/**
 * Supplier voucher service.
 * After an order is placed, splits order items by supplier and sends each
 * supplier an HTML email voucher listing the items they need to provide.
 */

import pool from '../db/index.js';
import { sendEmail } from './mailer.js';
import { getHingeCountForDoor } from '../../shared/manufacturing.js';

/**
 * Resolve which supplier (if any) provides the finish/panel material.
 */
async function resolveFinishSupplier(finishId) {
  if (!finishId) return null;

  // Try formex_materials first (linked via finishes → formex_materials)
  const { rows } = await pool.query(
    `SELECT fm.id, fm.formex_code AS code, fm.name, fm.price_chf,
            s.id AS supplier_id, s.name AS supplier_name, s.email AS supplier_email, s.code AS supplier_code
     FROM formex_materials fm
     JOIN suppliers s ON s.id = fm.supplier_id
     WHERE fm.id = $1 AND fm.active = 1 AND s.active = 1`,
    [finishId]
  );
  if (rows.length > 0) return { supplier: rows[0], item: rows[0], category: 'panel' };

  return null;
}

/**
 * Resolve drawer system supplier.
 */
async function resolveBlumHardware(hardwareId, type) {
  if (!hardwareId) return null;
  const { rows } = await pool.query(
    `SELECT bh.id, bh.code, bh.name, bh.price_chf, bh.type,
            s.id AS supplier_id, s.name AS supplier_name, s.email AS supplier_email, s.code AS supplier_code
     FROM blum_hardware bh
     JOIN suppliers s ON s.id = bh.supplier_id
     WHERE bh.id = $1 AND bh.active = 1 AND s.active = 1`,
    [hardwareId]
  );
  if (rows.length > 0) return { supplier: rows[0], item: rows[0], category: type };
  return null;
}

/**
 * Resolve handle supplier.
 */
async function resolveHandle(handleId) {
  if (!handleId) return null;
  const { rows } = await pool.query(
    `SELECT hv.id, hv.code, hv.name, hv.price_chf,
            s.id AS supplier_id, s.name AS supplier_name, s.email AS supplier_email, s.code AS supplier_code
     FROM handle_variants hv
     JOIN suppliers s ON s.id = hv.supplier_id
     WHERE hv.id = $1 AND hv.active = 1 AND s.active = 1`,
    [handleId]
  );
  if (rows.length > 0) return { supplier: rows[0], item: rows[0], category: 'handle' };
  return null;
}

/**
 * Resolve hinge supplier.
 */
async function resolveHinge(hingeId) {
  if (!hingeId) return null;
  const { rows } = await pool.query(
    `SELECT hv.id, hv.code, hv.name, hv.price_chf,
            s.id AS supplier_id, s.name AS supplier_name, s.email AS supplier_email, s.code AS supplier_code
     FROM hinge_variants hv
     JOIN suppliers s ON s.id = hv.supplier_id
     WHERE hv.id = $1 AND hv.active = 1 AND s.active = 1`,
    [hingeId]
  );
  if (rows.length > 0) return { supplier: rows[0], item: rows[0], category: 'hinge' };
  return null;
}

/**
 * Estimate quantity for each item based on the order config.
 */
function estimateQuantity(category, config) {
  const { modules = [], blocks = [], doorType, slidingPanelsCount } = config;
  const itemCount = modules.length || blocks.length || 1;

  switch (category) {
    case 'panel':
      return 1; // quantity expressed in panels by the price engine; we report 1 "lot"
    case 'drawer_system':
      return modules.reduce((sum, m) => sum + (m.drawers || 0), 0) || 1;
    case 'hinge':
      if (doorType === 'sliding') return 0;
      return itemCount * getHingeCountForDoor({
        heightMm: (config.heightMm || 2400) - (config.plinthHeightMm || 100) - 4
      });
    case 'handle':
      return doorType === 'sliding'
        ? (slidingPanelsCount || 2)
        : itemCount;
    case 'runner':
    case 'lift_system':
      return 1;
    default:
      return 1;
  }
}

/**
 * Build an HTML voucher email body for a single supplier.
 */
function buildVoucherHtml({ orderId, orderDate, customerName, supplierName, items }) {
  const formattedDate = new Date(orderDate).toLocaleDateString('fr-CH', {
    day: '2-digit', month: '2-digit', year: 'numeric'
  });

  const subtotal = items.reduce((sum, it) => sum + (it.unitPrice * it.qty), 0);

  const rows = items.map(it => `
    <tr>
      <td style="padding:8px 12px;border-bottom:1px solid #e5e7eb;">${it.code || '—'}</td>
      <td style="padding:8px 12px;border-bottom:1px solid #e5e7eb;">${it.name}</td>
      <td style="padding:8px 12px;border-bottom:1px solid #e5e7eb;text-align:center;">${it.qty}</td>
      <td style="padding:8px 12px;border-bottom:1px solid #e5e7eb;text-align:right;">${it.unitPrice != null ? it.unitPrice.toFixed(2) + ' CHF' : '—'}</td>
      <td style="padding:8px 12px;border-bottom:1px solid #e5e7eb;text-align:right;">${it.unitPrice != null ? (it.unitPrice * it.qty).toFixed(2) + ' CHF' : '—'}</td>
    </tr>`).join('');

  return `<!DOCTYPE html>
<html lang="fr">
<head><meta charset="utf-8"><title>Bon de commande #${orderId}</title></head>
<body style="margin:0;padding:0;background:#f9fafb;font-family:Arial,sans-serif;color:#111827;">
  <div style="max-width:680px;margin:32px auto;background:#fff;border-radius:8px;overflow:hidden;box-shadow:0 1px 4px rgba(0,0,0,.1);">

