import logger from './logger.js'

const MAX_PAGES = 100
const PAGE_SIZE = 100

/**
 * Walk every page of a DRF paginated list endpoint and return a single flat
 * array. Falls back to a raw array response for backward compat (some
 * endpoints don't paginate), and stops on any other unexpected shape.
 *
 * @param {import('axios').AxiosInstance} client  shared apiClient
 * @param {string} url  fully-qualified endpoint URL
 * @param {Object} [params]  extra query params (forwarded to every page)
 * @returns {Promise<Array>}
 */
export async function paginatedGet(client, url, params = {}) {
  const all = []
  let page = 1
  let hasNext = true

  logger.debug(`paginatedGet start`, { url })

  while (hasNext) {
    if (page > MAX_PAGES) {
      logger.warn(`paginatedGet hit ${MAX_PAGES}-page cap, stopping`, { url })
      break
    }

    const pageParams = { ...params, page, page_size: PAGE_SIZE }
    const response = await client.get(url, { params: pageParams })
    const data = response.data

    if (data && Array.isArray(data.results)) {
      all.push(...data.results)
      hasNext = !!data.next
      logger.debug(
        `paginatedGet page ${page}: +${data.results.length} (total ${all.length}, hasNext=${hasNext})`,
        { url },
      )
    } else if (Array.isArray(data)) {
      all.push(...data)
      hasNext = false
      logger.debug(`paginatedGet got non-paginated array of ${data.length}`, { url })
    } else {
      logger.warn(`paginatedGet unexpected response shape, stopping`, { url, page })
      hasNext = false
    }

    page++
  }

  logger.debug(`paginatedGet done`, { url, total: all.length })
  return all
}