import _ from "lodash-es"

export async function generateTaxonomy({ config: actionConfig }) {
  if (!Array.isArray(actionConfig.inputs)) {
    return {
      detail: actionConfig.indexOn ? {} : [],
      ref: actionConfig.name,
    }
  }
  const orderBy = actionConfig.orderBy || "date"
  const inputs = actionConfig.inputs
  const sortedInputs = actionConfig.sortAscending
    ? _.sortBy(inputs, orderBy)
    : _.sortBy(inputs, orderBy).reverse()
  const buildEntry = item => actionConfig.properties
    ? actionConfig.properties.reduce(
      (ent, prop) => ({ ...ent, [prop]: item[prop] }),
      {},
    )
    : item

  if (!actionConfig.indexOn) {
    return {
      detail: sortedInputs.map(buildEntry),
      ref: actionConfig.name,
    }
  }

  const groupOrder = []
  const groupSeen = new Set()
  for (const item of inputs) {
    const items = item?.[actionConfig.indexOn]
    const normalizedItems = Array.isArray(items)
      ? items
      : (items == null ? [] : [items])
    for (const value of normalizedItems) {
      if (!groupSeen.has(value)) {
        groupSeen.add(value)
        groupOrder.push(value)
      }
    }
  }

  const groups = new Map(groupOrder.map(value => [value, []]))
  for (const item of sortedInputs) {
    const items = item?.[actionConfig.indexOn]
    const normalizedItems = Array.isArray(items)
      ? items
      : (items == null ? [] : [items])
    if (normalizedItems.length === 0) continue
    const entry = buildEntry(item)
    for (const value of normalizedItems) {
      if (!groups.has(value)) {
        groups.set(value, [])
      }
      groups.get(value).push(entry)
    }
  }

  const taxonomy = Object.fromEntries(groups)
  return {
    detail: taxonomy,
    ref: actionConfig.name,
  }
}