// Run a numbl script with the bp_* helpers on its path, and turn its `sys`
// struct into a BeadSystem. Shared by the browser worker and the tests.

import { executeCode, RTV } from "numbl";
import { parseSystem } from "./parse";
import { relax } from "./relax";
import type { SymEig } from "./modes";
import type { BeadSystem } from "./types";

export interface HelperFile {
  name: string;
  source: string;
}

export function runScript(
  source: string,
  helpers: HelperFile[],
  onOutput: (text: string) => void
): { sys: BeadSystem; warnings: string[] } {
  const result = executeCode(source, { onOutput, displayResults: true }, helpers, "script.m");
  return parseSystem(result.variableValues.sys);
}

// Steps that change the system before it is simulated (now: static relaxation
// under the load). Returns notes for the run report.
export function prepareSystem(sys: BeadSystem): string[] {
  const notes: string[] = [];
  if (sys.relax) {
    const r = relax(sys);
    let sag = 0;
    for (let q = 0; q < r.pos.length; q++) sag = Math.max(sag, Math.abs(r.pos[q] - sys.pos0[q]));
    sys.pos0 = r.pos;
    notes.push(
      `Relaxed to equilibrium in ${r.iterations} iterations (largest net force ${r.residual.toExponential(1)} N; beads moved up to ${(sag * 1000).toPrecision(3)} mm).`
    );
  }
  return notes;
}

// Symmetric eigendecomposition through numbl's eig.
export const numblEig: SymEig = (A, n) => {
  const r = executeCode("[V, D] = eig(A); d = diag(D);", {
    initialVariableValues: { A: RTV.tensor(A, [n, n]) },
  });
  const V = r.variableValues.V as unknown as { data: Float64Array };
  const d = r.variableValues.d as unknown as { data: Float64Array } | number;
  const values = typeof d === "number" ? Float64Array.of(d) : d.data;
  return { values, vectors: V.data ?? Float64Array.of(1) };
};