factom-vote/src/write-vote/participate-vote.js

JS implementation of the Factom voting specification

const { getPublicAddress } = require('factom'),
    { getVoteIdentity } = require('../factom-identity'),
    { getVoteDefinition } = require('../read-vote/read-vote'),
    { generateVoteCommitEntry, generateVoteRevealEntry } = require('./participate-vote-struct');

async function commitVote(cli, identityResolvers, voteChainId, vote, identity, ecAddress, skipValidation) {

    if (!skipValidation) {
        const definition = await getVoteDefinition(cli, identityResolvers.publicKeysResolver, voteChainId);
        validateOptions(definition.data.vote.config, vote.vote);
        const { commitStart, commitEnd } = definition.data.vote.phasesBlockHeights;
        await validateBlockHeightInterval(cli, 'commit', commitStart, commitEnd);
    }

    const voter = await getVoteIdentity(identityResolvers, identity);
    const entry = await generateVoteCommitEntry(voteChainId, vote, voter);
    validateFunds(cli, entry.ecCost(), ecAddress, 'Cannot commit vote');

    return cli.add(entry, ecAddress);
}

function validateOptions(config, voterOptions) {
    const validNumberOfOptionsSelected = (config.allowAbstention && voterOptions.length === 0) ||
        (voterOptions.length >= config.minOptions && voterOptions.length <= config.maxOptions);

    if (!validNumberOfOptionsSelected) {
        throw new Error(`Invalid number of options selected. Min: ${config.minOptions}. Max: ${config.maxOptions}. Abstention allowed: ${config.allowAbstention}.`);
    }

    if (!voterOptions.every(o => config.options.includes(o))) {
        throw new Error('At least one of the selected options is not part of the vote available options.');
    }
}

async function revealVote(cli, publicKeysResolver, voteChainId, vote, voterId, ecAddress, skipValidation) {
    if (!skipValidation) {
        const definition = await getVoteDefinition(cli, publicKeysResolver, voteChainId);
        const { commitEnd, revealEnd } = definition.data.vote.phasesBlockHeights;
        await validateBlockHeightInterval(cli, 'reveal', commitEnd + 1, revealEnd);
    }

    const entry = generateVoteRevealEntry(voteChainId, vote, voterId);
    validateFunds(cli, entry.ecCost(), ecAddress, 'Cannot reveal vote');

    return cli.add(entry, ecAddress);
}

async function validateFunds(cli, ecCost, ecAddress, message) {
    const balance = await cli.getBalance(ecAddress);

    if (ecCost > balance) {
        throw new Error(`${message}. Not enough EC on ${getPublicAddress(ecAddress)}. Required: ${ecCost} EC. Available: ${balance} EC`);
    }
}

async function validateBlockHeightInterval(cli, action, start, end) {
    const currentHeight = await cli.getHeights().then(h => h.leaderHeight + 1);

    if (currentHeight < start || currentHeight > end) {
        throw new Error(`The height of the current block being built (${currentHeight}) is not within the block height range of the vote ${action}:  [${start}, ${end}]`);
    }
}


module.exports = {
    generateVoteCommitEntry,
    generateVoteRevealEntry,
    commitVote,
    revealVote
};