import { createHash } from 'node:crypto'
import { existsSync, mkdirSync, readFileSync, writeFileSync } from 'node:fs'
import path from 'node:path'
import { fileURLToPath } from 'node:url'

const PAGE_WIDTH = 842
const PAGE_HEIGHT = 595

const findFont = requestedPath => {
  const candidates = [
    requestedPath,
    process.env.INVOICE_PDF_FONT_PATH,
    'C:/Windows/Fonts/simhei.ttf',
    'C:/Windows/Fonts/msyh.ttf',
    '/usr/share/fonts/truetype/noto/NotoSansCJK-Regular.ttf',
    '/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf'
  ].filter(Boolean)
  const fontPath = candidates.find(candidate => existsSync(candidate))
  if (!fontPath) {
    throw new Error('未找到可用字体，请通过 INVOICE_PDF_FONT_PATH 指定支持中文的 TTF 字体')
  }
  if (path.extname(fontPath).toLowerCase() !== '.ttf') {
    throw new Error('模拟发票工具仅支持 TTF 字体')
  }
  return fontPath
}

const readTableDirectory = font => {
  const tableCount = font.readUInt16BE(4)
  const tables = new Map()
  for (let index = 0; index < tableCount; index += 1) {
    const offset = 12 + index * 16
    tables.set(font.toString('ascii', offset, offset + 4), {
      offset: font.readUInt32BE(offset + 8),
      length: font.readUInt32BE(offset + 12)
    })
  }
  return tables
}

const createGlyphMapper = font => {
  const cmapTable = readTableDirectory(font).get('cmap')
  if (!cmapTable) throw new Error('字体缺少 cmap 字符映射表')
  const base = cmapTable.offset
  const count = font.readUInt16BE(base + 2)
  let format12Offset = null
  let format4Offset = null

  for (let index = 0; index < count; index += 1) {
    const record = base + 4 + index * 8
    const platformId = font.readUInt16BE(record)
    const encodingId = font.readUInt16BE(record + 2)
    const subtableOffset = base + font.readUInt32BE(record + 4)
    const format = font.readUInt16BE(subtableOffset)
    if (format === 12 && (platformId === 0 || (platformId === 3 && encodingId === 10))) {
      format12Offset = subtableOffset
    }
    if (format === 4 && (platformId === 0 || platformId === 3)) {
      format4Offset = subtableOffset
    }
  }

  const fromFormat12 = codePoint => {
    if (format12Offset === null) return 0
    const groupCount = font.readUInt32BE(format12Offset + 12)
    let low = 0
    let high = groupCount - 1
    while (low <= high) {
      const middle = (low + high) >> 1
      const group = format12Offset + 16 + middle * 12
      const start = font.readUInt32BE(group)
      const end = font.readUInt32BE(group + 4)
      if (codePoint < start) high = middle - 1
      else if (codePoint > end) low = middle + 1
      else return font.readUInt32BE(group + 8) + codePoint - start
    }
    return 0
  }

  const fromFormat4 = codePoint => {
    if (format4Offset === null || codePoint > 0xffff) return 0
    const segmentCount = font.readUInt16BE(format4Offset + 6) / 2
    const endCodes = format4Offset + 14
    const startCodes = endCodes + segmentCount * 2 + 2
    const deltas = startCodes + segmentCount * 2
    const rangeOffsets = deltas + segmentCount * 2
    for (let index = 0; index < segmentCount; index += 1) {
      const end = font.readUInt16BE(endCodes + index * 2)
      if (codePoint > end) continue
      const start = font.readUInt16BE(startCodes + index * 2)
      if (codePoint < start) return 0
      const delta = font.readInt16BE(deltas + index * 2)
      const rangeOffsetPosition = rangeOffsets + index * 2
      const rangeOffset = font.readUInt16BE(rangeOffsetPosition)
      if (rangeOffset === 0) return (codePoint + delta) & 0xffff
      const glyphPosition = rangeOffsetPosition + rangeOffset + (codePoint - start) * 2
      if (glyphPosition + 2 > font.length) return 0
      const glyph = font.readUInt16BE(glyphPosition)
      return glyph === 0 ? 0 : (glyph + delta) & 0xffff
    }
    return 0
  }

  return codePoint => fromFormat12(codePoint) || fromFormat4(codePoint)
}

const utf16Hex = value => {
  const buffer = Buffer.from(value, 'utf16le')
  buffer.swap16()
  return buffer.toString('hex').toUpperCase()
}

