"use client";

/**
 * Hand-off from a study/homework result into the chat: the compact result
 * summary and the deck it belongs to travel in sessionStorage and the chat
 * picks them up on mount, pre-scoped. One-shot, like the deck seed.
 */

export type ChatSeed = {
  /** Deck to scope the chat to (when the result belongs to one). */
  deckId?: string;
  /** Human label for the context banner ("Study results"). */
  label: string;
  /** Compact text sent as an extra context chunk with the first request. */
  text: string;
};

const KEY = "freezmo.chat.seed.v1";

export function setChatSeed(seed: ChatSeed): void {
  try {
    window.sessionStorage.setItem(KEY, JSON.stringify(seed));
  } catch {
    /* private mode */
  }
}

export function takeChatSeed(): ChatSeed | null {
  try {
    const raw = window.sessionStorage.getItem(KEY);
    if (!raw) return null;
    window.sessionStorage.removeItem(KEY);
    const parsed = JSON.parse(raw) as ChatSeed;
    if (!parsed || typeof parsed.text !== "string" || !parsed.text.trim()) return null;
    return {
      deckId: typeof parsed.deckId === "string" ? parsed.deckId : undefined,
      label: typeof parsed.label === "string" && parsed.label.trim() ? parsed.label : "Study result",
      text: parsed.text.slice(0, 6000),
    };
  } catch {
    return null;
  }
}