const InvoiceRepository = require('../../repositories/invoice/InvoiceRepository');
const UnitOfWork = require('../../database/UnitOfWork'); // NEW
const TaxRepository = require('../../repositories/tax/taxRepository'); // NEW
const PoolInflowService = require('../pool/PoolInflowService');
const DocumentTemplateService = require('../template/DocumentTemplateService');
const MailService = require('../email/MailService');
const { GetObjectCommand, PutObjectCommand } = require('@aws-sdk/client-s3');
const { s3: sharedExoscaleClient } = require('../../utils/exoscaleUploader');
const { logger } = require('../../middleware/logger');
const puppeteer = require('puppeteer');
const fs = require('fs/promises');
const path = require('path');

const CompanySettingsRepository = require('../../repositories/settings/CompanySettingsRepository');
const CoffeeShippingFeeService = require('../subscriptions/CoffeeShippingFeeService');

class InvoiceService {
  constructor() {
    this.repo = new InvoiceRepository();
  }

  _inferImageMimeFromBase64(base64) {
    const s = String(base64 || '').trim();
    if (!s) return 'image/png';
    if (s.startsWith('iVBORw0KGgo')) return 'image/png';
    if (s.startsWith('/9j/')) return 'image/jpeg';
    if (s.startsWith('R0lGOD')) return 'image/gif';
    return 'image/png';
  }

  _templateHasVars(template, varNames) {
    if (!template) return false;
    return varNames.every((name) => {
      const re = new RegExp(`{{\\s*${name}\\s*}}`);
      return re.test(template);
    });
  }

  async _loadLocalInvoiceTemplateHtml() {
    try {
      const filePath = path.resolve(__dirname, '../../templates/invoice/invoiceTemplate.html');
      return await fs.readFile(filePath, 'utf8');
    } catch (e) {
      logger.warn('InvoiceService._loadLocalInvoiceTemplateHtml:error', { message: e?.message });
      return null;
    }
  }

  _resolvePieceCountForQr(abonement) {
    const packGroup = String(abonement?.pack_group || '').toLowerCase();
    if (packGroup.includes('120')) return 120;
    if (packGroup.includes('60')) return 60;

    const breakdown = Array.isArray(abonement?.pack_breakdown) ? abonement.pack_breakdown : [];
    const totalPacks = breakdown.reduce((sum, item) => sum + Number(item?.packs || 0), 0);
    const piecesByPack = totalPacks ? totalPacks * 10 : null;
    if (piecesByPack === 60 || piecesByPack === 120) return piecesByPack;

    return null;
  }

  async _resolveShippingFeeItem({ abonement, vatRate, lang }) {
    const pieceCount = this._resolvePieceCountForQr(abonement);
    if (!pieceCount) return null;

    const shippingFee = await CoffeeShippingFeeService.get(pieceCount);
    const unitPrice = Number(shippingFee?.price || 0);
    if (!(unitPrice > 0)) return null;

    return {
      product_id: null,
      sku: `SHIPPING-${pieceCount}`,
      description: lang === 'de' ? `Versandkosten (${pieceCount} Stk.)` : `Shipping fee (${pieceCount} pcs)` ,
      quantity: 1,
      unit_price: unitPrice,
      tax_rate: vatRate,
    };
  }

  async _buildInvoiceItems({ abonement, vatRate, lang }) {
    const breakdown = Array.isArray(abonement?.pack_breakdown) ? abonement.pack_breakdown : [];
    const items = breakdown.length
      ? breakdown.map((b) => ({
          product_id: Number(b.coffee_table_id) || null,
          sku: `COFFEE-${b.coffee_table_id || 'N/A'}`,
          description: b.coffee_title || `Coffee subscription: ${b.coffee_table_id}`,
          quantity: Number(b.packs || 1),
          unit_price: Number(b.price_per_pack || 0),
          tax_rate: b.tax_rate != null ? Number(b.tax_rate) : vatRate,
        }))
      : [
          {
            product_id: null,
            sku: 'SUBSCRIPTION',
            description: `Subscription ${abonement?.pack_group || ''}`,
            quantity: 1,
            unit_price: Number(abonement?.price || 0),
            tax_rate: vatRate,
          },
        ];

    const shippingItem = await this._resolveShippingFeeItem({ abonement, vatRate, lang });
    if (shippingItem) {
      items.push(shippingItem);
    }

