/**
 * Implements [Poseidon](https://www.poseidon-hash.info) ZK-friendly hash.
 *
 * There are many poseidon variants with different constants.
 * We don't provide them: you should construct them manually.
 * Check out [micro-starknet](https://github.com/paulmillr/micro-starknet) package for a proper example.
 * @module
 */
/*! noble-curves - MIT License (c) 2022 Paul Miller (paulmillr.com) */
import { _validateObject, bitGet } from "../utils.js";
import { FpInvertBatch, FpPow, validateField } from "./modular.js";
// Grain LFSR (Linear-Feedback Shift Register): https://eprint.iacr.org/2009/109.pdf
function grainLFSR(state) {
    let pos = 0;
    if (state.length !== 80)
        throw new Error('grainLFRS: wrong state length, should be 80 bits');
    const getBit = () => {
        const r = (offset) => state[(pos + offset) % 80];
        const bit = r(62) ^ r(51) ^ r(38) ^ r(23) ^ r(13) ^ r(0);
        state[pos] = bit;
        pos = ++pos % 80;
        return !!bit;
    };
    for (let i = 0; i < 160; i++)
        getBit();
    return () => {
        // https://en.wikipedia.org/wiki/Shrinking_generator
        while (true) {
            const b1 = getBit();
            const b2 = getBit();
            if (!b1)
                continue;
            return b2;
        }
    };
}
function assertValidPosOpts(opts) {
    const { Fp, roundsFull } = opts;
    validateField(Fp);
    _validateObject(opts, {
        t: 'number',
        roundsFull: 'number',
        roundsPartial: 'number',
    }, {
        isSboxInverse: 'boolean',
    });
    for (const i of ['t', 'roundsFull', 'roundsPartial']) {
        if (!Number.isSafeInteger(opts[i]) || opts[i] < 1)
            throw new Error('invalid number ' + i);
    }
    if (roundsFull & 1)
        throw new Error('roundsFull is not even' + roundsFull);
}
function poseidonGrain(opts) {
    assertValidPosOpts(opts);
    const { Fp } = opts;
    const state = Array(80).fill(1);
    let pos = 0;
    const writeBits = (value, bitCount) => {
        for (let i = bitCount - 1; i >= 0; i--)
            state[pos++] = Number(bitGet(value, i));
    };
    const _0n = BigInt(0);
    const _1n = BigInt(1);
    writeBits(_1n, 2); // prime field
    writeBits(opts.isSboxInverse ? _1n : _0n, 4); // b2..b5
    writeBits(BigInt(Fp.BITS), 12); // b6..b17
    writeBits(BigInt(opts.t), 12); // b18..b29
    writeBits(BigInt(opts.roundsFull), 10); // b30..b39
    writeBits(BigInt(opts.roundsPartial), 10); // b40..b49
    const getBit = grainLFSR(state);
    return (count, reject) => {
        const res = [];
        for (let i = 0; i < count; i++) {
            while (true) {
                let num = _0n;
                for (let i = 0; i < Fp.BITS; i++) {
                    num <<= _1n;
                    if (getBit())
                        num |= _1n;
                }
                if (reject && num >= Fp.ORDER)
                    continue; // rejection sampling
                res.push(Fp.create(num));
                break;
            }
        }
        return res;
    };
}
// NOTE: this is not standard but used often for constant generation for poseidon
// (grain LFRS-like structure)
export function grainGenConstants(opts, skipMDS = 0) {
    const { Fp, t, roundsFull, roundsPartial } = opts;
    const rounds = roundsFull + roundsPartial;
    const sample = poseidonGrain(opts);
    const roundConstants = [];
    for (let r = 0; r < rounds; r++)
        roundConstants.push(sample(t, true));
    if (skipMDS > 0)
        for (let i = 0; i < skipMDS; i++)
            sample(2 * t, false);
    const xs = sample(t, false);
    const ys = sample(t, false);
    // Construct MDS Matrix M[i][j] = 1 / (xs[i] + ys[j])
    const mds = [];
    for (let i = 0; i < t; i++) {
        const row = [];
        for (let j = 0; j < t; j++) {
            const xy = Fp.add(xs[i], ys[j]);
