import PDFDocument from 'pdfkit'
import crypto from 'crypto'
import { getChineseFont } from './font.js'

const HMAC_SECRET = process.env.HMAC_SECRET || 'newapi-dashboard-default-secret-key-change-in-production'
const DASHBOARD_URL = process.env.DASHBOARD_URL || 'https://www.lamclod.cn'

interface BillingReportData {
  siteName: string
  siteUrl: string
  userId: number
  username: string
  group: string
  startDate: string
  endDate: string
  totalQuota: number
  totalRequests: number
  modelSummary: { model: string; quota: number; count: number }[]
  topups: {
    create_time: number
    amount: number
    money: number
    payment_method: string
    status: string
    trade_no: string
  }[]
  logs: {
    created_at: number
    type: number
    model_name: string
    token_name: string
    group: string
    is_stream: boolean
    quota: number
    prompt_tokens: number
    completion_tokens: number
    use_time: number
    ip: string
    request_id: string
    other: string
  }[]
}

export function generateHmacSignature(data: {
  userId: number; startDate: string; endDate: string;
  totalQuota: number; totalRecords: number; generatedAt: string;
}): string {
  const signStr = `${data.userId}|${data.startDate}|${data.endDate}|${data.totalQuota}|${data.totalRecords}|${data.generatedAt}`
  return crypto.createHmac('sha256', HMAC_SECRET).update(signStr).digest('hex')
}

export function verifyHmacSignature(data: {
  userId: number; startDate: string; endDate: string;
  totalQuota: number; totalRecords: number; generatedAt: string; signature: string;
}): boolean {
  const expected = generateHmacSignature(data)
  return crypto.timingSafeEqual(Buffer.from(expected), Buffer.from(data.signature))
}

function fmtTime(ts: number): string {
  return new Date(ts * 1000).toLocaleString('zh-CN', {
    timeZone: 'Asia/Shanghai', year: 'numeric', month: '2-digit', day: '2-digit',
    hour: '2-digit', minute: '2-digit', second: '2-digit', hour12: false,
  })
}

function q2usd(q: number, d = 2): string { return (q / 500000).toFixed(d) }

function parseOther(other: string | any): any {
  if (!other) return {}
  if (typeof other === 'object') return other
  try { return JSON.parse(other) } catch { return {} }
}

const BLUE = '#1a4b8c'
const BLUE_LIGHT = '#e9eff8'
const BLUE_MID = '#3a7bd5'
const GRAY = '#666666'
const GRAY_LIGHT = '#f6f7f9'
const BLACK = '#1a1a1a'
const MARGIN = 50
const PAGE_W = 595.28 // A4
const CONTENT_W = PAGE_W - MARGIN * 2

// Draw watermark on existing page via switchToPage (final pass only)
function drawWatermarkOnPage(doc: PDFKit.PDFDocument, text: string) {
  doc.save()
  doc.opacity(0.03)
  doc.font(getChineseFont()).fontSize(9).fillColor('#999999')
  const label = `${text}   ${text}   ${text}`
  for (let row = 0; row < 6; row++) {
    doc.text(label, MARGIN, 120 + row * 100, { width: CONTENT_W, align: 'center', lineBreak: false })
  }
  doc.restore()
}

function hline(doc: PDFKit.PDFDocument, y: number, color = '#dddddd') {
  doc.save().moveTo(MARGIN, y).lineTo(MARGIN + CONTENT_W, y).strokeColor(color).lineWidth(0.5).stroke().restore()
}

function rect(doc: PDFKit.PDFDocument, x: number, y: number, w: number, h: number, color: string) {
  doc.save().rect(x, y, w, h).fill(color).restore()
}

function footer(doc: PDFKit.PDFDocument, site: string) {
  hline(doc, 778, '#cccccc')
  doc.font(getChineseFont()).fontSize(6.5).fillColor('#aaaaaa')
  doc.text(`${site} - API 使用账单报告`, MARGIN, 782, { width: CONTENT_W * 0.6, lineBreak: false })
}

export function generateBillingPDF(data: BillingReportData): Promise<Buffer> {
  return new Promise((resolve, reject) => {
    const doc = new PDFDocument({ size: 'A4', margin: MARGIN, bufferPages: true })
    const chunks: Buffer[] = []
    doc.on('data', (c: Buffer) => chunks.push(c))
    doc.on('end', () => resolve(Buffer.concat(chunks)))
    doc.on('error', reject)

