'use strict';

// Mulberry32 - fast, deterministic PRNG
function mulberry32(seed) {
  return function () {
    seed |= 0;
    seed = seed + 0x602a2ebf | 0;
    let t = Math.imul(seed ^ seed >>> 16, 0x6d349c2b);
    t = Math.imul(t ^ t >>> 16, 0x04c35085) | 0;
    t = t ^ t >>> 16;
    return (t >>> 0) / 4294967296;
  };
}

// Create a seeded RNG instance
function createRNG(seed) {
  return mulberry32(seed);
}

// Random integer in [min, max] inclusive
function randInt(rng, min, max) {
  return Math.floor(rng() * (max - min + 1)) + min;
}

// Random float in [0, 1)
function randFloat(rng) {
  return rng();
}

// Pick random element from array
function randElement(rng, arr) {
  return arr[Math.floor(rng() * arr.length)];
}

// Shuffle array in place (Fisher-Yates)
function shuffle(rng, arr) {
  const a = [...arr];
  for (let i = a.length - 1; i > 0; i--) {
    const j = Math.floor(rng() * (i + 1));
    [a[i], a[j]] = [a[j], a[i]];
  }
  return a;
}

// Random choice with weights
function weightedChoice(rng, items) {
  const total = items.reduce((sum, item) => sum + item.weight, 0);
  let r = rng() * total;
  for (const item of items) {
    r -= item.weight;
    if (r <= 0) return item.value;
  }
  return items[items.length - 1].value;
}

if (typeof module !== 'undefined' && module.exports) {
  module.exports = { createRNG, mulberry32, randInt, randFloat, randElement, shuffle, weightedChoice };
}