"use client";
import { api } from "@/lib/client/api";
import { PENDING_ATTACHMENTS_KEY } from "@/components/prompts/insert";
import type { PendingAttachment } from "@/lib/client/types";

/**
 * Library files → new chat hand-off (consumed by the Chat workstream).
 *
 * `useFilesInNewChat(fileIds)` copies the files into pending `message_attachments` (POST /api/library/files/attach),
 * stashes the descriptors in `sessionStorage["polyllm:pending-attachments"]` and returns the href
 * `/app/chat?attachments=<id,id>` to navigate to. A new chat view should, on mount, read `?attachments=` and
 * `consumePendingAttachments()` to seed the composer chips (the ids go straight into `message.attachmentIds`).
 */
export async function prepareFilesForNewChat(fileIds: string[]): Promise<{ href: string; attachments: PendingAttachment[] }> {
  const res = await api<{ attachments: PendingAttachment[] }>("/api/library/files/attach", { method: "POST", json: { fileIds } });
  try {
    window.sessionStorage.setItem(PENDING_ATTACHMENTS_KEY, JSON.stringify({ at: Date.now(), attachments: res.attachments }));
  } catch {
    /* ignore */
  }
  return { href: `/app/chat?attachments=${encodeURIComponent(res.attachments.map((a) => a.id).join(","))}`, attachments: res.attachments };
}

/** Reads and clears stashed pending attachments (null when absent or older than 5 minutes). */
export function consumePendingAttachments(): PendingAttachment[] | null {
  try {
    const raw = window.sessionStorage.getItem(PENDING_ATTACHMENTS_KEY);
    if (!raw) return null;
    window.sessionStorage.removeItem(PENDING_ATTACHMENTS_KEY);
    const d = JSON.parse(raw) as { at: number; attachments: PendingAttachment[] };
    if (!Array.isArray(d?.attachments) || Date.now() - (d.at ?? 0) > 5 * 60_000) return null;
    return d.attachments;
  } catch {
    return null;
  }
}