import type { QuickJSContext, QuickJSHandle } from "quickjs-emscripten";

import { call } from "../vmutil";

export default function unmarshalCustom(
  ctx: QuickJSContext,
  handle: QuickJSHandle,
  preUnmarshal: <T>(target: T, handle: QuickJSHandle) => T | undefined,
  custom: Iterable<(handle: QuickJSHandle, ctx: QuickJSContext) => any>,
): symbol | undefined {
  let obj: any;
  for (const c of custom) {
    obj = c(handle, ctx);
    if (obj) break;
  }
  return obj ? preUnmarshal(obj, handle) ?? obj : undefined;
}

export function symbol(handle: QuickJSHandle, ctx: QuickJSContext): symbol | undefined {
  if (ctx.typeof(handle) !== "symbol") return;
  const desc = ctx.getString(ctx.getProp(handle, "description"));
  return Symbol(desc);
}

export function date(handle: QuickJSHandle, ctx: QuickJSContext): Date | undefined {
  if (!ctx.dump(call(ctx, "a => a instanceof Date", undefined, handle))) return;
  const t = ctx.getNumber(call(ctx, "a => a.getTime()", undefined, handle));
  return new Date(t);
}

export const defaultCustom = [symbol, date];