/** 分期缴费：期数对齐、应缴日/金额计算（与 ProtocolFormDialog 逻辑一致） */

import { isInstallmentPayMode } from '@/utils/protocol-payment-presets'

const DAYS_PER_MONTH = 30

export const DEFAULT_INSTALLMENT_ADVANCE_DAYS = 30
export const DEFAULT_INSTALLMENT_RATIOS_6 = [50, 10, 10, 10, 10, 10]

export function defaultInstallmentRatios(count: number): number[] {
  if (count <= 0) return []
  if (count === 6) return [...DEFAULT_INSTALLMENT_RATIOS_6]
  const base = Math.floor(100 / count)
  const arr = Array(count - 1).fill(base)
  arr.push(100 - base * (count - 1))
  return arr
}

export function resizeInstallmentRatios(oldRatios: number[], newCount: number): number[] {
  if (newCount <= 0) return []
  if (newCount > oldRatios.length) {
    return [...oldRatios, ...Array(newCount - oldRatios.length).fill(0)]
  }
  if (newCount < oldRatios.length) {
    return oldRatios.slice(0, newCount)
  }
  return [...oldRatios]
}

/** 末位 = 100 - sum(前 n-1)；返回新数组 */
export function finalizeInstallmentRatios(ratios: number[]): number[] {
  if (!ratios.length) return []
  if (ratios.length === 1) return [100]
  const head = ratios.slice(0, -1).map((v) => Number(v || 0))
  const last = Math.round((100 - head.reduce((s, v) => s + v, 0)) * 100) / 100
  return [...head, last]
}

export function isInstallmentRatiosValid(ratios: number[]): boolean {
  if (!ratios.length) return false
  const head = ratios.slice(0, -1)
  const headSum = head.reduce((s, v) => s + Number(v || 0), 0)
  if (headSum > 100 + 0.001) return false
  const total = ratios.reduce((s, v) => s + Number(v || 0), 0)
  return Math.abs(total - 100) < 0.01
}

/** 历史数据：installmentRatios 存的是百分比（合计约 100） */
export function isLegacyInstallmentRatios(
  values: number[],
  contractAmount?: number | null
): boolean {
  if (!values.length) return false
  const nums = values.map((v) => Number(v || 0))
  const sum = nums.reduce((s, v) => s + v, 0)
  const max = Math.max(...nums)
  if (contractAmount != null && Math.abs(sum - Number(contractAmount)) < 0.02) {
    return false
  }
  return max <= 100 && Math.abs(sum - 100) < 0.05
}

/** 将存储值规范为各期金额（元）；兼容旧比例数据 */
export function normalizeInstallmentAmounts(
  values: number[],
  contractAmount: number | null | undefined,
  count: number
): number[] {
  if (!values.length) {
    return defaultInstallmentAmounts(contractAmount, count)
  }
  if (isLegacyInstallmentRatios(values, contractAmount)) {
    const sized =
      values.length === count ? values : resizeInstallmentRatios(values, count)
    return calcInstallmentDueAmountsByRatios(contractAmount, finalizeInstallmentRatios(sized))
  }
  const amounts = values.map((v) => Number(v || 0))
  if (amounts.length === count) return amounts
  return resizeInstallmentAmounts(amounts, count, contractAmount)
}

export function defaultInstallmentAmounts(
  contractAmount: number | null | undefined,
  count: number
): number[] {
  return calcInstallmentDueAmounts(contractAmount, count)
}

export function resizeInstallmentAmounts(
  oldAmounts: number[],
  newCount: number,
  contractAmount: number | null | undefined
): number[] {
  if (newCount <= 0) return []
  const head = oldAmounts.map((v) => Number(v || 0))
  if (newCount > head.length) {
    const existingSum = sumInstallmentAmounts(head)
    const remaining =
      contractAmount != null
        ? Math.max(0, Math.round((Number(contractAmount) - existingSum) * 100) / 100)
        : 0
    const extraCount = newCount - head.length
    const extra =
      remaining > 0 && contractAmount != null
        ? defaultInstallmentAmounts(remaining, extraCount)
        : Array(extraCount).fill(0)
    return [...head, ...extra]
  }
  if (newCount < head.length) {
    return head.slice(0, newCount)
  }
  return head
}

export function isInstallmentAmountsValid(
  amounts: number[],
  contractAmount: number | null | undefined
): boolean {
  if (!amounts.length || contractAmount == null) return false
  if (amounts.some((v) => Number(v) < 0)) return false
  const sum = amounts.reduce((s, v) => s + Number(v || 0), 0)
  return Math.abs(sum - Number(contractAmount)) < 0.01
}

export function sumInstallmentAmounts(amounts: number[]): number {
  const total = amounts.reduce((s, v) => s + Number(v || 0), 0)
  return Math.round(total * 100) / 100
}

