import { getVip98kInvocationHeaders } from "./vip98k-task-invocation";

type RecordValue = Record<string, unknown>;
export type Vip98kChatInvocation = {
  protocol: "openai-chat" | "openai-responses";
  path: "/v1/chat/completions" | "/v1/responses";
  headers: Record<string, string>;
};

function record(value: unknown): RecordValue | null {
  return value && typeof value === "object" && !Array.isArray(value)
    ? (value as RecordValue)
    : null;
}

function array(value: unknown): unknown[] {
  return Array.isArray(value) ? value : [];
}

/** Select an advertised protocol and its own route together, never by model name. */
export function selectVip98kChatInvocation(value: unknown): Vip98kChatInvocation | null {
  const model = record(value) || {};
  const primary = record(model.invocation);
  const defaultRoute = String(model.default_route_option_id ||
    getVip98kInvocationHeaders(primary?.headers)["X-Relay-Route-Option"] || "");
  const offers = array(model.serviceOffers || model.service_offers).flatMap((value) => {
    const offer = record(value);
    return array(offer?.route_options).map((value) => {
      const route = record(value);
      const invocation = record(route?.invocation);
      return { ...invocation, headers: {
        ...getVip98kInvocationHeaders(invocation?.headers),
        ...getVip98kInvocationHeaders({ "X-Relay-Route-Option": route?.id }),
      } };
    });
  });
  const candidates = [model.chatInvocation, primary, ...offers, ...array(model.invocations)]
    .map(record)
    .filter((item): item is RecordValue => Boolean(item))
    .filter((item) => {
      const example = record(item.request_example || item.requestExample);
      const modelId = String(model.modelId || model.id || "");
      return (!item.method || String(item.method).toUpperCase() === "POST") &&
        (!item.kind || item.kind === "chat") &&
        (!modelId || !example?.model || example.model === modelId) &&
        (item.path === "/v1/chat/completions" || item.path === "/v1/responses");
    });
  // Prefer the published default route when it supports this protocol. An
  // unscoped protocol example must not discard a route's execution contract.
  candidates.sort((a, b) => {
    const score = (item: RecordValue) => {
      const route = getVip98kInvocationHeaders(item.headers)["X-Relay-Route-Option"];
      return route && route === defaultRoute ? 2 : route ? 1 : 0;
    };
    return score(b) - score(a);
  });
  const selected = candidates[0];
  if (!selected) return null;
  return {
    protocol: selected.path === "/v1/responses" ? "openai-responses" : "openai-chat",
    path: selected.path as Vip98kChatInvocation["path"],
    headers: getVip98kInvocationHeaders(selected.headers),
  };
}

export function vip98kChatSupportsVision(value: unknown): boolean {
  const model = record(value) || {};
  const modes = [...array(model.inputModes || model.input_modes), ...array(model.capabilities)]
    .map((item) => String(item).toLowerCase().replace(/_/g, "-"));
  // A family name alone is not proof that the purchased route accepts images.
  return String(model.modality).toLowerCase() === "multimodal" ||
    modes.some((mode) => ["image", "image-url", "image-input", "image-understanding", "vision", "multimodal"].includes(mode));
}