    return items;
  }

  async _getCompanySettingsQrDataUri(pieceCount) {
    const safePieceCount = pieceCount === 120 ? 120 : 60;
    try {
      const repo = new CompanySettingsRepository();
      const row = await repo.get();
      if (!row) return null;
      const raw = safePieceCount === 120 ? row?.qr_code_120_base64 : row?.qr_code_60_base64;
      const value = (raw == null) ? '' : String(raw).trim();
      if (!value) return null;
      if (value.startsWith('data:image/')) return value;
      const mime = this._inferImageMimeFromBase64(value);
      return `data:${mime};base64,${value}`;
    } catch (e) {
      logger.warn('InvoiceService._getCompanySettingsQrDataUri:error', {
        pieceCount: safePieceCount,
        message: e?.message,
      });
      return null;
    }
  }

  async _buildQrCodeImageTag({ abonement }) {
    const pieceCount = this._resolvePieceCountForQr(abonement);
    if (!pieceCount) return '';

    const dataUri = await this._getCompanySettingsQrDataUri(pieceCount);
    if (!dataUri) return '';

    return `<img alt="QR Code" src="${this._escapeHtml(dataUri)}" />`;
  }

  _escapeHtml(value) {
    return String(value ?? '')
      .replace(/&/g, '&amp;')
      .replace(/</g, '&lt;')
      .replace(/>/g, '&gt;')
      .replace(/"/g, '&quot;')
      .replace(/'/g, '&#39;');
  }

  _formatAmount(amount, currency = 'EUR') {
    const numeric = Number(amount || 0);
    return `${numeric.toFixed(2)} ${currency}`;
  }

  async _s3BodyToString(body) {
    if (!body) return '';
    if (typeof body.transformToString === 'function') {
      return body.transformToString();
    }
    const chunks = [];
    for await (const chunk of body) {
      chunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk));
    }
    return Buffer.concat(chunks).toString('utf8');
  }

  _getEmailSubject(lang, invoiceNumber) {
    return lang === 'de'
      ? `ProfitPlanet Rechnung ${invoiceNumber}`
      : `ProfitPlanet Invoice ${invoiceNumber}`;
  }

  _buildItemsText(items, currency) {
    if (!Array.isArray(items) || !items.length) return '- Subscription item';
    return items.map((item, index) => {
      const qty = Number(item.quantity || 0);
      const lineGross = Number(item.line_gross || 0);
      return `${index + 1}. ${item.description || 'Coffee'} | qty: ${qty} | total: ${this._formatAmount(lineGross, currency)}`;
    }).join('\n');
  }

  _buildItemsHtml(items, currency) {
    if (!Array.isArray(items) || !items.length) {
      return '<li>Subscription item</li>';
    }
    return items.map((item) => {
      const desc = this._escapeHtml(item.description || 'Coffee');
      const qty = Number(item.quantity || 0);
      const unit = this._formatAmount(item.unit_price || 0, currency);
      const total = this._formatAmount(item.line_gross || 0, currency);
      return `<li><strong>${desc}</strong> — ${qty} x ${this._escapeHtml(unit)} = ${this._escapeHtml(total)}</li>`;
    }).join('');
  }

  _buildInvoiceText({ invoice, items, abonement, lang }) {
    const isDe = lang === 'de';
    const customerName = [abonement?.first_name, abonement?.last_name].filter(Boolean).join(' ') || invoice.buyer_name || '-';
    const issuedAt = invoice.issued_at ? new Date(invoice.issued_at).toISOString().slice(0, 10) : new Date().toISOString().slice(0, 10);

    return [
      isDe ? 'Ihre Rechnung wurde erstellt.' : 'Your invoice has been created.',
      `${isDe ? 'Rechnungsnummer' : 'Invoice number'}: ${invoice.invoice_number}`,
      `${isDe ? 'Kunde' : 'Customer'}: ${customerName}`,
      `${isDe ? 'Datum' : 'Date'}: ${issuedAt}`,
      `${isDe ? 'Positionen' : 'Items'}:`,
      this._buildItemsText(items, invoice.currency),
      `${isDe ? 'Gesamtbetrag' : 'Total'}: ${this._formatAmount(invoice.total_gross, invoice.currency)}`,
    ].join('\n');
  }

