# [ETH Taipei] Unirep workshop

## Github
- https://github.com/unirep/create-unirep-app

## CLI

npx create-unirep-app

yarn build
yarn start

## post

event Post(uint256 indexed epochKey, uint256 content);

function post(
        // epoch key 
        uint256[] memory publicSignals,
        uint256[8] memory proof,
        uint256 content
    ) public{
        unirep.verifyEpochKeyProof(publicSignals, proof);
        Unirep.EpochKeySignals memory signals = unirep.decodeEpochKeySignals(publicSignals);
        
        emit Post(signals.epochKey, content);
    }

## post test

    it('post', async() => {
        const userState = await genUserState(id, app)
        const {publicSignals, proof} = await userState.genEpochKeyProof()
        const content = 123

        await app.post(publicSignals, proof, content).then(t=>t.wait())
    })

## vote

function vote(
        uint256 epochKey,
        uint256 upvote,
        uint256 downvote,
        // epoch key 
        uint256[] memory publicSignals,
        uint256[8] memory proof
    ) public {
        unirep.verifyEpochKeyProof(publicSignals, proof);
        Unirep.EpochKeySignals memory signals = unirep.decodeEpochKeySignals(publicSignals);

        uint fieldIndex = upvote > 0 ? 0 : 1;
        uint val = upvote > 0 ? upvote : downvote;
        unirep.attest(
            epochKey,
            uint48(signals.epoch),
            fieldIndex,
            val
        );
    }

## vote-test

it('vote', async() => {
        const userState = await genUserState(id, app)
        const upvote = 3
        const downvote = 0

        const {publicSignals, proof} = await userState.genEpochKeyProof({nonce: 1, revealNonce: true})
        
        await app.vote(epk, upvote, downvote, publicSignals, proof).then(t=>t.wait())
    })

## circuit

pragma circom 2.0.0;

include "../../../node_modules/@unirep/circuits/circuits/epochKey.circom";
include "../../../node_modules/@unirep/circuits/circuits/circomlib/circuits/comparators.circom";

template NotEpochKey(STATE_TREE_DEPTH, EPOCH_KEY_NONCE_PER_EPOCH, FIELD_COUNT) {
    // Global state tree
    signal input state_tree_indexes[STATE_TREE_DEPTH];
    signal input state_tree_elements[STATE_TREE_DEPTH];
    // Global state tree leaf: Identity & user state root
    signal input identity_secret;

    signal output epoch_key;
    signal output state_tree_root;

    signal input reveal_nonce;
    signal input attester_id;
    signal input epoch;
    signal input nonce;

    signal input data[FIELD_COUNT];

    // Some arbitrary data to endorse
    signal input sig_data;
    signal input not_epoch_key; // the identity_secret doesn't own this key

    signal output control;

    // extend epoch key proof
    component epochKey = EpochKey(STATE_TREE_DEPTH, EPOCH_KEY_NONCE_PER_EPOCH, FIELD_COUNT);
    for(var i = 0; i < STATE_TREE_DEPTH; i++) {
        epochKey.state_tree_indexes[i] <== state_tree_indexes[i];
        epochKey.state_tree_elements[i] <== state_tree_elements[i];
    }
    epochKey.identity_secret <== identity_secret;
    epochKey.reveal_nonce <== reveal_nonce;
    epochKey.attester_id <== attester_id;
    epochKey.epoch <== epoch;
    epochKey.nonce <== nonce;
    for(var i = 0; i < FIELD_COUNT; i++) {
        epochKey.data[i] <== data[i];
    }
    epochKey.sig_data <== sig_data;
    control <== epochKey.control;
    epoch_key <== epochKey.epoch_key;
    state_tree_root <== epochKey.state_tree_root;
    
    component epoch_key_hashers[EPOCH_KEY_NONCE_PER_EPOCH]; 
    component is_equals[EPOCH_KEY_NONCE_PER_EPOCH];
    for(var i = 0; i < EPOCH_KEY_NONCE_PER_EPOCH; i++ ){
        epoch_key_hashers[i] = Poseidon(4);
        epoch_key_hashers[i].inputs[0] <== identity_secret;
        epoch_key_hashers[i].inputs[1] <== attester_id;
        epoch_key_hashers[i].inputs[2] <== epoch;
        epoch_key_hashers[i].inputs[3] <== i;

        is_equals[i] = IsEqual();
        is_equals[i].in[0] <== epoch_key_hashers[i].out;
        is_equals[i].in[1] <== not_epoch_key;
        is_equals[i].out === 0;
    }

}

## circuilt cli

cd packages/circuits &&
yarn buildsnark

## telegram group
https://t.me/+qc2_ppTWgc84Njg9