import { useApolloClient, useLazyQuery, useMutation } from '@apollo/client'
import { useCallback, useState } from 'react'
import useQrPayment from '@/components/use-qr-payment'
import useInvoice from '@/components/use-invoice'
import { InvoiceCanceledError, InvoiceExpiredError, WalletError, WalletPaymentError } from '@/wallets/errors'
import { GET_PAID_ACTION } from '@/fragments/paidAction'
import { useWalletPayment } from '@/wallets/payment'

/*
this is just like useMutation with a few changes:
1. pays an invoice returned by the mutation
2. takes an onPaid and onPayError callback, and additional options for payment behavior
  - namely forceWaitForPayment which will always wait for the invoice to be paid
  - and persistOnNavigate which will keep the invoice in the cache after navigation
3. onCompleted behaves a little differently, but analogously to useMutation, ie clientside side effects
  of completion can still rely on it
  a. it's called before the invoice is paid for optimistic updates
  b. it's called after the invoice is paid for pessimistic updates
4. we return a payError field in the result object if the invoice fails to pay
*/
export function usePaidMutation (mutation,
  { onCompleted, ...options } = {}) {
  options.optimisticResponse = addOptimisticResponseExtras(options.optimisticResponse)
  const [mutate, result] = useMutation(mutation, options)
  const [getPaidAction] = useLazyQuery(GET_PAID_ACTION, {
    fetchPolicy: 'network-only'
  })
  const waitForWalletPayment = useWalletPayment()
  const invoiceHelper = useInvoice()
  const waitForQrPayment = useQrPayment()
  const client = useApolloClient()
  // innerResult is used to store/control the result of the mutation when innerMutate runs
  const [innerResult, setInnerResult] = useState(result)

  const waitForPayment = useCallback(async (invoice, { alwaysShowQROnFailure = false, persistOnNavigate = false, waitFor, updateOnFallback }) => {
    let walletError
    let walletInvoice = invoice
    const start = Date.now()

    try {
      return await waitForWalletPayment(walletInvoice, { waitFor, updateOnFallback })
    } catch (err) {
      walletError = null
      if (err instanceof WalletError) {
        walletError = err
        // get the last invoice that was attempted but failed and was canceled
        if (err.invoice) walletInvoice = err.invoice
      }

      const invoiceError = err instanceof InvoiceCanceledError || err instanceof InvoiceExpiredError
      if (!invoiceError && !walletError) {
        // unexpected error, rethrow
        throw err
      }

      // bail if the payment took too long to prevent showing a QR code on an unrelated page
      // (if alwaysShowQROnFailure is not set) or user canceled the invoice or it expired
      const tooSlow = Date.now() - start > 1000
      const skipQr = (tooSlow && !alwaysShowQROnFailure) || invoiceError
      if (skipQr) {
        throw err
      }
    }

    const paymentAttempted = walletError instanceof WalletPaymentError
    if (paymentAttempted) {
      walletInvoice = await invoiceHelper.retry(walletInvoice, { update: updateOnFallback })
    }
    return await waitForQrPayment(walletInvoice, walletError, { persistOnNavigate, waitFor })
  }, [waitForWalletPayment, waitForQrPayment, invoiceHelper])

  const innerMutate = useCallback(async ({
    onCompleted: innerOnCompleted, ...innerOptions
  } = {}) => {
    innerOptions.optimisticResponse = addOptimisticResponseExtras(innerOptions.optimisticResponse)
    let { data, ...rest } = await mutate(innerOptions)

    // use the most inner callbacks/options if they exist
    const {
      onPaid, onPayError, forceWaitForPayment, persistOnNavigate,
      update, waitFor = inv => inv?.actionState === 'PAID', updateOnFallback
    } = { ...options, ...innerOptions }
    const ourOnCompleted = innerOnCompleted || onCompleted

    // get invoice without knowing the mutation name
    if (Object.values(data).length !== 1) {
      throw new Error('usePaidMutation: exactly one mutation at a time is supported')
    }
    const response = Object.values(data)[0]
    let invoice = response?.invoice

