// SPDX-License-Identifier: GPL-3.0
/*
    Copyright 2021 0KIMS association.


    snarkJS is a free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    snarkJS is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
    License for more details.

    You should have received a copy of the GNU General Public License
    along with snarkJS. If not, see <https://www.gnu.org/licenses/>.
*/

pragma solidity ^0.8.26;

contract LetheVerifier {
    // Scalar field size
    uint256 constant r    = 21888242871839275222246405745257275088548364400416034343698204186575808495617;
    // Base field size
    uint256 constant q   = 21888242871839275222246405745257275088696311157297823662689037894645226208583;

    // Verification Key data
    uint256 constant alphax  = 16428432848801857252194528405604668803277877773566238944394625302971855135431;
    uint256 constant alphay  = 16846502678714586896801519656441059708016666274385668027902869494772365009666;
    uint256 constant betax1  = 3182164110458002340215786955198810119980427837186618912744689678939861918171;
    uint256 constant betax2  = 16348171800823588416173124589066524623406261996681292662100840445103873053252;
    uint256 constant betay1  = 4920802715848186258981584729175884379674325733638798907835771393452862684714;
    uint256 constant betay2  = 19687132236965066906216944365591810874384658708175106803089633851114028275753;
    uint256 constant gammax1 = 11559732032986387107991004021392285783925812861821192530917403151452391805634;
    uint256 constant gammax2 = 10857046999023057135944570762232829481370756359578518086990519993285655852781;
    uint256 constant gammay1 = 4082367875863433681332203403145435568316851327593401208105741076214120093531;
    uint256 constant gammay2 = 8495653923123431417604973247489272438418190587263600148770280649306958101930;
    uint256 constant deltax1 = 17711228559591965165930086208779146984699080466916694617190736741568603279682;
    uint256 constant deltax2 = 9997131013895634976593209329400095611687047633648863566667168100530299859484;
    uint256 constant deltay1 = 132397800133926411764187433253920262287517717951159669165571340199762985306;
    uint256 constant deltay2 = 5547681596107033491651857378380187227719978380641416907955171372955732731991;

    
    uint256 constant IC0x = 16957439711134459545679882607348720577788853812364798636485546658439346073841;
    uint256 constant IC0y = 13869159198893148231185051988298714602515307670571880077080454488595381152378;
    
    uint256 constant IC1x = 2683962332009271564760559114047671421456229336014206301184470003714524110629;
    uint256 constant IC1y = 6566722425998463905703704539881493186070438571511900790342473843522790898249;
    
    uint256 constant IC2x = 10383099917188504568870536839384427935188051234207283520020736559871640996761;
    uint256 constant IC2y = 20601798410602329655881804281473680740584481025841523112004981526882081923254;
    
    uint256 constant IC3x = 17337595942456605928468540408851127407807371009943383187700903393275960628684;
    uint256 constant IC3y = 10043310184421437365710943450976508231270908881557046693971627919459806420785;
    
    uint256 constant IC4x = 18535040526618948423437236506646051043718661690470472061441801871976679921615;
    uint256 constant IC4y = 36278071899256934889693325804712631304063879192044972952885995426784851043;
    
    uint256 constant IC5x = 16884323701206513446229808476405453933049169942157084182083908489184150069364;
    uint256 constant IC5y = 257159595725016352386766169631248957903166850812178899097207863859566269438;
    
    uint256 constant IC6x = 9869977027440574569835284653751669492240876707834488562544316777684367982836;
    uint256 constant IC6y = 12978209224385401937609878003121447130222221673936650224507000389399004067212;
    
    uint256 constant IC7x = 4621495716445894682293654427885171705091088427932438142625960108208353708097;
    uint256 constant IC7y = 11488541574775023950898549188939867517926646550254370979261920260395538147332;
    
 
    // Memory data
    uint16 constant pVk = 0;
    uint16 constant pPairing = 128;

    uint16 constant pLastMem = 896;

    function verifyProof(uint[2] calldata _pA, uint[2][2] calldata _pB, uint[2] calldata _pC, uint[7] calldata _pubSignals) public view returns (bool) {
        assembly {
            function checkField(v) {
                if iszero(lt(v, r)) {
                    mstore(0, 0)
                    return(0, 0x20)
                }
            }
            
