import { NextRequest, NextResponse } from 'next/server'

// Types
interface ExtractedSection {
  title: string
  content: string
  type?: string
}

interface ExtractedContent {
  title?: string
  version?: string
  lastModified?: string
  sections?: ExtractedSection[]
  metadata?: Record<string, string>
}

interface UploadResponse {
  success: boolean
  documentId: string
  filename: string
  documentType: string
  extractedVersion?: string
  extractedContent?: ExtractedContent
  suggestedNextVersion?: string
}

// Helper: Detect version from filename
function detectVersionFromFilename(filename: string): string | undefined {
  const patterns = [
    /[vV](\d+(?:\.\d+)*)/,
    /version[_-]?(\d+(?:\.\d+)*)/i,
    /[_-]v?(\d+\.\d+(?:\.\d+)?)[_-]/,
  ]

  for (const pattern of patterns) {
    const match = filename.match(pattern)
    if (match) {
      return match[1]
    }
  }
  return undefined
}

// Helper: Suggest next version
function suggestNextVersion(currentVersion?: string): string {
  if (!currentVersion) return '1.0'

  const parts = currentVersion.split('.').map(Number)
  if (parts.length >= 2) {
    parts[parts.length - 1] += 1
  } else {
    parts.push(1)
  }
  return parts.join('.')
}

// Helper: Extract content from PDF/DOCX (simplified - would need proper libraries in production)
async function extractDocumentContent(
  _file: File,
  documentType: string
): Promise<ExtractedContent> {
  // In production, this would use libraries like:
  // - pdf-parse for PDFs
  // - mammoth for DOCX
  // For now, return mock extracted content based on document type

  const mockContentByType: Record<string, ExtractedContent> = {
    tom: {
      title: 'Technische und Organisatorische Maßnahmen',
      sections: [
        { title: 'Vertraulichkeit', content: 'Zugangskontrollen, Zugriffsbeschränkungen...', type: 'category' },
        { title: 'Integrität', content: 'Eingabekontrollen, Änderungsprotokolle...', type: 'category' },
        { title: 'Verfügbarkeit', content: 'Backup-Strategien, Disaster Recovery...', type: 'category' },
        { title: 'Belastbarkeit', content: 'Redundanz, Lasttests...', type: 'category' },
      ],
      metadata: {
        lastReview: new Date().toISOString(),
        responsible: 'Datenschutzbeauftragter',
      },
    },
    dsfa: {
      title: 'Datenschutz-Folgenabschätzung',
      sections: [
        { title: 'Beschreibung der Verarbeitung', content: 'Systematische Beschreibung...', type: 'section' },
        { title: 'Erforderlichkeit und Verhältnismäßigkeit', content: 'Bewertung...', type: 'section' },
        { title: 'Risiken für Betroffene', content: 'Risikoanalyse...', type: 'section' },
        { title: 'Abhilfemaßnahmen', content: 'Geplante Maßnahmen...', type: 'section' },
      ],
    },
    vvt: {
      title: 'Verzeichnis von Verarbeitungstätigkeiten',
      sections: [
        { title: 'Verantwortlicher', content: 'Name und Kontaktdaten...', type: 'field' },
        { title: 'Verarbeitungszwecke', content: 'Liste der Zwecke...', type: 'list' },
        { title: 'Datenkategorien', content: 'Personenbezogene Daten...', type: 'list' },
        { title: 'Empfängerkategorien', content: 'Interne und externe Empfänger...', type: 'list' },
      ],
    },
    loeschfristen: {
      title: 'Löschkonzept und Aufbewahrungsfristen',
      sections: [
        { title: 'Personalakten', content: '10 Jahre nach Ausscheiden', type: 'retention' },
        { title: 'Kundendaten', content: '3 Jahre nach letzter Aktivität', type: 'retention' },
        { title: 'Buchhaltungsbelege', content: '10 Jahre (HGB)', type: 'retention' },
        { title: 'Bewerbungsunterlagen', content: '6 Monate nach Absage', type: 'retention' },
      ],
    },
    consent: {
      title: 'Einwilligungserklärungen',
      sections: [
        { title: 'Newsletter-Einwilligung', content: 'Vorlage für Newsletter...', type: 'template' },
        { title: 'Marketing-Einwilligung', content: 'Vorlage für Marketing...', type: 'template' },
      ],
    },
    policy: {
      title: 'Datenschutzrichtlinie',
      sections: [
        { title: 'Geltungsbereich', content: 'Diese Richtlinie gilt für...', type: 'section' },
        { title: 'Verantwortlichkeiten', content: 'Rollen und Pflichten...', type: 'section' },
      ],
    },
  }

  return mockContentByType[documentType] || {
    title: 'Unbekanntes Dokument',
    sections: [],
  }
}

export async function POST(request: NextRequest) {
  try {
    const formData = await request.formData()
    const file = formData.get('file') as File | null
    const documentType = formData.get('documentType') as string || 'custom'
    const sessionId = formData.get('sessionId') as string || 'default'

    if (!file) {
      return NextResponse.json(
        { error: 'Keine Datei hochgeladen' },
        { status: 400 }
      )
    }

    // Validate file type
    const allowedTypes = [
      'application/pdf',
      'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
      'application/msword',
    ]

    if (!allowedTypes.includes(file.type)) {
      return NextResponse.json(
        { error: 'Ungültiger Dateityp. Erlaubt: PDF, DOCX, DOC' },
        { status: 400 }
      )
    }

    // Generate document ID
    const documentId = `doc-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`

    // Extract version from filename
    const extractedVersion = detectVersionFromFilename(file.name)

    // Extract content (in production, this would parse the actual file)
    const extractedContent = await extractDocumentContent(file, documentType)

    // Add version to extracted content if found
    if (extractedVersion) {
      extractedContent.version = extractedVersion
    }

    // Store file (in production, save to MinIO/S3)
    // For now, we just process and return metadata
    console.log(`[SDK Documents] Uploaded: ${file.name} (${file.size} bytes) for session ${sessionId}`)

    const response: UploadResponse = {
      success: true,
      documentId,
      filename: file.name,
      documentType,
      extractedVersion,
      extractedContent,
      suggestedNextVersion: suggestNextVersion(extractedVersion),
    }

    return NextResponse.json(response)
  } catch (error) {
    console.error('[SDK Documents] Upload error:', error)
    return NextResponse.json(
      { error: 'Upload fehlgeschlagen' },
      { status: 500 }
    )
  }
}

export async function GET(request: NextRequest) {
  const { searchParams } = new URL(request.url)
  const sessionId = searchParams.get('sessionId')

  if (!sessionId) {
    return NextResponse.json(
      { error: 'Session ID erforderlich' },
      { status: 400 }
    )
  }

  // In production, fetch uploaded documents from storage
  // For now, return empty list
  return NextResponse.json({
    uploads: [],
    sessionId,
  })
}