import { SCENARIO_PRESETS } from "./presets";
import type { MethodId, ProblemSpec } from "./types";

/** The default problem: the reference centre hit. */
export function defaultSpec(): ProblemSpec {
  return cloneSpec(SCENARIO_PRESETS[0].spec);
}

/** Deep-copy a spec (specs are plain data). */
export function cloneSpec(spec: ProblemSpec): ProblemSpec {
  return JSON.parse(JSON.stringify(spec)) as ProblemSpec;
}

/**
 * The part of the spec the modes stage depends on: the plate, the elastic
 * constants, the hole, the thread's length (its spring), the sample rate
 * (the 0.47 fs cutoff), the mode cap and the method's numerics. Two specs
 * with the same key have the same modes, so the host reuses them and runs
 * only the strike stage. The material's Q, the dashpot, the hammer, the
 * strike point, the probe, the microphone and the rest of the render
 * settings belong to the strike stage.
 */
export function modesKey(spec: ProblemSpec, method: MethodId): string {
  const { plate, material, hole, thread, render } = spec;
  return JSON.stringify({
    method,
    plate,
    E: material.E,
    nu: material.nu,
    rho: material.rho,
    hole,
    length: thread.length,
    fs: render.fs,
    modes: render.modes,
    numerics: method === "rr" ? spec.rr : spec.fem,
  });
}