import { Router, Request, Response } from 'express'
import { sessionAuth } from '../middleware/auth.js'
import { generateBillingPDF, verifyHmacSignature } from '../utils/pdf.js'
import db from '../db.js'

const router = Router()

// POST /api/billing/export/pdf
router.post('/export/pdf', sessionAuth, async (req: Request, res: Response) => {
  const session = req.session!
  const { startDate, endDate } = req.body
  const userInfo = JSON.parse(session.user_info)
  const site = db.prepare('SELECT name, url FROM sites WHERE id = ?').get(session.site_id) as any

  try {
    const startTs = Math.floor(new Date(startDate).getTime() / 1000)
    const endTs = Math.floor(new Date(endDate).getTime() / 1000)

    let allLogs: any[] = []
    let page = 1
    const pageSize = 100
    let hasMore = true

    while (hasMore) {
      const logRes = await fetch(
        `${session.site_url}/api/log/self?start_timestamp=${startTs}&end_timestamp=${endTs}&type=2&p=${page}&page_size=${pageSize}`,
        { headers: { 'Authorization': session.access_token } }
      )
      const logData = await logRes.json() as any
      if (!logData.success || !logData.data?.items?.length) {
        hasMore = false
      } else {
        allLogs = allLogs.concat(logData.data.items)
        hasMore = logData.data.items.length === pageSize
        page++
      }
      if (allLogs.length > 10000) hasMore = false
    }

    const modelMap = new Map<string, { quota: number; count: number }>()
    let totalQuota = 0
    for (const log of allLogs) {
      totalQuota += log.quota || 0
      const model = log.model_name || 'unknown'
      const existing = modelMap.get(model) || { quota: 0, count: 0 }
      existing.quota += log.quota || 0
      existing.count += 1
      modelMap.set(model, existing)
    }

    const modelSummary = Array.from(modelMap.entries())
      .map(([model, data]) => ({ model, ...data }))
      .sort((a, b) => b.quota - a.quota)

    const pdfBuffer = await generateBillingPDF({
      siteName: site.name,
      siteUrl: site.url,
      userId: userInfo.id,
      username: userInfo.username,
      group: userInfo.group || 'default',
      startDate,
      endDate,
      totalQuota,
      totalRequests: allLogs.length,
      modelSummary,
      logs: allLogs
    })

    res.setHeader('Content-Type', 'application/pdf')
    res.setHeader('Content-Disposition', `attachment; filename="${encodeURIComponent(site.name)}_billing_${startDate}_${endDate}.pdf"`)
    res.send(pdfBuffer)
  } catch (error: any) {
    res.status(500).json({ success: false, message: `Failed to generate report: ${error.message}` })
  }
})

// POST /api/billing/export/csv
router.post('/export/csv', sessionAuth, async (req: Request, res: Response) => {
  const session = req.session!
  const { startDate, endDate } = req.body
  const site = db.prepare('SELECT name FROM sites WHERE id = ?').get(session.site_id) as any

  try {
    const startTs = Math.floor(new Date(startDate).getTime() / 1000)
    const endTs = Math.floor(new Date(endDate).getTime() / 1000)

    let allLogs: any[] = []
    let page = 1
    let hasMore = true

    while (hasMore) {
      const logRes = await fetch(
        `${session.site_url}/api/log/self?start_timestamp=${startTs}&end_timestamp=${endTs}&type=2&p=${page}&page_size=100`,
        { headers: { 'Authorization': session.access_token } }
      )
      const logData = await logRes.json() as any
      if (!logData.success || !logData.data?.items?.length) {
        hasMore = false
      } else {
        allLogs = allLogs.concat(logData.data.items)
        hasMore = logData.data.items.length === 100
        page++
      }
      if (allLogs.length > 10000) hasMore = false
    }

    const BOM = '\uFEFF'
    const headers = ['Time', 'Model', 'Token', 'Quota', 'Cost(USD)', 'Prompt Tokens', 'Completion Tokens', 'Request ID']
    const rows = allLogs.map(log => [
      new Date((log.created_at || 0) * 1000).toLocaleString('zh-CN', { timeZone: 'Asia/Shanghai' }),
      log.model_name || '',
      log.token_name || '',
      log.quota || 0,
      ((log.quota || 0) / 500000).toFixed(6),
      log.prompt_tokens || 0,
      log.completion_tokens || 0,
      log.request_id || ''
    ])

    const csv = BOM + [headers, ...rows].map(row => row.map(cell => `"${cell}"`).join(',')).join('\n')

    res.setHeader('Content-Type', 'text/csv; charset=utf-8')
    res.setHeader('Content-Disposition', `attachment; filename="${encodeURIComponent(site.name)}_billing_${startDate}_${endDate}.csv"`)
    res.send(csv)
  } catch (error: any) {
    res.status(500).json({ success: false, message: `Failed to generate CSV: ${error.message}` })
  }
})

// POST /api/billing/verify — verify HMAC signature
router.post('/verify', (req: Request, res: Response) => {
  const { userId, startDate, endDate, totalQuota, totalRecords, generatedAt, signature } = req.body
  try {
    const valid = verifyHmacSignature({ userId, startDate, endDate, totalQuota, totalRecords, generatedAt, signature })
    res.json({ success: true, data: { valid } })
  } catch {
    res.json({ success: true, data: { valid: false } })
  }
})

export default router