const createPdfWriter = () => {
  const objects = []
  return {
    add(body) {
      objects.push(Buffer.isBuffer(body) ? body : Buffer.from(body, 'binary'))
      return objects.length
    },
    save(outputPath) {
      const header = Buffer.from('%PDF-1.7\n%\xFF\xFF\xFF\xFF\n', 'binary')
      const chunks = [header]
      const offsets = [0]
      let cursor = header.length
      objects.forEach((body, index) => {
        offsets.push(cursor)
        const prefix = Buffer.from(`${index + 1} 0 obj\n`, 'ascii')
        const suffix = Buffer.from('\nendobj\n', 'ascii')
        chunks.push(prefix, body, suffix)
        cursor += prefix.length + body.length + suffix.length
      })
      const xrefOffset = cursor
      const xref = [`xref\n0 ${objects.length + 1}\n`, '0000000000 65535 f \n']
      for (let index = 1; index <= objects.length; index += 1) {
        xref.push(`${String(offsets[index]).padStart(10, '0')} 00000 n \n`)
      }
      xref.push(`trailer\n<< /Size ${objects.length + 1} /Root 1 0 R >>\nstartxref\n${xrefOffset}\n%%EOF\n`)
      chunks.push(Buffer.from(xref.join(''), 'ascii'))
      mkdirSync(path.dirname(outputPath), { recursive: true })
      writeFileSync(outputPath, Buffer.concat(chunks))
    }
  }
}

const streamObject = (dictionary, data) => Buffer.concat([
  Buffer.from(`<< ${dictionary} /Length ${data.length} >>\nstream\n`, 'ascii'),
  data,
  Buffer.from('\nendstream', 'ascii')
])

const money = value => Number(value || 0).toFixed(2)

const chineseAmount = value => {
  const digits = '零壹贰叁肆伍陆柒捌玖'
  const units = ['', '拾', '佰', '仟', '万', '拾', '佰', '仟', '亿', '拾', '佰', '仟']
  const amount = Math.max(Number(value || 0), 0)
  const integer = Math.floor(amount)
  const chars = String(integer).split('').reverse()
  let result = ''
  let pendingZero = false
  chars.forEach((char, index) => {
    const digit = Number(char)
    if (digit === 0) {
      pendingZero = result.length > 0
      if (index === 4 || index === 8) result = units[index] + result
    } else {
      result = `${digits[digit]}${units[index]}${pendingZero ? '零' : ''}${result}`
      pendingZero = false
    }
  })
  const cents = Math.round((amount - integer) * 100)
  const jiao = Math.floor(cents / 10)
  const fen = cents % 10
  return `${result || '零'}元${jiao ? `${digits[jiao]}角` : ''}${fen ? `${digits[fen]}分` : '整'}`
}

const normalizeInvoice = input => {
  const digest = createHash('sha256').update(JSON.stringify(input)).digest('hex').toUpperCase()
  const total = Number(input.orderTotalPrice || 0)
  const taxRate = Number(input.taxRate ?? 0.13)
  const naked = Number(input.invoiceNakedPrice ?? total / (1 + taxRate))
  const tax = Number(input.invoiceTaxPrice ?? total - naked)
  return {
    ...input,
    invoiceDate: input.invoiceDate || new Date().toISOString().slice(0, 10),
    invoiceNumber: input.invoiceNumber || digest.slice(0, 20),
    checkCode: input.checkCode || digest.slice(20, 40),
    sellerName: input.sellerName || '模拟积分商城供应商',
    sellerTaxId: input.sellerTaxId || input.supplierId || 'SIMULATED-SUPPLIER',
    sellerAddress: input.sellerAddress || '模拟供应商注册地址',
    sellerContact: input.sellerContact || '400-000-0000',
    invoiceContent: input.invoiceContent || '积分商城商品',
    orderNum: Number(input.orderNum || 1),
    total,
    naked,
    tax,
    taxRate
  }
}

export const generateMockInvoicePdf = (invoiceInput, outputPath, options = {}) => {
  const invoice = normalizeInvoice(invoiceInput)
  const fontPath = findFont(options.fontPath)
  const font = readFileSync(fontPath)
  const glyphFor = createGlyphMapper(font)
  const glyphUnicode = new Map()
  const commands = []

