Imports System.Collections.Specialized
Imports System.Runtime.InteropServices
Imports DigitalData.Modules.Database
Imports DigitalData.Modules.Logging
Imports DigitalData.Modules.Windream
Imports ECM.JobRunner.Common
Imports Quartz
Imports Quartz.Logging.OperationName

Namespace Scheduler
    Public Class JobScheduler
        Private ReadOnly Settings As New NameValueCollection From {
            {"quartz.serializer.type", "binary"},
            {"quartz.threadPool.threadCount", 10}
        }

        Private ReadOnly LogConfig As LogConfig
        Private ReadOnly Logger As Logger
        Private ReadOnly Database As MSSQLServer
        Private ReadOnly Factory As Quartz.Impl.StdSchedulerFactory
        Private ReadOnly State As State
        Private ReadOnly Windream As Windream

        Private Scheduler As IScheduler

        Private Const JOB_TYPE_IMPORT As Integer = 1
        Private Const JOB_TYPE_INDEX As Integer = 2

        Public Sub New(pLogConfig As LogConfig, pDatabase As MSSQLServer, pState As State, pWindream As Windream)
            LogConfig = pLogConfig
            Logger = pLogConfig.GetLogger()
            Factory = New Impl.StdSchedulerFactory(Settings)
            Database = pDatabase
            Windream = pWindream
            State = pState
        End Sub

        Private Function BuildJobData(pJobConfig As JobConfig) As JobDataMap
            Return New JobDataMap From {
                {Constants.Scheduler.JOB_CONFIG_LOGCONFIG, LogConfig},
                {Constants.Scheduler.JOB_CONFIG_ARGUMENTS, pJobConfig.Arguments},
                {Constants.Scheduler.JOB_CONFIG_DATABASE, Database},
                {Constants.Scheduler.JOB_CONFIG_STATE, State},
                {Constants.Scheduler.JOB_CONFIG_WINDREAM, Windream}
            }
        End Function

        Public Async Function Start() As Task(Of Boolean)
            Try
                ' Log all quartz events into our standard log files
                Logging.LogProvider.SetCurrentLogProvider(New LogProvider(LogConfig))

                ' initialize the scheduler
                Scheduler = Await Factory.GetScheduler()
                Scheduler.ListenerManager.AddJobListener(New JobListener(LogConfig))

                ' start the scheduler
                Await Scheduler.Start()

                ' load job Config and setup job schedules
                ScheduleJobs()

                Return True
            Catch ex As Exception
                Logger.Error(ex)

                Return False
            End Try
        End Function

        Public Sub Reload()
            ' first reload the data from db
            State.Reload()

            ' now reschedule jobs
            ScheduleJobs()
        End Sub

        Public Async Function Shutdown() As Task
            Await Scheduler.Shutdown()
        End Function

        Public Async Function GetRunningJobs() As Task(Of IReadOnlyCollection(Of IJobExecutionContext))
            Return Await Scheduler.GetCurrentlyExecutingJobs()
        End Function

        Public Async Function ScheduleJob(pJobId As Integer) As Task
            Dim oJob = State.JobDefinitions.Where(Function(j) j.Id = pJobId).SingleOrDefault()

            If oJob IsNot Nothing Then
                Logger.Info("Scheduling Job [{0}] manually!", oJob.Name)
                Await PrepareScheduleJob(oJob, pStartManually:=True)
            End If
        End Function

        Private Async Sub ScheduleJobs()

            Logger.Info("Loading [{0}] Job Definitions..", State.JobDefinitions.Count)

            For Each oJob In State.JobDefinitions
                Await PrepareScheduleJob(oJob, pStartManually:=False)
            Next
        End Sub

        Private Async Function PrepareScheduleJob(pJob As JobDefinition, pStartManually As Boolean) As Task
            Logger.Debug("Loading Job Definition [{0}]", pJob.Name)
            Logger.Debug("Job Type is [{0}]", pJob.Type.Name)

            Select Case pJob.TypeId
                Case JOB_TYPE_IMPORT
                    Dim oJobConfig = BuildJobConfig(Of Jobs.FileImportJob)(pJob)
                    Await ScheduleJob(Of Jobs.FileImportJob)(oJobConfig)

                Case JOB_TYPE_INDEX
                    Dim oJobConfig = BuildJobConfig(Of Jobs.FileIndexJob)(pJob)
                    Await ScheduleJob(Of Jobs.FileIndexJob)(oJobConfig)

                Case Else
                    Logger.Warn("Job for TypeId [{0}] is not implemented!", pJob.TypeId)
            End Select
        End Function

