import { Router } from 'express'
import prisma from '../lib/prisma'
import { authMiddleware, AuthRequest } from '../middleware/auth'

const router = Router()

router.get('/dashboard', authMiddleware, async (req: AuthRequest, res) => {
  try {
    const orgId = req.user!.orgId
    const year = Number(req.query.year) || new Date().getFullYear()
    const yearPrefix = `${year}-`

    // 获取该年度所有工资条
    const payslips = await prisma.payslip.findMany({
      where: {
        orgId,
        month: { startsWith: yearPrefix },
      },
      include: {
        employee: { select: { department: true } },
      },
    })

    // 概览
    const totalEmployees = new Set(payslips.map(p => p.employeeId)).size
    const allNetPays = payslips.map(p => p.netPay).sort((a, b) => a - b)
    const avgSalary = payslips.length > 0 ? payslips.reduce((s, p) => s + p.netPay, 0) / payslips.length : 0
    const medianSalary = allNetPays.length > 0
      ? allNetPays.length % 2 === 0
        ? (allNetPays[allNetPays.length / 2 - 1] + allNetPays[allNetPays.length / 2]) / 2
        : allNetPays[Math.floor(allNetPays.length / 2)]
      : 0
    const totalAnnual = payslips.reduce((s, p) => s + p.netPay, 0)

    // 同比：与上一年度对比
    const prevYearPrefix = `${year - 1}-`
    const prevPayslips = await prisma.payslip.findMany({
      where: {
        orgId,
        month: { startsWith: prevYearPrefix },
      },
    })
    const prevTotal = prevPayslips.reduce((s, p) => s + p.netPay, 0)
    const yoy = prevTotal > 0 ? ((totalAnnual - prevTotal) / prevTotal) * 100 : undefined

    // 环比：与上个月对比（12月 vs 11月）
    const decPayslips = payslips.filter(p => p.month === `${year}-12`)
    const novPayslips = payslips.filter(p => p.month === `${year}-11`)
    const decTotal = decPayslips.reduce((s, p) => s + p.netPay, 0)
    const novTotal = novPayslips.reduce((s, p) => s + p.netPay, 0)
    const mom = novTotal > 0 ? ((decTotal - novTotal) / novTotal) * 100 : undefined

    // 部门薪酬对比
    const deptMap = new Map<string, { count: number; total: number }>()
    for (const p of payslips) {
      const dept = p.employee?.department || '未分配'
      const cur = deptMap.get(dept) || { count: 0, total: 0 }
      cur.count += 1
      cur.total += p.netPay
      deptMap.set(dept, cur)
    }
    const departments = Array.from(deptMap.entries())
      .map(([name, v]) => ({ name, count: v.count, avgSalary: v.count > 0 ? v.total / v.count : 0 }))
      .sort((a, b) => b.avgSalary - a.avgSalary)

    // 月度趋势
    const monthMap = new Map<string, number>()
    for (const p of payslips) {
      monthMap.set(p.month, (monthMap.get(p.month) || 0) + p.netPay)
    }
    const monthlyTrend = Array.from(monthMap.entries())
      .map(([month, total]) => ({ month: month.slice(5), total }))
      .sort((a, b) => a.month.localeCompare(b.month))

    res.json({
      success: true,
      data: {
        summary: { totalEmployees, avgSalary, medianSalary, totalAnnual, yoy, mom },
        departments,
        monthlyTrend,
      },
    })
  } catch (err) {
    res.status(500).json({ success: false, error: { code: 'INTERNAL_ERROR', message: '获取薪酬分析数据失败' } })
  }
})

export default router