/** 合同金额变更时，按原各期占比等比缩放金额 */
export function scaleInstallmentAmountsToContract(
  amounts: number[],
  contractAmount: number | null | undefined
): number[] {
  if (!amounts.length || contractAmount == null) return amounts
  const oldSum = sumInstallmentAmounts(amounts)
  if (oldSum <= 0) {
    return defaultInstallmentAmounts(contractAmount, amounts.length)
  }
  const target = Number(contractAmount)
  const scaled: number[] = []
  let sumCents = 0
  const totalCents = Math.round(target * 100)
  for (let i = 0; i < amounts.length; i++) {
    if (i === amounts.length - 1) {
      scaled.push((totalCents - sumCents) / 100)
    } else {
      const cents = Math.floor((totalCents * Number(amounts[i] || 0)) / oldSum)
      scaled.push(cents / 100)
      sumCents += cents
    }
  }
  return scaled
}

export function addMonthsYmd(dateStr: string, months: number): string {
  const compact = String(dateStr || '').replace(/-/g, '')
  if (compact.length !== 8) return ''
  const y = parseInt(compact.slice(0, 4), 10)
  const m = parseInt(compact.slice(4, 6), 10) - 1
  const d = parseInt(compact.slice(6, 8), 10)
  const date = new Date(y, m + months, d)
  const yy = date.getFullYear()
  const mm = String(date.getMonth() + 1).padStart(2, '0')
  const dd = String(date.getDate()).padStart(2, '0')
  return `${yy}${mm}${dd}`
}

/** 日期加 N 天，返回 YYYYMMDD（入参支持 YYYYMMDD 或 YYYY-MM-DD） */
export function addDaysYmd(dateStr: string, days: number): string {
  const compact = String(dateStr || '').replace(/-/g, '')
  if (compact.length !== 8) return ''
  const y = parseInt(compact.slice(0, 4), 10)
  const m = parseInt(compact.slice(4, 6), 10) - 1
  const d = parseInt(compact.slice(6, 8), 10)
  const date = new Date(y, m, d)
  date.setDate(date.getDate() + days)
  const yy = date.getFullYear()
  const mm = String(date.getMonth() + 1).padStart(2, '0')
  const dd = String(date.getDate()).padStart(2, '0')
  return `${yy}${mm}${dd}`
}

/** 整数部分按日历加月，小数部分按 30 天/月换算为天数 */
export function addIntervalMonthsYmd(dateStr: string, totalMonths: number): string {
  const compact = String(dateStr || '').replace(/-/g, '')
  if (compact.length !== 8 || !Number.isFinite(totalMonths) || totalMonths === 0) {
    return compact.length === 8 ? compact : ''
  }
  const wholeMonths = Math.trunc(totalMonths)
  const fracMonths = totalMonths - wholeMonths
  let result = compact
  if (wholeMonths !== 0) {
    result = addMonthsYmd(result, wholeMonths)
  }
  if (fracMonths !== 0) {
    const days = Math.round(fracMonths * DAYS_PER_MONTH)
    if (days !== 0) {
      result = addDaysYmd(result, days)
    }
  }
  return result
}

/** 分期应缴费时间：第 1 期=开始时间，第 2 期起在间隔递增基础上提前 advanceDays 天 */
export function calcFqInstallmentDueDate(
  startDate: string,
  index: number,
  intervalMonths: number,
  advanceDays: number = DEFAULT_INSTALLMENT_ADVANCE_DAYS
): string {
  const base = addIntervalMonthsYmd(startDate, index * intervalMonths)
  if (index >= 1) {
    return addDaysYmd(base, -Number(advanceDays || 0))
  }
  return base
}

export function calcInstallmentDueAmounts(
  contractAmount: number | null | undefined,
  count: number
): number[] {
  if (contractAmount == null || !count || count < 1) return []
  const totalCents = Math.round(Number(contractAmount) * 100)
  const baseCents = Math.floor(totalCents / count)
  const amounts: number[] = []
  let sumCents = 0
  for (let i = 0; i < count; i++) {
    if (i === count - 1) {
      amounts.push((totalCents - sumCents) / 100)
    } else {
      amounts.push(baseCents / 100)
      sumCents += baseCents
    }
  }
  return amounts
}

export function calcInstallmentDueAmountsByRatios(
  contractAmount: number | null | undefined,
  ratios: number[]
): number[] {
  if (contractAmount == null || !ratios.length) return []
  const totalCents = Math.round(Number(contractAmount) * 100)
  const amounts: number[] = []
  let sumCents = 0
  for (let i = 0; i < ratios.length; i++) {
    if (i === ratios.length - 1) {
      amounts.push((totalCents - sumCents) / 100)
    } else {
      const cents = Math.floor((totalCents * Number(ratios[i] || 0)) / 100)
      amounts.push(cents / 100)
      sumCents += cents
    }
  }
  return amounts
}

