' SOFTG API WhatsApp - cliente para o SOFTG ERP / PDV.
' Compativel com VB.NET / .NET Framework 4.8 (Visual Studio 2022). Usa somente sintaxe VB 2012 e assemblies do
' proprio Framework: System.Net.Http, System.Web.Extensions (JavaScriptSerializer) e System.Drawing (QR Code).
' Documentacao: https://api.whats.softgempresarialsistemas.com.br/
' Nunca grave o token no codigo-fonte: leia da configuracao protegida do ERP (DPAPI, cofre, etc.).
Option Strict On
Option Explicit On

Imports System.Collections.Generic
Imports System.Drawing
Imports System.IO
Imports System.Net
Imports System.Net.Http
Imports System.Text
Imports System.Threading
Imports System.Threading.Tasks
Imports System.Web.Script.Serialization

Namespace SoftG.WhatsApp

    ''' <summary>Erro devolvido pela API ({"erro","codigo"}). Nunca contem o token.</summary>
    Public Class SoftGWhatsAppException
        Inherits Exception

        Private ReadOnly _statusHttp As Integer
        Private ReadOnly _codigo As String
        Private ReadOnly _retryAfter As Integer

        Public Sub New(statusHttp As Integer, codigo As String, mensagem As String, Optional retryAfterSegundos As Integer = 0)
            MyBase.New(mensagem)
            _statusHttp = statusHttp
            _codigo = codigo
            _retryAfter = retryAfterSegundos
        End Sub

        ''' <summary>0 = falha de rede ou tempo esgotado; demais = HTTP da resposta.</summary>
        Public ReadOnly Property StatusHttp As Integer
            Get
                Return _statusHttp
            End Get
        End Property

        ''' <summary>Ex.: TOKEN_INVALIDO, WHATSAPP_DESCONECTADO, NUMERO_SEM_WHATSAPP, LIMITE_EXCEDIDO.</summary>
        Public ReadOnly Property Codigo As String
            Get
                Return _codigo
            End Get
        End Property

        ''' <summary>No 429 (limite por minuto), segundos a aguardar antes de repetir.</summary>
        Public ReadOnly Property RetryAfterSegundos As Integer
            Get
                Return _retryAfter
            End Get
        End Property

        ''' <summary>Falhas transitorias (rede, 429, 5xx) podem ser repetidas com a MESMA Idempotency-Key.</summary>
        Public ReadOnly Property PodeRepetir As Boolean
            Get
                Return _statusHttp = 0 OrElse _statusHttp = 429 OrElse _statusHttp >= 500
            End Get
        End Property
    End Class

    Public Class EnvioResultado
        ''' <summary>Id da mensagem na SOFTG API (use em StatusAsync).</summary>
        Public Property Id As String
        Public Property WhatsappId As String
        Public Property Status As String
        Public Property Destino As String
        Public Property CriadoEm As String
    End Class

    Public Class StatusMensagem
        ''' <summary>ENVIADA, ENTREGUE, LIDA ou FALHOU.</summary>
        Public Property Status As String
        Public Property CriadoEm As String
        Public Property EntregueEm As String
        Public Property LidaEm As String
        Public Property Erro As String
    End Class

    Public Class ConexaoQr
        ''' <summary>open (conectado), connecting (aguardando leitura) ou close.</summary>
        Public Property Estado As String
        ''' <summary>PNG do QR Code em data URI (data:image/png;base64,...). Vazio quando ja conectado.</summary>
        Public Property Base64 As String
        Public Property ExpiraEm As String
        ''' <summary>QR Code pronto para um PictureBox. Nothing quando ja conectado.</summary>
        Public Property QrCodeImagem As Image
    End Class

    Public Class NumeroVerificado
        Public Property Numero As String
        Public Property Existe As Boolean
        Public Property Jid As String
    End Class

    Public Class SoftGWhatsAppClient
        Implements IDisposable

        ' Uma instancia de HttpClient por cliente evita esgotamento de sockets; nao criar uma por requisicao.
        Private ReadOnly _http As HttpClient
        Private ReadOnly _instancia As String
        Private ReadOnly _token As String
        Private ReadOnly _json As New JavaScriptSerializer()

