import { load, type Cheerio, type CheerioAPI } from 'cheerio'
import type { AnyNode } from 'domhandler'

const CALLOUT_PUB_CLASS: Record<string, string> = {
  info: 'pub-callout-info',
  warning: 'pub-callout-warning',
  tip: 'pub-callout-tip',
  success: 'pub-callout-tip',
  danger: 'pub-callout-warning',
}

function stripTags(html: string): string {
  return html.replace(/<[^>]+>/g, ' ').replace(/\s+/g, ' ').trim()
}

function esc(text: string): string {
  return text
    .replace(/&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
}

function firstParagraphText($: CheerioAPI, $el: Cheerio<AnyNode>): string {
  const p = $el.find('p').first()
  const text = p.length ? stripTags(p.html() || '') : stripTags($el.html() || '')
  return text || 'Voir le contenu'
}

function isSolutionToggle(summary: string): boolean {
  return /solution|réponse|answer|corrigé|corrige|reveal|révéler/i.test(summary)
}

function transformToggleBlocks($: CheerioAPI): void {
  $('div[data-type="toggle-block"]').each((_, el) => {
    const $el = $(el)
    const opened = $el.attr('data-opened') !== 'false'
    const innerHtml = $el.html() || ''
    const $inner = load(`<div>${innerHtml}</div>`, { decodeEntities: false } as never)
    const summaryText = firstParagraphText($, $inner.root())

    const firstP = $inner('p').first()
    if (firstP.length && /cliquer|révéler|reveal|click/i.test(stripTags(firstP.html() || ''))) {
      firstP.remove()
    }
    $inner('h3').each((__, h) => {
      if (/solution|réponse|answer/i.test(stripTags($(h).html() || ''))) $(h).remove()
    })

    const bodyHtml = $inner.root().html() || innerHtml
    const isSolution = isSolutionToggle(summaryText)
    const summary = isSolution ? 'Voir la solution' : esc(summaryText.slice(0, 120))
    const cssClass = isSolution ? 'pub-solution' : 'pub-toggle'
    const summaryClass = isSolution ? '' : ' class="pub-toggle-trigger"'
    const bodyClass = isSolution ? 'pub-solution-body' : 'pub-toggle-body'
    const openAttr = opened ? ' open' : ''

    $el.replaceWith(
      `<details class="${cssClass}"${openAttr}><summary${summaryClass}>${summary}</summary><div class="${bodyClass}">${bodyHtml}</div></details>`,
    )
  })
}

function transformCalloutBlocks($: CheerioAPI): void {
  $('div[data-type="callout-block"]').each((_, el) => {
    const $el = $(el)
    if ($el.closest('.pub-exercise').length) return
    const type = ($el.attr('data-callout-type') || 'info').toLowerCase()
    const pubClass = CALLOUT_PUB_CLASS[type] || 'pub-callout-info'
    const inner = $el.html() || ''
    $el.replaceWith(`<div class="pub-callout ${pubClass}">${inner}</div>`)
  })
}

function extractExerciseMeta(headerHtml: string): { label: string; meta: string } {
  const text = stripTags(headerHtml)
  const match = text.match(/(exercice|exercise|تمرین)\s*(\d+)?/i)
  const label = match
    ? `${match[1].charAt(0).toUpperCase()}${match[1].slice(1).toLowerCase()}${match[2] ? ` ${match[2]}` : ''}`
    : 'Exercice'
  const meta = text.replace(new RegExp(label, 'i'), '').replace(/^[\s—–-]+/, '').trim()
  return { label, meta }
}

function isExerciseHeaderEl($: CheerioAPI, $el: Cheerio<AnyNode>): boolean {
  return $el.hasClass('pub-callout-warning')
    && /exercice|exercise|تمرین/i.test(stripTags($el.html() || ''))
}

function isEnonceHeadingEl($: CheerioAPI, $el: Cheerio<AnyNode>): boolean {
  if (!$el.is('h2, h3')) return false
  const text = stripTags($el.html() || '').toLowerCase()
  return /énoncé|enonce|problem|question|statement/.test(text)
}

