import { GOODS, BASE_PRICE, TYPICAL_STOCK, MAX_STOCK } from './constants.js';

// Deterministic price curve: scarce -> expensive. Clamped to [0.25x, 4x].
// Always pass the raw float planet.stock[good]; never reconstruct price from
// the floored integer stock shown in marketView rows.
export function priceOf(good, stock) {
  const ratio = TYPICAL_STOCK / Math.max(stock, 1);
  const mult = Math.min(4, Math.max(0.25, ratio));
  return Math.round(BASE_PRICE[good] * mult * 100) / 100;
}

// Lazily advance a planet's stocks to time t (no per-tick simulation).
export function advancePlanet(planet, t) {
  const dt = t - planet.stockTime;
  if (dt <= 0) return;
  for (const g of GOODS) {
    const rate = (planet.produces[g] || 0) - (planet.consumes[g] || 0);
    planet.stock[g] = Math.min(MAX_STOCK, Math.max(0, planet.stock[g] + rate * dt));
  }
  planet.stockTime = t;
}

// Execute a trade at the current price. deltaQty > 0 delivers goods,
// deltaQty < 0 removes them. Returns the unit price the trade executed at.
export function applyTrade(planet, t, good, deltaQty) {
  advancePlanet(planet, t);
  const price = priceOf(good, planet.stock[good]);
  planet.stock[good] = Math.min(MAX_STOCK, Math.max(0, planet.stock[good] + deltaQty));
  return price;
}

export function marketView(planet, t) {
  advancePlanet(planet, t);
  return GOODS.map((g) => ({
    good: g,
    stock: Math.floor(planet.stock[g]),
    price: priceOf(g, planet.stock[g]),
  }));
}