const Flume = require('flumedb')
const Reduce = require('flumeview-reduce')
const FlumeLog = require('flumelog-offset')
const {pull, once, drain} = require('pull-stream')
const codec = require('flumecodec')

function ledger (state, emitter) {
  state.accounts = {}
  state.entries = []

  const db = Flume(FlumeLog('.test.db', {codec: codec.json}))
    .use('entries', Reduce( 1, entriesReducer, null, null, []))
    .use('accounts', Reduce(1, accountReducer, null, null, {}))

  pull(db.accounts.stream({live: true}), drain(acct => console.log('account stream:', acct)))
  pull(db.entries.stream({live: true}), drain(entry => console.log('entries stream:', entry)))

  const onDone = () => console.log('DONE')
  pull(db.accounts.stream(), drain(acctState => {
    console.log('ACCOUNT STATE', acctState)
    state.accounts = acctState
    emitter.emit.RENDER
  }, onDone))
  pull(db.entries.stream(), drain(entryState => {
    console.log('ENTRY STATE', entryState)
    state.entries = entryState
    emitter.emit.RENDER
  }, onDone))

  function onLoad () {
    emitter.on('accounts', onEvent)
    emitter.on('entries', onEvent)
  }

  function onEvent (data) {
    db.append(data, (err, seq) => {
      if (err) throw err
      emitter.emit(state.events.RENDER)
    })
  }

  emitter.on('DOMContentLoaded', onLoad)

  function entriesReducer (acc, item) {
    if (item.type !== 'entries') return acc
    acc.push(item)

    return acc
  }

  function accountReducer (acc, item) { // TODO account for account creation of existing account
    if (item.type === 'entries') {
      const {msg} = item
      const debit = acc[msg.debit].debit += msg.amount
      const credit = acc[msg.credit].credit += msg.amount

      return acc
    }
    if (item.type !== 'accounts') return acc
    const { msg } = item

    if (!acc[msg.name]) {
      acc[msg.name] = msg

      return acc
    }

    Object.assign(acc[msg.name], msg)
    Object.assign(state.accounts[msg.name], msg)
    return acc
  }
}


module.exports = ledger