/**
 * VDA 4913 Parser - Field positions verified against real data
 */
window.EDIBridge = window.EDIBridge || {};

class VDAParser {
  static parse(content) {
    const lines = content.split(/\r?\n/).filter(l => l.length >= 3);
    const result = { interchanges: [] };
    let curI = null, curT = null, curDN = null;

    for (const line of lines) {
      const rt = line.substring(0, 3);
      switch (rt) {
        // VDA 4905 (DELFOR)
        case '511':
          curI = { header: this.parse511(line), articles: [], transports: [] };
          result.interchanges.push(curI);
          break;
        case '512':
          if (!curI) break;
          // In 4905, articles are children of the interchange
          curT = { article: this.parse512(line), schedules: [], deliveries: [] };
          curI.articles.push(curT);
          break;
        case '513':
          if (!curT || !curT.article) break; // Ensure we are in an article context
          const s513 = this.parse513(line);
          curT.schedules.push(...s513.schedules);
          if (s513.lastDn && s513.lastDn !== '00000000' && s513.lastDn.trim() !== '') {
            curT.deliveries.push({
              docNo: s513.lastDn,
              date: s513.lastDate,
              qty: s513.lastQty,
              unit: curT.article.unit || 'ST'
            });
          }
          curT.efz = s513.efz;
          curT.nullStellung = s513.nullStellung || '';
          break;
        case '514':
          if (!curT || !curT.article) break;
          curT.schedules.push(...this.parse514(line));
          break;
        case '519':
          if (curI) curI.trailer = this.parse519(line);
          break;

        // VDA 4913 (DESADV)
        case '711':
          curI = { header: this.parse711(line), transports: [], articles: [] };
          result.interchanges.push(curI);
          break;
        case '712':
          if (!curI) break;
          curT = { data: this.parse712(line), deliveryNotes: [] };
          curI.transports.push(curT);
          break;
        case '713':
          if (!curT) break;
          curDN = { header: this.parse713(line), positions: [], texts: [] };
          curT.deliveryNotes.push(curDN);
          break;
        case '714':
          if (!curDN) break;
          curDN.positions.push({ data: this.parse714(line), packaging: [] });
          break;
        case '715':
          if (!curDN) break;
          const lastP = curDN.positions[curDN.positions.length - 1];
          if (lastP) lastP.packaging.push(this.parse715(line));
          break;
        case '716':
          if (curDN) {
            curDN.texts.push(line.substring(5).trim());
            const revLvl = line.substring(5, 7).trim();
            if (revLvl && curDN.positions.length > 0) {
              const lastPos = curDN.positions[curDN.positions.length - 1];
              if (!lastPos.data.revisionLevel) lastPos.data.revisionLevel = revLvl;
            }
          }
          break;
        case '719':
          if (curI) curI.trailer = this.parse719(line);
          break;
      }
    }
    return result;
  }

  static getCustomerId(content) {
    if (!content) return null;
    const lines = content.split(/\r?\n/).filter(l => l.length >= 3);
    for (const line of lines) {
      const rt = line.substring(0, 3);
      if (rt === '711' || rt === '511') {
        return line.substring(5, 14).trim();
      }
    }
    return null;
  }

  // --- VDA 4905 Parsers ---
  static parse511(l) {
    return {
      version: l.substring(3, 5).trim(),
      customerId: l.substring(5, 14).trim(),
      supplierId: l.substring(14, 23).trim(),
      oldTransNo: l.substring(23, 28).trim(),
      newTransNo: l.substring(28, 33).trim(),
      date: l.substring(33, 39).trim()
    };
  }

  static parse512(l) {
    return {
      plant: l.substring(5, 8).trim(),
      docNum: l.substring(8, 17).trim(),
      docDate: l.substring(17, 23).trim(),
      custMat: l.substring(38, 60).trim(),
      suppMat: l.substring(60, 82).trim(),
      orderNo: l.substring(82, 94).trim(),
      unloadingPoint: l.substring(94, 99).trim(),
      unit: l.substring(103, 105).trim() || 'ST'
    };
  }

  static parse513(l) {
    const weDate = l.substring(5, 11).trim();
    const lastDn = l.substring(11, 19).trim();
    const lastDate = l.substring(19, 25).trim();
    // VDA 4905: Letzte Liefermenge hat 3 implizite Dezimalstellen → /1000
    const lastQty = (parseInt(l.substring(25, 37), 10) || 0) / 1000;
    // VDA 4905: EFZ hat ebenfalls 3 implizite Dezimalstellen → /1000
    const efz = (parseInt(l.substring(37, 47), 10) || 0) / 1000;

