Initial commit

internal/utils.go

@@ -0,0 +1,45 @@
+package internal
+
+import "strings"
+
+// normalizePhoneNumber removes all non-numeric characters except leading +
+// and standardizes US phone numbers to include the +1 country code
+// This prevents duplicate conversations due to different phone number formatting
+func normalizePhoneNumber(phoneNumber string) string {
+	if phoneNumber == "" {
+		return ""
+	}
+
+	// Check if it starts with +
+	hasPlus := strings.HasPrefix(phoneNumber, "+")
+
+	// Remove all non-numeric characters
+	var result strings.Builder
+	for _, ch := range phoneNumber {
+		if ch >= '0' && ch <= '9' {
+			result.WriteRune(ch)
+		}
+	}
+
+	normalized := result.String()
+	if normalized == "" {
+		return ""
+	}
+
+	// Standardize US phone numbers
+	if !hasPlus {
+		// 10 digits without country code - add +1 (US number)
+		if len(normalized) == 10 {
+			return "+1" + normalized
+		}
+		// 11 digits starting with 1 - add + (US number with 1 prefix)
+		if len(normalized) == 11 && normalized[0] == '1' {
+			return "+" + normalized
+		}
+		// Other lengths without + - keep as is (might be partial/invalid)
+		return normalized
+	}
+
+	// Already has +, keep it
+	return "+" + normalized
+}