feat: restore voice-call plugin parity

extensions/voice-call/src/voice-mapping.ts

@@ -0,0 +1,65 @@
+/**
+ * Voice mapping and XML utilities for voice call providers.
+ */
+
+/**
+ * Escape XML special characters for TwiML and other XML responses.
+ */
+export function escapeXml(text: string): string {
+  return text
+    .replace(/&/g, "&")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;")
+    .replace(/"/g, "&quot;")
+    .replace(/'/g, "&apos;");
+}
+
+/**
+ * Map of OpenAI voice names to similar Twilio Polly voices.
+ */
+const OPENAI_TO_POLLY_MAP: Record<string, string> = {
+  alloy: "Polly.Joanna", // neutral, warm
+  echo: "Polly.Matthew", // male, warm
+  fable: "Polly.Amy", // British, expressive
+  onyx: "Polly.Brian", // deep male
+  nova: "Polly.Salli", // female, friendly
+  shimmer: "Polly.Kimberly", // female, clear
+};
+
+/**
+ * Default Polly voice when no mapping is found.
+ */
+export const DEFAULT_POLLY_VOICE = "Polly.Joanna";
+
+/**
+ * Map OpenAI voice names to Twilio Polly equivalents.
+ * Falls through if already a valid Polly/Google voice.
+ *
+ * @param voice - OpenAI voice name (alloy, echo, etc.) or Polly voice name
+ * @returns Polly voice name suitable for Twilio TwiML
+ */
+export function mapVoiceToPolly(voice: string | undefined): string {
+  if (!voice) return DEFAULT_POLLY_VOICE;
+
+  // Already a Polly/Google voice - pass through
+  if (voice.startsWith("Polly.") || voice.startsWith("Google.")) {
+    return voice;
+  }
+
+  // Map OpenAI voices to Polly equivalents
+  return OPENAI_TO_POLLY_MAP[voice.toLowerCase()] || DEFAULT_POLLY_VOICE;
+}
+
+/**
+ * Check if a voice name is a known OpenAI voice.
+ */
+export function isOpenAiVoice(voice: string): boolean {
+  return voice.toLowerCase() in OPENAI_TO_POLLY_MAP;
+}
+
+/**
+ * Get all supported OpenAI voice names.
+ */
+export function getOpenAiVoiceNames(): string[] {
+  return Object.keys(OPENAI_TO_POLLY_MAP);
+}