import { assert } from "jsr:@std/assert";
import { describe, it } from "jsr:@std/testing/bdd";

/**
 * Tests if a function can run a given number of iterations within a target frame time.
 * @param fn The function to test.
 * @param iterations Number of times to run the function per frame.
 * @param fps Target frames per second.
 */
export function testPerformance(
  fn: () => unknown,
  iterations: number,
  fps: number,
) {
  console.log(`Performance Test - ${iterations} iterations at ${fps} FPS`);
  const frameTime = 1000 / fps;
  const startTime = performance.now();

  for (let i = 0; i < iterations; i++) {
    fn();
  }

  const endTime = performance.now();
  const elapsed = endTime - startTime;

  console.log(
    `Elapsed time: ${elapsed.toFixed(2)}ms (Target: ≤${
      frameTime.toFixed(2)
    }ms)`,
  );
  assert(
    elapsed <= frameTime,
    `Function took too long: ${elapsed.toFixed(2)}ms (Target: ≤${
      frameTime.toFixed(2)
    }ms)`,
  );
  // });
}