    // if the mutation returns an invoice, pay it
    if (invoice) {
      // adds payError, escalating to a normal error if the invoice is not canceled or
      // has an actionError
      const addPayError = (e, rest) => ({
        ...rest,
        payError: e,
        error: e instanceof InvoiceCanceledError && e.actionError ? e : undefined
      })

      const mergeData = obj => ({
        [Object.keys(data)[0]]: {
          ...data?.[Object.keys(data)[0]],
          ...obj
        }
      })

      // should we wait for the invoice to be paid?
      if (response?.paymentMethod === 'OPTIMISTIC' && !forceWaitForPayment) {
        // onCompleted is called before the invoice is paid for optimistic updates
        ourOnCompleted?.(data)
        // don't wait to pay the invoice
        waitForPayment(invoice, { persistOnNavigate, waitFor, updateOnFallback }).then((invoice) => {
          // invoice might have been retried during payment
          data = mergeData({ invoice })
          onPaid?.(client.cache, { data })
        }).catch(e => {
          console.error('usePaidMutation: failed to pay invoice', e)
          if (e.invoice) {
            // update the failed invoice for the Apollo cache update
            data = mergeData({ invoice: e.invoice })
          }
          // onPayError is called after the invoice fails to pay
          // useful for updating invoiceActionState to FAILED
          onPayError?.(e, client.cache, { data })
          setInnerResult(r => addPayError(e, r))
        })
      } else {
        // the action is pessimistic
        try {
          // wait for the invoice to be paid
          // returns the invoice that was paid since it might have been updated via retries
          invoice = await waitForPayment(invoice, { alwaysShowQROnFailure: true, persistOnNavigate, waitFor, updateOnFallback })
          if (!response.result) {
            // if the mutation didn't return any data, ie pessimistic, we need to fetch it
            const { data: { paidAction } } = await getPaidAction({ variables: { invoiceId: parseInt(invoice.id) } })
            // create new data object
            // ( hmac is only returned on invoice creation so we need to add it back to the data )
            data = mergeData({ ...paidAction, invoice: { ...paidAction.invoice, hmac: invoice.hmac } })
            // we need to run update functions on mutations now that we have the data
            update?.(client.cache, { data })
          }
          ourOnCompleted?.(data)
          onPaid?.(client.cache, { data })
        } catch (e) {
          console.error('usePaidMutation: failed to pay invoice', e)
          onPayError?.(e, client.cache, { data })
          rest = addPayError(e, rest)
        }
      }
    } else {
      // fee credits paid for it
      ourOnCompleted?.(data)
      onPaid?.(client.cache, { data })
    }

    setInnerResult({ data, ...rest })
    return { data, ...rest }
  }, [mutate, options, waitForPayment, onCompleted, client.cache, getPaidAction, setInnerResult])

  return [innerMutate, innerResult]
}

// all paid actions need these fields and they're easy to forget
function addOptimisticResponseExtras (optimisticResponse) {
  if (!optimisticResponse) return optimisticResponse
  const key = Object.keys(optimisticResponse)[0]
  optimisticResponse[key] = { invoice: null, paymentMethod: 'OPTIMISTIC', ...optimisticResponse[key] }
  return optimisticResponse
}

// most paid actions have the same cache modifications
// these let us preemptively update the cache before a query updates it
export const paidActionCacheMods = {
  update: (cache, { data }) => {
    const response = Object.values(data)[0]
    if (!response?.invoice) return
    const { invoice } = response

    cache.modify({
      id: `Invoice:${invoice.id}`,
      fields: {
        actionState: () => 'PENDING'
      }
    })
  },
  onPayError: (e, cache, { data }) => {
    const response = Object.values(data)[0]
    if (!response?.invoice) return
    const { invoice } = response

    cache.modify({
      id: `Invoice:${invoice.id}`,
      fields: {
        actionState: () => 'FAILED'
      }
    })
  },
  onPaid: (cache, { data }) => {
    const response = Object.values(data)[0]
    if (!response?.invoice) return
    const { invoice } = response

    cache.modify({
      id: `Invoice:${invoice.id}`,
      fields: {
        actionState: () => 'PAID',
        confirmedAt: () => new Date().toISOString(),
        satsReceived: () => invoice.satsRequested
      }
    })
  }
}