/**
 * Fetch current reward fund, pick `recent_claims` and `reward_balance`
 * @returns {Promise<{recentClaims: number, rewardBalance: number}>}
 */
const getFund = async () => {
    const response = await fetch(
        'https://api.hive.blog/', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({
                id: 0,
                jsonrpc: '2.0',
                method: 'condenser_api.get_reward_fund',
                params: ['post'],
            })
        }
    )
    const json = await response.json()
    const result = json.result
    return {
        recentClaims: parseInt(result.recent_claims, 10),
        rewardBalance: parseInt(result.reward_balance.split(' ')[0], 10),
    }
}

/**
 * Get HBD price. `quote` is the desired value (i.e. 1 USD), and the `base` is the current value.
 * @returns {Promise<{quote: number, base: number}>}
 */
const getHbdPrice = async () => {
    const response = await fetch(
        'https://api.hive.blog/', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({
                id: 0,
                jsonrpc: '2.0',
                method: 'condenser_api.get_current_median_history_price',
                params: [],
            })
        }
    )
    const json = await response.json()
    const result = json.result
    return {
        base: parseFloat(result.base.split(' ')[0]),
        quote: parseFloat(result.quote.split(' ')[0]),
    }
}

/**
 * Fetch user info. We mostly care about the `vests` of that user, and optionally
 * about the voting power that the user currently has.
 * @param username
 * @returns {Promise<{votingPower: number, vests: number, username: string}>}
 */
const getUser = async ({ username }) => {
    const response = await fetch(
        'https://api.hive.blog/', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({
                id: 0,
                jsonrpc: '2.0',
                method: 'condenser_api.get_accounts',
                params: [[username]],
            })
        }
    )
    const json = await response.json()
    const result = json.result[0]
    const totalVests = (
        parseFloat(result.vesting_shares.split(' ')[0])
        + parseFloat(result.received_vesting_shares.split(' ')[0])
        - parseFloat(result.delegated_vesting_shares.split(' ')[0])
    )
    return {
        username,
        vests: totalVests,
        votingPower: result.voting_power,
    }

}


/**
 * Estimate a USD vote value, based on an account `vests` and the current reward balance.
 * @param {number} vests        The amount of vests that an account holds
 * @param {number} votingPower  Voting power of that account, 0-100 (max by default)
 * @param {number} voteWeight   The weight of the vote, 0-100 (max by default)
 * @param {{recentClaims:number,rewardBalance:number}} fund
 * @param {number} hbdValue     The current value of HBD
 * @returns {number}
 */
const estimateVoteValue = ({
   vests = 0,
   votingPower = 100,
   voteWeight = 100,
   fund = {
       recentClaims: 0,
       rewardBalance: 0
   },
   hbdValue = 1.0,
}) => {
    const power = ((votingPower * 100) * (voteWeight * 100) / 10000) / 50
    const rShares = power * vests * 1000000 / 10000
    return rShares / fund.recentClaims * fund.rewardBalance * hbdValue
}

/**
 * Get the USD vote value of a given user. By default, it will check the vote value
 * when 100% voting power, but you can pass fullVotingPower=false to check the current vote value.
 * @param {string} username
 * @param {boolean} fullVotingPower
 * @returns {Promise<number>}
 */
const getUserVoteValue = async ({ username, fullVotingPower = true }) => {
    const fund = await getFund()
    const hbdPrice = await getHbdPrice()
    const user = await getUser({ username })
    return estimateVoteValue({
        vests: user.vests,
        votingPower: fullVotingPower ? 100 : user.votingPower,
        fund,
        hbdValue: hbdPrice.base,
    })
}

getUserVoteValue({ username: 'cryptosharon' })
    .then(voteValue => {
        console.info('Vote value: ' + voteValue)
    })