whatsapp-mcp/whatsapp-bridge/main.go

package main

import (
	"context"
	"database/sql"
	"encoding/binary"
	"encoding/json"
	"fmt"
	"math"
	"math/rand"
	"net/http"
	"os"
	"os/signal"
	"reflect"
	"strings"
	"syscall"
	"time"

	_ "github.com/mattn/go-sqlite3"
	"github.com/mdp/qrterminal"

	"bytes"

	"go.mau.fi/whatsmeow"
	waProto "go.mau.fi/whatsmeow/binary/proto"
	"go.mau.fi/whatsmeow/store/sqlstore"
	"go.mau.fi/whatsmeow/types"
	"go.mau.fi/whatsmeow/types/events"
	waLog "go.mau.fi/whatsmeow/util/log"
	"google.golang.org/protobuf/proto"
)

// Message represents a chat message for our client
type Message struct {
	Time     time.Time
	Sender   string
	Content  string
	IsFromMe bool
}

// Database handler for storing message history
type MessageStore struct {
	db *sql.DB
}

// Initialize message store
func NewMessageStore() (*MessageStore, error) {
	// Create directory for database if it doesn't exist
	if err := os.MkdirAll("store", 0755); err != nil {
		return nil, fmt.Errorf("failed to create store directory: %v", err)
	}

	// Open SQLite database for messages
	db, err := sql.Open("sqlite3", "file:store/messages.db?_foreign_keys=on")
	if err != nil {
		return nil, fmt.Errorf("failed to open message database: %v", err)
	}

	// Create tables if they don't exist
	_, err = db.Exec(`
		CREATE TABLE IF NOT EXISTS chats (
			jid TEXT PRIMARY KEY,
			name TEXT,
			last_message_time TIMESTAMP
		);
		
		CREATE TABLE IF NOT EXISTS messages (
			id TEXT,
			chat_jid TEXT,
			sender TEXT,
			content TEXT,
			timestamp TIMESTAMP,
			is_from_me BOOLEAN,
			PRIMARY KEY (id, chat_jid),
			FOREIGN KEY (chat_jid) REFERENCES chats(jid)
		);
	`)
	if err != nil {
		db.Close()
		return nil, fmt.Errorf("failed to create tables: %v", err)
	}

	return &MessageStore{db: db}, nil
}

// Close the database connection
func (store *MessageStore) Close() error {
	return store.db.Close()
}

// Store a chat in the database
func (store *MessageStore) StoreChat(jid, name string, lastMessageTime time.Time) error {
	_, err := store.db.Exec(
		"INSERT OR REPLACE INTO chats (jid, name, last_message_time) VALUES (?, ?, ?)",
		jid, name, lastMessageTime,
	)
	return err
}

// Store a message in the database
func (store *MessageStore) StoreMessage(id, chatJID, sender, content string, timestamp time.Time, isFromMe bool) error {
	// Only store if there's actual content
	if content == "" {
		return nil
	}

	_, err := store.db.Exec(
		"INSERT OR REPLACE INTO messages (id, chat_jid, sender, content, timestamp, is_from_me) VALUES (?, ?, ?, ?, ?, ?)",
		id, chatJID, sender, content, timestamp, isFromMe,
	)
	return err
}

// Get messages from a chat
func (store *MessageStore) GetMessages(chatJID string, limit int) ([]Message, error) {
	rows, err := store.db.Query(
		"SELECT sender, content, timestamp, is_from_me FROM messages WHERE chat_jid = ? ORDER BY timestamp DESC LIMIT ?",
		chatJID, limit,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var messages []Message
	for rows.Next() {
		var msg Message
		var timestamp time.Time
		err := rows.Scan(&msg.Sender, &msg.Content, &timestamp, &msg.IsFromMe)
		if err != nil {
			return nil, err
		}
		msg.Time = timestamp
		messages = append(messages, msg)
	}

	return messages, nil
}

// Get all chats
func (store *MessageStore) GetChats() (map[string]time.Time, error) {
	rows, err := store.db.Query("SELECT jid, last_message_time FROM chats ORDER BY last_message_time DESC")
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	chats := make(map[string]time.Time)
	for rows.Next() {
		var jid string
		var lastMessageTime time.Time
		err := rows.Scan(&jid, &lastMessageTime)
		if err != nil {
			return nil, err
		}
		chats[jid] = lastMessageTime
	}

	return chats, nil
}

// Extract text content from a message
func extractTextContent(msg *waProto.Message) string {
	if msg == nil {
		return ""
	}