    // Register Chinese font as default
    doc.font(getChineseFont())

    const now = new Date()
    const generatedAt = now.toISOString()
    const generatedLocal = now.toLocaleString('zh-CN', { timeZone: 'Asia/Shanghai', hour12: false })
    const reportId = 'RPT-' + crypto.createHash('md5').update(`${data.userId}-${generatedAt}`).digest('hex').substring(0, 12).toUpperCase()
    const totalUsd = q2usd(data.totalQuota)
    const days = Math.max(1, Math.ceil((new Date(data.endDate).getTime() - new Date(data.startDate).getTime()) / 86400000))

    // ===== PAGE 1: COVER =====
    rect(doc, 0, 0, PAGE_W, 100, BLUE)
    doc.fontSize(22).fillColor('#ffffff').text(data.siteName, MARGIN, 28, { width: CONTENT_W, align: 'center' })
    doc.fontSize(11).fillColor('#c0d0e8').text('API 使用账单报告', MARGIN, 58, { width: CONTENT_W, align: 'center' })
    doc.fontSize(7.5).fillColor('#8fabc8').text(reportId, MARGIN, 78, { width: CONTENT_W, align: 'center' })

    // Report info section
    let y = 120
    doc.fontSize(12).fillColor(BLUE).text('报告信息', MARGIN, y)
    hline(doc, y + 18, BLUE)
    y += 28

    const info: [string, string][] = [
      ['报告周期', `${data.startDate}  ~  ${data.endDate}  (${days} 天)`],
      ['用户 ID', String(data.userId)],
      ['用户名', data.username],
      ['用户组', data.group],
      ['站点地址', data.siteUrl],
      ['生成时间', generatedLocal],
      ['报告编号', reportId],
    ]
    for (const [k, v] of info) {
      doc.fontSize(9).fillColor(GRAY).text(k, MARGIN + 10, y, { width: 100, lineBreak: false })
      doc.fontSize(9).fillColor(BLACK).text(v, MARGIN + 120, y, { width: CONTENT_W - 130, lineBreak: false })
      y += 18
    }

    // Summary boxes
    y += 15
    doc.fontSize(12).fillColor(BLUE).text('概览', MARGIN, y)
    hline(doc, y + 18, BLUE)
    y += 28

    const boxW = (CONTENT_W - 20) / 3
    const boxes = [
      { title: '总消耗', val: `$ ${totalUsd}`, sub: `${data.totalQuota.toLocaleString()} 额度`, accent: BLUE },
      { title: '总请求数', val: data.totalRequests.toLocaleString(), sub: `${data.modelSummary.length} 个模型`, accent: '#0a7c50' },
      { title: '平均单价', val: `$ ${data.totalRequests > 0 ? q2usd(Math.round(data.totalQuota / data.totalRequests), 4) : '0'}`, sub: `共 ${days} 天`, accent: '#b45309' },
    ]
    for (let i = 0; i < 3; i++) {
      const bx = MARGIN + i * (boxW + 10)
      rect(doc, bx, y, boxW, 60, GRAY_LIGHT)
      rect(doc, bx, y, 3, 60, boxes[i].accent)
      doc.fontSize(7.5).fillColor(GRAY).text(boxes[i].title, bx + 12, y + 8, { width: boxW - 20, lineBreak: false })
      doc.fontSize(15).fillColor(boxes[i].accent).text(boxes[i].val, bx + 12, y + 22, { width: boxW - 20, lineBreak: false })
      doc.fontSize(7).fillColor('#aaaaaa').text(boxes[i].sub, bx + 12, y + 44, { width: boxW - 20, lineBreak: false })
    }