  const encode = value => Array.from(String(value ?? '')).map(character => {
    const glyph = glyphFor(character.codePointAt(0))
    if (glyph && !glyphUnicode.has(glyph)) glyphUnicode.set(glyph, character)
    return glyph.toString(16).padStart(4, '0')
  }).join('').toUpperCase()
  const text = (value, x, y, size = 10, color = '0 0 0') => {
    commands.push(`BT /F1 ${size} Tf ${color} rg 1 0 0 1 ${x} ${y} Tm <${encode(value)}> Tj ET`)
  }
  const line = (x1, y1, x2, y2, width = 0.7, color = '0.45 0.12 0.12') => {
    commands.push(`${color} RG ${width} w ${x1} ${y1} m ${x2} ${y2} l S`)
  }
  const rect = (x, y, width, height, color = '0.45 0.12 0.12') => {
    commands.push(`${color} RG 0.7 w ${x} ${y} ${width} ${height} re S`)
  }
  const wrappedText = (value, x, y, maxChars, size = 9, lineHeight = 13) => {
    const characters = Array.from(String(value || ''))
    for (let index = 0; index < characters.length; index += maxChars) {
      text(characters.slice(index, index + maxChars).join(''), x, y - index / maxChars * lineHeight, size)
    }
  }

  commands.push('1 1 1 rg 0 0 842 595 re f')
  text('增值税电子普通发票（模拟）', 280, 548, 22, '0.65 0.05 0.05')
  line(274, 540, 568, 540, 1.2, '0.65 0.05 0.05')
  text('仅供系统联调测试，禁止报销', 302, 522, 11, '0.75 0.1 0.1')

  text(`发票号码：${invoice.invoiceNumber}`, 610, 555, 9)
  text(`开票日期：${invoice.invoiceDate}`, 610, 538, 9)
  text(`校验码：${invoice.checkCode}`, 610, 521, 9)
  text(`结算单号：${invoice.settlementId || ''}`, 50, 521, 9)

  rect(42, 188, 758, 320)
  line(42, 414, 800, 414)
  line(42, 320, 800, 320)
  line(42, 280, 800, 280)
  line(42, 226, 800, 226)
  line(120, 414, 120, 508)
  line(120, 320, 120, 414)
  line(475, 414, 475, 508)
  line(475, 320, 475, 414)

  text('购买方', 68, 457, 12, '0.55 0.05 0.05')
  text('销售方', 68, 365, 12, '0.55 0.05 0.05')
  text('名称：', 132, 488, 9)
  wrappedText(invoice.invoiceTitle, 180, 488, 26, 9)
  text('纳税人识别号：', 132, 464, 9)
  text(invoice.invoiceCode, 235, 464, 9)
  text('地址、电话：', 487, 488, 9)
  wrappedText(`${invoice.invoiceAddress || ''} ${invoice.invoiceContact || ''}`, 574, 488, 20, 8)
  text('开户行及账号：', 487, 448, 9)
  wrappedText(`${invoice.bankName || ''} ${invoice.bankAccount || ''}`, 574, 448, 20, 8)

  text('名称：', 132, 395, 9)
  text(invoice.sellerName, 180, 395, 9)
  text('纳税人识别号：', 132, 371, 9)
  text(invoice.sellerTaxId, 235, 371, 9)
  text('地址、电话：', 487, 395, 9)
  wrappedText(`${invoice.sellerAddress} ${invoice.sellerContact}`, 574, 395, 20, 8)
  text('开户行及账号：', 487, 350, 9)
  wrappedText(`${invoice.sellerBankName || '模拟银行'} ${invoice.sellerBankAccount || '0000000000000000'}`, 574, 350, 20, 8)

  const columns = [42, 290, 382, 440, 495, 580, 655, 720, 800]
  columns.slice(1, -1).forEach(x => line(x, 226, x, 320))
  ;['货物或应税劳务、服务名称', '规格型号', '单位', '数量', '单价', '金额', '税率', '税额'].forEach((label, index) => {
    text(label, columns[index] + 7, 300, index === 0 ? 9 : 8)
  })
  wrappedText(`*商品*${invoice.invoiceContent}`, 50, 263, 28, 9)
  text(invoice.invoiceType || '电子发票', 300, 263, 8)
  text('项', 401, 263, 9)
  text(invoice.orderNum, 458, 263, 9)
  text(money(invoice.naked / invoice.orderNum), 503, 263, 8)
  text(money(invoice.naked), 590, 263, 8)
  text(`${(invoice.taxRate * 100).toFixed(0)}%`, 674, 263, 8)
  text(money(invoice.tax), 730, 263, 8)

  text('合计', 240, 203, 10)
  text(`¥${money(invoice.naked)}`, 590, 203, 10)
  text(`¥${money(invoice.tax)}`, 730, 203, 10)
  text(`价税合计（大写）：${chineseAmount(invoice.total)}`, 52, 164, 11)
  text(`（小写）：¥${money(invoice.total)}`, 600, 164, 11)
  text(`订单号：${invoice.orderIds || ''}`, 52, 132, 8)
  wrappedText(`备注：${invoice.remark || '模拟开票，仅用于开发与联调测试'}`, 52, 111, 70, 8)
  text('收款人：模拟收款员', 52, 65, 9)
  text('复核：模拟复核员', 285, 65, 9)
  text('开票人：模拟开票员', 510, 65, 9)
  text('销售方（章）', 682, 65, 9, '0.7 0.05 0.05')

