function ensureArray(value) {
  return Array.isArray(value) ? value : []
}

function pickFirstText() {
  for (let index = 0; index < arguments.length; index += 1) {
    const value = arguments[index]
    if (value === null || value === undefined) continue
    const text = String(value).trim()
    if (text) return text
  }
  return ''
}

function normalizeNumber(value, fallback = 0) {
  const num = Number(value)
  return Number.isFinite(num) ? num : fallback
}

function normalizeTodoEntry(raw) {
  if (raw && typeof raw === 'object') {
    return {
      ...raw,
      _todoCode: pickFirstText(raw.code, raw.no, raw.contractNo, raw.billNo, raw.orderNo, raw.referenceTypeNo)
    }
  }
  const text = pickFirstText(raw)
  return text ? { code: text, _todoCode: text } : null
}

function extractTodoEntries(item) {
  const sourceList = [item && item.items, item && item.codes, item && item.list, item && item.data]
  for (let index = 0; index < sourceList.length; index += 1) {
    const current = sourceList[index]
    if (!Array.isArray(current)) continue
    return current.map(entry => normalizeTodoEntry(entry)).filter(Boolean)
  }
  return []
}

export function extractTodoRows(response) {
  const payload = response && response.data !== undefined ? response.data : response
  if (Array.isArray(payload)) return payload
  if (!payload || typeof payload !== 'object') return []
  if (Array.isArray(payload.data)) return payload.data
  if (payload.data && Array.isArray(payload.data.data)) return payload.data.data
  return []
}

export function normalizeTodoList(rows = []) {
  return ensureArray(rows).map((item) => {
    const entries = extractTodoEntries(item)
    const count = Math.max(normalizeNumber(item && item.count, entries.length), entries.length)
    return {
      todoType: String(item && item.todoType !== undefined ? item.todoType : ''),
      todoTypeDesc: pickFirstText(item && item.todoTypeDesc),
      count,
      entries,
      codes: entries
        .map(entry => ({ code: pickFirstText(entry && entry._todoCode) }))
        .filter(entry => entry.code)
    }
  }).filter(item => item.count > 0 || item.entries.length > 0 || item.todoTypeDesc)
}