Public Class FreshserviceAPI
    Implements IFreshserviceAPI


    Public Sub New(portalURL As String, username As String, password As String)
        Me.PortalURL = portalURL
        Me.UserName = username
        Me.Password = password
    End Sub

    Public Property PortalURL As String = "" Implements IFreshserviceAPI.PortalURL
    Public Property UserName As String = "" Implements IFreshserviceAPI.UserName
    Public Property Password As String = "" Implements IFreshserviceAPI.Password


    Public Function GetTicket(id As Long) As HelpdeskTicket Implements IFreshserviceAPI.GetTicket

        Dim ticket As HelpdeskTicket = Nothing

        Dim ticketResourceURL As String = $"{Me.PortalURL.TrimEnd("/"c)}/helpdesk/tickets/{id}.json"
        Dim response As HttpWebResponse = HttpUtil.SubmitHttpRequest(ticketResourceURL,
                                                            method:=HttpMethod.Get,
                                                            basicAuthUser:=Me.UserName,
                                                            basicAuthPassword:=Me.Password)
        If response IsNot Nothing Then
            ticket = GetItemFromResponse(response, Function(root As TicketResponseRoot)
                                                       Return root.helpdesk_ticket
                                                   End Function)
        End If

        Return ticket

    End Function

    Public Function CreateTicket(ticket As HelpdeskTicket) As HelpdeskTicket Implements IFreshserviceAPI.CreateTicket

        Dim createdTicket As HelpdeskTicket = Nothing

        Dim ticketResourceURL As String = $"{Me.PortalURL.TrimEnd("/"c)}/helpdesk/tickets.json"
        Dim response As HttpWebResponse = HttpUtil.SubmitHttpRequest(ticketResourceURL,
                                                            method:=HttpMethod.Post,
                                                            basicAuthUser:=Me.UserName,
                                                            basicAuthPassword:=Me.Password,
                                                            requestBodyContent:=ticket.ToPostJson)

        If response IsNot Nothing Then
            createdTicket = GetItemFromResponse(response, Function(root As TicketPostResponseRoot)
                                                              Return root.item.helpdesk_ticket
                                                          End Function)
        End If

        Return createdTicket

    End Function

    Public Function UpdateTicket(ticket As HelpdeskTicket, id As Long) As HelpdeskTicket Implements IFreshserviceAPI.UpdateTicket

        Dim updatedTicket As HelpdeskTicket = Nothing

        Dim ticketResourceURL As String = $"{Me.PortalURL.TrimEnd("/"c)}/helpdesk/tickets/{id}.json"
        Dim response As HttpWebResponse = HttpUtil.SubmitHttpRequest(ticketResourceURL,
                                                            method:=HttpMethod.Put,
                                                            basicAuthUser:=Me.UserName,
                                                            basicAuthPassword:=Me.Password,
                                                            requestBodyContent:=ticket.ToPostJson)



        If response IsNot Nothing Then
            updatedTicket = GetItemFromResponse(response, Function(root As TicketPutttResponseRoot)
                                                              Return root.ticket
                                                          End Function)
        End If



        Return updatedTicket

    End Function

    Public Function GetNote(id As Long) As Note Implements IFreshserviceAPI.GetNote

        Throw New NotImplementedException()

    End Function

    Public Function CreateNote(note As Note, ticketID As Long) As Note Implements IFreshserviceAPI.CreateNote

        Dim createdNote As Note = Nothing

        Dim noteResourceURL As String = $"{Me.PortalURL.TrimEnd("/"c)}/helpdesk/tickets/{ticketID}/conversations/note.json"
        Dim response As HttpWebResponse = HttpUtil.SubmitHttpRequest(noteResourceURL,
                                                            method:=HttpMethod.Post,
                                                            basicAuthUser:=Me.UserName,
                                                            basicAuthPassword:=Me.Password,
                                                            requestBodyContent:=note.ToPostJson())
        If response IsNot Nothing Then
            createdNote = GetItemFromResponse(response, Function(root As NoteResponseRoot)
                                                            Return root.note
                                                        End Function)
        End If

        Return createdNote

    End Function


    Public Function CreateNoteWithAttachment(noteBody As String, attachment As Attachment, ticketID As Long) As Attachment Implements IFreshserviceAPI.CreateNoteWithAttachment