            if (Fp.is0(xy))
                throw new Error(`Error generating MDS matrix: xs[${i}] + ys[${j}] resulted in zero.`);
            row.push(xy);
        }
        mds.push(FpInvertBatch(Fp, row));
    }
    return { roundConstants, mds };
}
export function validateOpts(opts) {
    assertValidPosOpts(opts);
    const { Fp, mds, reversePartialPowIdx: rev, roundConstants: rc } = opts;
    const { roundsFull, roundsPartial, sboxPower, t } = opts;
    // MDS is TxT matrix
    if (!Array.isArray(mds) || mds.length !== t)
        throw new Error('Poseidon: invalid MDS matrix');
    const _mds = mds.map((mdsRow) => {
        if (!Array.isArray(mdsRow) || mdsRow.length !== t)
            throw new Error('invalid MDS matrix row: ' + mdsRow);
        return mdsRow.map((i) => {
            if (typeof i !== 'bigint')
                throw new Error('invalid MDS matrix bigint: ' + i);
            return Fp.create(i);
        });
    });
    if (rev !== undefined && typeof rev !== 'boolean')
        throw new Error('invalid param reversePartialPowIdx=' + rev);
    if (roundsFull & 1)
        throw new Error('roundsFull is not even' + roundsFull);
    const rounds = roundsFull + roundsPartial;
    if (!Array.isArray(rc) || rc.length !== rounds)
        throw new Error('Poseidon: invalid round constants');
    const roundConstants = rc.map((rc) => {
        if (!Array.isArray(rc) || rc.length !== t)
            throw new Error('invalid round constants');
        return rc.map((i) => {
            if (typeof i !== 'bigint' || !Fp.isValid(i))
                throw new Error('invalid round constant');
            return Fp.create(i);
        });
    });
    if (!sboxPower || ![3, 5, 7, 17].includes(sboxPower))
        throw new Error('invalid sboxPower');
    const _sboxPower = BigInt(sboxPower);
    let sboxFn = (n) => FpPow(Fp, n, _sboxPower);
    // Unwrapped sbox power for common cases (195->142μs)
    if (sboxPower === 3)
        sboxFn = (n) => Fp.mul(Fp.sqrN(n), n);
    else if (sboxPower === 5)
        sboxFn = (n) => Fp.mul(Fp.sqrN(Fp.sqrN(n)), n);
    return Object.freeze({ ...opts, rounds, sboxFn, roundConstants, mds: _mds });
}
export function splitConstants(rc, t) {
    if (typeof t !== 'number')
        throw new Error('poseidonSplitConstants: invalid t');
    if (!Array.isArray(rc) || rc.length % t)
        throw new Error('poseidonSplitConstants: invalid rc');
    const res = [];
    let tmp = [];
    for (let i = 0; i < rc.length; i++) {
        tmp.push(rc[i]);
        if (tmp.length === t) {
            res.push(tmp);
            tmp = [];
        }
    }
    return res;
}
/** Poseidon NTT-friendly hash. */
export function poseidon(opts) {
    const _opts = validateOpts(opts);
    const { Fp, mds, roundConstants, rounds: totalRounds, roundsPartial, sboxFn, t } = _opts;
    const halfRoundsFull = _opts.roundsFull / 2;
    const partialIdx = _opts.reversePartialPowIdx ? t - 1 : 0;
    const poseidonRound = (values, isFull, idx) => {
        values = values.map((i, j) => Fp.add(i, roundConstants[idx][j]));
        if (isFull)
            values = values.map((i) => sboxFn(i));
        else
            values[partialIdx] = sboxFn(values[partialIdx]);
        // Matrix multiplication
        values = mds.map((i) => i.reduce((acc, i, j) => Fp.add(acc, Fp.mulN(i, values[j])), Fp.ZERO));
        return values;
    };
    const poseidonHash = function poseidonHash(values) {
        if (!Array.isArray(values) || values.length !== t)
            throw new Error('invalid values, expected array of bigints with length ' + t);
        values = values.map((i) => {
            if (typeof i !== 'bigint')
                throw new Error('invalid bigint=' + i);
            return Fp.create(i);
        });
        let lastRound = 0;
        // Apply r_f/2 full rounds.