	// Try to get text content
	if text := msg.GetConversation(); text != "" {
		return text
	} else if extendedText := msg.GetExtendedTextMessage(); extendedText != nil {
		return extendedText.GetText()
	}

	// For now, we're ignoring non-text messages
	return ""
}

// SendMessageResponse represents the response for the send message API
type SendMessageResponse struct {
	Success bool   `json:"success"`
	Message string `json:"message"`
}

// SendMessageRequest represents the request body for the send message API
type SendMessageRequest struct {
	Recipient string `json:"recipient"`
	Message   string `json:"message"`
	MediaPath string `json:"media_path,omitempty"`
}

// Function to send a WhatsApp message
func sendWhatsAppMessage(client *whatsmeow.Client, recipient string, message string, mediaPath string) (bool, string) {
	if !client.IsConnected() {
		return false, "Not connected to WhatsApp"
	}

	// Create JID for recipient
	var recipientJID types.JID
	var err error

	// Check if recipient is a JID
	isJID := strings.Contains(recipient, "@")

	if isJID {
		// Parse the JID string
		recipientJID, err = types.ParseJID(recipient)
		if err != nil {
			return false, fmt.Sprintf("Error parsing JID: %v", err)
		}
	} else {
		// Create JID from phone number
		recipientJID = types.JID{
			User:   recipient,
			Server: "s.whatsapp.net", // For personal chats
		}
	}

	msg := &waProto.Message{}

	// Check if we have media to send
	if mediaPath != "" {
		// Read media file
		mediaData, err := os.ReadFile(mediaPath)
		if err != nil {
			return false, fmt.Sprintf("Error reading media file: %v", err)
		}

		// Determine media type and mime type based on file extension
		fileExt := strings.ToLower(mediaPath[strings.LastIndex(mediaPath, ".")+1:])
		var mediaType whatsmeow.MediaType
		var mimeType string

		// Handle different media types
		switch fileExt {
		// Image types
		case "jpg", "jpeg":
			mediaType = whatsmeow.MediaImage
			mimeType = "image/jpeg"
		case "png":
			mediaType = whatsmeow.MediaImage
			mimeType = "image/png"
		case "gif":
			mediaType = whatsmeow.MediaImage
			mimeType = "image/gif"
		case "webp":
			mediaType = whatsmeow.MediaImage
			mimeType = "image/webp"

		// Audio types
		case "ogg":
			mediaType = whatsmeow.MediaAudio
			mimeType = "audio/ogg; codecs=opus"

		// Video types
		case "mp4":
			mediaType = whatsmeow.MediaVideo
			mimeType = "video/mp4"
		case "avi":
			mediaType = whatsmeow.MediaVideo
			mimeType = "video/avi"
		case "mov":
			mediaType = whatsmeow.MediaVideo
			mimeType = "video/quicktime"

		// Document types (for any other file type)
		default:
			mediaType = whatsmeow.MediaDocument
			mimeType = "application/octet-stream"
		}

		// Upload media to WhatsApp servers
		resp, err := client.Upload(context.Background(), mediaData, mediaType)
		if err != nil {
			return false, fmt.Sprintf("Error uploading media: %v", err)
		}

		fmt.Println("Media uploaded", resp)

		// Create the appropriate message type based on media type
		switch mediaType {
		case whatsmeow.MediaImage:
			msg.ImageMessage = &waProto.ImageMessage{
				Caption:       proto.String(message),
				Mimetype:      proto.String(mimeType),
				URL:           &resp.URL,
				DirectPath:    &resp.DirectPath,
				MediaKey:      resp.MediaKey,
				FileEncSHA256: resp.FileEncSHA256,
				FileSHA256:    resp.FileSHA256,
				FileLength:    &resp.FileLength,
			}
		case whatsmeow.MediaAudio:
			// Handle ogg audio files
			var seconds uint32 = 30 // Default fallback
			var waveform []byte = nil

