import type { Note } from '@/lib/types'

const MD_IMG = /!\[[^\]]*\]\(([^)\s]+)\)/g
const HTML_IMG = /<img[^>]+src=["']([^"']+)["'][^>]*>/gi

/** SSR-safe HTML entity decode so excerpt text matches server and client. */
function decodeHtmlEntities(text: string): string {
  return text
    .replace(/&nbsp;/gi, ' ')
    .replace(/&amp;/g, '&')
    .replace(/&lt;/g, '<')
    .replace(/&gt;/g, '>')
    .replace(/&quot;/g, '"')
    .replace(/(?:&#0*39;|&apos;)/g, "'")
    .replace(/&#(\d+);/g, (_, code: string) => {
      const n = Number(code)
      return n > 0 && n < 0x110000 ? String.fromCodePoint(n) : `&#${code};`
    })
    .replace(/&#x([0-9a-f]+);/gi, (_, hex: string) => {
      const n = parseInt(hex, 16)
      return n > 0 && n < 0x110000 ? String.fromCodePoint(n) : `&#x${hex};`
    })
}

/**
 * Plain-text preview for list view (light markdown stripping).
 */
export function stripMarkdownPreview(raw: string, maxLen = 180): string {
  if (!raw?.trim()) return ''
  const t = raw
    .replace(/^#{1,6}\s+/gm, '')
    .replace(/```[\s\S]*?```/g, ' ')
    .replace(/\*\*([^*]+)\*\*/g, '$1')
    .replace(/\*([^*]+)\*/g, '$1')
    .replace(/`([^`]+)`/g, '$1')
    .replace(/\[(.+?)]\([^)]+\)/g, '$1')
    .replace(/^\s*[-*+]\s+/gm, '')
    .replace(/^\s*\d+\.\s+/gm, '')
    .replace(/\n+/g, ' ')
    .replace(/\s+/g, ' ')
    .trim()
  if (t.length > maxLen) {
    return `${t.slice(0, maxLen).trim()}…`
  }
  return t
}

export function getNoteDisplayTitle(note: { title: string | null; content: string; type: string }, untitled: string): string {
  const title = note.title?.trim()
  if (title) return title
  if (note.type === 'checklist') {
    const line = note.content?.split('\n').find((l) => l.trim())
    if (line) return stripMarkdownPreview(line, 80) || untitled
  }
  const preview = stripMarkdownPreview(note.content || '', 100)
  return preview || untitled
}

export function getNoteFeedImage(note: Note): string | null {
  const first = note.images?.[0]?.trim()
  if (first) return first

  const content = note.content || ''
  MD_IMG.lastIndex = 0
  const md = MD_IMG.exec(content)
  if (md?.[1]) return md[1]

  HTML_IMG.lastIndex = 0
  const html = HTML_IMG.exec(content)
  if (html?.[1]) return html[1]

  return null
}

/** Plain excerpt for collection cards (HTML + markdown noise stripped). */
export function getNotePlainExcerpt(note: Note, maxLen = 240): string {
  let raw = note.content || ''
  raw = raw.replace(/!\[[^\]]*\]\([^)]+\)/g, ' ')
  raw = raw.replace(/<[^>]+>/g, ' ')
  raw = decodeHtmlEntities(raw)
  return stripMarkdownPreview(raw, maxLen)
}

/** Adapte un SVG miniature (viewBox 4:3 liste) pour remplir une vignette carte 16:10. */
export function prepareNoteIllustrationForGrid(svg: string): string {
  return svg.replace(/<svg([^>]*)>/i, (_, attrs: string) => {
    let next = attrs.replace(/\s(width|height)=["'][^"']*["']/gi, '')
    if (/preserveAspectRatio=/i.test(next)) {
      next = next.replace(/preserveAspectRatio=["'][^"']*["']/i, 'preserveAspectRatio="xMidYMid slice"')
    } else {
      next += ' preserveAspectRatio="xMidYMid slice"'
    }
    return `<svg${next} width="100%" height="100%">`
  })
}