From d1a0977a655e0069fff2245efe8f88a749979e85 Mon Sep 17 00:00:00 2001
From: Arjun Porwal <65214523+ap211unitech@users.noreply.github.com>
Date: Tue, 25 Feb 2025 19:07:12 +0530
Subject: [PATCH] feat: max transfer value while teleport (#11332)

---
 packages/page-parachains/src/Teleport.tsx     | 55 +++++++++++++++++--
 .../react-components/src/InputBalance.tsx     |  2 +-
 2 files changed, 50 insertions(+), 7 deletions(-)

diff --git a/packages/page-parachains/src/Teleport.tsx b/packages/page-parachains/src/Teleport.tsx
index f440ba56bb..2dfd74ecdb 100644
--- a/packages/page-parachains/src/Teleport.tsx
+++ b/packages/page-parachains/src/Teleport.tsx
@@ -2,16 +2,17 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { SubmittableExtrinsicFunction } from '@polkadot/api/types';
+import type { DeriveBalancesAll } from '@polkadot/api-derive/types';
 import type { LinkOption } from '@polkadot/apps-config/endpoints/types';
 import type { Option } from '@polkadot/apps-config/settings/types';
 import type { BN } from '@polkadot/util';
 
-import React, { useMemo, useState } from 'react';
+import React, { useEffect, useMemo, useState } from 'react';
 
-import { ChainImg, Dropdown, InputAddress, InputBalance, MarkWarning, Modal, TxButton } from '@polkadot/react-components';
-import { useApi, useApiUrl, useTeleport } from '@polkadot/react-hooks';
-import { Available } from '@polkadot/react-query';
-import { BN_ZERO, isFunction } from '@polkadot/util';
+import { ChainImg, Dropdown, InputAddress, InputBalance, MarkWarning, Modal, styled, TxButton } from '@polkadot/react-components';
+import { useApi, useApiUrl, useCall, useTeleport } from '@polkadot/react-hooks';
+import { Available, FormatBalance } from '@polkadot/react-query';
+import { BN_HUNDRED, BN_ZERO, isFunction, nextTick } from '@polkadot/util';
 
 import { useTranslation } from './translate.js';
 
@@ -48,6 +49,8 @@ function Teleport ({ onClose }: Props): React.ReactElement<Props> | null {
   const [senderId, setSenderId] = useState<string | null>(null);
   const [recipientParaId, setParaId] = useState(INVALID_PARAID);
   const { allowTeleport, destinations, isParaTeleport, oneWay } = useTeleport();
+  const balances = useCall<DeriveBalancesAll>(api.derive.balances?.all, [senderId]);
+  const [maxTransfer, setMaxTransfer] = useState<BN | null>(null);
 
   const call = useMemo(
     (): SubmittableExtrinsicFunction<'promise'> => {
@@ -125,7 +128,31 @@ function Teleport ({ onClose }: Props): React.ReactElement<Props> | null {
     [api, amount, isParaTeleport, recipientId, recipientParaId]
   );
 
-  const hasAvailable = !!amount;
+  const hasAvailable = !!amount && (maxTransfer ? amount.lte(maxTransfer) : true);
+
+  useEffect(() => {
+    if (balances && balances.accountId.eq(senderId) && senderId && recipientId && api.call.transactionPaymentApi && api.tx.balances) {
+      nextTick(async (): Promise<void> => {
+        try {
+          const extrinsic = call(...params);
+          const { partialFee } = await extrinsic.paymentInfo(senderId);
+
+          const adjFee = partialFee.muln(110).div(BN_HUNDRED);
+          const maxTransfer = (balances.transferable || balances.availableBalance).sub(adjFee);
+
+          setMaxTransfer(
+            api.consts.balances && maxTransfer.gt(api.consts.balances.existentialDeposit)
+              ? maxTransfer.sub(api.consts.balances.existentialDeposit)
+              : null
+          );
+        } catch (error) {
+          console.error(error);
+        }
+      });
+    } else {
+      setMaxTransfer(null);
+    }
+  }, [api.call.transactionPaymentApi, api.consts.balances, api.tx.balances, balances, call, params, recipientId, senderId]);
 
   return (
     <Modal
@@ -182,6 +209,11 @@ function Teleport ({ onClose }: Props): React.ReactElement<Props> | null {
             label={t('amount')}
             onChange={setAmount}
           />
+          {maxTransfer &&
+          <StyledInfo>
+            <span>Max -</span>
+            <FormatBalance value={maxTransfer} />
+          </StyledInfo>}
           <InputBalance
             defaultValue={destApi?.consts.balances?.existentialDeposit}
             isDisabled
@@ -206,3 +238,14 @@ function Teleport ({ onClose }: Props): React.ReactElement<Props> | null {
 }
 
 export default React.memo(Teleport);
+
+const StyledInfo = styled.p`
+  align-items: center;
+  display: flex;
+  font-size: var(--font-size-small);
+  gap: 3px;
+  justify-content: flex-end;
+  span:first-of-type {
+    font-weight: var(--font-weight-bold);
+  }
+`;
diff --git a/packages/react-components/src/InputBalance.tsx b/packages/react-components/src/InputBalance.tsx
index f1f15a8cf5..60013cc6f5 100644
--- a/packages/react-components/src/InputBalance.tsx
+++ b/packages/react-components/src/InputBalance.tsx
@@ -95,7 +95,7 @@ function InputBalance ({ autoFocus, children, className = '', defaultValue: inDe
       labelExtra={
         <LabelledExtra>
           {labelExtra}
-          {!!si && (siSymbol || TokenUnit.abbr) &&
+          {!!si && (siSymbol || TokenUnit.abbr) && !isDisabled &&
           <p>
             {t('(enter value in standard units)')}
           </p>