  _buildInvoiceMailText({ invoice, items, abonement, lang }) {
    const isDe = lang === 'de';
    const customerName = [abonement?.first_name, abonement?.last_name].filter(Boolean).join(' ') || invoice.buyer_name || '-';
    return [
      isDe ? `Vielen Dank für Ihr Abonnement, ${customerName}.` : `Thank you for your subscription, ${customerName}.`,
      isDe ? 'Ihre Rechnung ist als PDF im Anhang enthalten.' : 'Your invoice is attached as a PDF.',
      `${isDe ? 'Rechnungsnummer' : 'Invoice number'}: ${invoice.invoice_number}`,
      `${isDe ? 'Gesamtbetrag' : 'Total'}: ${this._formatAmount(invoice.total_gross, invoice.currency)}`,
      '',
      `${isDe ? 'Positionen' : 'Items'}:`,
      this._buildItemsText(items, invoice.currency),
    ].join('\n');
  }

  _buildInvoiceMailHtml({ invoice, abonement, lang }) {
    const isDe = lang === 'de';
    const customerName = [abonement?.first_name, abonement?.last_name].filter(Boolean).join(' ') || invoice.buyer_name || 'Customer';
    const logoUrl = process.env.MAIL_LOGO_URL || process.env.BREVO_LOGO_URL || process.env.APP_LOGO_URL || '';

    return `<!doctype html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>${this._escapeHtml(invoice.invoice_number)}</title>
  </head>
  <body style="margin:0;padding:0;background:#f5f7fb;font-family:Arial,sans-serif;color:#1f2937;">
    <table role="presentation" width="100%" cellspacing="0" cellpadding="0" style="background:#f5f7fb;padding:24px 0;">
      <tr>
        <td align="center">
          <table role="presentation" width="640" cellspacing="0" cellpadding="0" style="max-width:640px;background:#ffffff;border-radius:12px;overflow:hidden;box-shadow:0 8px 24px rgba(0,0,0,0.08);">
            <tr>
              <td style="padding:24px 28px;background:#111827;color:#ffffff;">
                ${logoUrl ? `<img src="${this._escapeHtml(logoUrl)}" alt="ProfitPlanet" style="max-height:44px;display:block;margin-bottom:12px;">` : ''}
                <h1 style="margin:0;font-size:22px;line-height:1.3;">${isDe ? 'Danke für Ihr Abonnement!' : 'Thank you for your subscription!'}</h1>
              </td>
            </tr>
            <tr>
              <td style="padding:24px 28px;">
                <p style="margin:0 0 12px 0;font-size:15px;line-height:1.6;">${isDe ? 'Hallo' : 'Hi'} ${this._escapeHtml(customerName)},</p>
                <p style="margin:0 0 18px 0;font-size:15px;line-height:1.6;">${isDe ? 'vielen Dank für Ihr Abonnement. Ihre Rechnung haben wir als PDF angehängt.' : 'thank you for your subscription. We attached your invoice as a PDF.'}</p>

                <table role="presentation" width="100%" cellspacing="0" cellpadding="0" style="border:1px solid #e5e7eb;border-radius:8px;overflow:hidden;margin-bottom:18px;">
                  <tr>
                    <td style="padding:12px 14px;background:#f9fafb;font-size:13px;color:#6b7280;">${isDe ? 'Rechnungsnummer' : 'Invoice number'}</td>
                    <td style="padding:12px 14px;background:#f9fafb;font-size:13px;text-align:right;font-weight:700;">${this._escapeHtml(invoice.invoice_number || '')}</td>
                  </tr>
                  <tr>
                    <td style="padding:12px 14px;font-size:13px;color:#6b7280;">${isDe ? 'Gesamtbetrag' : 'Total'}</td>
                    <td style="padding:12px 14px;font-size:13px;text-align:right;font-weight:700;">${this._escapeHtml(this._formatAmount(invoice.total_gross, invoice.currency))}</td>
                  </tr>
                </table>

                <p style="margin:0;font-size:13px;color:#6b7280;">${isDe ? 'Falls diese E-Mail nicht korrekt angezeigt wird, nutzen Sie bitte den Textinhalt oder kontaktieren Sie unseren Support.' : 'If this email is not displayed correctly, please use the text version or contact support.'}</p>
              </td>
            </tr>
          </table>
        </td>
      </tr>
    </table>
  </body>
</html>`;
  }

