gochat/internal/channel/twilio/pipeline.go

package twilio

// Pipeline integration for Twilio SMS/WhatsApp channel with gochat's message processing system.
// Reference: gochat's Telegram pipeline architecture — same pattern adapted for Twilio.
//
// Flow:
//   WebhookHandler.ProcessInboundSMS → IncomingProcessor.ProcessInboundSMS
//     → channelpkg.IncomingMessage → core message processing
//
// Twilio SMS specifics:
//   - Sender identification by phone number (E.164 format)
//   - Support for plain SMS text and MMS media attachments
//   - Delivery status tracking via callback events
//   - WhatsApp via Twilio uses same pipeline with different ChannelType

import (
	"context"
	"fmt"

	channelpkg "github.com/gochat/gochat/internal/channel"
	"github.com/gochat/gochat/internal/model"
	applogger "github.com/gochat/gochat/pkg/logger"
)

// IncomingProcessor transforms raw Twilio webhook data into gochat's unified IncomingMessage.
type IncomingProcessor struct {
	service *TwilioService
}

// NewIncomingProcessor creates a Twilio incoming message processor.
func NewIncomingProcessor(service *TwilioService) *IncomingProcessor {
	return &IncomingProcessor{service: service}
}

// ProcessInboundSMS transforms an inbound SMS/MMS message into a gochat IncomingMessage.
func (p *IncomingProcessor) ProcessInboundSMS(ctx context.Context, inbox *model.Inbox, sms InboundSMS) (*channelpkg.IncomingMessage, error) {
	// Use the sender's phone number as the contact source identifier
	fromPhone := sms.From
	if fromPhone == "" {
		return nil, fmt.Errorf("twilio ProcessInboundSMS: no From number")
	}

	// Normalize phone number to E.164
	normalizedFrom := p.service.ParsePhoneNumber(fromPhone)

	incomingMsg := &channelpkg.IncomingMessage{
		ChannelType:  channelpkg.ChannelTwilioSMS,
		SourceID:     sms.MessageSID, // Twilio MessageSID as source ID
		SenderID:    normalizedFrom,
		SenderName:  normalizedFrom, // Phone number as display name (may be enriched later)
		SenderType:  channelpkg.SenderContact,
		InboxID:     inbox.ID,
		AccountID:   inbox.AccountID,
		Extra:       make(channelpkg.ChannelConfig),
	}

	// Store Twilio message metadata
	incomingMsg.Extra["message_sid"] = sms.MessageSID
	incomingMsg.Extra["account_sid"] = sms.AccountSID
	incomingMsg.Extra["from_city"] = sms.FromCity
	incomingMsg.Extra["from_state"] = sms.FromState
	incomingMsg.Extra["from_country"] = sms.FromCountry
	incomingMsg.Extra["from_zip"] = sms.FromZip

	// Handle media attachments (MMS)
	numMedia := 0
	if sms.NumMedia != "" {
		if n, err := fmt.Sscanf(sms.NumMedia, "%d", &numMedia); err != nil || n != 1 {
			numMedia = 0
		}
	}

	if numMedia > 0 && len(sms.MediaURL) > 0 {
		// MMS message with media attachments
		incomingMsg.ContentType = channelpkg.ContentImage
		incomingMsg.Content = sms.MediaURL[0] // Primary media URL
		incomingMsg.Extra["num_media"] = numMedia
		incomingMsg.Extra["media_urls"] = sms.MediaURL
		incomingMsg.Extra["media_content_types"] = sms.MediaContentType

		// Build attachment list
		for i, url := range sms.MediaURL {
			ct := "image"
			if i < len(sms.MediaContentType) {
				ct = sms.MediaContentType[i]
			}
			incomingMsg.Attachments = append(incomingMsg.Attachments, channelpkg.Attachment{
				URL:         url,
				ContentType: ct,
			})
		}

		// If there's text alongside media, add it to extra
		if sms.Body != "" {
			incomingMsg.Extra["body"] = sms.Body
		}
	} else {
		// Pure SMS text message
		incomingMsg.ContentType = channelpkg.ContentText
		incomingMsg.Content = sms.Body
	}

	applogger.L().Debugf("Twilio ProcessInboundSMS: from=%s body_len=%d media=%d",
		normalizedFrom, len(sms.Body), numMedia)

	return incomingMsg, nil
}

// ProcessDeliveryStatus transforms a Twilio delivery status callback into a channel event.
func (p *IncomingProcessor) ProcessDeliveryStatus(ctx context.Context, inbox *model.Inbox, status DeliveryStatus) (*channelpkg.IncomingMessage, error) {
	toPhone := p.service.ParsePhoneNumber(status.To)

	incomingMsg := &channelpkg.IncomingMessage{
		ChannelType:  channelpkg.ChannelTwilioSMS,
		SourceID:     status.MessageSID,
		SenderID:    toPhone,
		SenderType:  channelpkg.SenderSystem, // delivery status is system-generated
		InboxID:     inbox.ID,
		AccountID:   inbox.AccountID,
		ContentType: channelpkg.ContentText,
		Extra:       make(channelpkg.ChannelConfig),
	}

	// Map Twilio delivery status to gochat content
	switch status.MessageStatus {
	case "delivered":
		incomingMsg.Content = fmt.Sprintf("Message %s delivered", status.MessageSID)
	case "undelivered", "failed":
		incomingMsg.Content = fmt.Sprintf("Message %s failed: status=%s error=%s",
			status.MessageSID, status.MessageStatus, status.ErrorCode)
	default:
		applogger.L().Debugf("Twilio ProcessDeliveryStatus: unhandled status %s", status.MessageStatus)
		return nil, nil
	}

	incomingMsg.Extra["message_sid"] = status.MessageSID
	incomingMsg.Extra["message_status"] = status.MessageStatus
	if status.ErrorCode != "" {
		incomingMsg.Extra["error_code"] = status.ErrorCode
	}

	return incomingMsg, nil
}