tasks
SyncLock _TaskQueue
Task.Execute()
_TaskQueue.Remove(Task)
End SyncLock
Next Task
End Sub

End Class