const crypto = require('crypto');
const AdmZip = require('adm-zip');
const xml2js = require('xml2js');
const db = require('./db');

function getConfig() {
  const rows = db.prepare('SELECT key, value FROM config').all();
  const config = {};
  for (const r of rows) {
    config[r.key] = r.value;
  }
  return config;
}

// 1. Authentifizierung & WWSVC-Headers nach Spezifikation
function generateHeaders(appId, passId, algo = 'md5') {
  const ts = new Date().toISOString();
  const reqId = crypto.randomUUID ? crypto.randomUUID() : Math.random().toString(36).substring(2);
  
  // WWSVC Hash: MD5 über appId + ts
  const rawString = `${appId || ''}${ts}`;
  const hash = crypto.createHash(algo === 'sha256' ? 'sha256' : 'md5').update(rawString).digest('hex');

  return {
    'WWSVC-HASH': hash,
    'WWSVC-TS': ts,
    'WWSVC-REQID': reqId,
    'User-Agent': 'Getraenkekarte-POS-Client/1.0'
  };
}

function formatDate(d) {
  const pad = n => String(n).padStart(2, '0');
  return `${pad(d.getDate())}.${pad(d.getMonth() + 1)}.${d.getFullYear()}`;
}

function formatTime(d) {
  const pad = n => String(n).padStart(2, '0');
  return `${pad(d.getHours())}:${pad(d.getMinutes())}:${pad(d.getSeconds())}`;
}

// QR-Code Setup Handshake
async function processQrSetup(qrPayload) {
  let data = qrPayload;
  if (typeof qrPayload === 'string') {
    try {
      data = JSON.parse(qrPayload.trim());
    } catch (e) {
      throw new Error('Ungültiges QR-Code JSON-Format');
    }
  }

  if (data.$type !== 'ww-setup') {
    throw new Error('Ungültiger QR-Code-Typ: $type muss "ww-setup" sein');
  }

  const { url, servicepasslink } = data;
  const mdcDeviceId = data.mdcDeviceId || data.cr || data.cashRegisterNumber || '1';

  if (!url || !servicepasslink) {
    throw new Error('Fehlende Pflichtfelder (url oder servicepasslink) im QR-Code');
  }

  const cleanUrl = url.replace(/\/$/, '');

  // 1. GET ServicePass: GET /@LNK{servicepasslink}
  const linkUrl = `${cleanUrl}/@LNK${servicepasslink}`;
  const res = await fetch(linkUrl, {
    method: 'GET',
    headers: { 'User-Agent': 'Getraenkekarte-POS-Client/1.0' }
  });

  if (!res.ok) {
    throw new Error(`Fehler beim Abruf von ServicePass (@LNK): ${res.status} ${res.statusText}`);
  }

  const resJson = await res.json();
  const servicePass = resJson.SERVICEPASS || resJson.servicepass || resJson;
  const passId = servicePass.PASSID || servicePass.passId || servicePass.id;
  const appId = servicePass.APPID || servicePass.appId || servicePass.key;

  if (!passId || !appId) {
    throw new Error(`Unerwartete ServicePass-Antwort: ${JSON.stringify(resJson)}`);
  }

  // 2. In lokaler SQLite Datenbank speichern
  const upsert = db.prepare('INSERT INTO config (key, value) VALUES (?, ?) ON CONFLICT(key) DO UPDATE SET value = excluded.value');
  upsert.run('pos_url', cleanUrl);
  upsert.run('pos_pass_id', passId);
  upsert.run('pos_app_id', appId);
  upsert.run('pos_cash_register', String(mdcDeviceId));

  db.prepare('INSERT INTO sync_logs (status, message) VALUES (?, ?)')
    .run('SUCCESS', `QR-Code Handshake erfolgreich. Pass-ID: ${passId}, Kasse: ${mdcDeviceId}`);

  // 3. Direkt automatischen Initial-Sync ausführen
  let syncResult = null;
  try {
    syncResult = await performSync('ERSTEINRICHTUNG');
  } catch(syncErr) {
    console.warn('Initialer Sync nach Setup Fehler:', syncErr.message);
  }

  return {
    success: true,
    url: cleanUrl,
    passId,
    appId,
    mdcDeviceId: String(mdcDeviceId),
    syncResult
  };
}