        Shared Sub New()
            ' .NET Framework 4.8 em sistemas antigos pode negociar TLS 1.0; a API exige TLS 1.2 ou superior.
            ServicePointManager.SecurityProtocol = ServicePointManager.SecurityProtocol Or SecurityProtocolType.Tls12
        End Sub

        ''' <param name="baseUrl">https://api.whats.softgempresarialsistemas.com.br/v1</param>
        ''' <param name="instancia">Ex.: cli_loja_exemplo_a1b2 (aba APIs do painel SoftG)</param>
        ''' <param name="token">Token sgw_... da conexao</param>
        Public Sub New(baseUrl As String, instancia As String, token As String)
            If String.IsNullOrWhiteSpace(baseUrl) Then Throw New ArgumentException("Informe a URL base.", "baseUrl")
            If String.IsNullOrWhiteSpace(instancia) Then Throw New ArgumentException("Informe a instancia.", "instancia")
            If String.IsNullOrWhiteSpace(token) Then Throw New ArgumentException("Informe o token.", "token")
            Dim uri As New Uri(baseUrl.TrimEnd("/"c) & "/")
            If uri.Scheme <> Uri.UriSchemeHttps AndAlso Not uri.IsLoopback Then
                Throw New ArgumentException("A SOFTG API WhatsApp exige HTTPS.", "baseUrl")
            End If
            _instancia = instancia.Trim()
            _token = token.Trim()
            _http = New HttpClient()
            _http.BaseAddress = uri
            _http.Timeout = TimeSpan.FromSeconds(120)
            _json.MaxJsonLength = 48 * 1024 * 1024
        End Sub

        ''' <summary>Gera uma chave nova por operacao de negocio. Guarde-a junto do registro do ERP para repetir com seguranca.</summary>
        Public Shared Function NovaChaveIdempotencia(prefixo As String) As String
            Return prefixo & "-" & Guid.NewGuid().ToString("N")
        End Function

        ''' <summary>Testa URL, instancia e token. Retorna o estado do WhatsApp: open, connecting ou close.</summary>
        Public Async Function TestarAsync(Optional cancelamento As CancellationToken = Nothing) As Task(Of String)
            Dim resposta = Await ChamarAsync(HttpMethod.Get, "", Nothing, Nothing, cancelamento).ConfigureAwait(False)
            Return Texto(resposta, "estado")
        End Function

        ''' <summary>Estado da conexao: open, connecting ou close.</summary>
        Public Async Function EstadoAsync(Optional cancelamento As CancellationToken = Nothing) As Task(Of String)
            Dim resposta = Await ChamarAsync(HttpMethod.Get, "instance/connectionState/" & _instancia, Nothing, Nothing, cancelamento).ConfigureAwait(False)
            Return Texto(resposta, "estado")
        End Function

        ''' <summary>
        ''' Gera o QR Code para conectar o numero. Mostre QrCodeImagem e chame de novo a cada 20 s ate Estado = "open".
        ''' </summary>
        Public Async Function ConectarQrAsync(Optional cancelamento As CancellationToken = Nothing) As Task(Of ConexaoQr)
            Dim resposta = Await ChamarAsync(HttpMethod.Get, "instance/connect/" & _instancia, Nothing, Nothing, cancelamento).ConfigureAwait(False)
            Dim resultado As New ConexaoQr()
            resultado.Estado = Texto(resposta, "estado")
            resultado.Base64 = Texto(resposta, "base64")
            resultado.ExpiraEm = Texto(resposta, "expiraEm")
            If Not String.IsNullOrEmpty(resultado.Base64) Then
                Dim bytes As Byte() = Convert.FromBase64String(resultado.Base64.Substring(resultado.Base64.IndexOf(","c) + 1))
                resultado.QrCodeImagem = Image.FromStream(New MemoryStream(bytes))
            End If
            Return resultado
        End Function