  _buildItemsTableRows(items, currency) {
    if (!Array.isArray(items) || !items.length) {
      return `<tr><td>1</td><td>Subscription item</td><td>1</td><td>-</td><td>-</td></tr>`;
    }
    return items.map((item, i) => {
      const desc = this._escapeHtml(item.description || 'Coffee');
      const qty = Number(item.quantity || 0);
      const unit = this._formatAmount(item.unit_price || 0, currency);
      const total = this._formatAmount(item.line_gross || 0, currency);
      return `<tr><td>${i + 1}</td><td>${desc}</td><td>${qty}</td><td>${unit}</td><td>${total}</td></tr>`;
    }).join('');
  }

  async _loadInvoiceHtmlTemplate() {
    // Load the latest active invoice template from the contract manager (S3)
    try {
      const templates = await DocumentTemplateService.getActiveTemplatesForUserType('both', 'invoice');
      if (!Array.isArray(templates) || !templates.length) return null;
      const selected = templates[0]; // latest active version
      if (!selected?.storageKey) return null;
      const command = new GetObjectCommand({
        Bucket: process.env.EXOSCALE_BUCKET,
        Key: selected.storageKey,
      });
      const obj = await sharedExoscaleClient.send(command);
      const html = await this._s3BodyToString(obj.Body) || null;
      if (!html) return null;
      return html;
    } catch (e) {
      logger.warn('InvoiceService._loadInvoiceHtmlTemplate:error', { message: e?.message });
      return null;
    }
  }

  _getProfitPlanetBankBlockHtml({ bankAccountHolder, bankIban, bankBic }) {
    return `<strong>${this._escapeHtml(bankAccountHolder)}</strong><br>${this._escapeHtml(bankIban)}<br>${this._escapeHtml(bankBic)}`;
  }

  _prepareVariablesForTemplate(templateHtml, variables) {
    // Ensure backwards compatibility with older templates that only contain {{paymentInfoText}}
    // by injecting the Profit Planet bank block (and optionally QR) into paymentInfoText.
    if (!templateHtml) return variables;

    const supportsBankVars = this._templateHasVars(templateHtml, ['bankAccountHolder', 'bankIban', 'bankBic']);
    const supportsQrVar = this._templateHasVars(templateHtml, ['qrCodeImage']);

    const bankBlock = this._getProfitPlanetBankBlockHtml({
      bankAccountHolder: variables.bankAccountHolder || 'Profit Planet GmbH',
      bankIban: variables.bankIban || '',
      bankBic: variables.bankBic || '',
    });

    const next = { ...variables };
    if (!supportsBankVars) {
      // Replace the default instruction text entirely with bank info
      next.paymentInfoText = bankBlock;
    }

    if (!supportsQrVar && variables.qrCodeImage) {
      // Append QR under payment info text when there's no dedicated placeholder
      next.paymentInfoText = `${next.paymentInfoText || ''}<br><br>${variables.qrCodeImage}`;
    }

    return next;
  }

  async _buildInvoiceTemplateVariables({ invoice, items, abonement, lang }) {
    const isDe = lang === 'de';
    const isGift = abonement?.details?.is_for_self === false;
    const issuedAt = invoice.issued_at ? new Date(invoice.issued_at).toISOString().slice(0, 10) : new Date().toISOString().slice(0, 10);
    const dueAt = invoice.due_at ? new Date(invoice.due_at).toISOString().slice(0, 10) : '-';
    const vatRate = invoice.vat_rate != null ? Number(invoice.vat_rate) : 0;

    // Hardcoded bank info (Profit Planet)
    const bankAccountHolder = 'Profit Planet GmbH';
    const bankIban = 'AT16 2081 5000 4639 9507';
    const bankBic = 'STSPAT2GXXX';

    // Hardcoded footer/contact info (Profit Planet)
    const footerText = [
      'Profit Planet GmbH',
      'Kärntner Straße 227',
      '8053 Graz',
      '',
      'Kontakt',
      'Telefon: 0676 344 0274',
      'E-Mail: office@profit-planet.com',
      '',
      'Profit Planet GmbH',
      bankIban,
      bankBic,
    ].join('<br>');

    // Hardcoded company address (Profit Planet)
    const companyInfo = {
      company_name: 'Profit Planet GmbH',
      company_street: 'Kärntner Straße 227',
      company_postal_city: '8053 Graz',
      company_country: '',
    };