			// Try to analyze the ogg file
			if strings.Contains(mimeType, "ogg") {
				analyzedSeconds, analyzedWaveform, err := analyzeOggOpus(mediaData)
				if err == nil {
					seconds = analyzedSeconds
					waveform = analyzedWaveform
				} else {
					return false, fmt.Sprintf("Failed to analyze Ogg Opus file: %v", err)
				}
			} else {
				fmt.Printf("Not an Ogg Opus file: %s\n", mimeType)
			}

			msg.AudioMessage = &waProto.AudioMessage{
				Mimetype:      proto.String(mimeType),
				URL:           &resp.URL,
				DirectPath:    &resp.DirectPath,
				MediaKey:      resp.MediaKey,
				FileEncSHA256: resp.FileEncSHA256,
				FileSHA256:    resp.FileSHA256,
				FileLength:    &resp.FileLength,
				Seconds:       proto.Uint32(seconds),
				PTT:           proto.Bool(true),
				Waveform:      waveform,
			}
		case whatsmeow.MediaVideo:
			msg.VideoMessage = &waProto.VideoMessage{
				Caption:       proto.String(message),
				Mimetype:      proto.String(mimeType),
				URL:           &resp.URL,
				DirectPath:    &resp.DirectPath,
				MediaKey:      resp.MediaKey,
				FileEncSHA256: resp.FileEncSHA256,
				FileSHA256:    resp.FileSHA256,
				FileLength:    &resp.FileLength,
			}
		case whatsmeow.MediaDocument:
			msg.DocumentMessage = &waProto.DocumentMessage{
				Title:         proto.String(mediaPath[strings.LastIndex(mediaPath, "/")+1:]),
				Caption:       proto.String(message),
				Mimetype:      proto.String(mimeType),
				URL:           &resp.URL,
				DirectPath:    &resp.DirectPath,
				MediaKey:      resp.MediaKey,
				FileEncSHA256: resp.FileEncSHA256,
				FileSHA256:    resp.FileSHA256,
				FileLength:    &resp.FileLength,
			}
		}
	} else {
		msg.Conversation = proto.String(message)
	}

	// Send message
	_, err = client.SendMessage(context.Background(), recipientJID, msg)

	if err != nil {
		return false, fmt.Sprintf("Error sending message: %v", err)
	}

	return true, fmt.Sprintf("Message sent to %s", recipient)
}

// Start a REST API server to expose the WhatsApp client functionality
func startRESTServer(client *whatsmeow.Client, port int) {
	// Handler for sending messages
	http.HandleFunc("/api/send", func(w http.ResponseWriter, r *http.Request) {
		// Only allow POST requests
		if r.Method != http.MethodPost {
			http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
			return
		}

		// Parse the request body
		var req SendMessageRequest
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
			http.Error(w, "Invalid request format", http.StatusBadRequest)
			return
		}

		// Validate request
		if req.Recipient == "" {
			http.Error(w, "Recipient is required", http.StatusBadRequest)
			return
		}

		if req.Message == "" && req.MediaPath == "" {
			http.Error(w, "Message or media path is required", http.StatusBadRequest)
			return
		}

		fmt.Println("Received request to send message", req.Message, req.MediaPath)

		// Send the message
		success, message := sendWhatsAppMessage(client, req.Recipient, req.Message, req.MediaPath)
		fmt.Println("Message sent", success, message)
		// Set response headers
		w.Header().Set("Content-Type", "application/json")

		// Set appropriate status code
		if !success {
			w.WriteHeader(http.StatusInternalServerError)
		}

		// Send response
		json.NewEncoder(w).Encode(SendMessageResponse{
			Success: success,
			Message: message,
		})
	})

	// Start the server
	serverAddr := fmt.Sprintf(":%d", port)
	fmt.Printf("Starting REST API server on %s...\n", serverAddr)

	// Run server in a goroutine so it doesn't block
	go func() {
		if err := http.ListenAndServe(serverAddr, nil); err != nil {
			fmt.Printf("REST API server error: %v\n", err)
		}
	}()
}

func main() {
	// Set up logger
	logger := waLog.Stdout("Client", "INFO", true)
	logger.Infof("Starting WhatsApp client...")