    // Disclaimer
    y += 80
    hline(doc, y)
    y += 8
    doc.fontSize(7).fillColor('#aaaaaa')
    doc.text('本报告由系统自动生成，包含 HMAC-SHA256 数字签名用于完整性验证。', MARGIN, y, { width: CONTENT_W })
    doc.text(`验证接口: POST ${DASHBOARD_URL}/api/billing/verify`, MARGIN, y + 12, { width: CONTENT_W })

    footer(doc, data.siteName)

    // ===== PAGE 2: FINANCIAL SUMMARY =====
    doc.addPage()

    rect(doc, MARGIN, MARGIN, CONTENT_W, 25, BLUE)
    doc.fontSize(11).fillColor('#ffffff').text('财务汇总 - 按模型消耗统计', MARGIN + 12, MARGIN + 7)

    y = MARGIN + 40

    // Total line
    rect(doc, MARGIN, y, CONTENT_W, 46, BLUE_LIGHT)
    doc.fontSize(9).fillColor(BLUE).text('总消耗:', MARGIN + 10, y + 6)
    doc.fontSize(14).fillColor(BLUE).text(`$ ${totalUsd} USD`, MARGIN + 10, y + 17, { continued: false })
    doc.fontSize(7.5).fillColor(GRAY).text(
      `${data.totalQuota.toLocaleString()} 额度  |  ${data.totalRequests.toLocaleString()} 次请求`,
      MARGIN + 10, y + 36, { width: CONTENT_W - 20, lineBreak: false }
    )
    y += 56

    // Model table header
    const mc = { n: MARGIN + 5, m: MARGIN + 35, req: MARGIN + 215, quota: MARGIN + 290, usd: MARGIN + 370, pct: MARGIN + 430 }
    rect(doc, MARGIN, y, CONTENT_W, 16, BLUE)
    doc.fontSize(7).fillColor('#ffffff')
    doc.text('#', mc.n, y + 4, { width: 25, lineBreak: false })
    doc.text('模型', mc.m, y + 4, { width: 175, lineBreak: false })
    doc.text('请求数', mc.req, y + 4, { width: 70, lineBreak: false })
    doc.text('额度', mc.quota, y + 4, { width: 75, lineBreak: false })
    doc.text('费用 (USD)', mc.usd, y + 4, { width: 55, lineBreak: false })
    doc.text('占比', mc.pct, y + 4, { width: 60, lineBreak: false })
    y += 18

    for (let i = 0; i < data.modelSummary.length; i++) {
      if (y > 740) {
        footer(doc, data.siteName)
        doc.addPage()
        y = MARGIN + 10
      }
      const m = data.modelSummary[i]
      const pct = data.totalQuota > 0 ? (m.quota / data.totalQuota * 100) : 0
      if (i % 2 === 0) rect(doc, MARGIN, y - 1, CONTENT_W, 14, GRAY_LIGHT)
      doc.fontSize(6.5).fillColor(BLACK)
      doc.text(String(i + 1), mc.n, y + 2, { width: 25, lineBreak: false })
      doc.text(m.model, mc.m, y + 2, { width: 175, lineBreak: false })
      doc.text(m.count.toLocaleString(), mc.req, y + 2, { width: 70, lineBreak: false })
      doc.text(m.quota.toLocaleString(), mc.quota, y + 2, { width: 75, lineBreak: false })
      doc.text(q2usd(m.quota), mc.usd, y + 2, { width: 55, lineBreak: false })
      const barW = 40
      rect(doc, mc.pct, y + 1, barW, 8, '#e0e0e0')
      rect(doc, mc.pct, y + 1, Math.max(1, barW * pct / 100), 8, BLUE_MID)
      doc.fontSize(5.5).fillColor(GRAY).text(`${pct.toFixed(1)}%`, mc.pct + barW + 3, y + 2, { width: 25, lineBreak: false })
      y += 14
    }