        Dim createdAttachment As Attachment = Nothing

        Dim responseJson As String = ""

        Using client = New HttpClient()
            Dim basicAuthCreds As String = Convert.ToBase64String(ASCIIEncoding.ASCII.GetBytes(UserName & ":" & Password))
            client.DefaultRequestHeaders.Authorization = New Headers.AuthenticationHeaderValue("Basic", basicAuthCreds)
            Using formData = New MultipartFormDataContent()

                formData.Add(New StringContent(noteBody), name:="helpdesk_note[body]")

                formData.Add(New ByteArrayContent(attachment.file_data),
                             name:="helpdesk_note[attachments][][resource]",
                             fileName:=attachment.content_file_name)

                Dim noteResourceURL As String = $"{Me.PortalURL.TrimEnd("/"c)}/helpdesk/tickets/{ticketID}/conversations/note.json"
                HttpUtil.SetSslProtocal()
                Dim response = client.PostAsync(noteResourceURL, formData).Result
                If response.IsSuccessStatusCode Then
                    Using streamReader As New StreamReader(response.Content.ReadAsStreamAsync().Result)
                        responseJson = streamReader.ReadToEnd()
                    End Using
                End If
            End Using
        End Using

        If Not String.IsNullOrWhiteSpace(responseJson) Then
            Dim noteRoot = JsonConvert.DeserializeObject(Of NoteResponseRoot)(responseJson)
            If noteRoot IsNot Nothing Then
                Dim createdNote As Note = noteRoot.note
                If createdNote IsNot Nothing Then
                    If createdNote.attachments?.Any() Then
                        attachment = createdNote.attachments.First()
                    End If
                End If
            End If
        End If

        Return attachment

    End Function


    Public Function FindAgentUser(emailAddress As String) As User Implements IFreshserviceAPI.FindAgentUser

        Dim user As User = Nothing


        If String.IsNullOrWhiteSpace(emailAddress) Then
            '//Fresh will pull ALL agents if you pass a blank email address
            '//we don't want that.
            Return Nothing
        End If

        Dim usersResourceURL As String = $"{Me.PortalURL.TrimEnd("/"c)}/agents.json?query={WebUtility.UrlEncode("email is " & emailAddress)}"
        Dim response As HttpWebResponse = HttpUtil.SubmitHttpRequest(usersResourceURL,
                                                                     basicAuthUser:=Me.UserName,
                                                                     basicAuthPassword:=Me.Password,
                                                                     method:=HttpMethod.Get)
        If response IsNot Nothing Then

            user = GetItemFromResponse(response, Function(agentItems As List(Of AgentListItem))
                                                     If agentItems?.Any() Then
                                                         Dim agent = agentItems.First()
                                                         If agent IsNot Nothing Then
                                                             Return If(agent Is Nothing, Nothing, agent.agent.user)
                                                         End If
                                                     End If
                                                     Return Nothing
                                                 End Function)

        End If


        Return user

    End Function




    Private Function GetItemFromResponse(Of ItemType, ItemRootType)(response As HttpWebResponse,
                                                                    itemExtractor As Func(Of ItemRootType, ItemType)) As ItemType

        Dim item As ItemType = Nothing

        Dim responseBodyJSON As String = ""
        Using streamReader As New StreamReader(response.GetResponseStream())
            responseBodyJSON = streamReader.ReadToEnd()
            Dim jsonRoot As ItemRootType = JsonConvert.DeserializeObject(Of ItemRootType)(responseBodyJSON)
            item = itemExtractor(jsonRoot)
        End Using

        Return item

    End Function

Public Class HelpdeskTicket


    <JsonProperty("email")>
    Public Property RequesterEmail As String

    Public Property category As Object

    Public Property cc_email As CcEmail

    <JsonConverter(GetType(IsoDateTimeConverter))>
    Public Property created_at As DateTime?

    Public Property deleted As Boolean?

    Public Property department_id_value As Object

    Public Property display_id As Integer?

    <JsonConverter(GetType(IsoDateTimeConverter))>
    Public Property due_by As DateTime?

    Public Property email_config_id As Object

    <JsonConverter(GetType(IsoDateTimeConverter))>
    Public Property frDueBy As DateTime?

    Public Property fr_escalated As Boolean?