// Datenabruf-Ablauf: CASPOS.EXEC (Vorbereitung) & CASPOS.GET (Download) via WEBWARE Slash-Format
async function performSync(syncType = 'ERSTEINRICHTUNG') {
  const config = getConfig();
  const { pos_url, pos_pass_id, pos_app_id, pos_cash_register, last_sync_time } = config;

  if (!pos_url || !pos_pass_id || !pos_app_id) {
    throw new Error('POS Cloud Zugangsdaten unvollständig (URL, PassId oder AppId fehlt)');
  }

  const cleanUrl = pos_url.trim().replace(/\/$/, '');
  const devId = pos_cash_register || '1';

  // A) Differenzabgleich Vorbereitung wenn ART=AENDERUNGEN
  if (syncType === 'AENDERUNGEN') {
    let fromDate = new Date(Date.now() - 24 * 60 * 60 * 1000);
    if (last_sync_time) {
      const parsed = new Date(last_sync_time);
      if (!isNaN(parsed.getTime())) fromDate = parsed;
    }

    const execPath = `/WWSVC/EXECURL/${pos_pass_id}/CASPOS.EXEC/ART=AENDERUNGEN/AENDERUNGEN_ABDATUM=${formatDate(fromDate)}/AENDERUNGEN_ABUHRZEIT=${formatTime(fromDate)}/MDCDEVICEID=${devId}`;
    const execHeaders = generateHeaders(pos_app_id, pos_pass_id);
    try {
      await fetch(`${cleanUrl}${execPath}`, { method: 'GET', headers: execHeaders });
    } catch(e) {
      console.warn('CASPOS.EXEC Hinweis:', e.message);
    }
  }

  // B) Download mit CASPOS.GET im Webware-Format (/WWSVC/EXECURL/{passId}/CASPOS.GET/ART=.../MDCDEVICEID=...)
  const getPath = `/WWSVC/EXECURL/${pos_pass_id}/CASPOS.GET/ART=${syncType}/MDCDEVICEID=${devId}/LAGER=1/LAGERORTE=1/VK1=1/VK2=1/VK3=1/VK4=1/VK5=1/VK6=1`;
  const getUrl = `${cleanUrl}${getPath}`;

  const headers = generateHeaders(pos_app_id, pos_pass_id);
  
  const response = await fetch(getUrl, {
    method: 'GET',
    headers: headers
  });

  if (!response.ok) {
    throw new Error(`POS Cloud HTTP Error: ${response.status} ${response.statusText}`);
  }

  const arrayBuffer = await response.arrayBuffer();
  const buffer = Buffer.from(arrayBuffer);
  
  const result = await parseAndStoreZip(buffer);

  db.prepare('INSERT INTO config (key, value) VALUES (?, ?) ON CONFLICT(key) DO UPDATE SET value = excluded.value')
    .run('last_sync_time', new Date().toISOString());

  return result;
}

// Inhalt ZIP & Dateitypen (JSON & XML Parsing für SoftEngine CASPOS Cloud)
async function parseAndStoreZip(buffer) {
  const zip = new AdmZip(buffer);
  const zipEntries = zip.getEntries();
  
  let productsCount = 0;
  let groupsCount = 0;
  let deletionsCount = 0;

  const insertGroup = db.prepare(`
    INSERT INTO product_groups (id, name, sort_order)
    VALUES (?, ?, ?)
    ON CONFLICT(id) DO UPDATE SET name=excluded.name
  `);

  const insertProduct = db.prepare(`
    INSERT INTO products (id, text1, text2, langtext1, langtext2, langtext3, langtext4, group_id, preis1, unit, active)
    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 1)
    ON CONFLICT(id) DO UPDATE SET
      text1=excluded.text1,
      text2=excluded.text2,
      langtext1=excluded.langtext1,
      langtext2=excluded.langtext2,
      langtext3=excluded.langtext3,
      langtext4=excluded.langtext4,
      group_id=excluded.group_id,
      preis1=excluded.preis1,
      unit=excluded.unit,
      active=1,
      updated_at=CURRENT_TIMESTAMP
  `);

  const deactivateProduct = db.prepare(`
    UPDATE products SET active = 0 WHERE id = ?
  `);

  const parser = new xml2js.Parser({ explicitArray: false, ignoreAttrs: false });

  for (const entry of zipEntries) {
    const fileName = entry.entryName.toLowerCase();
    const rawContent = entry.getData().toString('utf8');

