import { describe, it, expect } from 'vitest';
import { createWorld, advance } from '../src/sim/world.js';
import { priceOf, advancePlanet } from '../src/sim/economy.js';
import { GOODS, BASE_PRICE } from '../src/sim/constants.js';

describe('balance', () => {
  it('the NPC economy stays alive over a long horizon', () => {
    const w = createWorld('balance-1');
    advance(w, 120);
    const alive = w.npcs.filter((n) => n.alive);
    expect(alive.length).toBeGreaterThan(w.npcs.length * 0.5);
    expect(w.stats.trades).toBeGreaterThan(w.npcs.length * 3);
  });

  it('price gradients survive NPC arbitrage (the player can still profit)', () => {
    const w = createWorld('balance-1');
    advance(w, 60);
    let bestSpread = 0;
    for (const good of GOODS) {
      let lo = Infinity, hi = 0;
      for (const planet of w.galaxy.planets) {
        advancePlanet(planet, w.t);
        const price = priceOf(good, planet.stock[good]);
        lo = Math.min(lo, price);
        hi = Math.max(hi, price);
      }
      bestSpread = Math.max(bestSpread, (hi - lo) / BASE_PRICE[good]);
    }
    expect(bestSpread).toBeGreaterThan(0.5); // at least one good still has a fat margin somewhere
  });
});