        ''' <summary>Alternativa ao QR: codigo de 8 letras para digitar no celular (Conectar com numero de telefone).</summary>
        Public Async Function CodigoPareamentoAsync(numero As String, Optional cancelamento As CancellationToken = Nothing) As Task(Of String)
            Dim resposta = Await ChamarAsync(HttpMethod.Get, "instance/connect/" & _instancia & "?number=" & Uri.EscapeDataString(SoDigitos(numero)), Nothing, Nothing, cancelamento).ConfigureAwait(False)
            If Texto(resposta, "estado") = "open" Then Return ""
            Return Texto(resposta, "pairingCode")
        End Function

        ''' <summary>Desconecta o WhatsApp e apaga a sessao: para voltar e preciso ler um novo QR Code.</summary>
        Public Async Function DesconectarAsync(Optional cancelamento As CancellationToken = Nothing) As Task
            Await ChamarAsync(HttpMethod.Delete, "instance/logout/" & _instancia, Nothing, Nothing, cancelamento).ConfigureAwait(False)
        End Function

        ''' <summary>Envia texto. Use *negrito*, _italico_, ~tachado~ e vbLf para quebrar linha.</summary>
        Public Async Function EnviarTextoAsync(numero As String, texto As String,
                                               Optional idempotencyKey As String = Nothing,
                                               Optional cancelamento As CancellationToken = Nothing) As Task(Of EnvioResultado)
            Dim corpo As New Dictionary(Of String, Object)()
            corpo("number") = SoDigitos(numero)
            corpo("text") = texto
            Return ParaEnvio(Await ChamarAsync(HttpMethod.Post, "message/sendText/" & _instancia, corpo, idempotencyKey, cancelamento).ConfigureAwait(False))
        End Function

        ''' <summary>
        ''' Envia PDF (DANFE, boleto), XML, imagem, video ou audio a partir de um arquivo local (ate 25 MB).
        ''' O tipo e definido pela extensao; o servidor confere a assinatura do arquivo.
        ''' </summary>
        Public Async Function EnviarArquivoAsync(numero As String, caminho As String,
                                                 Optional legenda As String = Nothing,
                                                 Optional idempotencyKey As String = Nothing,
                                                 Optional cancelamento As CancellationToken = Nothing) As Task(Of EnvioResultado)
            Dim info As New FileInfo(caminho)
            If Not info.Exists Then Throw New FileNotFoundException("Arquivo nao encontrado.", caminho)
            If info.Length > 25L * 1024 * 1024 Then Throw New SoftGWhatsAppException(413, "ARQUIVO_MUITO_GRANDE", "Arquivo acima de 25 MB.")
            Dim mime As String = MimePorExtensao(info.Extension)
            Dim base64 As String = Convert.ToBase64String(File.ReadAllBytes(caminho))
            Dim corpo As New Dictionary(Of String, Object)()
            corpo("number") = SoDigitos(numero)
            If mime.StartsWith("audio/") Then
                corpo("audio") = base64
                Return ParaEnvio(Await ChamarAsync(HttpMethod.Post, "message/sendWhatsAppAudio/" & _instancia, corpo, idempotencyKey, cancelamento).ConfigureAwait(False))
            End If
            corpo("mediatype") = If(mime.StartsWith("image/"), "image", If(mime.StartsWith("video/"), "video", "document"))
            corpo("mimetype") = mime
            corpo("media") = base64
            corpo("fileName") = info.Name
            If Not String.IsNullOrEmpty(legenda) Then corpo("caption") = legenda
            Return ParaEnvio(Await ChamarAsync(HttpMethod.Post, "message/sendMedia/" & _instancia, corpo, idempotencyKey, cancelamento).ConfigureAwait(False))
        End Function