    // Total row
    hline(doc, y, BLUE)
    y += 4
    doc.fontSize(7).fillColor(BLUE)
    doc.text('合计', mc.m, y, { width: 175, lineBreak: false })
    doc.text(data.totalRequests.toLocaleString(), mc.req, y, { width: 70, lineBreak: false })
    doc.text(data.totalQuota.toLocaleString(), mc.quota, y, { width: 75, lineBreak: false })
    doc.text(`$ ${totalUsd}`, mc.usd, y, { width: 55, lineBreak: false })
    doc.text('100%', mc.pct, y, { width: 60, lineBreak: false })

    footer(doc, data.siteName)

    // ===== TOPUP RECORDS =====
    if (data.topups.length > 0) {
      doc.addPage()

      rect(doc, MARGIN, MARGIN, CONTENT_W, 25, BLUE)
      doc.fontSize(11).fillColor('#ffffff').text(`充值记录  (共 ${data.topups.length.toLocaleString()} 条)`, MARGIN + 12, MARGIN + 7)

      y = MARGIN + 35

      const successTopups = data.topups.filter(t => t.status === 'success')
      const totalTopupAmount = successTopups.reduce((s, t) => s + (t.amount || 0), 0)
      const totalTopupMoney = successTopups.reduce((s, t) => s + (t.money || 0), 0)
      rect(doc, MARGIN, y, CONTENT_W, 22, BLUE_LIGHT)
      doc.fontSize(8).fillColor(BLUE).text(
        `充值成功:  $ ${totalTopupAmount.toFixed(2)} USD  |  ¥ ${totalTopupMoney.toFixed(2)} CNY  |  ${successTopups.length} 笔交易`,
        MARGIN + 10, y + 6, { width: CONTENT_W - 20, lineBreak: false }
      )
      y += 30

      const tc = {
        time: MARGIN + 5,
        amount: MARGIN + 110,
        money: MARGIN + 185,
        method: MARGIN + 260,
        status: MARGIN + 320,
        trade: MARGIN + 360,
      }
      function drawTopupHeader() {
        rect(doc, MARGIN, y, CONTENT_W, 16, BLUE)
        doc.fontSize(7).fillColor('#ffffff')
        doc.text('时间', tc.time, y + 4, { width: 100, lineBreak: false })
        doc.text('充值金额 (USD)', tc.amount, y + 4, { width: 70, lineBreak: false })
        doc.text('支付金额 (CNY)', tc.money, y + 4, { width: 70, lineBreak: false })
        doc.text('支付方式', tc.method, y + 4, { width: 55, lineBreak: false })
        doc.text('状态', tc.status, y + 4, { width: 35, lineBreak: false })
        doc.text('订单号', tc.trade, y + 4, { width: 135, lineBreak: false })
        y += 18
      }
      drawTopupHeader()

      for (let i = 0; i < data.topups.length; i++) {
        if (y > 760) {
          footer(doc, data.siteName)
          doc.addPage()
          y = MARGIN + 5
          drawTopupHeader()
        }
        const t = data.topups[i]
        if (i % 2 === 0) rect(doc, MARGIN, y - 1, CONTENT_W, 13, GRAY_LIGHT)
        doc.fontSize(6.5).fillColor(BLACK)
        doc.text(fmtTime(t.create_time), tc.time, y + 2, { width: 100, lineBreak: false })
        doc.text(`$ ${(t.amount || 0).toFixed(2)}`, tc.amount, y + 2, { width: 70, lineBreak: false })
        doc.text(`¥ ${(t.money || 0).toFixed(2)}`, tc.money, y + 2, { width: 70, lineBreak: false })
        doc.text(t.payment_method || '-', tc.method, y + 2, { width: 55, lineBreak: false })
        const statusMap: Record<string, string> = { success: '成功', pending: '待支付', expired: '已过期' }
        doc.text(statusMap[t.status] || t.status || '-', tc.status, y + 2, { width: 35, lineBreak: false })
        doc.text(t.trade_no || '-', tc.trade, y + 2, { width: 135, lineBreak: false })
        y += 13
      }