        for (let i = 0; i < halfRoundsFull; i++)
            values = poseidonRound(values, true, lastRound++);
        // Apply r_p partial rounds.
        for (let i = 0; i < roundsPartial; i++)
            values = poseidonRound(values, false, lastRound++);
        // Apply r_f/2 full rounds.
        for (let i = 0; i < halfRoundsFull; i++)
            values = poseidonRound(values, true, lastRound++);
        if (lastRound !== totalRounds)
            throw new Error('invalid number of rounds');
        return values;
    };
    // For verification in tests
    poseidonHash.roundConstants = roundConstants;
    return poseidonHash;
}
export class PoseidonSponge {
    constructor(Fp, rate, capacity, hash) {
        this.pos = 0;
        this.isAbsorbing = true;
        this.Fp = Fp;
        this.hash = hash;
        this.rate = rate;
        this.capacity = capacity;
        this.state = new Array(rate + capacity);
        this.clean();
    }
    process() {
        this.state = this.hash(this.state);
    }
    absorb(input) {
        for (const i of input)
            if (typeof i !== 'bigint' || !this.Fp.isValid(i))
                throw new Error('invalid input: ' + i);
        for (let i = 0; i < input.length;) {
            if (!this.isAbsorbing || this.pos === this.rate) {
                this.process();
                this.pos = 0;
                this.isAbsorbing = true;
            }
            const chunk = Math.min(this.rate - this.pos, input.length - i);
            for (let j = 0; j < chunk; j++) {
                const idx = this.capacity + this.pos++;
                this.state[idx] = this.Fp.add(this.state[idx], input[i++]);
            }
        }
    }
    squeeze(count) {
        const res = [];
        while (res.length < count) {
            if (this.isAbsorbing || this.pos === this.rate) {
                this.process();
                this.pos = 0;
                this.isAbsorbing = false;
            }
            const chunk = Math.min(this.rate - this.pos, count - res.length);
            for (let i = 0; i < chunk; i++)
                res.push(this.state[this.capacity + this.pos++]);
        }
        return res;
    }
    clean() {
        this.state.fill(this.Fp.ZERO);
        this.isAbsorbing = true;
        this.pos = 0;
    }
    clone() {
        const c = new PoseidonSponge(this.Fp, this.rate, this.capacity, this.hash);
        c.pos = this.pos;
        c.state = [...this.state];
        return c;
    }
}
/**
 * The method is not defined in spec, but nevertheless used often.
 * Check carefully for compatibility: there are many edge cases, like absorbing an empty array.
 * We cross-test against:
 * - https://github.com/ProvableHQ/snarkVM/tree/staging/algorithms
 * - https://github.com/arkworks-rs/crypto-primitives/tree/main
 */
export function poseidonSponge(opts) {
    for (const i of ['rate', 'capacity']) {
        if (typeof opts[i] !== 'number' || !Number.isSafeInteger(opts[i]))
            throw new Error('invalid number ' + i);
    }
    const { rate, capacity } = opts;
    const t = opts.rate + opts.capacity;
    // Re-use hash instance between multiple instances
    const hash = poseidon({ ...opts, t });
    const { Fp } = opts;
    return () => new PoseidonSponge(Fp, rate, capacity, hash);
}
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