mimc.nr

use crate::default::Default;
use crate::hash::Hasher;

// mimc-p/p implementation
// constants are (publicly generated) random numbers, for instance using keccak as a ROM.
// You must use constants generated for the native field
// Rounds number should be ~ log(p)/log(exp)
// For 254 bit primes, exponent 7 and 91 rounds seems to be recommended
//
// Uncommenting this results in deprecated warnings in the stdlib
// #[deprecated]
fn mimc<let N: u32>(x: Field, k: Field, constants: [Field; N], exp: Field) -> Field {
    //round 0
    let mut t = x + k;
    let mut h = t.pow_32(exp);
    //next rounds
    for i in 1..constants.len() {
        t = h + k + constants[i];
        h = t.pow_32(exp);
    }
    h + k
}

global MIMC_BN254_ROUNDS: u32 = 91;
//generated from seed "mimc" using keccak256
global MIMC_BN254_CONSTANTS: [Field; MIMC_BN254_ROUNDS] = [
    0,
    20888961410941983456478427210666206549300505294776164667214940546594746570981,
    15265126113435022738560151911929040668591755459209400716467504685752745317193,
    8334177627492981984476504167502758309043212251641796197711684499645635709656,
    1374324219480165500871639364801692115397519265181803854177629327624133579404,
    11442588683664344394633565859260176446561886575962616332903193988751292992472,
    2558901189096558760448896669327086721003508630712968559048179091037845349145,
    11189978595292752354820141775598510151189959177917284797737745690127318076389,
    3262966573163560839685415914157855077211340576201936620532175028036746741754,
    17029914891543225301403832095880481731551830725367286980611178737703889171730,
    4614037031668406927330683909387957156531244689520944789503628527855167665518,
    19647356996769918391113967168615123299113119185942498194367262335168397100658,
    5040699236106090655289931820723926657076483236860546282406111821875672148900,
    2632385916954580941368956176626336146806721642583847728103570779270161510514,
    17691411851977575435597871505860208507285462834710151833948561098560743654671,
    11482807709115676646560379017491661435505951727793345550942389701970904563183,
    8360838254132998143349158726141014535383109403565779450210746881879715734773,
    12663821244032248511491386323242575231591777785787269938928497649288048289525,
    3067001377342968891237590775929219083706800062321980129409398033259904188058,
    8536471869378957766675292398190944925664113548202769136103887479787957959589,
    19825444354178182240559170937204690272111734703605805530888940813160705385792,
    16703465144013840124940690347975638755097486902749048533167980887413919317592,
    13061236261277650370863439564453267964462486225679643020432589226741411380501,
    10864774797625152707517901967943775867717907803542223029967000416969007792571,
    10035653564014594269791753415727486340557376923045841607746250017541686319774,
    3446968588058668564420958894889124905706353937375068998436129414772610003289,
    4653317306466493184743870159523234588955994456998076243468148492375236846006,
    8486711143589723036499933521576871883500223198263343024003617825616410932026,
    250710584458582618659378487568129931785810765264752039738223488321597070280,
    2104159799604932521291371026105311735948154964200596636974609406977292675173,
    16313562605837709339799839901240652934758303521543693857533755376563489378839,
    6032365105133504724925793806318578936233045029919447519826248813478479197288,
    14025118133847866722315446277964222215118620050302054655768867040006542798474,
    7400123822125662712777833064081316757896757785777291653271747396958201309118,
    1744432620323851751204287974553233986555641872755053103823939564833813704825,
    8316378125659383262515151597439205374263247719876250938893842106722210729522,
    6739722627047123650704294650168547689199576889424317598327664349670094847386,
    21211457866117465531949733809706514799713333930924902519246949506964470524162,
    13718112532745211817410303291774369209520657938741992779396229864894885156527,
    5264534817993325015357427094323255342713527811596856940387954546330728068658,
    18884137497114307927425084003812022333609937761793387700010402412840002189451,
    5148596049900083984813839872929010525572543381981952060869301611018636120248,
    19799686398774806587970184652860783461860993790013219899147141137827718662674,
    19240878651604412704364448729659032944342952609050243268894572835672205984837,
    10546185249390392695582524554167530669949955276893453512788278945742408153192,
    5507959600969845538113649209272736011390582494851145043668969080335346810411,