      footer(doc, data.siteName)
    }

    // ===== DETAIL RECORDS =====
    doc.addPage()

    rect(doc, MARGIN, MARGIN, CONTENT_W, 25, BLUE)
    doc.fontSize(11).fillColor('#ffffff').text(`调用明细  (共 ${data.logs.length.toLocaleString()} 条)`, MARGIN + 12, MARGIN + 7)

    y = MARGIN + 35

    // Column layout: 时间 | 令牌 | 分组 | 类型 | 模型 | 流式 | 用时/首字 | 输入(命中/创建) | 输出 | 花费 | 详情
    const typeMap: Record<number, string> = { 1: '充值', 2: '消费', 3: '管理', 4: '系统' }
    const dc = [
      { x: MARGIN + 2, w: 68, label: '时间' },
      { x: MARGIN + 70, w: 34, label: '令牌' },
      { x: MARGIN + 104, w: 28, label: '分组' },
      { x: MARGIN + 132, w: 22, label: '类型' },
      { x: MARGIN + 154, w: 68, label: '模型' },
      { x: MARGIN + 222, w: 18, label: '流式' },
      { x: MARGIN + 240, w: 40, label: '用时/首字' },
      { x: MARGIN + 280, w: 58, label: '输入(命中/创建)' },
      { x: MARGIN + 338, w: 28, label: '输出' },
      { x: MARGIN + 366, w: 36, label: '花费' },
      { x: MARGIN + 402, w: 93, label: '详情' },
    ]

    function drawDetailHeader() {
      rect(doc, MARGIN, y, CONTENT_W, 14, BLUE)
      doc.fontSize(4.5).fillColor('#ffffff')
      for (const c of dc) doc.text(c.label, c.x, y + 3, { width: c.w, lineBreak: false })
      y += 16
    }

    drawDetailHeader()

    for (let i = 0; i < data.logs.length; i++) {
      if (y > 760) {
        footer(doc, data.siteName)
        doc.addPage()
        y = MARGIN + 5
        drawDetailHeader()
      }
      const log = data.logs[i]
      const other = parseOther(log.other)
      const cacheHit = other.cache_tokens || 0
      const cacheCreate = other.cache_creation_tokens || 0
      const frt = other.frt || 0
      if (i % 2 === 0) rect(doc, MARGIN, y - 1, CONTENT_W, 12, GRAY_LIGHT)
      doc.fontSize(4.5).fillColor(BLACK)
      doc.text(fmtTime(log.created_at), dc[0].x, y + 1, { width: dc[0].w, lineBreak: false })
      doc.text(log.token_name || '-', dc[1].x, y + 1, { width: dc[1].w, lineBreak: false })
      doc.text(log.group || '-', dc[2].x, y + 1, { width: dc[2].w, lineBreak: false })
      doc.text(typeMap[log.type] || String(log.type || '-'), dc[3].x, y + 1, { width: dc[3].w, lineBreak: false })
      doc.text(log.model_name || '-', dc[4].x, y + 1, { width: dc[4].w, lineBreak: false })
      doc.text(log.is_stream ? '是' : '否', dc[5].x, y + 1, { width: dc[5].w, lineBreak: false })
      const timing = `${log.use_time || 0}s${frt ? '/' + Math.round(frt) + 'ms' : ''}`
      doc.text(timing, dc[6].x, y + 1, { width: dc[6].w, lineBreak: false })
      // 输入(命中/创建): e.g. "1234(500/100)"
      let inputStr = String(log.prompt_tokens || 0)
      if (cacheHit > 0 || cacheCreate > 0) {
        inputStr += `(${cacheHit}/${cacheCreate})`
      }
      doc.text(inputStr, dc[7].x, y + 1, { width: dc[7].w, lineBreak: false })
      doc.text(String(log.completion_tokens || 0), dc[8].x, y + 1, { width: dc[8].w, lineBreak: false })
      doc.text('$' + q2usd(log.quota || 0, 4), dc[9].x, y + 1, { width: dc[9].w, lineBreak: false })
      doc.text(log.request_id || '-', dc[10].x, y + 1, { width: dc[10].w, lineBreak: false })
      y += 12
    }

