frontend/src/lib/brain.ts

// Client for the daemon's brain proxy. Every call degrades to null —
// the scripted engine is the floor, the model is the ceiling. Puck is
// never dead, just less eloquent.

import type { FairyState, WireEvent } from "../engine";
import { moodFor } from "../engine";

interface BrainFairyState {
  mood: string;
  mischief: number;
  obsession: string;
}

const forBrain = (fs: FairyState): BrainFairyState => ({
  mood: moodFor(fs),
  mischief: fs.mischief,
  obsession: fs.obsession,
});

async function post(path: string, body: unknown, timeoutMs: number): Promise<string | null> {
  try {
    const res = await fetch(path, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(body),
      signal: AbortSignal.timeout(timeoutMs),
    });
    if (!res.ok) return null; // 503 = no brain configured; scripted fallback is the design
    const data: unknown = await res.json();
    const text = (data as { text?: unknown }).text;
    return typeof text === "string" && text.length > 0 ? text : null;
  } catch {
    return null;
  }
}

/** Fairy-voiced line for a real wire event. Null → use the template line. */
export function brainNarrate(event: WireEvent, fs: FairyState): Promise<string | null> {
  return post("/api/brain/narrate", { event, fairy_state: forBrain(fs) }, 25000);
}

/** In-character chat reply. Null → use the scripted keyword reply. */
export function brainChat(
  message: string,
  fs: FairyState,
  history: { who: string; text: string }[],
): Promise<string | null> {
  return post("/api/brain/chat", { message, fairy_state: forBrain(fs), history }, 25000);
}