import moment from 'moment'
export function appendTag (row, keywords, field = 'Libellé') {
  // Append row.tag
  // if row.libellé contains one of words and not invert it gets tagged
  // if row.libellé contains no words and invert it gets tagged
  // according to keywords [{name: string, words: [], invert: bool}]
  row.tags = keywords.filter(k => {
    return strContains(row[field], k.words, k.invert)
  })
}

function strContains (string, words, invert) {
  // Does a string contain one of words or the opposite
  if (!words) {
    return true
  }
  if (invert) {
    return words.every(v => {
      return string.toLowerCase().indexOf(v.toLowerCase()) < 0
    })
  } else {
    return words.some(v => {
      return string.toLowerCase().indexOf(v.toLowerCase()) >= 0
    })
  }
}

export function formatDate (row, field = 'Date') {
  row[field] = moment(row[field], 'DD/MM/YYYY', true)
}

export function total (rows, field = 'Montant') {
  var sum = rows.map(x => parseFloat(x[field]))
    .reduce((sum, x) => sum + x, 0)
  return Math.round(sum)
}

export function tag_filter (rows, tags, invert=false) {
  // filter rows by tags
  // invert inverts the selection
  return rows.filter(row => {
    if (invert) {
      return tags.some(t => {
        return row.tags.map(t => t.name.toLowerCase())
          .indexOf(t.toLowerCase()) < 0
      })
    } else {
      return tags.every(t => {
        return row.tags.map(t => t.name.toLowerCase())
          .indexOf(t.toLowerCase()) > -1
      })
    }
  })
}

function objectMap (object, mapFn) {
  // map a function on object value
  return Object.keys(object).reduce(function(result, key) {
    result[key] = mapFn(object[key])
    return result
  }, {})
}

export function groupBy (rows, grouping, agg) {
  // Group rows by field then apply agg
  var groups = rows.reduce((stock, row) => {
    var group = grouping(row)
    if (stock[group]) {
      stock[group].push(row)
    } else {
      stock[group] = [row]
    }
    return stock
  }, {})
  return objectMap(groups, group => agg(group))
}