    // For gift subscriptions: "Bill To" = recipient, "Ordered by" = purchaser
    // For self subscriptions: "Bill To" = the subscriber
    let customerName;
    let customerEmail = '';
    let orderedByBlock = '';

    if (isGift) {
      // Recipient info for "Bill To"
      const recipientName = abonement?.details?.recipient_name || '';
      const recipientEmail = abonement?.email || invoice.buyer_email || '';
      customerName = recipientName || recipientEmail || '-';
      customerEmail = recipientName ? recipientEmail : '';

      // Purchaser info for "Ordered by"
      const purchaserName = invoice.buyer_name || [abonement?.first_name, abonement?.last_name].filter(Boolean).join(' ') || '';
      if (purchaserName) {
        const orderedByLabel = isDe ? 'Bestellt von' : 'Ordered By';
        orderedByBlock = `<div class="meta-block"><h3>${this._escapeHtml(orderedByLabel)}</h3><p><span class="highlight">${this._escapeHtml(purchaserName)}</span></p></div>`;
      }
    } else {
      customerName = [abonement?.first_name, abonement?.last_name].filter(Boolean).join(' ') || invoice.buyer_name || '-';
      customerEmail = abonement?.email || invoice.buyer_email || '';
    }

    const qrCodeImage = await this._buildQrCodeImageTag({ abonement });

    return {
      lang: isDe ? 'de' : 'en',
      documentTitle: isDe ? 'Rechnung' : 'Invoice',
      invoiceNumber: this._escapeHtml(invoice.invoice_number || ''),
      invoiceNumberLabel: isDe ? 'Rechnungsnummer' : 'Invoice Number',
      fromLabel: isDe ? 'Von' : 'From',
      toLabel: isDe ? 'An' : 'Bill To',
      detailsLabel: isDe ? 'Details' : 'Details',
      dateLabel: isDe ? 'Datum' : 'Date',
      dueDateLabel: isDe ? 'Fällig am' : 'Due Date',
      statusLabel: 'Status',
      invoiceStatus: this._escapeHtml((invoice.status || 'issued').toUpperCase()),
      companyName: this._escapeHtml(companyInfo.company_name || 'ProfitPlanet GmbH'),
      companyStreet: this._escapeHtml(companyInfo.company_street || ''),
      companyPostalCity: this._escapeHtml(companyInfo.company_postal_city || ''),
      companyCountry: this._escapeHtml(companyInfo.company_country || 'Germany'),
      customerName: this._escapeHtml(customerName),
      customerEmail: this._escapeHtml(customerEmail),
      customerStreet: this._escapeHtml(invoice.buyer_street || ''),
      customerPostalCity: this._escapeHtml([invoice.buyer_postal_code, invoice.buyer_city].filter(Boolean).join(' ')),
      customerCountry: this._escapeHtml(invoice.buyer_country || ''),
      orderedByBlock,
      issuedAt: this._escapeHtml(issuedAt),
      dueAt: this._escapeHtml(dueAt),
      descriptionHeader: isDe ? 'Beschreibung' : 'Description',
      qtyHeader: isDe ? 'Menge' : 'Qty',
      unitPriceHeader: isDe ? 'Stückpreis' : 'Unit Price',
      totalHeader: isDe ? 'Gesamt' : 'Total',
      itemsRows: this._buildItemsTableRows(items, invoice.currency),
      subtotalLabel: isDe ? 'Nettobetrag' : 'Subtotal (net)',
      taxLabel: isDe ? 'MwSt.' : 'Tax',
      vatRateDisplay: vatRate ? `${vatRate}%` : '0%',
      totalNet: this._escapeHtml(this._formatAmount(invoice.total_net, invoice.currency)),
      totalTax: this._escapeHtml(this._formatAmount(invoice.total_tax, invoice.currency)),
      totalLabel: isDe ? 'Gesamtbetrag (brutto)' : 'Total (gross)',
      totalGross: this._escapeHtml(this._formatAmount(invoice.total_gross, invoice.currency)),
      paymentInfoTitle: isDe ? 'Zahlungsinformationen' : 'Payment Information',
      paymentInfoText: isDe
        ? 'Bitte überweisen Sie den Gesamtbetrag unter Angabe der Rechnungsnummer.'
        : 'Please transfer the total amount stating the invoice number as reference.',
      bankAccountHolder: this._escapeHtml(bankAccountHolder),
      bankIban: this._escapeHtml(bankIban),
      bankBic: this._escapeHtml(bankBic),
      qrCodeImage,
      footerText,
      // Legacy key used by S3-stored templates
      itemsHtml: this._buildItemsHtml(items, invoice.currency),
    };
  }