	// Create database connection for storing session data
	dbLog := waLog.Stdout("Database", "INFO", true)

	// Create directory for database if it doesn't exist
	if err := os.MkdirAll("store", 0755); err != nil {
		logger.Errorf("Failed to create store directory: %v", err)
		return
	}

	container, err := sqlstore.New("sqlite3", "file:store/whatsapp.db?_foreign_keys=on", dbLog)
	if err != nil {
		logger.Errorf("Failed to connect to database: %v", err)
		return
	}

	// Get device store - This contains session information
	deviceStore, err := container.GetFirstDevice()
	if err != nil {
		if err == sql.ErrNoRows {
			// No device exists, create one
			deviceStore = container.NewDevice()
			logger.Infof("Created new device")
		} else {
			logger.Errorf("Failed to get device: %v", err)
			return
		}
	}

	// Create client instance
	client := whatsmeow.NewClient(deviceStore, logger)
	if client == nil {
		logger.Errorf("Failed to create WhatsApp client")
		return
	}

	// Initialize message store
	messageStore, err := NewMessageStore()
	if err != nil {
		logger.Errorf("Failed to initialize message store: %v", err)
		return
	}
	defer messageStore.Close()

	// Setup event handling for messages and history sync
	client.AddEventHandler(func(evt interface{}) {
		switch v := evt.(type) {
		case *events.Message:
			// Process regular messages
			handleMessage(client, messageStore, v, logger)

		case *events.HistorySync:
			// Process history sync events
			handleHistorySync(client, messageStore, v, logger)

		case *events.Connected:
			logger.Infof("Connected to WhatsApp")

		case *events.LoggedOut:
			logger.Warnf("Device logged out, please scan QR code to log in again")
		}
	})

	// Create channel to track connection success
	connected := make(chan bool, 1)

	// Connect to WhatsApp
	if client.Store.ID == nil {
		// No ID stored, this is a new client, need to pair with phone
		qrChan, _ := client.GetQRChannel(context.Background())
		err = client.Connect()
		if err != nil {
			logger.Errorf("Failed to connect: %v", err)
			return
		}

		// Print QR code for pairing with phone
		for evt := range qrChan {
			if evt.Event == "code" {
				fmt.Println("\nScan this QR code with your WhatsApp app:")
				qrterminal.GenerateHalfBlock(evt.Code, qrterminal.L, os.Stdout)
			} else if evt.Event == "success" {
				connected <- true
				break
			}
		}

		// Wait for connection
		select {
		case <-connected:
			fmt.Println("\nSuccessfully connected and authenticated!")
		case <-time.After(3 * time.Minute):
			logger.Errorf("Timeout waiting for QR code scan")
			return
		}
	} else {
		// Already logged in, just connect
		err = client.Connect()
		if err != nil {
			logger.Errorf("Failed to connect: %v", err)
			return
		}
		connected <- true
	}

	// Wait a moment for connection to stabilize
	time.Sleep(2 * time.Second)

	if !client.IsConnected() {
		logger.Errorf("Failed to establish stable connection")
		return
	}

	fmt.Println("\n✓ Connected to WhatsApp! Type 'help' for commands.")

	// Start REST API server
	startRESTServer(client, 8080)

	// Create a channel to keep the main goroutine alive
	exitChan := make(chan os.Signal, 1)
	signal.Notify(exitChan, syscall.SIGINT, syscall.SIGTERM)

	fmt.Println("REST server is running. Press Ctrl+C to disconnect and exit.")

	// Wait for termination signal
	<-exitChan

	fmt.Println("Disconnecting...")
	// Disconnect client
	client.Disconnect()
}

// GetChatName determines the appropriate name for a chat based on JID and other info
func GetChatName(client *whatsmeow.Client, messageStore *MessageStore, jid types.JID, chatJID string, conversation interface{}, sender string, logger waLog.Logger) string {
	// First, check if chat already exists in database with a name
	var existingName string
	err := messageStore.db.QueryRow("SELECT name FROM chats WHERE jid = ?", chatJID).Scan(&existingName)
	if err == nil && existingName != "" {
		// Chat exists with a name, use that
		logger.Infof("Using existing chat name for %s: %s", chatJID, existingName)
		return existingName
	}

	// Need to determine chat name
	var name string

	if jid.Server == "g.us" {
		// This is a group chat
		logger.Infof("Getting name for group: %s", chatJID)

		// Use conversation data if provided (from history sync)
		if conversation != nil {
			// Extract name from conversation if available
			// This uses type assertions to handle different possible types
			var displayName, convName *string
			// Try to extract the fields we care about regardless of the exact type
			v := reflect.ValueOf(conversation)
			if v.Kind() == reflect.Ptr && !v.IsNil() {
				v = v.Elem()