    const schedules = [];
    let offset = 47;
    for (let i = 0; i < 5; i++) {
      const dateRaw = l.substring(offset, offset + 6);
      const qtyStr = l.substring(offset + 6, offset + 15).trim();
      if (dateRaw.trim() && dateRaw.trim() !== '000000') {
        // VDA 4905: Abrufmengen haben 3 implizite Dezimalstellen → /1000
        schedules.push({ date: dateRaw, qty: (parseInt(qtyStr, 10) || 0) / 1000 });
      }
      offset += 15;
    }
    // Null-Stellung (6 Zeichen JJMMTT) steht nach den 5 Abrufzeilen
    const nullStellungRaw = l.substring(offset, offset + 6).trim();
    const nullStellung = (nullStellungRaw && nullStellungRaw !== '000000') ? nullStellungRaw : '';
    return { weDate, lastDn, lastDate, lastQty, efz, nullStellung, schedules };
  }

  static parse514(l) {
    const schedules = [];
    let offset = 5;
    for (let i = 0; i < 8; i++) {
      const dateRaw = l.substring(offset, offset + 6);
      const qtyStr = l.substring(offset + 6, offset + 15).trim();
      if (dateRaw.trim() && dateRaw.trim() !== '000000') {
        // VDA 4905: Abrufmengen haben 3 implizite Dezimalstellen → /1000
        schedules.push({ date: dateRaw, qty: (parseInt(qtyStr, 10) || 0) / 1000 });
      }
      offset += 15;
    }
    return schedules;
  }

  static parse519(l) {
    return {
      count511: parseInt(l.substring(5, 12), 10) || 0,
      count512: parseInt(l.substring(12, 19), 10) || 0,
      count513: parseInt(l.substring(19, 26), 10) || 0,
      count514: parseInt(l.substring(26, 33), 10) || 0
    };
  }

  // --- VDA 4913 Parsers ---

  static parse711(l) {
    return {
      version: l.substring(3, 5).trim(),
      targetId: l.substring(5, 14).trim(),
      sourceId: l.substring(14, 23).trim(),
      transNo1: l.substring(23, 28).trim(),
      transNo2: l.substring(28, 33).trim(),
      date: l.substring(33, 39).trim(),
      altId: l.substring(39, 48).trim()
    };
  }

  static parse712(l) {
    return {
      refNo: l.substring(5, 13).trim(),
      carrierName: l.substring(16, 30).trim(),
      date: l.substring(30, 36).trim(),
      time: l.substring(36, 40).trim(),
      grossWeight: parseInt(l.substring(40, 47)) || 0,
      netWeight: parseInt(l.substring(47, 54)) || 0,
    };
  }

  static parse713(l) {
    return {
      dnNo: l.substring(5, 13).trim(),
      date: l.substring(13, 19).trim(),
      unloadingPoint: l.substring(19, 24).trim(),
      qualifier: l.substring(24, 30).trim(),
      orderNo: l.substring(30, 38).trim(),
    };
  }

  static parse714(l) {
    // Qty: [53-65] with 3 implied decimals (VDA Standard) → /1000
    const qtyRaw = parseInt(l.substring(52, 65)) || 0;
    const qty = qtyRaw / 1000;
    return {
      custMat: l.substring(5, 27).trim(),
      suppMat: l.substring(27, 49).trim(),
      qty: qty,
      unit: l.substring(65, 67).trim(),
      refNo: l.substring(77, 90).trim(), 
      // VDA 4913 standard uses different fields for batch/refs, keeping compatibility
      batchNo: l.substring(90, 105).trim() || l.substring(113, 127).trim(),
    };
  }

  static parse715(l) {
    const count = parseInt(l.substring(59, 62)) || 1;
    const labelFrom = l.substring(78, 87).trim();
    const labelTo = l.substring(87, 96).trim();
    return {
      packMatCust: l.substring(5, 27).trim(),
      packMatSupp: l.substring(27, 49).trim(),
      qty: count,
      labelFrom: labelFrom,
      labelTo: labelTo,
    };
  }

  static parse719(l) {
    return { lineCount: parseInt(l.substring(5, 12)) || 0 };
  }
}

window.EDIBridge.VDAParser = VDAParser;