    <div style="background:#1e293b;color:#fff;padding:28px 32px;">
      <h1 style="margin:0;font-size:20px;font-weight:700;">Bon de commande — APEX Configurateur</h1>
      <p style="margin:6px 0 0;opacity:.75;font-size:14px;">Référence commande&nbsp;: <strong>#${orderId}</strong> &nbsp;|&nbsp; ${formattedDate}</p>
    </div>

    <div style="padding:24px 32px;">
      <table style="width:100%;border-collapse:collapse;margin-bottom:24px;">
        <tr>
          <td style="padding:4px 0;color:#6b7280;font-size:13px;width:140px;">Fournisseur</td>
          <td style="padding:4px 0;font-weight:600;">${supplierName}</td>
        </tr>
        <tr>
          <td style="padding:4px 0;color:#6b7280;font-size:13px;">Client</td>
          <td style="padding:4px 0;">${customerName || '—'}</td>
        </tr>
      </table>

      <h2 style="font-size:15px;font-weight:600;margin:0 0 12px;color:#1e293b;">Articles à fournir</h2>
      <table style="width:100%;border-collapse:collapse;font-size:14px;">
        <thead>
          <tr style="background:#f1f5f9;">
            <th style="padding:8px 12px;text-align:left;font-weight:600;color:#374151;">Code</th>
            <th style="padding:8px 12px;text-align:left;font-weight:600;color:#374151;">Désignation</th>
            <th style="padding:8px 12px;text-align:center;font-weight:600;color:#374151;">Qté</th>
            <th style="padding:8px 12px;text-align:right;font-weight:600;color:#374151;">PU (CHF)</th>
            <th style="padding:8px 12px;text-align:right;font-weight:600;color:#374151;">Total</th>
          </tr>
        </thead>
        <tbody>${rows}</tbody>
        <tfoot>
          <tr>
            <td colspan="4" style="padding:10px 12px;text-align:right;font-weight:700;border-top:2px solid #e5e7eb;">Sous-total</td>
            <td style="padding:10px 12px;text-align:right;font-weight:700;border-top:2px solid #e5e7eb;">${subtotal.toFixed(2)} CHF</td>
          </tr>
        </tfoot>
      </table>
    </div>

    <div style="padding:16px 32px 24px;font-size:12px;color:#9ca3af;border-top:1px solid #e5e7eb;">
      Ce document est généré automatiquement par le configurateur APEX. Pour toute question : configurateur@apex.ch
    </div>
  </div>
</body>
</html>`;
}

/**
 * Main entry point — called from orders route after insert.
 * Splits the order by supplier and sends each supplier their voucher.
 *
 * @param {number} orderId
 * @param {Object} config  - the order config JSON (finishId, hardware, modules, blocks, doorType, …)
 * @param {string} customerName
 * @param {string} orderDate  - ISO date string (defaults to now)
 */
export async function sendSupplierVouchers(orderId, config, customerName, orderDate = new Date().toISOString()) {
  const suppliers = await buildSupplierVoucherPayload(config);

  if (suppliers.length === 0) {
    console.log(`[supplier-voucher] Commande #${orderId} : aucun fournisseur résolu, aucun email envoyé.`);
    return;
  }

  // Send one email per supplier
  const sends = [];
  for (const supplier of suppliers) {
    const html = buildVoucherHtml({
      orderId,
      orderDate,
      customerName,
      supplierName: supplier.supplierName,
      items: supplier.items
    });
    sends.push(
      sendEmail({
        to: supplier.supplierEmail,
        subject: `Bon de commande #${orderId} — APEX Configurateur`,
        html
      }).then(() => {
        console.log(`[supplier-voucher] Email envoyé à ${supplier.supplierName} <${supplier.supplierEmail}> pour commande #${orderId}`);
      })
    );
  }

  await Promise.all(sends);
}

/**
 * Build supplier payload from order config.
 * Used by email sender and by admin API preview.
 *
 * @param {Object} config
 * @returns {Promise<Array<{supplierId:number, supplierCode:string|null, supplierName:string, supplierEmail:string, items:Array, subtotal:number}>>}
 */
export async function buildSupplierVoucherPayload(config) {
  const { hardware = {} } = config;
  const { handleVariantId, hingeVariantId, drawerSystemId } = hardware;

  // Resolve all items in parallel
  const [finishResult, drawerResult, handleResult, hingeResult] = await Promise.all([
    resolveFinishSupplier(config.finishId),
    resolveBlumHardware(drawerSystemId, 'drawer_system'),
    resolveHandle(handleVariantId),
    resolveHinge(hingeVariantId)
  ]);

  // Group items by supplier_id
  const supplierMap = new Map(); // supplier_id → { supplier info, items[] }

  for (const result of [finishResult, drawerResult, handleResult, hingeResult]) {
    if (!result) continue;
    const { supplier, item, category } = result;
    const sid = supplier.supplier_id;

    if (!supplierMap.has(sid)) {
      supplierMap.set(sid, {
        code: supplier.supplier_code || null,
        name: supplier.supplier_name,
        email: supplier.supplier_email,
        items: []
      });
    }

    const qty = estimateQuantity(category, config);
    if (qty > 0) {
      supplierMap.get(sid).items.push({
        code: item.code,
        name: item.name,
        unitPrice: item.price_chf,
        qty,
        category
      });
    }
  }

  return Array.from(supplierMap, ([supplierId, supplierData]) => {
    const subtotal = supplierData.items.reduce((sum, item) => sum + ((item.unitPrice || 0) * item.qty), 0);
    return {
      supplierId,
      supplierCode: supplierData.code || null,
      supplierName: supplierData.name,
      supplierEmail: supplierData.email,
      items: supplierData.items,
      subtotal
    };
  });
}