const driver = require('bigchaindb-driver')
// or ES6+
import driver from 'bigchaindb-driver'

const driver = require('bigchaindb-driver')
const base58 = require('bs58');
const crypto = require('crypto');
const { Ed25519Sha256 } = require('crypto-conditions');

// BigchainDB server instance (e.g. https://example.com/api/v1/)
const API_PATH = 'http://localhost:9984/api/v1/'

// Create a new keypair.
const alice = new driver.Ed25519Keypair()

// Construct a transaction payload
const tx = driver.Transaction.makeCreateTransaction(
    // Define the asset to store, in this example it is the current temperature
    // (in Celsius) for the city of Berlin.
    { city: 'Berlin, DE', temperature: 22, datetime: new Date().toString() },

    // Metadata contains information about the transaction itself
    // (can be `null` if not needed)
    { what: 'My first BigchainDB transaction' },

    // A transaction needs an output
    [ driver.Transaction.makeOutput(
            driver.Transaction.makeEd25519Condition(alice.publicKey))
    ],
    alice.publicKey
)

// Sign the transaction with private keys
const txSigned = driver.Transaction.signTransaction(tx, alice.privateKey)

// Or use delegateSignTransaction to provide your own signature function
function signTransaction() {
    // get privateKey from somewhere
    const privateKeyBuffer = Buffer.from(base58.decode(alice.privateKey))
    return function sign(serializedTransaction, input, index) {
        const transactionUniqueFulfillment = input.fulfills ? serializedTransaction
                .concat(input.fulfills.transaction_id)
                .concat(input.fulfills.output_index) : serializedTransaction
        const transactionHash = crypto.createHash('sha3-256').update(transactionUniqueFulfillment).digest()
        const ed25519Fulfillment = new Ed25519Sha256();
        ed25519Fulfillment.sign(transactionHash, privateKeyBuffer);
        return ed25519Fulfillment.serializeUri();
    };
}
const txSigned = driver.Transaction.delegateSignTransaction(tx, signTransaction())

// Send the transaction off to BigchainDB
const conn = new driver.Connection(API_PATH)

conn.postTransactionCommit(txSigned)
    .then(retrievedTx => console.log('Transaction', retrievedTx.id, 'successfully posted.'))

git clone git@github.com:bigchaindb/js-bigchaindb-driver.git
cd js-bigchaindb-driver/

npm i
npm run dev