import type { MessageEnvelope } from "./protocol";

const STORAGE_KEY = "linuxcnc-web-wasm:xyzac-power-off-checkpoint";

function payloadOf(message: MessageEnvelope): Record<string, unknown> {
  return message.payload && typeof message.payload === "object" ? message.payload as Record<string, unknown> : {};
}

export function persistPowerOffCheckpoint(message: MessageEnvelope): { status: string; storage: string; reason?: string } | null {
  const payload = payloadOf(message);
  const checkpoint = payload.recovery_checkpoint;
  if (message.kind !== "COMMAND_RESULT" || payload.status !== "verified" || payload.command !== "POWER" || payload.active !== false || !checkpoint || typeof checkpoint !== "object") return null;
  try {
    if (!globalThis.localStorage) return { status: "blocked", storage: "browser_local_storage", reason: "local_storage_unavailable" };
    globalThis.localStorage.setItem(STORAGE_KEY, JSON.stringify(checkpoint));
    return { status: "verified", storage: "browser_local_storage" };
  } catch (error) {
    return { status: "blocked", storage: "browser_local_storage", reason: error instanceof Error ? error.message : String(error) };
  }
}

export function attachPersistedPowerOffCheckpoint(payload: unknown): unknown {
  if (!payload || typeof payload !== "object" || Array.isArray(payload)) return payload;
  try {
    const raw = globalThis.localStorage?.getItem(STORAGE_KEY);
    if (!raw) return payload;
    const checkpoint = JSON.parse(raw);
    return { ...(payload as Record<string, unknown>), recovery_checkpoint: checkpoint };
  } catch {
    return payload;
  }
}

export function clearPersistedPowerOffCheckpoint(message: MessageEnvelope): void {
  const payload = payloadOf(message);
  if (message.kind !== "COMMAND_RESULT" || payload.status !== "verified" || payload.command !== "POWER" || payload.active !== true) return;
  try { globalThis.localStorage?.removeItem(STORAGE_KEY); } catch { /* storage cleanup is best effort */ }
}

export { STORAGE_KEY };