import { NextRequest, NextResponse } from 'next/server'
import { auth } from '@/auth'
import { extractArticleFromHtml } from '@/lib/clip/extract-article'
import { analyzeClipContent } from '@/lib/clip/analyze-clip'
import { resolveClipLocale, wrapClipPlainParagraph } from '@/lib/clip/rtl-content'

function isBlockedUrl(url: string): boolean {
  try {
    const parsed = new URL(url)
    const hostname = parsed.hostname.toLowerCase()
    const blocked = ['localhost', '127.0.0.1', '0.0.0.0', '::1', '169.254.169.254']
    if (blocked.includes(hostname)) return true
    if (hostname.startsWith('10.') || hostname.startsWith('172.') || hostname.startsWith('192.168.')) return true
    if (parsed.protocol !== 'http:' && parsed.protocol !== 'https:') return true
    return false
  } catch {
    return true
  }
}

async function fetchPageHtml(url: string): Promise<string | null> {
  const controller = new AbortController()
  const timeoutId = setTimeout(() => controller.abort(), 15000)
  try {
    const response = await fetch(url, {
      headers: {
        'User-Agent': 'Mozilla/5.0 (compatible; MementoClipper/1.0)',
        Accept: 'text/html,application/xhtml+xml',
      },
      signal: controller.signal,
      redirect: 'follow',
    })
    if (!response.ok) return null
    const ct = response.headers.get('content-type') || ''
    if (!ct.includes('text/html') && !ct.includes('application/xhtml')) return null
    return await response.text()
  } catch {
    return null
  } finally {
    clearTimeout(timeoutId)
  }
}

export async function POST(request: NextRequest) {
  try {
    const session = await auth()
    if (!session?.user?.id) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    const body = await request.json()
    const url = typeof body.url === 'string' ? body.url.trim() : ''
    const htmlInput = typeof body.html === 'string' ? body.html : ''
    const selection = typeof body.selection === 'string' ? body.selection.trim() : ''

    if (!url || isBlockedUrl(url)) {
      return NextResponse.json({ error: 'Invalid URL' }, { status: 400 })
    }

    let title = ''
    let textContent = ''
    let contentHtml = ''

    if (body.mode === 'link') {
      title = new URL(url).hostname
      textContent = url
      contentHtml = `<p><a href="${url}" rel="noopener noreferrer">${url}</a></p>`
    } else if (body.mode === 'selection' && selection) {
      title = typeof body.title === 'string' ? body.title : new URL(url).hostname
      textContent = selection
      const locale = resolveClipLocale(url, title, selection)
      contentHtml = wrapClipPlainParagraph(selection, locale)
    } else {
      const html = htmlInput || (await fetchPageHtml(url))
      if (!html) {
        return NextResponse.json({ error: 'Could not fetch page content' }, { status: 422 })
      }
      const extracted = extractArticleFromHtml(html, url)
      if (!extracted) {
        return NextResponse.json({ error: 'Could not extract readable article' }, { status: 422 })
      }
      title = extracted.title || (typeof body.title === 'string' ? body.title : '')
      textContent = extracted.textContent
      contentHtml = extracted.content
    }

    const analysis = await analyzeClipContent({ url, title, textContent })

    return NextResponse.json({
      title: analysis.title,
      summary: analysis.summary,
      tags: analysis.tags,
      readingTime: analysis.readingTimeMinutes,
      content: contentHtml,
      excerpt: textContent.slice(0, 500),
    })
  } catch (error) {
    console.error('[POST /api/clip/analyze]', error)
    return NextResponse.json({ error: 'Analysis failed' }, { status: 500 })
  }
}