Add new view bill run presenter (#541)

https://eaflood.atlassian.net/browse/WATER-4223

This presenter has been added to format the bill run data used in a new bill run page that will replace the existing one in the legacy service.

The page displays top-level details about the bill run (date created type, region etc) and then a summary for each bill linked to the bill run. This presenter handles the top-level information returned by `FetchBillRunService`.

app/presenters/bill-runs/view-bill-run.presenter.js

@@ -0,0 +1,135 @@
+'use strict'
+
+/**
+ * Formats bill run data ready for presenting in the view bill run page
+ * @module ViewBillRunPresenter
+ */
+
+const {
+  capitalize,
+  formatLongDate,
+  formatMoney
+} = require('../base.presenter.js')
+
+function go (billRun) {
+  const {
+    batchType,
+    billingBatchId,
+    billRunNumber,
+    createdAt,
+    creditNoteCount,
+    creditNoteValue,
+    invoiceCount,
+    invoiceValue,
+    isSummer,
+    netTotal,
+    region,
+    scheme,
+    status,
+    transactionFileReference,
+    toFinancialYearEnding
+  } = billRun
+
+  const billRunType = _billRunType(batchType, isSummer, scheme)
+  const regionName = capitalize(region.displayName)
+
+  return {
+    billsCount: _billsCount(creditNoteCount, invoiceCount, billRunType),
+    billRunId: billingBatchId,
+    billRunNumber,
+    billRunStatus: status,
+    billRunTotal: _billRunTotal(netTotal),
+    billRunType,
+    chargeScheme: _chargeScheme(scheme),
+    creditsCount: _creditsCount(creditNoteCount),
+    creditsTotal: formatMoney(creditNoteValue),
+    dateCreated: formatLongDate(createdAt),
+    debitsCount: _debitsCount(invoiceCount),
+    debitsTotal: formatMoney(invoiceValue),
+    displayCreditDebitTotals: _displayCreditDebitTotals(billRun),
+    financialYear: _financialYear(toFinancialYearEnding),
+    pageTitle: _pageTitle(regionName, billRunType),
+    region: regionName,
+    transactionFile: transactionFileReference
+  }
+}
+
+function _billsCount (creditsCount, debitsCount, billRunType) {
+  const total = creditsCount + debitsCount
+
+  if (total === 1) {
+    return `1 ${billRunType} bill`
+  }
+
+  return `${total} ${billRunType} bills`
+}
+
+function _billRunTotal (valueInPence) {
+  const valueAsMoney = formatMoney(valueInPence)
+
+  if (valueInPence < 0) {
+    return `${valueAsMoney} credit`
+  }
+
+  return valueAsMoney
+}
+
+function _billRunType (batchType, isSummer, scheme) {
+  if (batchType !== 'two_part_tariff') {
+    return capitalize(batchType)
+  }
+
+  if (scheme === 'sroc') {
+    return 'Two-part tariff'
+  }
+
+  if (isSummer) {
+    return 'Two-part tariff summer'
+  }
+
+  return 'Two-part tariff winter and all year'
+}
+
+function _chargeScheme (scheme) {
+  if (scheme === 'sroc') {
+    return 'Current'
+  }
+
+  return 'Old'
+}
+
+function _creditsCount (count) {
+  if (count === 1) {
+    return '1 credit note'
+  }
+
+  return `${count} credit notes`
+}
+
+function _debitsCount (count) {
+  if (count === 1) {
+    return '1 invoice'
+  }
+
+  return `${count} invoices`
+}
+
+function _displayCreditDebitTotals (billRun) {
+  const { batchType } = billRun
+
+  return batchType === 'supplementary'
+}
+
+function _financialYear (financialYearEnding) {
+  return `${financialYearEnding - 1} to ${financialYearEnding}`
+}
+
+function _pageTitle (regionName, billRunType) {
+  const lowercaseBillRunType = billRunType.toLowerCase()
+
+  return `${regionName} ${lowercaseBillRunType}`
+}
+
+module.exports = {
+  go
+}