import { ConsentType, ConsentStatus } from '@prisma/client';
import crypto from 'crypto';
import prisma from '../lib/prisma.js';
import * as consentService from './consent.service.js';
import * as appSettingService from './appSetting.service.js';
import PDFDocument from 'pdfkit';

/**
 * Kunden-Lookup per consentHash
 */
export async function getCustomerByConsentHash(hash: string) {
  const customer = await prisma.customer.findUnique({
    where: { consentHash: hash },
    select: {
      id: true,
      firstName: true,
      lastName: true,
      customerNumber: true,
      salutation: true,
      email: true,
    },
  });

  if (!customer) return null;

  const consents = await consentService.getCustomerConsents(customer.id);

  return { customer, consents };
}

/**
 * Alle 4 Einwilligungen über den öffentlichen Link erteilen
 */
export async function grantAllConsentsPublic(hash: string, ipAddress: string) {
  const customer = await prisma.customer.findUnique({
    where: { consentHash: hash },
    select: { id: true, firstName: true, lastName: true },
  });

  if (!customer) {
    throw new Error('Ungültiger Link');
  }

  const results = [];
  for (const type of Object.values(ConsentType)) {
    const result = await consentService.updateConsent(customer.id, type, {
      status: ConsentStatus.GRANTED,
      source: 'public-link',
      ipAddress,
      createdBy: `${customer.firstName} ${customer.lastName} (Public-Link)`,
    });
    results.push(result);
  }

  return results;
}

/**
 * consentHash generieren falls nicht vorhanden
 */
export async function ensureConsentHash(customerId: number): Promise<string> {
  const customer = await prisma.customer.findUnique({
    where: { id: customerId },
    select: { consentHash: true },
  });

  if (!customer) {
    throw new Error('Kunde nicht gefunden');
  }

  if (customer.consentHash) {
    return customer.consentHash;
  }

  const hash = crypto.randomUUID();
  await prisma.customer.update({
    where: { id: customerId },
    data: { consentHash: hash },
  });

  return hash;
}

/**
 * Platzhalter in Text ersetzen
 */
function replacePlaceholders(html: string, customer: {
  firstName: string;
  lastName: string;
  customerNumber: string;
  salutation?: string | null;
  email?: string | null;
}): string {
  return html
    .replace(/\{\{vorname\}\}/gi, customer.firstName || '')
    .replace(/\{\{nachname\}\}/gi, customer.lastName || '')
    .replace(/\{\{kundennummer\}\}/gi, customer.customerNumber || '')
    .replace(/\{\{anrede\}\}/gi, customer.salutation || '')
    .replace(/\{\{email\}\}/gi, customer.email || '')
    .replace(/\{\{datum\}\}/gi, new Date().toLocaleDateString('de-DE', {
      day: '2-digit',
      month: '2-digit',
      year: 'numeric',
    }));
}

/**
 * Datenschutzerklärung als HTML abrufen (mit Platzhaltern ersetzt)
 */
export async function getPrivacyPolicyHtml(customerId?: number): Promise<string> {
  const html = await appSettingService.getSetting('privacyPolicyHtml');

  if (!html) {
    return '<p>Keine Datenschutzerklärung hinterlegt.</p>';
  }

  if (!customerId) return html;

  const customer = await prisma.customer.findUnique({
    where: { id: customerId },
    select: {
      firstName: true,
      lastName: true,
      customerNumber: true,
      salutation: true,
      email: true,
    },
  });

  if (!customer) return html;

  return replacePlaceholders(html, customer);
}

/**
 * HTML zu Plain-Text konvertieren (für PDF)
 */
function htmlToText(html: string): string {
  return html
    .replace(/<h[1-6][^>]*>(.*?)<\/h[1-6]>/gi, '\n$1\n')
    .replace(/<br\s*\/?>/gi, '\n')
    .replace(/<\/p>/gi, '\n\n')
    .replace(/<li[^>]*>(.*?)<\/li>/gi, '  • $1\n')
    .replace(/<[^>]+>/g, '')
    .replace(/&amp;/g, '&')
    .replace(/&lt;/g, '<')
    .replace(/&gt;/g, '>')
    .replace(/&quot;/g, '"')
    .replace(/&#39;/g, "'")
    .replace(/&nbsp;/g, ' ')
    .replace(/\n{3,}/g, '\n\n')
    .trim();
}

/**
 * Datenschutzerklärung als PDF generieren
 */
export async function generateConsentPdf(customerId: number): Promise<Buffer> {
  const html = await getPrivacyPolicyHtml(customerId);
  const text = htmlToText(html);

  return new Promise((resolve, reject) => {
    const doc = new PDFDocument({ size: 'A4', margin: 50 });
    const chunks: Buffer[] = [];

    doc.on('data', (chunk: Buffer) => chunks.push(chunk));
    doc.on('end', () => resolve(Buffer.concat(chunks)));
    doc.on('error', reject);

    // Titel
    doc.fontSize(18).font('Helvetica-Bold').text('Datenschutzerklärung', { align: 'center' });
    doc.moveDown(1);

    // Datum
    doc.fontSize(10).font('Helvetica')
      .text(`Erstellt am: ${new Date().toLocaleDateString('de-DE')}`, { align: 'right' });
    doc.moveDown(1);

    // Inhalt
    doc.fontSize(11).font('Helvetica').text(text, {
      align: 'left',
      lineGap: 4,
    });

    doc.end();
  });
}