const { createRequire } = require('node:module');
const path = require('node:path');
const req = createRequire(path.resolve(__dirname, '../../server/package.json'));

function syntheticReceiptText({ status = 'success', final = true, direction = 'debit', amount = '10.00',
  currency = '人民币', payerAccount = '000011112222', payeeAccount = '000033334444',
  reference = 'SYNTHETIC-REFERENCE', bookedOn = '2026-10-01' } = {}) {
  const words = { success: '交易成功', failed: '交易失败', pending: '处理中', booked: '' };
  return [final ? '中国建设银行单位客户专用回单' : '中国建设银行网上银行电子回执',
    '合成公司测试回单 SYNTHETIC', `记账日期 ${bookedOn}`, direction === 'credit' ? '贷' : '借',
    `金额 ${amount}`, `币别 ${currency}`, `付款人账号 ${payerAccount}`, `收款人账号 ${payeeAccount}`, `凭证号码 ${reference}`,
    ...(words[status] ? [`单据状态 ${words[status]}`] : []),
    ...(!final ? ['本回执不作为收、付款方交易的最终依据，正式回单请在交易成功后另打印。'] : [])].join('\n');
}

async function syntheticBankReceiptPdf({ pages = 1, tag = 'SYNTHETIC', ...options } = {}) {
  const { PDFDocument, PDFHexString, beginText, endText, setFontAndSize, moveText, showText } = req('pdf-lib');
  const doc = await PDFDocument.create(); doc.setTitle(tag);
  const text = syntheticReceiptText(options);
  const hex = (s) => Buffer.from(s, 'utf16le').swap16().toString('hex').toUpperCase();
  const codes = [...new Set([...text.replace(/\n/g, '')])].map((c) => `<${hex(c)}> <${hex(c)}>`);
  const cmap = `/CIDInit /ProcSet findresource begin 12 dict begin begincmap
/CIDSystemInfo << /Registry (Adobe) /Ordering (UCS) /Supplement 0 >> def
/CMapName /Synthetic-UCS def /CMapType 2 def
1 begincodespacerange <0000> <FFFF> endcodespacerange
${codes.length} beginbfchar\n${codes.join('\n')}\nendbfchar
endcmap CMapName currentdict /CMap defineresource pop end end`;
  const toUnicode = doc.context.register(doc.context.flateStream(cmap));
  const cid = doc.context.register(doc.context.obj({ Type: 'Font', Subtype: 'CIDFontType0', BaseFont: 'STSong-Light',
    CIDSystemInfo: { Registry: PDFHexString.fromText('Adobe'), Ordering: PDFHexString.fromText('GB1'), Supplement: 4 }, DW: 1000 }));
  const font = doc.context.register(doc.context.obj({ Type: 'Font', Subtype: 'Type0', BaseFont: 'STSong-Light',
    Encoding: 'Identity-H', DescendantFonts: [cid], ToUnicode: toUnicode }));
  for (let n = 0; n < pages; n++) {
    const page = doc.addPage([595, 842]);
    const name = page.node.newFontDictionary('SYN', font);
    text.split('\n').forEach((line, index) => page.pushOperators(beginText(), setFontAndSize(name, 10),
      moveText(30, 790 - index * 22), showText(PDFHexString.of(hex(line))), endText()));
  }
  return Buffer.from(await doc.save());
}

function syntheticDocumentEvidence(options) {
  return req('./src/services/paymentReceiptDocument').classifyReceiptText(syntheticReceiptText(options));
}

module.exports = { syntheticReceiptText, syntheticBankReceiptPdf, syntheticDocumentEvidence };