  async _buildFallbackInvoiceHtml({ invoice, items, abonement, lang }) {
    const variables = await this._buildInvoiceTemplateVariables({ invoice, items, abonement, lang });

    const template = await this._loadInvoiceHtmlTemplate();
    if (template) {
      const varsForTemplate = this._prepareVariablesForTemplate(template, variables);
      return this._renderTemplate(template, varsForTemplate);
    }

    // Absolute fallback if template file is missing
    const isDe = lang === 'de';
    return `<!doctype html>
<html>
  <head><meta charset="utf-8"><title>${this._escapeHtml(invoice.invoice_number)}</title></head>
  <body>
    <h2>${isDe ? 'Rechnung' : 'Invoice'} ${this._escapeHtml(invoice.invoice_number)}</h2>
    <p>${isDe ? 'Kunde' : 'Customer'}: ${variables.customerName}</p>
    <p>${isDe ? 'Datum' : 'Date'}: ${variables.issuedAt}</p>
    <h3>${isDe ? 'Positionen' : 'Items'}</h3>
    <ul>${variables.itemsHtml}</ul>
    <p><strong>${isDe ? 'Gesamtbetrag' : 'Total'}: ${variables.totalGross}</strong></p>
  </body>
</html>`;
  }

  async _loadInvoiceTemplateHtml({ lang = 'en' } = {}) {
    try {
      const templates = await DocumentTemplateService.getActiveTemplatesForUserType('both', 'invoice');
      if (!Array.isArray(templates) || !templates.length) return null;

      const selected = templates.find((t) => t.lang === lang) || templates.find((t) => t.lang === 'en') || templates[0];
      if (!selected?.storageKey) return null;

      const command = new GetObjectCommand({
        Bucket: process.env.EXOSCALE_BUCKET,
        Key: selected.storageKey,
      });
      const obj = await sharedExoscaleClient.send(command);
      const html = await this._s3BodyToString(obj.Body);
      if (!html) return await this._loadLocalInvoiceTemplateHtml();
      return html;
    } catch (error) {
      logger.warn('InvoiceService._loadInvoiceTemplateHtml:error', { message: error?.message });
      return await this._loadLocalInvoiceTemplateHtml();
    }
  }

  _renderTemplate(template, variables) {
    if (!template) return null;
    return template.replace(/{{\s*([\w]+)\s*}}/g, (_, key) => variables[key] ?? '');
  }

  async _renderPdfFromHtml(html) {
    const browser = await puppeteer.launch({
      headless: 'new',
      args: ['--no-sandbox', '--disable-setuid-sandbox']
    });
    try {
      const page = await browser.newPage();
      await page.setContent(html, { waitUntil: 'networkidle0' });
      const pdfBuffer = await page.pdf({
        format: 'A4',
        printBackground: true,
        margin: { top: '16mm', right: '14mm', bottom: '16mm', left: '14mm' }
      });
      return Buffer.isBuffer(pdfBuffer) ? pdfBuffer : Buffer.from(pdfBuffer);
    } finally {
      await browser.close();
    }
  }

  async _storeInvoicePdf(invoice, pdfBuffer) {
    if (!pdfBuffer) return null;
    const safeUser = invoice.user_id || 'unknown';
    const key = `invoices/${safeUser}/${invoice.invoice_number || `invoice-${invoice.id}`}.pdf`;
    await sharedExoscaleClient.send(new PutObjectCommand({
      Bucket: process.env.EXOSCALE_BUCKET,
      Key: key,
      Body: pdfBuffer,
      ContentType: 'application/pdf',
    }));
    await this.repo.updateStorageKey(invoice.id, key);
    return key;
  }

  async _sendInvoiceEmail({ invoice, abonement, lang = 'en' }) {
    const recipientEmail = invoice.buyer_email || abonement?.email;
    if (!recipientEmail) {
      logger.warn('InvoiceService._sendInvoiceEmail:missing_recipient', { invoiceId: invoice.id });
      return;
    }

    const items = await this.repo.getItemsByInvoiceId(invoice.id);
    const text = this._buildInvoiceMailText({ invoice, items, abonement, lang });
    const subject = this._getEmailSubject(lang, invoice.invoice_number);