    footer(doc, data.siteName)

    // ===== LAST PAGE: SIGNATURE =====
    doc.addPage()

    rect(doc, MARGIN, MARGIN, CONTENT_W, 25, BLUE)
    doc.fontSize(11).fillColor('#ffffff').text('报告验证与数字签名', MARGIN + 12, MARGIN + 7)

    y = MARGIN + 40

    const signature = generateHmacSignature({
      userId: data.userId, startDate: data.startDate, endDate: data.endDate,
      totalQuota: data.totalQuota, totalRecords: data.logs.length, generatedAt,
    })

    rect(doc, MARGIN, y, CONTENT_W, 130, GRAY_LIGHT)
    y += 10
    const sigRows: [string, string][] = [
      ['报告编号', reportId],
      ['生成时间', generatedLocal],
      ['记录总数', data.logs.length.toLocaleString()],
      ['总额度', `${data.totalQuota.toLocaleString()} ( $ ${totalUsd} USD )`],
      ['算法', 'HMAC-SHA256'],
      ['签名', signature],
    ]
    for (const [k, v] of sigRows) {
      doc.fontSize(8).fillColor(GRAY).text(k, MARGIN + 12, y, { width: 100, lineBreak: false })
      const isSig = k === '签名'
      doc.fontSize(isSig ? 6.5 : 8).fillColor(isSig ? BLUE : BLACK)
        .text(v, MARGIN + 120, y, { width: CONTENT_W - 140, lineBreak: false })
      y += 18
    }

    y += 20
    doc.fontSize(9).fillColor(BLUE).text('验证说明', MARGIN, y)
    hline(doc, y + 14, BLUE)
    y += 22

    const instructions = [
      '本报告由系统自动生成，包含数字签名用于完整性验证。',
      '验证方式: 将签名数据提交至 POST /api/billing/verify 接口。',
      '任何对报告数据的修改都将导致签名验证失败。',
      '本文件仅供财务审计用途。',
    ]
    for (let i = 0; i < instructions.length; i++) {
      doc.fontSize(7.5).fillColor(GRAY).text(`${i + 1}. ${instructions[i]}`, MARGIN + 5, y, { width: CONTENT_W - 10 })
      y += 14
    }

    y += 15
    rect(doc, MARGIN, y, CONTENT_W, 25, '#fff7e0')
    rect(doc, MARGIN, y, 3, 25, '#b45309')
    doc.fontSize(7).fillColor('#b45309')
    doc.text(`由 ${data.siteName} Dashboard 生成  |  ${DASHBOARD_URL}  |  ${generatedLocal}`, MARGIN + 12, y + 8, { width: CONTENT_W - 20, lineBreak: false })

    footer(doc, data.siteName)

    // Final pass: draw watermarks + page numbers on all pages
    const total = doc.bufferedPageRange().count
    for (let i = 0; i < total; i++) {
      doc.switchToPage(i)
      drawWatermarkOnPage(doc, data.siteName)
      doc.font(getChineseFont()).fontSize(6.5).fillColor('#aaaaaa')
      doc.text(`${i + 1} / ${total}`, MARGIN + CONTENT_W - 50, 782, { width: 50, align: 'right', lineBreak: false })
    }

    doc.end()
  })
}