    // JSON Format von SoftEngine CASPOS (z.B. Casposdata_Products.json)
    if (fileName.endsWith('.json')) {
      let json = {};
      try { json = JSON.parse(rawContent); } catch(e) {}

      // 1. Warengruppen
      const groupsData = json.productGroups?.data || (Array.isArray(json.productGroups) ? json.productGroups : []);
      for (const g of groupsData) {
        const id = String(g.id || g.groupId || '');
        const name = g.name || g.text || g.text1 || ('Kategorie ' + id);
        if (id) {
          insertGroup.run(id, name, 0);
          groupsCount++;
        }
      }

      // 2. Artikel
      const productsData = json.products?.data || (Array.isArray(json.products) ? json.products : (Array.isArray(json) ? json : []));
      for (const item of productsData) {
        const id = String(item.id || item.articleNo || '');
        const text1 = item.text1 || item.name || item.title || 'Unbekannt';
        const text2 = item.text2 || item.description || item.additionalText || '';
        const groupId = String(item.groupId || item.warengruppe || '');

        // Langtexte aus Attributen / Descriptions / Feldern extrahieren
        let langtext1 = item.langtext1 || item.Langtext1 || item.longText1 || item.LongText1 || '';
        let langtext2 = item.langtext2 || item.Langtext2 || item.longText2 || item.LongText2 || '';
        let langtext3 = item.langtext3 || item.Langtext3 || item.longText3 || item.LongText3 || '';
        let langtext4 = item.langtext4 || item.Langtext4 || item.longText4 || item.LongText4 || '';

        // Falls in descriptions Array oder attributes Array abgelegt
        if (Array.isArray(item.descriptions)) {
          if (item.descriptions[0]?.text) langtext1 = item.descriptions[0].text;
          if (item.descriptions[1]?.text) langtext2 = item.descriptions[1].text;
          if (item.descriptions[2]?.text) langtext3 = item.descriptions[2].text;
          if (item.descriptions[3]?.text) langtext4 = item.descriptions[3].text;
        }

        if (Array.isArray(item.attributes)) {
          for (const attr of item.attributes) {
            const attrName = (attr.name || attr.title || '').toLowerCase();
            const attrVal = attr.value || attr.text || '';
            if (attrName.includes('langtext 1') || attrName.includes('langtext1')) langtext1 = attrVal;
            if (attrName.includes('langtext 2') || attrName.includes('langtext2')) langtext2 = attrVal;
            if (attrName.includes('langtext 3') || attrName.includes('langtext3')) langtext3 = attrVal;
            if (attrName.includes('langtext 4') || attrName.includes('langtext4')) langtext4 = attrVal;
          }
        }

        // Preis 1 ermitteln (VK1)
        let preis1 = 0;
        if (Array.isArray(item.prices) && item.prices.length > 0) {
          const vk1Obj = item.prices.find(p => String(p.level) === '1') || item.prices[0];
          if (vk1Obj && vk1Obj.value !== undefined) {
            preis1 = parseFloat(String(vk1Obj.value).replace(',', '.'));
          }
        } else if (typeof item.prices === 'object' && item.prices !== null) {
          preis1 = parseFloat(String(item.prices.vk1 || item.prices.price1 || 0).replace(',', '.'));
        } else if (item.preis1 !== undefined) {
          preis1 = parseFloat(String(item.preis1).replace(',', '.'));
        } else if (item.price !== undefined) {
          preis1 = parseFloat(String(item.price).replace(',', '.'));
        }

        const unit = item.contentUnit || item.salesUnit || item.unit || '';

        if (id) {
          insertProduct.run(id, text1, text2, langtext1, langtext2, langtext3, langtext4, groupId, isNaN(preis1) ? 0 : preis1, unit);
          productsCount++;
        }
      }