    // Build the full set of template variables once – used by both S3 and local paths
    const variables = await this._buildInvoiceTemplateVariables({ invoice, items, abonement, lang });

    const templateHtml = await this._loadInvoiceTemplateHtml({ lang });
    let html = null;

    if (templateHtml) {
      const supportsBankVars = this._templateHasVars(templateHtml, ['bankAccountHolder', 'bankIban', 'bankBic']);
      const supportsQrVar = this._templateHasVars(templateHtml, ['qrCodeImage']);
      const pieceCountForQr = this._resolvePieceCountForQr(abonement);
      logger.info('InvoiceService._sendInvoiceEmail:template_compat', {
        invoiceId: invoice?.id,
        lang,
        supportsBankVars,
        supportsQrVar,
        pieceCountForQr,
        hasQrImage: Boolean(variables?.qrCodeImage),
      });

      const varsForTemplate = this._prepareVariablesForTemplate(templateHtml, variables);
      html = this._renderTemplate(templateHtml, varsForTemplate);

      // Final guard: if we still didn't embed QR but we expected one, force local template
      const missingQr = variables.qrCodeImage && !html.includes('data:image/png;base64,');
      if (missingQr) {
        const localTemplate = await this._loadLocalInvoiceTemplateHtml();
        if (localTemplate) {
          const varsForLocal = this._prepareVariablesForTemplate(localTemplate, variables);
          html = this._renderTemplate(localTemplate, varsForLocal);
        }
      }
    }

    const htmlForPdf = html || await this._buildFallbackInvoiceHtml({ invoice, items, abonement, lang });
    const pdfBuffer = await this._renderPdfFromHtml(htmlForPdf);
    await this._storeInvoicePdf(invoice, pdfBuffer);

    const mailHtml = this._buildInvoiceMailHtml({ invoice, abonement, lang });

    await MailService.sendInvoiceEmail({
      email: recipientEmail,
      subject,
      text,
      html: mailHtml,
      attachments: [{
        name: `${invoice.invoice_number || `invoice-${invoice.id}`}.pdf`,
        content: pdfBuffer.toString('base64')
      }],
      lang,
    });
  }

  // NEW: resolve current standard VAT rate for a buyer country code
  async resolveVatRateForCountry(countryCode) {
    if (!countryCode) return null;
    const uow = new UnitOfWork();
    await uow.start();
    const taxRepo = new TaxRepository(uow);
    try {
      const country = await taxRepo.getCountryByCode(String(countryCode).toUpperCase());
      if (!country) {
        await uow.commit();
        return null;
      }
      // get current vat row for this country
      const [rows] = await taxRepo.conn.query(
        `SELECT standard_rate FROM vat_rates WHERE country_id = ? AND effective_to IS NULL LIMIT 1`,
        [country.id]
      );
      await uow.commit();
      const rate = rows?.[0]?.standard_rate;
      return rate == null ? null : Number(rate);
    } catch (e) {
      await uow.rollback();
      throw e;
    }
  }

  // Issue invoice for a subscription period, with items from pack_breakdown
  async issueForAbonement(abonement, periodStart, periodEnd, { actorUserId, lang = 'en' } = {}) {
    console.log('[INVOICE ISSUE] Inputs:', {
      abonement_id: abonement?.id,
      abonement_user_id: abonement?.user_id,
      abonement_purchaser_user_id: abonement?.purchaser_user_id,
      actorUserId,
      periodStart,
      periodEnd,
    });

    const buyerName = [abonement.first_name, abonement.last_name].filter(Boolean).join(' ') || null;
    const buyerEmail = abonement.email || null;
    const addr = {
      street: abonement.street || null,
      postal_code: abonement.postal_code || null,
      city: abonement.city || null,
      country: abonement.country || null,
    };
    const currency = abonement.currency || 'EUR';

    // NEW: resolve invoice vat_rate (standard) from buyer country
    const vat_rate = await this.resolveVatRateForCountry(addr.country);

    const items = await this._buildInvoiceItems({ abonement, vatRate: vat_rate, lang });

    const context = {
      source: 'abonement',
      pack_group: abonement.pack_group || null,
      period_start: periodStart,
      period_end: periodEnd,
      referred_by: abonement.referred_by || null,
    };
    
