Imports System.ServiceModel
Imports System.ServiceProcess
Imports DigitalData.Modules.Logging
Imports DigitalData.Modules.Database
Imports DigitalData.Modules
Imports System.ServiceModel.Description
Imports DigitalData.Modules.Config
Imports System.ServiceModel.Channels

Public Class WindowsService
    Inherits ServiceBase

    Private ServiceHost As ServiceHost(Of EDMIService)
    Private LogConfig As LogConfig
    Private LogConfigScheduler As LogConfig
    Private Logger As Logger

    Private Firebird As Firebird
    Private MSSQL_ECM As MSSQLServer
    Private MSSQL_IDB As MSSQLServer
    Private MSSQL_Config As MSSQLServer

    Private ConfigManager As ConfigManager(Of Config)
    Private Config As Config
    Private Filesystem As Filesystem.File
    Private GlobalState As GlobalState
    Private Scheduler As Scheduler

    Public Sub New()
        ServiceName = SERVICE_NAME
    End Sub

    Public Shared Sub Main()
        Run(New WindowsService())
    End Sub

    Protected Overrides Sub OnStart(args As String())
        Try
            ' Init
            Dim oServicePath As String = AppDomain.CurrentDomain.BaseDirectory
            Dim oServiceVersion As String = My.Application.Info.Version.ToString()

            ' Initializing Logger
            LogConfig = New LogConfig(LogConfig.PathType.CustomPath, IO.Path.Combine(oServicePath, "Log"), FileKeepRangeInDays:=3)
            LogConfigScheduler = New LogConfig(LogConfig.PathType.CustomPath, IO.Path.Combine(oServicePath, "Log"), Suffix:="Scheduler", FileKeepRangeInDays:=3)
            Logger = LogConfig.GetLogger()

            ' Log Initial
            Logger.Info("Service [{0}] is starting...", SERVICE_DISPLAY_NAME)
            Logger.Info("ServiceDirectory: [{0}]", oServicePath)
            Logger.Info("Version: [{0}]", oServiceVersion)

            ' Initializing Config
            Logger.Info("Loading Config")
            ConfigManager = New ConfigManager(Of Config)(LogConfig, oServicePath)
            Config = ConfigManager.Config

            ' Setup Reload-timer for config
            Dim oTimer As New Timers.Timer(60000)
            AddHandler oTimer.Elapsed, AddressOf ReloadTimer_Tick
            oTimer.Start()

            ' Setting Debug Flag
            If ConfigManager.Config.Debug Then
                Logger.Info("Debug Flag is set to TRUE. Logging will be more verbose.")
            Else
                Logger.Info("Debug Flag is set to FALSE. Logging will be less verbose.")
            End If
            LogConfig.Debug = ConfigManager.Config.Debug
            LogConfigScheduler.Debug = ConfigManager.Config.Debug

            Logger.Debug("Connecting to Databases...")
            Firebird = StartFirebird()
            MSSQL_ECM = GetMSSQL_ECM(LogConfig)
            MSSQL_IDB = GetMSSQL_IDB(LogConfig)
            MSSQL_Config = GetMSSQL_Config(LogConfig)
            Logger.Debug("Connection to Databases established!")

            Logger.Debug("Initializing EDMI Functions...")
            Filesystem = New Filesystem.File(LogConfig)
            GlobalState = New GlobalState(LogConfig, MSSQL_IDB, MSSQL_ECM)

            Dim oMSSQLServer = GetMSSQL_Config(LogConfigScheduler)
            Scheduler = New Scheduler(LogConfigScheduler, oMSSQLServer, GlobalState.TableStore, GlobalState)

            Logger.Debug("Loading Global Data ...")
            GlobalState.LoadObjectStores()
            GlobalState.LoadConnections()
            GlobalState.LoadDoctypes()
            GlobalState.LoadClientConfig(Config)

            Logger.Debug("Starting Scheduler ...")
            Scheduler.Start()

            Logger.Debug("Preparing WCF ServiceHost ...")
            EDMIService.MSSQL_ECM = MSSQL_ECM
            EDMIService.MSSQL_IDB = MSSQL_IDB
            EDMIService.Firebird = Firebird
            EDMIService.LogConfig = LogConfig
            EDMIService.AppConfig = Config
            EDMIService.GlobalState = GlobalState
            EDMIService.Scheduler = Scheduler

            Logger.Debug("Starting WCF ServiceHost ...")

            Dim oBaseAddresses() As Uri = {New Uri(SERVICE_BASE_ADDRESS)}
            ServiceHost = New ServiceHost(Of EDMIService)(oBaseAddresses)
            ServiceHost.EnableMetadataExchange(False)
            ' MEX-Endpoints explizit entfernen, da sie Port-Konflikte verursachen
            Dim oMexEndpoints = ServiceHost.Description.Endpoints _
            .Where(Function(e) e.Contract.ContractType = GetType(IMetadataExchange)) _
            .ToList()

            For Each oEndpoint In oMexEndpoints
                ServiceHost.Description.Endpoints.Remove(oEndpoint)
                Logger.Debug("OnStart -> Removed MEX endpoint: {0}", oEndpoint.Address.ToString)
            Next

