#Region "Microsoft.VisualBasic::e1ea725da821d59758c31270653c458d, Parallel\IpcParallel\TaskBuilder.vb"

    ' Author:
    ' 
    '       asuka (amethyst.asuka@gcmodeller.org)
    '       xie (genetics@smrucc.org)
    '       xieguigang (xie.guigang@live.com)
    ' 
    ' Copyright (c) 2018 GPL3 Licensed
    ' 
    ' 
    ' GNU GENERAL PUBLIC LICENSE (GPL3)
    ' 
    ' 
    ' This program is free software: you can redistribute it and/or modify
    ' it under the terms of the GNU General Public License as published by
    ' the Free Software Foundation, either version 3 of the License, or
    ' (at your option) any later version.
    ' 
    ' This program is distributed in the hope that it will be useful,
    ' but WITHOUT ANY WARRANTY; without even the implied warranty of
    ' MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    ' GNU General Public License for more details.
    ' 
    ' You should have received a copy of the GNU General Public License
    ' along with this program. If not, see <http://www.gnu.org/licenses/>.



    ' /********************************************************************************/

    ' Summaries:

    ' Class TaskBuilder
    ' 
    '     Constructor: (+1 Overloads) Sub New
    ' 
    '     Function: FromStream, GetArgumentValue, GetArgumentValueNumber, GetMethod, GetParameters
    '               Initialize, PostError, Run
    ' 
    '     Sub: PostFinished
    ' 
    ' /********************************************************************************/

#End Region

Imports System.IO
Imports System.Reflection
#If netcore5 = 1 Then
Imports Microsoft.VisualBasic.ApplicationServices.Development.NetCore5
#End If
Imports Microsoft.VisualBasic.ComponentModel
Imports Microsoft.VisualBasic.Language
Imports Microsoft.VisualBasic.MIME.application.json
Imports Microsoft.VisualBasic.Net.Tcp
Imports Microsoft.VisualBasic.Parallel
Imports Microsoft.VisualBasic.Serialization.JSON
Imports Parallel.IpcStream

''' <summary>
''' Run on slave node
''' </summary>
Public Class TaskBuilder : Implements ITaskDriver

    ReadOnly masterPort As Integer
    ReadOnly masterHost As String
    ReadOnly emit As New StreamEmit

    <DebuggerStepThrough>
    Sub New(port As Integer, Optional master As String = "localhost")
        masterPort = port
        masterHost = master
    End Sub

    Private Iterator Function GetParameters(params As ParameterInfo(), n As Integer) As IEnumerable(Of Object)
        For i As Integer = 0 To n - 1
            Dim par As Object = GetArgumentValue(i)
            Dim targetType As Type = params(i).ParameterType

            If par Is Nothing Then
                Yield par
            ElseIf par.GetType.IsInheritsFrom(targetType) Then
                Yield Conversion.CTypeDynamic(par, targetType)
            ElseIf par.GetType Is GetType(SocketRef) Then
                ' is a common parameter value between
                ' the parallel batchs
                Dim socket As SocketRef = DirectCast(par, SocketRef)

                Using buffer As ObjectStream = socket.Open
                    Yield FromStream(buffer)
                End Using
            Else
                Yield par
            End If
        Next
    End Function

    Private Function Initialize(ByRef api As MethodInfo, ByRef target As Object, ByRef args As Object()) As Integer
        Dim task As IDelegate = GetMethod()
        Dim params As ParameterInfo()

        api = task.GetMethod
        params = api.GetParameters
        target = task.GetMethodTarget

        Dim n As Integer = GetArgumentValueNumber()
        Dim argList As New List(Of Object)(GetParameters(params, n))

        Call Console.WriteLine("run task:")
        Call Console.WriteLine(task.GetJson(indent:=False, simpleDict:=True))

        ' fix for optional parameter values
        For i As Integer = n To params.Length - 1
            If Not params(i).IsOptional Then
                Return PostError(New Exception($"missing parameter value for [{i}]{params(i).Name}!"))
            Else
                argList.Add(params(i).DefaultValue)
            End If
        Next

        args = argList.ToArray

        Return 0
    End Function

    Public Function Run() As Integer Implements ITaskDriver.Run
        Dim api As MethodInfo = Nothing
        Dim target As Object = Nothing
        Dim args As Object() = Nothing

        Try
            Dim i As New Value(Of Integer)

            If 0 <> (i = Initialize(api, target, args)) Then
                Return i
            End If
        Catch ex As Exception
            Call PostError(ex)
            Return 500
        End Try

        ' send debug message
        Call New TcpRequest(masterHost, masterPort).SendMessage(New RequestStream(IPCSocket.Protocol, Protocols.PostStart))

        Try
            Call PostFinished(api.Invoke(target, args), Protocols.PostResult)
        Catch ex As Exception
            Call PostError(ex)
        Finally
            Call Console.WriteLine("job done!")
        End Try

        Return 0
    End Function

    Private Function GetArgumentValueNumber() As Integer
        Dim resp = New TcpRequest(masterHost, masterPort).SendMessage(New RequestStream(IPCSocket.Protocol, Protocols.GetArgumentNumber))
        Dim n As Integer = BitConverter.ToInt32(resp.ChunkBuffer, Scan0)

        Return n
    End Function

    Private Function GetMethod() As IDelegate
        Dim resp = New TcpRequest(masterHost, masterPort).SendMessage(New RequestStream(IPCSocket.Protocol, Protocols.GetTask))
        Dim json As String = resp.GetUTF8String
        Dim target As IDelegate = json.LoadJSON(Of IDelegate)

        Return target
    End Function

    Private Function FromStream(stream As ObjectStream) As Object
        Dim type As Type = stream.type.GetType(
            knownFirst:=True,
            searchPath:={stream.type.assembly}
        )

#If netcore5 = 1 Then
        Call deps.TryHandleNetCore5AssemblyBugs(package:=type)
#End If

        Using buf As MemoryStream = stream.openMemoryBuffer
            Return emit.handleCreate(buf, type, stream.method)
        End Using
    End Function

    ''' <summary>
    ''' <see cref="SocketRef"/> -> target
    ''' </summary>
    ''' <param name="i"></param>
    ''' <returns></returns>
    Private Function GetArgumentValue(i As Integer) As Object
        Dim request As New RequestStream(IPCSocket.Protocol, Protocols.GetArgumentByIndex, BitConverter.GetBytes(i))
        Dim resp = New TcpRequest(masterHost, masterPort).SendMessage(request)
        Dim stream As New ObjectStream(resp.ChunkBuffer)

        If stream.IsNothing Then
            ' 20210516 object value is nothing?
            Return Nothing
        Else
            Dim socket As SocketRef = SocketRef.GetSocket(stream)

            Using buffer As ObjectStream = socket.Open
                Return FromStream(buffer)
            End Using
        End If
    End Function

    Private Function PostError(err As Exception) As Integer
        Call PostFinished(New IPCError(err), Protocols.PostError)

        Return 500
    End Function

    Private Sub PostFinished(result As Object, protocol As Protocols)
        Dim socket As SocketRef = SocketRef.WriteBuffer(result, emit)

        Using buf As ObjectStream = emit.handleSerialize(socket)
            Dim request As New RequestStream(
                protocolCategory:=IPCSocket.Protocol,
                protocol:=protocol,
                buffer:=buf.Serialize
            )

            If TypeOf result Is IPCError Then
                Call Console.WriteLine($"post error...")
            Else
                Call Console.WriteLine($"post result...")
            End If

            Call New TcpRequest(masterHost, masterPort).SendMessage(request)
        End Using
    End Sub
End Class