import * as Chunk from "../Chunk.js";
import * as Context from "../Context.js";
import { pipe } from "../Function.js";
import * as Hash from "../Hash.js";
import * as PCGRandom from "../Utils.js";
import * as core from "./core.js";
/** @internal */
const RandomSymbolKey = "effect/Random";
/** @internal */
export const RandomTypeId = /*#__PURE__*/Symbol.for(RandomSymbolKey);
/** @internal */
export const randomTag = /*#__PURE__*/Context.GenericTag("effect/Random");
/** @internal */
class RandomImpl {
seed;
[RandomTypeId] = RandomTypeId;
PRNG;
constructor(seed) {
this.seed = seed;
this.PRNG = new PCGRandom.PCGRandom(seed);
}
get next() {
return core.sync(() => this.PRNG.number());
}
get nextBoolean() {
return core.map(this.next, n => n > 0.5);
}
get nextInt() {
return core.sync(() => this.PRNG.integer(Number.MAX_SAFE_INTEGER));
}
nextRange(min, max) {
return core.map(this.next, n => (max - min) * n + min);
}
nextIntBetween(min, max) {
return core.sync(() => this.PRNG.integer(max - min) + min);
}
shuffle(elements) {
return shuffleWith(elements, n => this.nextIntBetween(0, n));
}
}
const shuffleWith = (elements, nextIntBounded) => {
return core.suspend(() => pipe(core.sync(() => Array.from(elements)), core.flatMap(buffer => {
const numbers = [];
for (let i = buffer.length; i >= 2; i = i - 1) {
numbers.push(i);
}
return pipe(numbers, core.forEachSequentialDiscard(n => pipe(nextIntBounded(n), core.map(k => swap(buffer, n - 1, k)))), core.as(Chunk.fromIterable(buffer)));
})));
};
const swap = (buffer, index1, index2) => {
const tmp = buffer[index1];
buffer[index1] = buffer[index2];
buffer[index2] = tmp;
return buffer;
};
export const make = seed => new RandomImpl(Hash.hash(seed));
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