// ============================================================
// MODEL VISION SUPPORT
// ============================================================
// Can this model be shown a picture?
//
// Three answers, not two: true, false, and "the gateway does not say". Only an
// explicit false is actionable. Most of a roster carries no supports_vision at
// all, and treating silence as blindness would route perfectly good models
// through a delegation they do not need.
//
// Asked of the gateway, never inferred from the model id: "gemini-3.8-flash"
// says nothing about whether this deployment's copy of it accepts images, and a
// name-matching rule is the kind of thing that quietly rots.
//
// Cached briefly. This is asked on requests that carry an attachment, and a
// /model/info round trip per request would add latency to exactly the requests
// that are already the slowest.
var CACHE_MS = 5 * 60 * 1000;
var cache = { at: 0, byId: null };

async function roster() {
  if (cache.byId && Date.now() - cache.at < CACHE_MS) return cache.byId;
  var axios = require('axios');
  var { getLiteLLMAdminHeaders, liteLLMBaseUrl } = require('./litellm');
  var response = await axios.get(liteLLMBaseUrl() + '/model/info',
    { headers: getLiteLLMAdminHeaders(), timeout: 10000 });
  var byId = Object.create(null);
  ((response.data && response.data.data) || []).forEach(function (model) {
    var id = model && model.model_name;
    if (!id) return;
    var info = model.model_info || {};
    byId[id] = typeof info.supports_vision === 'boolean' ? info.supports_vision : null;
  });
  cache = { at: Date.now(), byId: byId };
  return byId;
}

/** true, false, or null when the gateway does not say (or cannot be reached). */
async function supportsVision(modelId) {
  if (!modelId || !process.env.LITELLM_API_BASE) return null;
  try {
    var byId = await roster();
    return Object.prototype.hasOwnProperty.call(byId, modelId) ? byId[modelId] : null;
  } catch (e) {
    // The gateway being unreachable is not evidence about the model.
    return null;
  }
}

function forget() { cache = { at: 0, byId: null }; }

module.exports = { supportsVision, forget, CACHE_MS };