        Private Function BuildJobConfig(Of TJob As IJob)(pJob As JobDefinition) As JobConfig
            Return New JobConfig With {
                .Name = pJob.Name,
                .Enabled = pJob.Active,
                .Arguments = New Dictionary(Of String, String) From {
                    {"Id", pJob.Id},
                    {"Name", pJob.Name}
                },
                .CronSchedule = pJob.CronSchedule
            }
        End Function

        Private Async Function ScheduleJob(Of T As IJob)(pJobConfig As JobConfig, pStartManually As Boolean) As Task
            If pStartManually = True Then
                Logger.Debug("Manual run, scheduling..")
                Await DoScheduleJobWithoutDelay(Of T)(pJobConfig)
            ElseIf Await Scheduler.CheckExists(New JobKey(GetJobName(pJobConfig))) Then
                Logger.Debug("Job already exists, rescheduling..")
                Await DoRescheduleJob(Of T)(pJobConfig)
            Else
                Logger.Debug("Job does not exist, scheduling..")
                Await DoScheduleJob(Of T)(pJobConfig)
            End If
        End Function

        ''' <summary>
        ''' Updates the Trigger and Schedule for a given JobConfig
        ''' </summary>
        ''' <typeparam name="T"></typeparam>
        ''' <param name="pJobConfig"></param>
        ''' <returns></returns>
        Private Async Function DoRescheduleJob(Of T As IJob)(pJobConfig As JobConfig) As Task
            Dim oJobKey As New JobKey(pJobConfig.Name)
            Dim oTriggerKey As New TriggerKey(GetTriggerName(pJobConfig))
            Dim oTrigger = BuildTrigger(pJobConfig)

            Await Scheduler.RescheduleJob(oTriggerKey, oTrigger)
        End Function

        Private Async Function DoScheduleJob(Of T As IJob)(pJobConfig As JobConfig) As Task
            Dim oTriggerName As String = GetTriggerName(pJobConfig)
            Dim oTrigger As ITrigger = BuildTrigger(pJobConfig)

            Dim oJobName As String = GetJobName(pJobConfig)
            Dim oJobData As JobDataMap = BuildJobData(pJobConfig)
            Dim oJob As IJobDetail = BuildJob(Of T)(pJobConfig, oJobData)

            If pJobConfig.Enabled Then
                Await Scheduler.ScheduleJob(oJob, oTrigger)

                Logger.Info("Job [{0}] scheduled.", oJobName)
            Else
                Logger.Info("Job [{0}] is disabled.", oJobName)
            End If

            If pJobConfig.StartWithoutDelay Then
                Await DoScheduleJobWithoutDelay(Of T)(pJobConfig)
            End If
        End Function

        Private Async Function DoScheduleJobWithoutDelay(Of T As IJob)(pJobConfig As JobConfig) As Task
            Dim oJobName As String = GetJobName(pJobConfig)
            Dim oJobData As JobDataMap = BuildJobData(pJobConfig)
            Dim oJob As IJobDetail = BuildJob(Of T)(pJobConfig, oJobData)

            Dim oTriggerName As String = GetTriggerName(pJobConfig)
            Dim oNoDelayTrigger = TriggerBuilder.Create().
                    WithIdentity(oTriggerName & "-NO-DELAY").
                    StartAt(DateBuilder.FutureDate(10, IntervalUnit.Second)).
                    Build()

            Logger.Info("Job {0} will start in 10 Seconds.", oJobName)
            Await Scheduler.ScheduleJob(oJob, oNoDelayTrigger)
        End Function

        Private Function BuildJob(Of T As IJob)(pJobConfig As JobConfig, pJobData As JobDataMap) As IJobDetail
            Dim oJobName = GetJobName(pJobConfig)
            Return JobBuilder.Create(Of T)().
                WithIdentity(pJobConfig.Name).
                UsingJobData(pJobData).
                Build()
        End Function

        Private Function BuildTrigger(pJobConfig As JobConfig) As ITrigger
            Dim oTriggerName As String = GetTriggerName(pJobConfig)
            Return TriggerBuilder.Create().
                WithIdentity(oTriggerName).
                WithCronSchedule(pJobConfig.CronSchedule).
                StartNow().
                Build()
        End Function

        Private Function GetJobName(pJobConfig As JobConfig) As String
            Return pJobConfig.Name
        End Function

        Private Function GetTriggerName(pJobConfig As JobConfig) As String
            Dim oJobName As String = pJobConfig.Name
            Return $"{oJobName}-TRIGGER"
        End Function

    End Class
End Namespace