    // CHANGED: prioritize token user id for invoice ownership
    const userIdForInvoice =
      actorUserId ?? abonement.user_id ?? abonement.purchaser_user_id ?? null;

    console.log('[INVOICE ISSUE] Resolved user_id for invoice:', userIdForInvoice);

    const invoice = await this.repo.createInvoiceWithItems({
      source_type: 'subscription',
      source_id: abonement.id,
      user_id: userIdForInvoice,
      buyer_name: buyerName,
      buyer_email: buyerEmail,
      buyer_street: addr.street,
      buyer_postal_code: addr.postal_code,
      buyer_city: addr.city,
      buyer_country: addr.country,
      currency,
      items,
      status: 'issued',
      issued_at: new Date(),
      due_at: periodEnd,
      context,
      vat_rate, // NEW: persist on invoice
    });

    console.log('[INVOICE ISSUE] Created invoice:', {
      id: invoice?.id,
      user_id: invoice?.user_id,
      source_type: invoice?.source_type,
      source_id: invoice?.source_id,
      total_net: invoice?.total_net,
      total_tax: invoice?.total_tax,
      total_gross: invoice?.total_gross,
    });

    try {
      await this._sendInvoiceEmail({
        invoice,
        abonement,
        lang,
      });
      logger.info('InvoiceService.issueForAbonement:invoice_email_sent', {
        invoiceId: invoice?.id,
        userId: invoice?.user_id,
        hasEmail: Boolean(invoice?.buyer_email || abonement?.email),
      });
    } catch (mailError) {
      logger.error('InvoiceService.issueForAbonement:invoice_email_error', {
        invoiceId: invoice?.id,
        message: mailError?.message,
        stack: mailError?.stack,
        brevoStatus: mailError?.statusCode ?? mailError?.response?.status ?? null,
        brevoData: mailError?.body ?? mailError?.response?.data ?? mailError?.response?.text ?? null,
      });
    }

    return invoice;
  }

  async markPaid(invoiceId, { payment_method, transaction_id, amount, paid_at = new Date(), details } = {}) {
    const paidInvoice = await this.repo.markPaid(invoiceId, { payment_method, transaction_id, amount, paid_at, details });

    let poolResult = null;
    try {
      const inflowResult = await PoolInflowService.bookForPaidInvoice({
        invoiceId: paidInvoice?.id,
        paidAt: paid_at,
        actorUserId: null,
      });
      poolResult = inflowResult;
      console.log('[INVOICE PAID] Pool inflow booking result:', {
        invoiceId: paidInvoice?.id,
        ...inflowResult,
      });
    } catch (e) {
      poolResult = { error: e?.message || 'Pool inflow booking failed' };
      console.error('[INVOICE PAID] Pool inflow booking failed:', e);
    }

    // Attach pool result to returned data so the frontend can display it
    if (paidInvoice) {
      paidInvoice._poolResult = poolResult;
    }
    return paidInvoice;
  }

  async listMine(userId, { status, limit = 50, offset = 0 } = {}) {
    return this.repo.listByUser(userId, { status, limit, offset });
  }

  async listByAbonement(abonementId) {
    return this.repo.findByAbonement(abonementId);
  }

  async adminList({ status, limit = 200, offset = 0 } = {}) {
    return this.repo.listAll({ status, limit, offset });
  }

  async updateStatus(invoiceId, newStatus) {
    const invoice = await this.repo.getById(invoiceId);
    if (!invoice) throw new Error(`Invoice ${invoiceId} not found.`);

    // If transitioning to 'paid', use the full markPaid flow for pool inflow booking
    if (newStatus === 'paid' && invoice.status !== 'paid') {
      return this.markPaid(invoiceId, {
        payment_method: 'admin_manual',
        amount: invoice.total_gross ?? 0,
        paid_at: new Date(),
      });
    }

    return this.repo.updateStatus(invoiceId, newStatus);
  }

  async getInvoiceDetail(invoiceId) {
    const invoice = await this.repo.getById(invoiceId);
    if (!invoice) throw new Error(`Invoice ${invoiceId} not found.`);
    const items = await this.repo.getItemsByInvoiceId(invoiceId);
    const payments = await this.repo.getPaymentsByInvoiceId(invoiceId);
    return { invoice, items, payments };
  }
}

module.exports = InvoiceService;