feat: Add call duration to call detail view

internal/sip/callflow.go

@@ -52,11 +52,18 @@ func (s *CallFlowStore) AddPacket(p *Packet) *CallFlow {
 	}
 
 	flow, exists := s.flows[p.CallID]
+
+	// Determine timestamp to use
+	ts := p.Timestamp
+	if ts.IsZero() {
+		ts = time.Now()
+	}
+
 	if !exists {
 		flow = &CallFlow{
 			CallID:    p.CallID,
 			Packets:   make([]*Packet, 0),
-			StartTime: time.Now(),
+			StartTime: ts,
 			From:      p.From,
 			To:        p.To,
 			State:     CallStateInitial,
@@ -65,7 +72,10 @@ func (s *CallFlowStore) AddPacket(p *Packet) *CallFlow {
 	}
 
 	flow.Packets = append(flow.Packets, p)
-	flow.EndTime = time.Now()
+	// Always update EndTime to the latest packet's timestamp
+	if ts.After(flow.EndTime) {
+		flow.EndTime = ts
+	}
 
 	// Update call state based on packet
 	s.updateState(flow, p)

internal/tui/model.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
+	"time"
 
 	"telephony-inspector/internal/capture"
 	"telephony-inspector/internal/config"
@@ -713,6 +714,11 @@ func (m Model) renderCallDetail() string {
 	b.WriteString(fmt.Sprintf("From: %s\n", flow.From))
 	b.WriteString(fmt.Sprintf("To: %s\n", flow.To))
 	b.WriteString(fmt.Sprintf("State: %s\n", flow.State))
+
+	// Calculate and display duration
+	duration := flow.EndTime.Sub(flow.StartTime)
+	b.WriteString(fmt.Sprintf("Duration: %s\n", duration.Round(time.Millisecond)))
+
 	b.WriteString(fmt.Sprintf("Packets: %d\n\n", len(flow.Packets)))
 
 	// Network Summary Section