// dt-realtime: mint ephemeral OpenAI Realtime session tokens
add_action('rest_api_init', function () {
  register_rest_route('dt/v1', '/realtime-session', [
    'methods'  => 'POST',
    'callback' => function (\WP_REST_Request $req) {
      $model = 'gpt-realtime-mini'; // or 'gpt-realtime' for higher quality
      $voice = 'alloy';             // built-in voice id (e.g., alloy, verse, breeze)
      $instructions = <<<TXT
You are Buck, Lead Hand at Triple 7 Ranch, northwest Dakota Territory, 1871.
Speak first-person, present tense, plain, practical, modest, friendly.
Keep replies to 1–3 sentences. Answer the question directly first. Avoid post-1889 topics.
Use cowboy lingo lightly (beeves, remuda, dally, chuckwagon, riata) and end ~1 in 3 replies with a light chuckle (do not say the word 'grin').
TXT;

      $body = [
        'model'        => $model,
        'voice'        => $voice,
        'modalities'   => ['audio', 'text'],
        'instructions' => $instructions,
        // Optional: steer turn-taking and latency
        'input_audio_format'  => 'pcm16',
        'output_audio_format' => 'pcm16',
        'turn_detection'      => ['type' => 'server_vad', 'threshold' => 0.5, 'prefix_padding_ms' => 150, 'silence_duration_ms' => 550],
      ];

      $ch = curl_init('https://api.openai.com/v1/realtime/sessions');
      curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_HTTPHEADER => [
          'Authorization: Bearer ' . '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',
          'Content-Type: application/json'
        ],
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => json_encode($body),
        CURLOPT_TIMEOUT => 10
      ]);
      $resp = curl_exec($ch);
      $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
      $err  = curl_error($ch);
      curl_close($ch);

      if ($err || $code < 200 || $code >= 300) {
        return new \WP_REST_Response(['error' => 'OpenAI session create failed', 'detail' => $resp ?: $err], 500);
      }

      $json = json_decode($resp, true);
      // This field name comes from OpenAI: client_secret.value (the ephemeral token)
      $token = $json['client_secret']['value'] ?? null;
      if (!$token) {
        return new \WP_REST_Response(['error' => 'No client token in response', 'detail' => $json], 500);
      }

      // Pass through model for client convenience
      return new \WP_REST_Response(['token' => $token, 'model' => $body['model']], 200);
    },
    'permission_callback' => '__return_true', // If needed, add nonce/cap check
  ]);
});