      // 3. Deletions
      const deletionsData = json.deletions?.data || (Array.isArray(json.deletions) ? json.deletions : []);
      for (const del of deletionsData) {
        const id = String(del.id || del.articleNo || del);
        if (id) {
          deactivateProduct.run(id);
          deletionsCount++;
        }
      }
    }

    // XML Format Fallback
    if (fileName.endsWith('.xml')) {
      let parsed = {};
      try { parsed = await parser.parseStringPromise(rawContent); } catch(e) {}
      const root = parsed.root || parsed;

      let groups = root.ProductGroups?.ProductGroup || root.productGroups?.productGroup || [];
      if (!Array.isArray(groups)) groups = [groups];
      for (const g of groups) {
        const id = String(g.id || g.groupId || '');
        const name = g.name || g.text || ('Kategorie ' + id);
        if (id) { insertGroup.run(id, name, 0); groupsCount++; }
      }

      let items = root.Products?.Product || root.products?.product || [];
      if (!Array.isArray(items)) items = [items];
      for (const item of items) {
        const id = String(item.id || item.articleNo || '');
        const text1 = item.text1 || item.name || 'Unbekannt';
        const text2 = item.text2 || '';
        const langtext1 = item.langtext1 || item.Langtext1 || '';
        const langtext2 = item.langtext2 || item.Langtext2 || '';
        const langtext3 = item.langtext3 || item.Langtext3 || '';
        const langtext4 = item.langtext4 || item.Langtext4 || '';
        const groupId = String(item.groupId || '');
        let preis1 = parseFloat(String(item.preis1 || item.price || 0).replace(',', '.'));
        if (id) { insertProduct.run(id, text1, text2, langtext1, langtext2, langtext3, langtext4, groupId, isNaN(preis1) ? 0 : preis1, ''); productsCount++; }
      }
    }
  }

  const msg = `Import: ${productsCount} Artikel, ${groupsCount} Gruppen, ${deletionsCount} Deaktiviert`;
  db.prepare('INSERT INTO sync_logs (status, message, items_count) VALUES (?, ?, ?)')
    .run('SUCCESS', msg, productsCount);

  return { productsCount, groupsCount, deletionsCount, message: msg };
}

function importJsonData(data) {
  const insertProduct = db.prepare(`
    INSERT INTO products (id, text1, text2, langtext1, langtext2, langtext3, langtext4, group_id, preis1, unit, active)
    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 1)
    ON CONFLICT(id) DO UPDATE SET
      text1=excluded.text1,
      text2=excluded.text2,
      langtext1=excluded.langtext1,
      langtext2=excluded.langtext2,
      langtext3=excluded.langtext3,
      langtext4=excluded.langtext4,
      group_id=excluded.group_id,
      preis1=excluded.preis1,
      unit=excluded.unit,
      active=1,
      updated_at=CURRENT_TIMESTAMP
  `);

  const insertGroup = db.prepare(`
    INSERT INTO product_groups (id, name, sort_order)
    VALUES (?, ?, ?)
    ON CONFLICT(id) DO UPDATE SET name=excluded.name
  `);

  let count = 0;
  const tx = db.transaction(() => {
    if (data.groups && Array.isArray(data.groups)) {
      for (const g of data.groups) {
        insertGroup.run(String(g.id), g.name, g.sortOrder || 0);
      }
    }
    if (data.products && Array.isArray(data.products)) {
      for (const p of data.products) {
        insertProduct.run(
          String(p.id || Math.random().toString(36).substring(2)),
          p.text1 || 'Unbekannt',
          p.text2 || '',
          p.langtext1 || '',
          p.langtext2 || '',
          p.langtext3 || '',
          p.langtext4 || '',
          String(p.groupId || ''),
          parseFloat(String(p.preis1 || p.price || 0).replace(',', '.')),
          p.unit || ''
        );
        count++;
      }
    }
  });
  tx();
  return count;
}

module.exports = {
  processQrSetup,
  performSync,
  parseAndStoreZip,
  importJsonData,
  getConfig
};