        ''' <summary>Envia uma localizacao (ex.: endereco da loja).</summary>
        Public Async Function EnviarLocalizacaoAsync(numero As String, nome As String, endereco As String, latitude As Double, longitude As Double,
                                                     Optional idempotencyKey As String = Nothing,
                                                     Optional cancelamento As CancellationToken = Nothing) As Task(Of EnvioResultado)
            Dim corpo As New Dictionary(Of String, Object)()
            corpo("number") = SoDigitos(numero)
            corpo("name") = nome
            corpo("address") = endereco
            corpo("latitude") = latitude
            corpo("longitude") = longitude
            Return ParaEnvio(Await ChamarAsync(HttpMethod.Post, "message/sendLocation/" & _instancia, corpo, idempotencyKey, cancelamento).ConfigureAwait(False))
        End Function

        ''' <summary>Confere quais numeros tem WhatsApp (ate 50 por chamada), resolvendo o 9o digito.</summary>
        Public Async Function VerificarNumerosAsync(numeros As IEnumerable(Of String), Optional cancelamento As CancellationToken = Nothing) As Task(Of List(Of NumeroVerificado))
            Dim lista As New List(Of String)()
            For Each numero In numeros
                lista.Add(SoDigitos(numero))
            Next
            Dim corpo As New Dictionary(Of String, Object)()
            corpo("numbers") = lista
            Dim bruto = Await ChamarBrutoAsync(HttpMethod.Post, "chat/whatsappNumbers/" & _instancia, corpo, Nothing, cancelamento).ConfigureAwait(False)
            Dim resultado As New List(Of NumeroVerificado)()
            For Each item In _json.Deserialize(Of List(Of Dictionary(Of String, Object)))(bruto)
                Dim verificado As New NumeroVerificado()
                verificado.Numero = Texto(item, "numero")
                verificado.Existe = item.ContainsKey("existe") AndAlso CBool(item("existe"))
                verificado.Jid = Texto(item, "jid")
                resultado.Add(verificado)
            Next
            Return resultado
        End Function

        ''' <summary>Status atual da mensagem enviada: ENVIADA, ENTREGUE, LIDA ou FALHOU.</summary>
        Public Async Function StatusAsync(id As String, Optional cancelamento As CancellationToken = Nothing) As Task(Of StatusMensagem)
            Dim resposta = Await ChamarAsync(HttpMethod.Get, "message/status/" & _instancia & "/" & Uri.EscapeDataString(id), Nothing, Nothing, cancelamento).ConfigureAwait(False)
            Dim status As New StatusMensagem()
            status.Status = Texto(resposta, "status")
            status.CriadoEm = Texto(resposta, "criadoEm")
            status.EntregueEm = Texto(resposta, "entregueEm")
            status.LidaEm = Texto(resposta, "lidaEm")
            status.Erro = Texto(resposta, "erro")
            Return status
        End Function

        Private Shared Function SoDigitos(numero As String) As String
            Dim sb As New StringBuilder()
            For Each c As Char In If(numero, "")
                If Char.IsDigit(c) Then sb.Append(c)
            Next
            Return sb.ToString()
        End Function

        Private Shared Function MimePorExtensao(extensao As String) As String
            Select Case extensao.ToLowerInvariant()
                Case ".pdf" : Return "application/pdf"
                Case ".xml" : Return "application/xml"
                Case ".txt" : Return "text/plain"
                Case ".csv" : Return "text/csv"
                Case ".jpg", ".jpeg" : Return "image/jpeg"
                Case ".png" : Return "image/png"
                Case ".webp" : Return "image/webp"
                Case ".gif" : Return "image/gif"
                Case ".mp4" : Return "video/mp4"
                Case ".mov" : Return "video/quicktime"
                Case ".ogg", ".opus" : Return "audio/ogg"
                Case ".mp3" : Return "audio/mpeg"
                Case ".m4a" : Return "audio/mp4"
                Case ".wav" : Return "audio/wav"
                Case ".docx" : Return "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
                Case ".xlsx" : Return "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
                Case ".zip" : Return "application/zip"
                Case Else : Throw New SoftGWhatsAppException(422, "MIDIA_INVALIDA", "Tipo de arquivo nao suportado: " & extensao)
            End Select
        End Function

