import { computed, unref } from 'vue'
import { getInArticleAdAfterBlockIds } from '../lib/content-in-article-ad.js'
import { getContentLightboxImages } from '../lib/content-gallery-images.js'
import { parseMarkdownBlocks } from '../lib/markdown-block-parser.js'
import { createHeadingIdFactory } from '../lib/markdown-toc.js'

/**
 * 공개 Markdown 본문의 렌더링 블록 계산 상태를 만든다.
 * @param {Object} options - 계산 옵션
 * @param {import('vue').Ref<string>|string} options.content - Markdown 본문
 * @param {import('vue').Ref<boolean>|boolean} options.interactive - 관리자 라이브 편집 여부
 * @param {import('vue').Ref<string>|string} options.inArticleAdCode - 인아티클 광고 코드
 * @returns {{
 *   blocks: import('vue').ComputedRef<Array<Object>>,
 *   normalizedInArticleAdCode: import('vue').ComputedRef<string>,
 *   inArticleAdAfterBlockIds: import('vue').ComputedRef<string[]>,
 *   headingIdsByBlock: import('vue').ComputedRef<Record<string, string>>,
 *   renderBlocks: import('vue').ComputedRef<Array<Object>>,
 *   tailInsertBeforeLine: import('vue').ComputedRef<number>,
 *   contentLightboxImages: import('vue').ComputedRef<Array<Object>>
 * }} 본문 블록 계산 결과
 */
export const useContentMarkdownBlocks = (options) => {
  const blocks = computed(() => parseMarkdownBlocks(String(unref(options.content) || '')))
  const normalizedInArticleAdCode = computed(() => String(unref(options.inArticleAdCode) || '').trim())

  /**
   * 본문 인아티클 광고를 삽입할 블록 ID 목록을 반환한다.
   * @returns {string[]} 삽입 기준 블록 ID 목록
   */
  const inArticleAdAfterBlockIds = computed(() => {
    if (unref(options.interactive) || !normalizedInArticleAdCode.value) {
      return []
    }

    return getInArticleAdAfterBlockIds(blocks.value)
  })

  const headingIdsByBlock = computed(() => {
    const createHeadingId = createHeadingIdFactory()
    const ids = {}

    for (const block of blocks.value) {
      if (block.type === 'heading' && block.level >= 1 && block.level <= 3) {
        ids[block.id] = createHeadingId(block.text)
      }
    }

    return ids
  })

  /**
   * 공개 본문 렌더링용 블록 목록을 반환한다.
   * 인아티클 광고는 별도 v-if 대신 블록으로 삽입해 fragment 주석을 줄인다.
   * @returns {Array<Object>} 렌더링 블록 목록
   */
  const renderBlocks = computed(() => {
    const sourceBlocks = blocks.value
    const adAfterBlockIds = inArticleAdAfterBlockIds.value

    if (unref(options.interactive) || !adAfterBlockIds.length) {
      return sourceBlocks
    }

    const adAfterIdSet = new Set(adAfterBlockIds)
    const result = []

    for (const block of sourceBlocks) {
      result.push(block)

      if (adAfterIdSet.has(block.id)) {
        result.push({
          id: `in-article-ad-after-${block.id}`,
          type: 'in-article-ad',
          meta: {
            afterBlockId: block.id
          }
        })
      }
    }

    return result
  })

  /** @type {import('vue').ComputedRef<number>} 문서 맨 아래 단일 이미지 삽입 줄 */
  const tailInsertBeforeLine = computed(() => {
    const lastBlock = blocks.value[blocks.value.length - 1]

    if (typeof lastBlock?.meta?.endLine === 'number') {
      return lastBlock.meta.endLine + 1
    }

    return String(unref(options.content) || '').split('\n').length
  })

  const contentLightboxImages = computed(() => getContentLightboxImages(blocks.value))

  return {
    blocks,
    normalizedInArticleAdCode,
    inArticleAdAfterBlockIds,
    headingIdsByBlock,
    renderBlocks,
    tailInsertBeforeLine,
    contentLightboxImages
  }
}