				// Try to find DisplayName field
				if displayNameField := v.FieldByName("DisplayName"); displayNameField.IsValid() && displayNameField.Kind() == reflect.Ptr && !displayNameField.IsNil() {
					dn := displayNameField.Elem().String()
					displayName = &dn
				}

				// Try to find Name field
				if nameField := v.FieldByName("Name"); nameField.IsValid() && nameField.Kind() == reflect.Ptr && !nameField.IsNil() {
					n := nameField.Elem().String()
					convName = &n
				}
			}

			// Use the name we found
			if displayName != nil && *displayName != "" {
				name = *displayName
			} else if convName != nil && *convName != "" {
				name = *convName
			}
		}

		// If we didn't get a name, try group info
		if name == "" {
			groupInfo, err := client.GetGroupInfo(jid)
			if err == nil && groupInfo.Name != "" {
				name = groupInfo.Name
			} else {
				// Fallback name for groups
				name = fmt.Sprintf("Group %s", jid.User)
			}
		}

		logger.Infof("Using group name: %s", name)
	} else {
		// This is an individual contact
		logger.Infof("Getting name for contact: %s", chatJID)

		// Just use contact info (full name)
		contact, err := client.Store.Contacts.GetContact(jid)
		if err == nil && contact.FullName != "" {
			name = contact.FullName
		} else if sender != "" {
			// Fallback to sender
			name = sender
		} else {
			// Last fallback to JID
			name = jid.User
		}

		logger.Infof("Using contact name: %s", name)
	}

	return name
}

// Handle regular incoming messages
func handleMessage(client *whatsmeow.Client, messageStore *MessageStore, msg *events.Message, logger waLog.Logger) {
	// Extract text content
	content := extractTextContent(msg.Message)
	if content == "" {
		return // Skip non-text messages
	}

	// Save message to database
	chatJID := msg.Info.Chat.String()
	sender := msg.Info.Sender.User

	// Get appropriate chat name (pass nil for conversation since we don't have one for regular messages)
	name := GetChatName(client, messageStore, msg.Info.Chat, chatJID, nil, sender, logger)

	// Update chat in database with the message timestamp (keeps last message time updated)
	err := messageStore.StoreChat(chatJID, name, msg.Info.Timestamp)
	if err != nil {
		logger.Warnf("Failed to store chat: %v", err)
	}

	// Store message in database
	err = messageStore.StoreMessage(
		msg.Info.ID,
		chatJID,
		sender,
		content,
		msg.Info.Timestamp,
		msg.Info.IsFromMe,
	)
	if err != nil {
		logger.Warnf("Failed to store message: %v", err)
	} else {
		// Log message reception
		timestamp := msg.Info.Timestamp.Format("2006-01-02 15:04:05")
		direction := "←"
		if msg.Info.IsFromMe {
			direction = "→"
		}
		fmt.Printf("[%s] %s %s: %s\n", timestamp, direction, sender, content)
	}
}

// Handle history sync events
func handleHistorySync(client *whatsmeow.Client, messageStore *MessageStore, historySync *events.HistorySync, logger waLog.Logger) {
	fmt.Printf("Received history sync event with %d conversations\n", len(historySync.Data.Conversations))

	syncedCount := 0
	for _, conversation := range historySync.Data.Conversations {
		// Parse JID from the conversation
		if conversation.ID == nil {
			continue
		}

		chatJID := *conversation.ID

		// Try to parse the JID
		jid, err := types.ParseJID(chatJID)
		if err != nil {
			logger.Warnf("Failed to parse JID %s: %v", chatJID, err)
			continue
		}

		// Get appropriate chat name by passing the history sync conversation directly
		name := GetChatName(client, messageStore, jid, chatJID, conversation, "", logger)

		// Process messages
		messages := conversation.Messages
		if len(messages) > 0 {
			// Update chat with latest message timestamp
			latestMsg := messages[0]
			if latestMsg == nil || latestMsg.Message == nil {
				continue
			}

			// Get timestamp from message info
			timestamp := time.Time{}
			if ts := latestMsg.Message.GetMessageTimestamp(); ts != 0 {
				timestamp = time.Unix(int64(ts), 0)
			} else {
				continue
			}

			messageStore.StoreChat(chatJID, name, timestamp)