  commands.push('q 0.92 0.92 0.92 rg BT /F1 34 Tf 0.866 0.5 -0.5 0.866 235 170 Tm')
  commands.push(`<${encode('模拟发票  禁止报销')}> Tj ET Q`)
  commands.push('0.75 0.08 0.08 RG 2 w 798 88 m 798 111.196 779.196 130 756 130 c 732.804 130 714 111.196 714 88 c 714 64.804 732.804 46 756 46 c 779.196 46 798 64.804 798 88 c S')

  const content = Buffer.from(commands.join('\n'), 'ascii')
  const toUnicodeEntries = [...glyphUnicode.entries()].map(([glyph, character]) =>
    `<${glyph.toString(16).padStart(4, '0').toUpperCase()}> <${utf16Hex(character)}>`)
  const toUnicodeBlocks = []
  for (let index = 0; index < toUnicodeEntries.length; index += 100) {
    const entries = toUnicodeEntries.slice(index, index + 100)
    toUnicodeBlocks.push(`${entries.length} beginbfchar`, ...entries, 'endbfchar')
  }
  const toUnicode = Buffer.from([
    '/CIDInit /ProcSet findresource begin', '12 dict begin', 'begincmap',
    '/CIDSystemInfo << /Registry (Adobe) /Ordering (UCS) /Supplement 0 >> def',
    '/CMapName /MockInvoiceUnicode def', '/CMapType 2 def',
    '1 begincodespacerange', '<0000> <FFFF>', 'endcodespacerange',
    ...toUnicodeBlocks,
    'endcmap', 'CMapName currentdict /CMap defineresource pop', 'end', 'end'
  ].join('\n'), 'ascii')

  const writer = createPdfWriter()
  writer.add('<< /Type /Catalog /Pages 2 0 R >>')
  writer.add('<< /Type /Pages /Kids [3 0 R] /Count 1 >>')
  writer.add(`<< /Type /Page /Parent 2 0 R /MediaBox [0 0 ${PAGE_WIDTH} ${PAGE_HEIGHT}] /Resources << /Font << /F1 5 0 R >> >> /Contents 4 0 R >>`)
  writer.add(streamObject('', content))
  writer.add('<< /Type /Font /Subtype /Type0 /BaseFont /MockInvoiceFont /Encoding /Identity-H /DescendantFonts [6 0 R] /ToUnicode 9 0 R >>')
  writer.add('<< /Type /Font /Subtype /CIDFontType2 /BaseFont /MockInvoiceFont /CIDSystemInfo << /Registry (Adobe) /Ordering (Identity) /Supplement 0 >> /FontDescriptor 7 0 R /DW 1000 /CIDToGIDMap /Identity >>')
  writer.add('<< /Type /FontDescriptor /FontName /MockInvoiceFont /Flags 4 /FontBBox [-1000 -1000 3000 3000] /ItalicAngle 0 /Ascent 1000 /Descent -300 /CapHeight 800 /StemV 80 /FontFile2 8 0 R >>')
  writer.add(streamObject(`/Length1 ${font.length}`, font))
  writer.add(streamObject('', toUnicode))
  writer.save(outputPath)
  return outputPath
}

const parseArguments = argv => {
  const options = {}
  for (let index = 0; index < argv.length; index += 1) {
    if (argv[index] === '--input') options.input = argv[++index]
    else if (argv[index] === '--data') options.data = argv[++index]
    else if (argv[index] === '--output') options.output = argv[++index]
    else if (argv[index] === '--font') options.font = argv[++index]
  }
  return options
}

if (process.argv[1] && path.resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
  try {
    const options = parseArguments(process.argv.slice(2))
    if (!options.input && !options.data) {
      throw new Error('请使用 --input <json文件> 或 --data <json字符串> 传入开票信息')
    }
    const input = options.input
      ? JSON.parse(readFileSync(path.resolve(options.input), 'utf8'))
      : JSON.parse(options.data)
    const defaultName = `mock-invoice-${String(input.settlementId || Date.now()).replace(/[^a-zA-Z0-9_-]/g, '_')}.pdf`
    const outputPath = path.resolve(options.output || path.join('output', 'pdf', defaultName))
    generateMockInvoicePdf(input, outputPath, { fontPath: options.font })
    console.log(outputPath)
  } catch (error) {
    console.error(error instanceof Error ? error.message : String(error))
    process.exitCode = 1
  }
}