    Public Property group_id As Object

    Public Property id As Long?

    Public Property impact As Integer?

    Public Property isescalated As Boolean?

    Public Property item_category As Object

    Public Property notes As List(Of NoteResponseRoot)

    Public Property owner_id As Object

    Public Property priority As Integer?

    Public Property requester_id As Long?

    Public Property responder_id As Object

    Public Property source As Integer?

    Public Property spam As Boolean?

    Public Property status As Integer?

    Public Property sub_category As Object

    Public Property subject As String

    Public Property ticket_type As String

    Public Property to_email As Object

    <JsonConverter(GetType(IsoDateTimeConverter))>
    Public Property updated_at As DateTime?

    Public Property urgency As Integer?

    Public Property description As String

    Public Property description_html As String

    Public Property status_name As String

    Public Property requester_status_name As String

    Public Property priority_name As String

    Public Property source_name As String

    Public Property requester_name As String

    Public Property responder_name As String

    Public Property to_emails As Object

    Public Property department_name As Object

    Public Property assoc_problem_id As Object

    Public Property assoc_change_id As Object

    Public Property assoc_change_cause_id As Object

    Public Property assoc_asset_id As Object

    Public Property urgency_name As String

    Public Property impact_name As String

    Public Property attachments As List(Of Object)

    Public Property custom_field As Dictionary(Of String, Object)

    Public Property tags As List(Of Object)
End Class


Public Class CcEmail

    Public Property cc_emails As List(Of String)

    Public Property fwd_emails As List(Of Object)

    Public Property reply_cc As List(Of String)

    Public Property tkt_cc As List(Of String)
End Class


Public Class TicketResponseRoot

    Public Property helpdesk_ticket As HelpdeskTicket
End Class

Public Class TicketPostResponseRoot

    Public Property redirect As Object

    Public Property item As TicketResponseRoot

End Class

Public Class TicketPutttResponseRoot

    Public Property ticket As HelpdeskTicket

End Class

Imports System.IO
Imports System.Net
Imports System.Net.Http
Imports System.Security.Authentication
Imports System.Text

Namespace HttpUtils

    Public Class HttpUtil

        Public Shared Function SubmitHttpRequest(resourceURL As String,
                                                 method As HttpMethod,
                                                 basicAuthUser As String,
                                                 basicAuthPassword As String,
                                                 Optional requestBodyContent As String = Nothing) As HttpWebResponse

            Dim httpWebrequest As HttpWebRequest = WebRequest.Create(resourceURL)
            httpWebrequest.Method = method.Method
            httpWebrequest.Accept = "application/json"
            httpWebrequest.ContentType = "application/json"
            httpWebrequest.Timeout = 25000
            Dim basicAuthCreds As String = Convert.ToBase64String(ASCIIEncoding.ASCII.GetBytes(basicAuthUser & ":" & basicAuthPassword))
            httpWebrequest.Headers.Add("Authorization", "Basic " + basicAuthCreds)


            If requestBodyContent IsNot Nothing Then
                Using writer As New StreamWriter(httpWebrequest.GetRequestStream())
                    writer.Write(requestBodyContent)
                End Using
            End If


            Dim httpResponse As HttpWebResponse = Nothing
            Try
                SetSslProtocal()
                httpResponse = httpWebrequest.GetResponse()
            Catch WebEx As WebException
                Throw New HttpApiException(requestBody:=requestBodyContent,
                                           message:=$"HttpUtil.SubmitHttpRequest -- HTTP Error occurred at {DateTime.Now.ToString()}, see inner exception for details",
                                           innerException:=WebEx)
            End Try

            Return httpResponse

        End Function


        ''' <summary>
        '''   Sets the Security Protocal to avoid error:
        '''  "Additional information: The underlying connection was closed: An unexpected error occurred on a send.
        '''  (Authentication failed because remote party has closed the transport stream)
        '''   See: https://stackoverflow.com/a/47517067/614263
        ''' </summary>
        Public Shared Sub SetSslProtocal()
            Const _Tls12 As SslProtocols = DirectCast(&HC00, SslProtocols)
            Const Tls12 As SecurityProtocolType = DirectCast(_Tls12,
             SecurityProtocolType)
            ServicePointManager.SecurityProtocol = Tls12
        End Sub


    End Class


End Namespace