export function calcUnpaidAmountsByRatios(
  remaining: number,
  ratios: number[],
  unpaidIndices: number[]
): number[] {
  if (remaining <= 0 || !unpaidIndices.length) return []
  const subset = unpaidIndices.map((i) => Number(ratios[i] || 0))
  const ratioSum = subset.reduce((s, v) => s + v, 0)
  if (ratioSum <= 0) return []
  const totalCents = Math.round(Number(remaining) * 100)
  const amounts: number[] = []
  let sumCents = 0
  for (let j = 0; j < unpaidIndices.length; j++) {
    if (j === unpaidIndices.length - 1) {
      amounts.push((totalCents - sumCents) / 100)
    } else {
      const cents = Math.floor((totalCents * subset[j]) / ratioSum)
      amounts.push(cents / 100)
      sumCents += cents
    }
  }
  return amounts
}

type PaymentLike = Record<string, unknown> | null | undefined
type DetailLike = Record<string, any>

function resolveFqAmounts(payment: PaymentLike, count: number, details?: DetailLike[]): number[] {
  const contract = payment?.contractAmount != null ? Number(payment.contractAmount) : null
  const stored = Array.isArray(payment?.installmentRatios)
    ? (payment!.installmentRatios as number[])
    : []
  if (stored.length === count && contract != null) {
    const baseAmounts = isLegacyInstallmentRatios(stored, contract)
      ? calcInstallmentDueAmountsByRatios(contract, finalizeInstallmentRatios(stored))
      : stored.map((v) => Number(v || 0))
    const paidRows = (details || []).filter((d) => String(d.payStatus) === 'yjf')
    if (paidRows.length > 0) {
      const amounts = [...baseAmounts]
      paidRows.forEach((d) => {
        const no = Number(d.installmentNo)
        if (no >= 1 && no <= count) amounts[no - 1] = Number(d.dueAmount) || 0
      })
      return amounts
    }
    return baseAmounts
  }
  return calcInstallmentDueAmounts(contract, count)
}

/**
 * 分期模式下按 installmentCount 补齐缺失期次（保留已有明细数据），仅用于编辑表单。
 */
export function alignFqPaymentDetailsForDisplay(
  payment: PaymentLike,
  details: DetailLike[]
): DetailLike[] {
  if (!payment || !isInstallmentPayMode(String(payment.payMode || ''))) return details
  const count = Number(payment.installmentCount)
  if (!count || count < 1) return details

  const rows = [...details]
  const byNo = new Map<number, DetailLike>()
  const unnumbered: DetailLike[] = []
  for (const row of rows) {
    const no = row.installmentNo
    if (no != null && no !== '') {
      byNo.set(Number(no), row)
    } else {
      unnumbered.push(row)
    }
  }

  const needed = new Set(Array.from({ length: count }, (_, i) => i + 1))
  const have = new Set(byNo.keys())
  let missing = false
  for (const n of needed) {
    if (!have.has(n)) {
      missing = true
      break
    }
  }
  if (!missing && rows.length >= count) {
    return sortFqPaymentDetails(rows).slice(0, count)
  }

  const amounts = resolveFqAmounts(payment, count, rows)
  const startDate = String(payment.installmentStartDate || '')
  const interval = Number(payment.installmentIntervalMonths || 0)
  const advanceDays = Number(payment.installmentAdvanceDays ?? DEFAULT_INSTALLMENT_ADVANCE_DAYS)

  const result: DetailLike[] = []
  for (let i = 0; i < count; i++) {
    const no = i + 1
    if (byNo.has(no)) {
      result.push(byNo.get(no)!)
      continue
    }
    if (i < unnumbered.length) {
      const raw = { ...unnumbered[i], installmentNo: no }
      if (!raw.installmentDueDate && startDate && interval) {
        raw.installmentDueDate = calcFqInstallmentDueDate(startDate, i, interval, advanceDays)
      }
      result.push(raw)
      continue
    }
    result.push({
      installmentNo: no,
      installmentDueDate:
        startDate && interval ? calcFqInstallmentDueDate(startDate, i, interval, advanceDays) : '',
      dueAmount: amounts[i] ?? null,
      payStatus: 'dfj',
      transferType: '',
      transferAmount: null,
      attachments: []
    })
  }
  return result
}

export function sortFqPaymentDetails(details: DetailLike[]): DetailLike[] {
  return [...details].sort((a, b) => {
    const na = a.installmentNo != null && a.installmentNo !== '' ? Number(a.installmentNo) : 9999
    const nb = b.installmentNo != null && b.installmentNo !== '' ? Number(b.installmentNo) : 9999
    if (na !== nb) return na - nb
    return Number(a.orderNum || 0) - Number(b.orderNum || 0)
  })
}

/** 编辑表单：将缴费明细行数与分期期数对齐（不覆盖已有行） */
export function syncFqPaymentDetailRowCount(
  payment: {
    payMode: string
    installmentCount: number | null
    contractAmount: number | null
    installmentStartDate: string
    installmentIntervalMonths: number | null
    installmentAdvanceDays?: number | null
    installmentRatios?: number[]
  },
  paymentDetails: DetailLike[]
): void {
  if (!isInstallmentPayMode(payment.payMode)) return
  const count = Number(payment.installmentCount)
  if (!count || count < 1) return

  const aligned = alignFqPaymentDetailsForDisplay(payment, paymentDetails)
  paymentDetails.splice(0, paymentDetails.length, ...aligned)
}