			// Store messages
			for _, msg := range messages {
				if msg == nil || msg.Message == nil {
					continue
				}

				// Extract text content
				var content string
				if msg.Message.Message != nil {
					if conv := msg.Message.Message.GetConversation(); conv != "" {
						content = conv
					} else if ext := msg.Message.Message.GetExtendedTextMessage(); ext != nil {
						content = ext.GetText()
					}
				}

				// Log the message content for debugging
				logger.Infof("Message content: %v", content)

				// Skip non-text messages
				if content == "" {
					continue
				}

				// Determine sender
				var sender string
				isFromMe := false
				if msg.Message.Key != nil {
					if msg.Message.Key.FromMe != nil {
						isFromMe = *msg.Message.Key.FromMe
					}
					if !isFromMe && msg.Message.Key.Participant != nil && *msg.Message.Key.Participant != "" {
						sender = *msg.Message.Key.Participant
					} else if isFromMe {
						sender = client.Store.ID.User
					} else {
						sender = jid.User
					}
				} else {
					sender = jid.User
				}

				// Store message
				msgID := ""
				if msg.Message.Key != nil && msg.Message.Key.ID != nil {
					msgID = *msg.Message.Key.ID
				}

				// Get message timestamp
				timestamp := time.Time{}
				if ts := msg.Message.GetMessageTimestamp(); ts != 0 {
					timestamp = time.Unix(int64(ts), 0)
				} else {
					continue
				}

				err = messageStore.StoreMessage(
					msgID,
					chatJID,
					sender,
					content,
					timestamp,
					isFromMe,
				)
				if err != nil {
					logger.Warnf("Failed to store history message: %v", err)
				} else {
					syncedCount++
					// Log successful message storage
					logger.Infof("Stored message: [%s] %s -> %s: %s", timestamp.Format("2006-01-02 15:04:05"), sender, chatJID, content)
				}
			}
		}
	}

	fmt.Printf("History sync complete. Stored %d text messages.\n", syncedCount)
}

// Request history sync from the server
func requestHistorySync(client *whatsmeow.Client) {
	if client == nil {
		fmt.Println("Client is not initialized. Cannot request history sync.")
		return
	}

	if !client.IsConnected() {
		fmt.Println("Client is not connected. Please ensure you are connected to WhatsApp first.")
		return
	}

	if client.Store.ID == nil {
		fmt.Println("Client is not logged in. Please scan the QR code first.")
		return
	}

	// Build and send a history sync request
	historyMsg := client.BuildHistorySyncRequest(nil, 100)
	if historyMsg == nil {
		fmt.Println("Failed to build history sync request.")
		return
	}

	_, err := client.SendMessage(context.Background(), types.JID{
		Server: "s.whatsapp.net",
		User:   "status",
	}, historyMsg)

	if err != nil {
		fmt.Printf("Failed to request history sync: %v\n", err)
	} else {
		fmt.Println("History sync requested. Waiting for server response...")
	}
}

// analyzeOggOpus tries to extract duration and generate a simple waveform from an Ogg Opus file
func analyzeOggOpus(data []byte) (duration uint32, waveform []byte, err error) {
	// Try to detect if this is a valid Ogg file by checking for the "OggS" signature
	// at the beginning of the file
	if len(data) < 4 || string(data[0:4]) != "OggS" {
		return 0, nil, fmt.Errorf("not a valid Ogg file (missing OggS signature)")
	}

	// Parse Ogg pages to find the last page with a valid granule position
	var lastGranule uint64
	var sampleRate uint32 = 48000 // Default Opus sample rate
	var preSkip uint16 = 0
	var foundOpusHead bool

	// Scan through the file looking for Ogg pages
	for i := 0; i < len(data); {
		// Check if we have enough data to read Ogg page header
		if i+27 >= len(data) {
			break
		}

		// Verify Ogg page signature
		if string(data[i:i+4]) != "OggS" {
			// Skip until next potential page
			i++
			continue
		}

		// Extract header fields
		granulePos := binary.LittleEndian.Uint64(data[i+6 : i+14])
		pageSeqNum := binary.LittleEndian.Uint32(data[i+18 : i+22])
		numSegments := int(data[i+26])

		// Extract segment table
		if i+27+numSegments >= len(data) {
			break
		}
		segmentTable := data[i+27 : i+27+numSegments]

