/** Strapi query fragments. Only the fields the pages actually render are requested. */

const list = (prefix: string, names: readonly string[]) =>
  names.map((name, i) => `${prefix}[${i}]=${name}`).join('&')

const IMAGE_FIELDS = ['url', 'alternativeText', 'width', 'height'] as const

export const ARTICLE_SUMMARY_QUERY = [
  list('fields', ['title', 'slug', 'publishedAt']),
  list('populate[cover][fields]', IMAGE_FIELDS),
  list('populate[category][fields]', ['name', 'slug']),
  'sort[0]=publishedAt:desc',
].join('&')

export const ARTICLE_DETAIL_QUERY = [
  list('fields', ['title', 'slug', 'content', 'publishedAt']),
  list('populate[cover][fields]', IMAGE_FIELDS),
  list('populate[category][fields]', ['name', 'slug']),
  // The byline is the admin user who created the entry; Strapi exposes the
  // name fields only because the content type sets populateCreatorFields.
  list('populate[createdBy][fields]', ['firstname', 'lastname']),
].join('&')

export const PAGE_SIZE = 12

export const pagination = (page: number, pageSize = PAGE_SIZE) =>
  `pagination[page]=${page}&pagination[pageSize]=${pageSize}`

/** Reads a positive integer query param, falling back to 1. */
export const pageParam = (value: unknown): number => {
  const page = Number(value)
  return Number.isInteger(page) && page > 0 ? page : 1
}

export type Locale = 'it' | 'en'

/** Reads the `lang` query param, falling back to the site default `it`. */
export const localeParam = (value: unknown): Locale => (value === 'en' ? 'en' : 'it')