const _ = require('lodash/fp')
const pgp = require('pg-promise')()
const uuid = require('uuid')

const BN = require('./bn')
const db = require('./db')
const wallet = require('./wallet')

function createTransactionBatch (cryptoCode) {
  const sql = `INSERT INTO transaction_batches (id, crypto_code) VALUES ($1, $2) RETURNING *`

  return db.one(sql, [uuid.v4(), cryptoCode])
}

function addTransactionToBatch (tx) {
  const sql = `SELECT * FROM transaction_batches WHERE crypto_code=$1 AND status='open' ORDER BY created_at DESC LIMIT 1`
  const sql2 = `UPDATE cash_in_txs SET batch_id=$1 WHERE id=$2`

  return db.oneOrNone(sql, [tx.cryptoCode])
    .then(batch => {
      if (_.isNil(batch))
        return createTransactionBatch(tx.cryptoCode)
      return Promise.resolve(batch)
    })
    .then(batch => db.none(sql2, [batch.id, tx.id]))
}

function closeTransactionBatch (t, batch) {
  const sql = `UPDATE transaction_batches SET status='ready', closed_at=now() WHERE id=$1`

  return t.none(sql, [batch.id])
}

function confirmSentBatch (t, batch, tx) {
  return t.none(`UPDATE transaction_batches SET status='sent', error_message=NULL WHERE id=$1`, [batch.id])
    .then(() =>
      t.none(`UPDATE cash_in_txs SET tx_hash=$1, fee=$2, send=true, send_confirmed=true, send_time=now(), send_pending=false, error=NULL, error_code=NULL WHERE batch_id=$3`, [tx.txid, tx.fee.toString(), batch.id])
    )
}

function setErroredBatch (t, batch, errorMsg) {
  const sql = `UPDATE transaction_batches SET status='failed', error_message=$1 WHERE id=$2`

  return t.none(sql, [errorMsg, batch.id])
}

function getBatchTransactions (t, batch) {
  const sql = `SELECT * FROM cash_in_txs WHERE batch_id=$1`
  return t.manyOrNone(sql, [batch.id])
}

function getBatchesByStatus (t, statuses) {
  const sql = `SELECT *, EXTRACT(EPOCH FROM (now() - created_at)) as time_elapsed FROM transaction_batches WHERE status in ($1^)`

  return t.manyOrNone(sql, [_.map(pgp.as.text, statuses).join(',')])
}

function submitBatch (t, settings, batch) {
  getBatchTransactions(t, batch)
    .then(txs => {
      wallet.sendCoinsBatch(settings, txs, batch.crypto_code)
        .then(res => confirmSentBatch(t, batch, res))
        .catch(err => setErroredBatch(t, batch, err.message))
    })
}

function processBatches (settings, lifecycle) {
  const transaction = t => {
    getBatchesByStatus(t, ['open', 'failed', 'ready'])
      .then(batches => {
        _.each(batch => {
          const elapsedMS = batch.time_elapsed * 1000

          if (elapsedMS >= lifecycle) {
            return closeTransactionBatch(t, batch)
              .then(() => submitBatch(t, settings, batch))
          }
        }, batches)
      })
  }

  return db.tx(
    new pgp.txMode.TransactionMode({ tiLevel: pgp.txMode.isolationLevel }),
    transaction
  )
}

module.exports = {
  createTransactionBatch,
  closeTransactionBatch,
  addTransactionToBatch,
  processBatches
}