gochat/internal/channel/twilio/service.go

package twilio

// TwilioService provides high-level operations for the Twilio SMS channel.
// Reference: Twilio SMS API — https://www.twilio.com/docs/sms
//
// This service coordinates:
//   - Sending SMS/MMS messages via Twilio REST API
//   - Fetching phone number information
//   - Validating account credentials
//   - Processing delivery status callbacks
//   - Managing channel configuration
//
// Design: Follows the same service pattern as LineService and WhatsAppService.

import (
	"context"
	"encoding/json"
	"fmt"
	"strings"
	"time"

	"github.com/go-resty/resty/v2"

	applogger "github.com/gochat/gochat/pkg/logger"
)

// TwilioService provides Twilio SMS API operations.
type TwilioService struct {
	repo   *Repository
	client *resty.Client
}

// NewTwilioService creates a Twilio SMS service instance.
func NewTwilioService(repo *Repository) *TwilioService {
	client := resty.New()
	client.SetTimeout(30 * time.Second)
	return &TwilioService{
		repo:   repo,
		client: client,
	}
}

// === Message Sending ===

// SendMessage sends an SMS or MMS message via Twilio REST API.
// Reference: https://www.twilio.com/docs/sms/api/message-resource
func (s *TwilioService) SendMessage(ctx context.Context, accountSID, authToken, from, to, body string, mediaURLs []string) (*OutboundSMSResponse, error) {
	apiURL := fmt.Sprintf("https://api.twilio.com/2010-04-01/Accounts/%s/Messages.json", accountSID)

	formData := map[string]string{
		"From": from,
		"To":   to,
		"Body": body,
	}

	// Add media URLs for MMS
	for i, mediaURL := range mediaURLs {
		formData[fmt.Sprintf("MediaUrl%d", i)] = mediaURL
	}

	var result OutboundSMSResponse
	resp, err := s.client.R().
		SetContext(ctx).
		SetBasicAuth(accountSID, authToken).
		SetFormData(formData).
		SetResult(&result).
		Post(apiURL)

	if err != nil {
		return nil, fmt.Errorf("twilio SendMessage: API call failed: %w", err)
	}
	if resp.StatusCode() != 201 {
		// Parse Twilio error response
		var errResp map[string]interface{}
		if json.Unmarshal(resp.Body(), &errResp) == nil {
			msg, _ := errResp["message"].(string)
			code, _ := errResp["code"].(float64)
			return nil, fmt.Errorf("twilio SendMessage: API error %d: %s", int(code), msg)
		}
		return nil, fmt.Errorf("twilio SendMessage: API returned status %d", resp.StatusCode())
	}

	applogger.L().Debugf("Twilio SendMessage: SID=%s to=%s", result.SID, to)
	return &result, nil
}

// === Phone Number Info ===

// GetPhoneNumberInfo fetches details about a Twilio phone number.
func (s *TwilioService) GetPhoneNumberInfo(ctx context.Context, accountSID, authToken, phoneSID string) (*PhoneNumberInfo, error) {
	apiURL := fmt.Sprintf("https://api.twilio.com/2010-04-01/Accounts/%s/IncomingPhoneNumbers/%s.json", accountSID, phoneSID)

	var result PhoneNumberInfo
	resp, err := s.client.R().
		SetContext(ctx).
		SetBasicAuth(accountSID, authToken).
		SetResult(&result).
		Get(apiURL)

	if err != nil {
		return nil, fmt.Errorf("twilio GetPhoneNumberInfo: API call failed: %w", err)
	}
	if resp.StatusCode() != 200 {
		return nil, fmt.Errorf("twilio GetPhoneNumberInfo: API returned status %d", resp.StatusCode())
	}

	return &result, nil
}

// === Credential Validation ===

// ValidateCredentials verifies Twilio account SID and auth token.
func (s *TwilioService) ValidateCredentials(ctx context.Context, accountSID, authToken string) error {
	apiURL := fmt.Sprintf("https://api.twilio.com/2010-04-01/Accounts/%s.json", accountSID)

	resp, err := s.client.R().
		SetContext(ctx).
		SetBasicAuth(accountSID, authToken).
		Get(apiURL)

	if err != nil {
		return fmt.Errorf("twilio ValidateCredentials: API call failed: %w", err)
	}
	if resp.StatusCode() != 200 {
		return fmt.Errorf("twilio ValidateCredentials: invalid credentials (status %d)", resp.StatusCode())
	}
	return nil
}

// === Configuration ===

// UpdateChannel updates Twilio SMS channel configuration fields.
func (s *TwilioService) UpdateChannel(ctx context.Context, channelID uint, updates map[string]interface{}) error {
	return s.repo.UpdateFields(ctx, channelID, updates)
}

// MarkReauthorizationRequired flags a channel needing credential reconfiguration.
func (s *TwilioService) MarkReauthorizationRequired(ctx context.Context, channelID uint) error {
	return s.UpdateChannel(ctx, channelID, map[string]interface{}{
		"reauthorization_required": true,
	})
}

// ParsePhoneNumber normalizes a phone number to E.164 format.
func (s *TwilioService) ParsePhoneNumber(phone string) string {
	// Strip all non-digit characters
	phone = strings.ReplaceAll(phone, "-", "")
	phone = strings.ReplaceAll(phone, " ", "")
	phone = strings.ReplaceAll(phone, "+", "")
	phone = strings.ReplaceAll(phone, ".", "")
	phone = strings.ReplaceAll(phone, "(", "")
	phone = strings.ReplaceAll(phone, ")", "")

	// Add + prefix for E.164
	if !strings.HasPrefix(phone, "+") {
		phone = "+" + phone
	}
	return phone
}