            Logger.Debug("Listing Endpoints:")
            For Each oEndpoint In ServiceHost.Description.Endpoints
                Logger.Debug("Name: {0}", oEndpoint.Name)
                Logger.Debug("Address: {0}", oEndpoint.Address.ToString)
                Logger.Debug("Listen Uri: {0}", oEndpoint.ListenUri.AbsoluteUri)
                Logger.Debug("Binding: {0}", oEndpoint.Binding.Name)
                Logger.Debug("Contract: {0}", oEndpoint.Contract.Name)
            Next

            Logger.Debug("Starting WFC ServiceHost..")
            Try
                ServiceHost.Open()
                Logger.Debug("WCF ServiceHost started!")
            Catch ex As System.ServiceModel.AddressAlreadyInUseException
                Logger.Error("Port is already in use! Check if another instance is running. Details: {0}", ex.Message)
                GracefullyStop()
            Catch ex As Exception
                Logger.Warn("⚠ Unexpected error while opening ServiceHost: {0}", ex.Message)
                Logger.Error(ex)
                GracefullyStop()
            End Try
            Logger.Info("✔ Service [{0}] started successfully!", SERVICE_DISPLAY_NAME)
        Catch ex As Exception
            Logger.Warn("⚠ Unexpected Error while starting the service: {0}", ex.Message)
            Logger.Error(ex)
            GracefullyStop()
        End Try
    End Sub

    Private Sub ReloadTimer_Tick()
        If ConfigManager.Reload() = False Then
            Logger.Warn("⚠ Could not reload config, check the service and config file.")
        End If

        Config = ConfigManager.Config
        LogConfig.Debug = ConfigManager.Config.Debug
    End Sub

    Private Function StartFirebird() As Firebird
        Logger.Debug("Connecting to Firebird")

        If Config.Firebird_Datasource = String.Empty Then
            Logger.Info("Firebird database not configured. Skipping.")
            Return Nothing
        End If

        Try
            Dim oFirebird = New Firebird(
                LogConfig,
                Config.Firebird_Datasource,
                Config.Firebird_DatabaseName,
                Config.Firebird_DatabaseUser,
                Config.Firebird_DatabasePassword
            )

            Logger.Info("Database connection established.")
            Return oFirebird
        Catch ex As Exception
            Logger.Warn("⚠ StartFirebird: Could not connect to firebird database.")
            Logger.Error(ex)
            Return Nothing
        End Try
    End Function

    Private Function GetMSSQL_ECM(pLogConfig As LogConfig) As MSSQLServer
        Logger.Debug("Connecting to ECM MSSQL")
        If Config.ConnectionString_ECM = String.Empty Then
            Logger.Warn("⚠ Configuration for ConnectionString_ECM is missing.")
            Throw New ArgumentNullException("ConnectionString_ECM")
        End If

        Dim oMSSQL = New MSSQLServer(pLogConfig, Config.ConnectionString_ECM)
        Logger.Info("✔ Database connection to ECM Database established.")
        Return oMSSQL
    End Function

    Private Function GetMSSQL_IDB(pLogConfig As LogConfig) As MSSQLServer
        Logger.Debug("Connecting to IDB MSSQL")
        If Config.ConnectionString_IDB = String.Empty Then
            Logger.Warn("⚠ Configuration for ConnectionString_IDB is missing.")
            Throw New ArgumentNullException("ConnectionString_IDB")
        End If

        Dim oMSSQL = New MSSQLServer(pLogConfig, Config.ConnectionString_IDB)
        Logger.Info("✔ Database connection to IDB Database established.")
        Return oMSSQL
    End Function

    Private Function GetMSSQL_Config(pLogConfig As LogConfig) As MSSQLServer
        Logger.Debug("Connecting to Config MSSQL...")
        If Config.ConnectionString_Config = String.Empty Then
            If Config.ConnectionString_ECM <> String.Empty Then
                Logger.Debug("Using ConnectionString_ECM for Config Database connection!")
                Return GetMSSQL_ECM(pLogConfig)
            Else
                Logger.Warn("⚠ Configuration for ConnectionString_Config is missing and ConnectionString_ECM is also missing.")
                Throw New ArgumentNullException("ConnectionString_Config")
            End If
        End If

        Dim oMSSQL = New MSSQLServer(pLogConfig, Config.ConnectionString_Config)
        Logger.Info("✔ Database connection to Config Database established.")
        Return oMSSQL
    End Function

    Protected Overrides Sub OnStop()
        GracefullyStop()
    End Sub

    Private Sub GracefullyStop()
        Logger.Info("GracefullyStop - Service {0} is stopping!", SERVICE_DISPLAY_NAME)
        If ServiceHost IsNot Nothing Then
            Try
                If ServiceHost.State = CommunicationState.Faulted Then
                    Logger.Warn("⚠ GracefullyStop - ServiceHost is in Faulted state. Using Abort() instead of Close().")
                    ServiceHost.Abort()
                Else
                    ServiceHost.Close()
                End If
            Catch ex As Exception
                Logger.Warn("⚠ GracefullyStop - Error while closing ServiceHost: {0}", ex.Message)
                Logger.Error(ex)
                ServiceHost.Abort()
            Finally
                ServiceHost = Nothing
            End Try
        End If

        If Scheduler IsNot Nothing Then
            Logger.Info("GracefullyStop - Stopping Scheduler.")
            Scheduler.Stop()
        End If
    End Sub
End Class