        Private Shared Function Texto(dados As Dictionary(Of String, Object), chave As String) As String
            If dados Is Nothing OrElse Not dados.ContainsKey(chave) OrElse dados(chave) Is Nothing Then Return ""
            Return Convert.ToString(dados(chave), Globalization.CultureInfo.InvariantCulture)
        End Function

        Private Shared Function ParaEnvio(resposta As Dictionary(Of String, Object)) As EnvioResultado
            Dim envio As New EnvioResultado()
            envio.Id = Texto(resposta, "id")
            envio.WhatsappId = Texto(resposta, "whatsappId")
            envio.Status = Texto(resposta, "status")
            envio.Destino = Texto(resposta, "destino")
            envio.CriadoEm = Texto(resposta, "criadoEm")
            Return envio
        End Function

        Private Async Function ChamarAsync(metodo As HttpMethod, caminho As String, corpo As Object, idempotencyKey As String,
                                           cancelamento As CancellationToken) As Task(Of Dictionary(Of String, Object))
            Dim bruto = Await ChamarBrutoAsync(metodo, caminho, corpo, idempotencyKey, cancelamento).ConfigureAwait(False)
            Return _json.Deserialize(Of Dictionary(Of String, Object))(bruto)
        End Function

        Private Async Function ChamarBrutoAsync(metodo As HttpMethod, caminho As String, corpo As Object, idempotencyKey As String,
                                                cancelamento As CancellationToken) As Task(Of String)
            Using request As New HttpRequestMessage(metodo, caminho)
                ' Token por requisicao (e nao em DefaultRequestHeaders) para nunca vazar entre clientes.
                request.Headers.Add("apikey", _token)
                If Not String.IsNullOrEmpty(idempotencyKey) Then request.Headers.Add("Idempotency-Key", idempotencyKey)
                If corpo IsNot Nothing Then request.Content = New StringContent(_json.Serialize(corpo), Encoding.UTF8, "application/json")
                Dim response As HttpResponseMessage
                Try
                    response = Await _http.SendAsync(request, cancelamento).ConfigureAwait(False)
                Catch ex As HttpRequestException
                    Throw New SoftGWhatsAppException(0, "REDE", "Falha de comunicacao com a SOFTG API WhatsApp: " & ex.Message)
                Catch ex As TaskCanceledException
                    If cancelamento.IsCancellationRequested Then Throw
                    Throw New SoftGWhatsAppException(0, "TEMPO_ESGOTADO", "Tempo limite excedido ao chamar a SOFTG API WhatsApp.")
                End Try
                Using response
                    Dim texto As String = Await response.Content.ReadAsStringAsync().ConfigureAwait(False)
                    If response.IsSuccessStatusCode Then Return texto
                    Dim codigo As String = "HTTP_" & CInt(response.StatusCode).ToString()
                    Dim mensagem As String = response.ReasonPhrase
                    Try
                        Dim erro = _json.Deserialize(Of Dictionary(Of String, Object))(texto)
                        If erro IsNot Nothing Then
                            If erro.ContainsKey("codigo") AndAlso erro("codigo") IsNot Nothing Then codigo = CStr(erro("codigo"))
                            If erro.ContainsKey("erro") AndAlso erro("erro") IsNot Nothing Then mensagem = CStr(erro("erro"))
                        End If
                    Catch ex As ArgumentException
                        ' Corpo nao JSON (ex.: pagina de erro do proxy): mantem o codigo HTTP.
                    Catch ex As InvalidOperationException
                    End Try
                    Dim retryAfter As Integer = 0
                    If response.Headers.RetryAfter IsNot Nothing AndAlso response.Headers.RetryAfter.Delta.HasValue Then
                        retryAfter = CInt(response.Headers.RetryAfter.Delta.Value.TotalSeconds)
                    End If
                    Throw New SoftGWhatsAppException(CInt(response.StatusCode), codigo, mensagem, retryAfter)
                End Using
            End Using
        End Function

        Public Sub Dispose() Implements IDisposable.Dispose
            _http.Dispose()
        End Sub
    End Class

End Namespace