import { PayInfo, PayOptions, PayCallback, PayResult } from './interface.uts'

let appId = ''
let busy = false
let sequence = 0

// Host calls only after authenticated server reconciliation of the saved transaction.
export function resetPending(): void {
  busy = false
  sequence += 1
}

export function configure(id: string): boolean {
  if (busy || id.trim().length == 0) return false
  appId = id
  return true
}

export function invoke(options: PayOptions, callback: PayCallback,
  nativePay: (payload: string, loading: boolean, done: (raw: string) => void) => void): void {
  if (busy) {
    const result: PayResult = { resultCode: '103', errorMsg: '已有支付正在进行，请勿重复点击', needsQuery: true }
    callback(result)
    return
  }
  let valid = false
  let payload: string = ''
  try {
    // Swift infers an optional from the generated PayInfo! property unless
    // the local type is explicit. Check before narrowing on both platforms.
    const candidate: PayInfo | null = options.payInfo
    if (candidate != null) {
      const info: PayInfo = candidate as PayInfo
      const values = new Array<string>(info.appid ?? '', info.partnerid ?? '', info.prepayid ?? '',
        info.package ?? '', info.noncestr ?? '', info.timestamp ?? '', info.sign ?? '')
      valid = appId.length > 0 && values[0] == appId && values[3] == 'Sign=DYPay'
      values.forEach((value: string) => { if (value.trim().length == 0) valid = false })
      if (!/^[0-9]{1,10}$/.test(values[5]) || values[4].length > 32) valid = false
      // UTS JSON.stringify returns string | null. Serialize before taking the
      // payment lock, and never pass a nullable value to a native String API.
      if (valid) {
        payload = JSON.stringify(info) ?? ''
        if (payload.length == 0) valid = false
      }
    }
  } catch (e) { valid = false }
  if (!valid) {
    const result: PayResult = { resultCode: '-1', errorMsg: '支付参数不完整或 AppID 不匹配，请重新下单', needsQuery: false }
    callback(result)
    return
  }
  busy = true
  sequence += 1
  const current = sequence
  const timer = setTimeout(() => {
    if (!busy || sequence != current) return
    busy = false
    sequence += 1
    const result: PayResult = { resultCode: '3', errorMsg: '支付结果等待超时，请查询订单，勿重复付款', needsQuery: true }
    callback(result)
  }, 300000)
  const complete = (raw: string): void => {
    if (!busy || sequence != current) return
    busy = false
    clearTimeout(timer)
    let result: PayResult = { resultCode: '3', errorMsg: '支付结果未知，请查询订单', needsQuery: true }
    try {
      const parsed = JSON.parseObject(raw)
      if (parsed != null) {
        result.resultCode = parsed.getString('resultCode') ?? '3'
        result.errorMsg = parsed.getString('errorMsg') ?? ''
      }
    } catch (e) { /* An invalid native result must never become a payment success. */ }
    callback(result)
  }
  try {
    nativePay(payload, options.showLoading ?? true, complete)
  } catch (e) {
    complete('{"resultCode":"2","errorMsg":"无法调用支付 SDK，请查询订单后重试"}')
  }
}