// Domain index query APIs for deterministic first-order logic enumeration (V1.1)
// All returned arrays are owned by the index — no copies on read.

import { GeometryWorld } from './world.js'

// ---------------------------------------------------------------------------
// Selector queries
// ---------------------------------------------------------------------------

/**
 * Return all element subject IDs that match the given CSS selector string.
 * Supported selector forms:
 *   - tag name:  "div", "button", "span"
 *   - class:     ".button", ".card"
 * Returns a sorted array owned by the world selectorIndex.
 * If the selector is not indexed, returns an empty array.
 */
export function getElementsBySelector(world: GeometryWorld, selector: string): number[] {
  const normalized = selector.trim()
  return world.selectorIndex.get(normalized) ?? []
}

// ---------------------------------------------------------------------------
// Ancestor / descendant queries
// ---------------------------------------------------------------------------

/**
 * Return all descendant element subject IDs of `parentId`.
 * If `selector` is provided, filter to those matching the selector.
 * Returns a sorted array owned by the world ancestorIndex (or a filtered copy).
 */
export function getDescendants(world: GeometryWorld, parentId: number, selector?: string): number[] {
  const all = world.ancestorIndex.get(parentId) ?? []
  if (!selector) {
    return all
  }
  const matched = getElementsBySelector(world, selector)
  if (matched.length === 0) {
    return []
  }
  // Intersect two sorted arrays without allocating intermediates.
  const out: number[] = []
  let i = 0
  let j = 0
  while (i < all.length && j < matched.length) {
    const a = all[i]
    const b = matched[j]
    if (a === b) {
      out.push(a)
      i++
      j++
    } else if (a < b) {
      i++
    } else {
      j++
    }
  }
  return out
}

// ---------------------------------------------------------------------------
// Text geometry queries
// ---------------------------------------------------------------------------

/**
 * Return line box fragment IDs for the given text node subject ID.
 * Returns a sorted array owned by the world lineBoxIndex.
 */
export function getLineBoxes(world: GeometryWorld, textNodeId: number): number[] {
  return world.lineBoxIndex.get(textNodeId) ?? []
}

/**
 * Return text run IDs for the given text node subject ID.
 * Returns a sorted array owned by the world textRunIndex.
 */
export function getTextRuns(world: GeometryWorld, textNodeId: number): number[] {
  return world.textRunIndex.get(textNodeId) ?? []
}