    18177751737739153338153217698774510185696788019377850245260475034576050820091,
    19603444733183990109492724100282114612026332366576932662794133334264283907557,
    10548274686824425401349248282213580046351514091431715597441736281987273193140,
    1823201861560942974198127384034483127920205835821334101215923769688644479957,
    11867589662193422187545516240823411225342068709600734253659804646934346124945,
    18718569356736340558616379408444812528964066420519677106145092918482774343613,
    10530777752259630125564678480897857853807637120039176813174150229243735996839,
    20486583726592018813337145844457018474256372770211860618687961310422228379031,
    12690713110714036569415168795200156516217175005650145422920562694422306200486,
    17386427286863519095301372413760745749282643730629659997153085139065756667205,
    2216432659854733047132347621569505613620980842043977268828076165669557467682,
    6309765381643925252238633914530877025934201680691496500372265330505506717193,
    20806323192073945401862788605803131761175139076694468214027227878952047793390,
    4037040458505567977365391535756875199663510397600316887746139396052445718861,
    19948974083684238245321361840704327952464170097132407924861169241740046562673,
    845322671528508199439318170916419179535949348988022948153107378280175750024,
    16222384601744433420585982239113457177459602187868460608565289920306145389382,
    10232118865851112229330353999139005145127746617219324244541194256766741433339,
    6699067738555349409504843460654299019000594109597429103342076743347235369120,
    6220784880752427143725783746407285094967584864656399181815603544365010379208,
    6129250029437675212264306655559561251995722990149771051304736001195288083309,
    10773245783118750721454994239248013870822765715268323522295722350908043393604,
    4490242021765793917495398271905043433053432245571325177153467194570741607167,
    19596995117319480189066041930051006586888908165330319666010398892494684778526,
    837850695495734270707668553360118467905109360511302468085569220634750561083,
    11803922811376367215191737026157445294481406304781326649717082177394185903907,
    10201298324909697255105265958780781450978049256931478989759448189112393506592,
    13564695482314888817576351063608519127702411536552857463682060761575100923924,
    9262808208636973454201420823766139682381973240743541030659775288508921362724,
    173271062536305557219323722062711383294158572562695717740068656098441040230,
    18120430890549410286417591505529104700901943324772175772035648111937818237369,
    20484495168135072493552514219686101965206843697794133766912991150184337935627,
    19155651295705203459475805213866664350848604323501251939850063308319753686505,
    11971299749478202793661982361798418342615500543489781306376058267926437157297,
    18285310723116790056148596536349375622245669010373674803854111592441823052978,
    7069216248902547653615508023941692395371990416048967468982099270925308100727,
    6465151453746412132599596984628739550147379072443683076388208843341824127379,
    16143532858389170960690347742477978826830511669766530042104134302796355145785,
    19362583304414853660976404410208489566967618125972377176980367224623492419647,
    1702213613534733786921602839210290505213503664731919006932367875629005980493,
    10781825404476535814285389902565833897646945212027592373510689209734812292327,
    4212716923652881254737947578600828255798948993302968210248673545442808456151,
    7594017890037021425366623750593200398174488805473151513558919864633711506220,
    18979889247746272055963929241596362599320706910852082477600815822482192194401,
    13602139229813231349386885113156901793661719180900395818909719758150455500533,
];

//mimc implementation with hardcoded parameters for BN254 curve.
#[field(bn254)]
#[deprecated]
pub fn mimc_bn254<let N: u32>(array: [Field; N]) -> Field {
    let exponent = 7;
    let mut r = 0;
    for elem in array {
        let h = mimc(elem, r, MIMC_BN254_CONSTANTS, exponent);
        r = r + elem + h;
    }
    r
}

pub struct MimcHasher {
    _state: [Field],
}

impl Hasher for MimcHasher {
    #[field(bn254)]
    fn finish(self) -> Field {
        let exponent = 7;
        let mut r = 0;
        for i in 0..self._state.len() {
            let h = mimc(self._state[i], r, MIMC_BN254_CONSTANTS, exponent);
            r = r + self._state[i] + h;
        }
        r
    }

    fn write(&mut self, input: Field) {
        self._state = self._state.push_back(input);
    }
}

impl Default for MimcHasher {
    fn default() -> Self {
        MimcHasher { _state: &[] }
    }
}