		// Calculate page size
		pageSize := 27 + numSegments
		for _, segLen := range segmentTable {
			pageSize += int(segLen)
		}

		// Check if we're looking at an OpusHead packet (should be in first few pages)
		if !foundOpusHead && pageSeqNum <= 1 {
			// Look for "OpusHead" marker in this page
			pageData := data[i : i+pageSize]
			headPos := bytes.Index(pageData, []byte("OpusHead"))
			if headPos >= 0 && headPos+12 < len(pageData) {
				// Found OpusHead, extract sample rate and pre-skip
				// OpusHead format: Magic(8) + Version(1) + Channels(1) + PreSkip(2) + SampleRate(4) + ...
				headPos += 8 // Skip "OpusHead" marker
				// PreSkip is 2 bytes at offset 10
				if headPos+12 <= len(pageData) {
					preSkip = binary.LittleEndian.Uint16(pageData[headPos+10 : headPos+12])
					sampleRate = binary.LittleEndian.Uint32(pageData[headPos+12 : headPos+16])
					foundOpusHead = true
					fmt.Printf("Found OpusHead: sampleRate=%d, preSkip=%d\n", sampleRate, preSkip)
				}
			}
		}

		// Keep track of last valid granule position
		if granulePos != 0 {
			lastGranule = granulePos
		}

		// Move to next page
		i += pageSize
	}

	if !foundOpusHead {
		fmt.Println("Warning: OpusHead not found, using default values")
	}

	// Calculate duration based on granule position
	if lastGranule > 0 {
		// Formula for duration: (lastGranule - preSkip) / sampleRate
		durationSeconds := float64(lastGranule-uint64(preSkip)) / float64(sampleRate)
		duration = uint32(math.Ceil(durationSeconds))
		fmt.Printf("Calculated Opus duration from granule: %f seconds (lastGranule=%d)\n",
			durationSeconds, lastGranule)
	} else {
		// Fallback to rough estimation if granule position not found
		fmt.Println("Warning: No valid granule position found, using estimation")
		durationEstimate := float64(len(data)) / 2000.0 // Very rough approximation
		duration = uint32(durationEstimate)
	}

	// Make sure we have a reasonable duration (at least 1 second, at most 300 seconds)
	if duration < 1 {
		duration = 1
	} else if duration > 300 {
		duration = 300
	}

	// Generate waveform
	waveform = placeholderWaveform(duration)

	fmt.Printf("Ogg Opus analysis: size=%d bytes, calculated duration=%d sec, waveform=%d bytes\n",
		len(data), duration, len(waveform))

	return duration, waveform, nil
}

// min returns the smaller of x or y
func min(x, y int) int {
	if x < y {
		return x
	}
	return y
}

// placeholderWaveform generates a synthetic waveform for WhatsApp voice messages
// that appears natural with some variability based on the duration
func placeholderWaveform(duration uint32) []byte {
	// WhatsApp expects a 64-byte waveform for voice messages
	const waveformLength = 64
	waveform := make([]byte, waveformLength)

	// Seed the random number generator for consistent results with the same duration
	rand.Seed(int64(duration))

	// Create a more natural looking waveform with some patterns and variability
	// rather than completely random values

	// Base amplitude and frequency - longer messages get faster frequency
	baseAmplitude := 35.0
	frequencyFactor := float64(min(int(duration), 120)) / 30.0

	for i := range waveform {
		// Position in the waveform (normalized 0-1)
		pos := float64(i) / float64(waveformLength)

		// Create a wave pattern with some randomness
		// Use multiple sine waves of different frequencies for more natural look
		val := baseAmplitude * math.Sin(pos*math.Pi*frequencyFactor*8)
		val += (baseAmplitude / 2) * math.Sin(pos*math.Pi*frequencyFactor*16)

		// Add some randomness to make it look more natural
		val += (rand.Float64() - 0.5) * 15

		// Add some fade-in and fade-out effects
		fadeInOut := math.Sin(pos * math.Pi)
		val = val * (0.7 + 0.3*fadeInOut)

		// Center around 50 (typical voice baseline)
		val = val + 50

		// Ensure values stay within WhatsApp's expected range (0-100)
		if val < 0 {
			val = 0
		} else if val > 100 {
			val = 100
		}

		waveform[i] = byte(val)
	}

	return waveform
}