            // G1 function to multiply a G1 value(x,y) to value in an address
            function g1_mulAccC(pR, x, y, s) {
                let success
                let mIn := mload(0x40)
                mstore(mIn, x)
                mstore(add(mIn, 32), y)
                mstore(add(mIn, 64), s)

                success := staticcall(sub(gas(), 2000), 7, mIn, 96, mIn, 64)

                if iszero(success) {
                    mstore(0, 0)
                    return(0, 0x20)
                }

                mstore(add(mIn, 64), mload(pR))
                mstore(add(mIn, 96), mload(add(pR, 32)))

                success := staticcall(sub(gas(), 2000), 6, mIn, 128, pR, 64)

                if iszero(success) {
                    mstore(0, 0)
                    return(0, 0x20)
                }
            }

            function checkPairing(pA, pB, pC, pubSignals, pMem) -> isOk {
                let _pPairing := add(pMem, pPairing)
                let _pVk := add(pMem, pVk)

                mstore(_pVk, IC0x)
                mstore(add(_pVk, 32), IC0y)

                // Compute the linear combination vk_x
                
                g1_mulAccC(_pVk, IC1x, IC1y, calldataload(add(pubSignals, 0)))
                
                g1_mulAccC(_pVk, IC2x, IC2y, calldataload(add(pubSignals, 32)))
                
                g1_mulAccC(_pVk, IC3x, IC3y, calldataload(add(pubSignals, 64)))
                
                g1_mulAccC(_pVk, IC4x, IC4y, calldataload(add(pubSignals, 96)))
                
                g1_mulAccC(_pVk, IC5x, IC5y, calldataload(add(pubSignals, 128)))
                
                g1_mulAccC(_pVk, IC6x, IC6y, calldataload(add(pubSignals, 160)))
                
                g1_mulAccC(_pVk, IC7x, IC7y, calldataload(add(pubSignals, 192)))
                

                // -A
                mstore(_pPairing, calldataload(pA))
                mstore(add(_pPairing, 32), mod(sub(q, calldataload(add(pA, 32))), q))

                // B
                mstore(add(_pPairing, 64), calldataload(pB))
                mstore(add(_pPairing, 96), calldataload(add(pB, 32)))
                mstore(add(_pPairing, 128), calldataload(add(pB, 64)))
                mstore(add(_pPairing, 160), calldataload(add(pB, 96)))

                // alpha1
                mstore(add(_pPairing, 192), alphax)
                mstore(add(_pPairing, 224), alphay)

                // beta2
                mstore(add(_pPairing, 256), betax1)
                mstore(add(_pPairing, 288), betax2)
                mstore(add(_pPairing, 320), betay1)
                mstore(add(_pPairing, 352), betay2)

                // vk_x
                mstore(add(_pPairing, 384), mload(add(pMem, pVk)))
                mstore(add(_pPairing, 416), mload(add(pMem, add(pVk, 32))))


                // gamma2
                mstore(add(_pPairing, 448), gammax1)
                mstore(add(_pPairing, 480), gammax2)
                mstore(add(_pPairing, 512), gammay1)
                mstore(add(_pPairing, 544), gammay2)

                // C
                mstore(add(_pPairing, 576), calldataload(pC))
                mstore(add(_pPairing, 608), calldataload(add(pC, 32)))

                // delta2
                mstore(add(_pPairing, 640), deltax1)
                mstore(add(_pPairing, 672), deltax2)
                mstore(add(_pPairing, 704), deltay1)
                mstore(add(_pPairing, 736), deltay2)


                let success := staticcall(sub(gas(), 2000), 8, _pPairing, 768, _pPairing, 0x20)

                isOk := and(success, mload(_pPairing))
            }

            let pMem := mload(0x40)
            mstore(0x40, add(pMem, pLastMem))

            // Validate that all evaluations ∈ F
            
            checkField(calldataload(add(_pubSignals, 0)))
            
            checkField(calldataload(add(_pubSignals, 32)))
            
            checkField(calldataload(add(_pubSignals, 64)))
            
            checkField(calldataload(add(_pubSignals, 96)))
            
            checkField(calldataload(add(_pubSignals, 128)))
            
            checkField(calldataload(add(_pubSignals, 160)))
            
            checkField(calldataload(add(_pubSignals, 192)))
            

            // Validate all evaluations
            let isValid := checkPairing(_pA, _pB, _pC, _pubSignals, pMem)

            mstore(0, isValid)
             return(0, 0x20)
         }
     }
 }