function bundleExerciseSequences($: CheerioAPI, $root: Cheerio<AnyNode>): void {
  const nodes = $root.children().toArray()
  const out: string[] = []
  let i = 0

  while (i < nodes.length) {
    const $node = $(nodes[i])
    if (!isExerciseHeaderEl($, $node)) {
      out.push($.html(nodes[i]) || '')
      i++
      continue
    }

    const { label, meta } = extractExerciseMeta($node.html() || '')
    const bodyParts: string[] = []
    let solutionHtml = ''
    let j = i + 1

    if (j < nodes.length && isEnonceHeadingEl($, $(nodes[j]))) {
      bodyParts.push($.html(nodes[j]) || '')
      j++
    }

    while (j < nodes.length) {
      const $sib = $(nodes[j])
      if (isExerciseHeaderEl($, $sib)) break
      if ($sib.is('details')) {
        const sum = stripTags($sib.find('summary').first().text())
        $sib.removeClass('pub-toggle').addClass('pub-solution')
        $sib.find('summary').first().text('Voir la solution')
        $sib.find('.pub-toggle-body').removeClass('pub-toggle-body').addClass('pub-solution-body')
        solutionHtml = $.html(nodes[j]) || ''
        j++
        break
      }
      if ($sib.is('h2') && bodyParts.length > 0) break
      bodyParts.push($.html(nodes[j]) || '')
      j++
    }

    const metaSpan = meta ? `<span class="pub-exercise-meta">${esc(meta)}</span>` : ''
    out.push(`<div class="pub-exercise">
      <div class="pub-exercise-header"><span class="pub-exercise-num">${esc(label)}</span>${metaSpan}</div>
      <div class="pub-exercise-body">${bodyParts.join('')}</div>
      ${solutionHtml}
    </div>`)
    i = j
  }

  $root.html(out.join(''))
}

function promoteDefinitionBlocks($: CheerioAPI): void {
  const headings = $('h2, h3').toArray()
  for (const el of headings) {
    const $h = $(el)
    if ($h.closest('.pub-exercise, .pub-definition').length) continue

    const title = stripTags($h.html() || '')
    const $next = $h.next()
    if (!title || title.length > 80 || !$next.length) continue

    const isShortTitle = title.split(/\s+/).length <= 6
    const looksLikeDefinition = /définition|definition|concept/i.test(title)
      || (isShortTitle && $next.is('p, ul, ol') && !/énoncé|exercice|chapitre|partie/i.test(title))

    if (!looksLikeDefinition) continue

    const chunks: Cheerio<AnyNode>[] = []
    let $cursor: Cheerio<AnyNode> | null = $next
    while ($cursor?.length) {
      const tag = $cursor.prop('tagName')?.toLowerCase()
      if (tag === 'h2' || tag === 'h3') break
      if ($cursor.is('p, ul, ol, blockquote')) {
        chunks.push($cursor)
        $cursor = $cursor.next()
      } else break
    }

    if (chunks.length === 0) continue

    const bodyHtml = chunks.map((c) => $.html(c)).join('')
    chunks.forEach((c) => c.remove())
    $h.replaceWith(`<div class="pub-definition">
      <div class="pub-definition-term">${esc(title)}</div>
      <div class="pub-definition-body">${bodyHtml}</div>
    </div>`)
  }
}

function cleanEditorArtifacts($: CheerioAPI): void {
  $('button').remove()
  $('div[data-type="outline-block"]').remove()
  $('.link-preview-searchable').remove()
  $('[contenteditable]').removeAttr('contenteditable')
}

/** Convertit le HTML TipTap en blocs web (exercices, toggles, callouts…). */
export function transformEditorBlocksForPublish(html: string): string {
  if (!html?.trim()) return ''

  const $ = load(`<div id="pub-root">${html}</div>`, { decodeEntities: false } as never)
  const $root = $('#pub-root')

  cleanEditorArtifacts($)
  transformToggleBlocks($)
  transformCalloutBlocks($)
  bundleExerciseSequences($, $root)
  promoteDefinitionBlocks($)
  cleanEditorArtifacts($)

  return $root.html() || ''
}