import { BREADCRUMB_PAGE_TYPE_PARENTS } from '#base_modules/WebManager/config/general'

/**
 * Utility functions that identify candidate pages for buildBreadcrumbs database queries.
 * Breadcrumbs climb hierarchically from a target page to the home page.
 * To avoid querying all published pages in a locale, queries are filtered down to two
 * predictable sets of candidates:
 *  1. Path-based ancestors: The small chain of parent paths above the target page.
 *  2. Group-key ancestors: Static relationships where pages belong to a specific parent
 *     type regardless of location (e.g., blog-item under blog).
 */

export const BREADCRUMB_PARENT_GROUP_KEYS = [
  ...new Set(Object.values(BREADCRUMB_PAGE_TYPE_PARENTS)),
]

/**
 * The paths a page can climb to, nearest parent first, ending at the home page (`''`).
 *
 *   'blog/post/hello' → ['blog/post', 'blog', '']
 *   'about'           → ['']
 *   ''                → ['']
 *
 * The page's own path is never included — a page cannot be its own parent.
 */
export function ancestorPaths(path: string) {
  const segments = path.split('/').filter(Boolean)
  const paths: string[] = []

  for (let depth = segments.length - 1; depth >= 1; depth--) {
    paths.push(segments.slice(0, depth).join('/'))
  }

  paths.push('')

  return paths
}

/**
 * True when `path` is an already loaded path or an ancestor of one. Only false after a
 * group-key jump to another branch, never during a path climb.
 */
export function ancestorsAlreadyLoaded(path: string, loadedPaths: Iterable<string>) {
  for (const loaded of loadedPaths) {
    // The trailing slash keeps 'blog' from matching 'blogging'; '' matches every path.
    if (loaded === path || loaded.startsWith(path === '' ? '' : `${path}/`)) return true
  }

  return false
}