validate address balance and set minAmount for ripple transaction

src/actions/ripple/SendFormActions.js

@@ -60,7 +60,7 @@ export const observe = (prevState: ReducersState, action: Action): ThunkAction =
     }
 
     if (shouldUpdate) {
-        const validated = dispatch(ValidationActions.validation());
+        const validated = dispatch(ValidationActions.validation(prevState.sendFormRipple));
         dispatch({
             type: SEND.VALIDATION,
             networkType: 'ripple',

src/actions/ripple/SendFormValidationActions.js

@@ -1,5 +1,5 @@
 /* @flow */
-
+import TrezorConnect from 'trezor-connect';
 import BigNumber from 'bignumber.js';
 import * as SEND from 'actions/constants/send';
 import { findDevice, getPendingAmount } from 'reducers/utils';
@@ -9,6 +9,7 @@ import type {
     Dispatch,
     GetState,
     PayloadAction,
+    PromiseAction,
     BlockchainFeeLevel,
 } from 'flowtype';
 import type { State, FeeLevel } from 'reducers/SendFormRippleReducer';
@@ -59,7 +60,7 @@ export const onFeeUpdated = (network: string, feeLevels: Array<BlockchainFeeLeve
 /*
 * Recalculate amount, total and fees
 */
-export const validation = (): PayloadAction<State> => (dispatch: Dispatch, getState: GetState): State => {
+export const validation = (prevState: State): PayloadAction<State> => (dispatch: Dispatch, getState: GetState): State => {
     // clone deep nested object
     // to avoid overrides across state history
     let state: State = JSON.parse(JSON.stringify(getState().sendFormRipple));
@@ -74,6 +75,9 @@ export const validation = (): PayloadAction<State> => (dispatch: Dispatch, getSt
     state = dispatch(amountValidation(state));
     state = dispatch(feeValidation(state));
     state = dispatch(destinationTagValidation(state));
+    if (state.touched.address && prevState.address !== state.address) {
+        dispatch(addressBalanceValidation(state));
+    }
     return state;
 };
 
@@ -135,6 +139,43 @@ const addressValidation = ($state: State): PayloadAction<State> => (dispatch: Di
     return state;
 };
 
+/*
+* Address balance validation
+* Fetch data from trezor-connect and set minimum required amount in reducer
+*/
+const addressBalanceValidation = ($state: State): PromiseAction<void> => async (dispatch: Dispatch, getState: GetState): Promise<void> => {
+    const { network } = getState().selectedAccount;
+    if (!network) return;
+
+    let minAmount: string = '0';
+    const response = await TrezorConnect.rippleGetAccountInfo({
+        account: {
+            descriptor: $state.address,
+        },
+        coin: network.shortcut,
+    });
+    if (response.success) {
+        const empty = response.payload.sequence <= 0 && response.payload.balance === '0';
+        if (empty) {
+            minAmount = toDecimalAmount(response.payload.reserve, network.decimals);
+        }
+    }
+
+    // TODO: consider checking local (known) accounts reserve instead of async fetching
+
+    // a2 (not empty): rJX2KwzaLJDyFhhtXKi3htaLfaUH2tptEX
+    // a4 (empty): r9skfe7kZkvqss7oMB3tuj4a59PXD5wRa2
+
+    dispatch({
+        type: SEND.CHANGE,
+        networkType: 'ripple',
+        state: {
+            ...getState().sendFormRipple,
+            minAmount,
+        },
+    });
+};
+
 /*
 * Address label assignation
 */
@@ -193,13 +234,21 @@ const amountValidation = ($state: State): PayloadAction<State> => (dispatch: Dis
         state.errors.amount = 'Amount is not a number';
     } else {
         const pendingAmount: BigNumber = getPendingAmount(pending, state.networkSymbol);
-
         if (!state.amount.match(XRP_6_RE)) {
             state.errors.amount = 'Maximum 6 decimals allowed';
         } else if (new BigNumber(state.total).greaterThan(new BigNumber(account.balance).minus(pendingAmount))) {
             state.errors.amount = 'Not enough funds';
         }
     }
+
+    if (!state.errors.amount && new BigNumber(account.balance).minus(state.total).lt(account.reserve)) {
+        state.errors.amount = `Not enough funds. Reserved amount for this account is ${account.reserve} ${state.networkSymbol}`;
+    }
+
+    if (!state.errors.amount && new BigNumber(state.amount).lt(state.minAmount)) {
+        state.errors.amount = `Amount is too low. Minimum amount for creating a new account is ${state.minAmount} ${state.networkSymbol}`;
+    }
+
     return state;
 };