Support trade type === BUY (#24)

src/services/tradeService.ts

@@ -1,5 +1,9 @@
 import grpc from 'grpc';
-import { Swap, calculateExpectedAmount } from 'tdex-sdk';
+import {
+  Swap,
+  calculateExpectedAmount,
+  calculateProposeAmount,
+} from 'tdex-sdk';
 
 import {
   Balance,
@@ -111,6 +115,7 @@ class Trade {
     let quoteAsset = undefined;
     try {
       const market = call.request.getMarket();
+      const tradeType = call.request.getType();
       const swapRequestMessage = call.request.getSwapRequest();
       if (!market || !swapRequestMessage)
         throw {
@@ -147,16 +152,28 @@ class Trade {
       );
       const balanceP = balances[assetP];
       const balanceR = balances[assetR];
-      const expectedAmount = calculateExpectedAmount(
-        balanceP,
-        balanceR,
-        amountP,
-        marketFound.fee
-      );
 
-      //TODO Here we need to take into account a little slippage so the check need to be a range between a min and max spread
-      if (expectedAmount !== amountR)
-        throw new Error('Not valid amount_r for the proposed amount_p');
+      if (tradeType === TradeProposeRequest.Type.BUY) {
+        const proposeAmount = calculateProposeAmount(
+          balanceP,
+          balanceR,
+          amountR,
+          marketFound.fee
+        );
+        // TODO check possible slippage due network congestion
+        if (proposeAmount !== amountP)
+          throw new Error('Not valid amount_p for the requested amount_r');
+      } else {
+        const expectedAmount = calculateExpectedAmount(
+          balanceP,
+          balanceR,
+          amountP,
+          marketFound.fee
+        );
+        //TODO Here we need to take into account a little slippage so the check need to be a range between a min and max spread
+        if (expectedAmount !== amountR)
+          throw new Error('Not valid amount_r for the proposed amount_p');
+      }
 
       // Let's stop the market to not process other concurrent swaps
       await marketModel.updateMarket({ quoteAsset }, { tradable: false });

test/e2e.spec.ts

@@ -4,7 +4,11 @@ import { sleep, faucet, mint, fetchUtxos } from './helpers';
 import { networks } from 'liquidjs-lib';
 import { markets, balances, tradePropose, tradeComplete } from './grpc/trader';
 import Wallet, { fromWIF, WalletInterface } from '../src/components/wallet';
-import { Swap, calculateExpectedAmount } from 'tdex-sdk';
+import {
+  Swap,
+  calculateExpectedAmount,
+  calculateProposeAmount,
+} from 'tdex-sdk';
 import { SwapAccept } from 'tdex-protobuf/js/swap_pb';
 
 describe('End to end testing', () => {
@@ -119,7 +123,66 @@ describe('End to end testing', () => {
     // check if market got back to be tradabale
     const tradableMarketsAgain = await markets();
     expect(tradableMarketsAgain.length).toStrictEqual(1);
-  }, 35000);
+
+    /**
+     * Now let's try to BUY
+     */
+
+    const balancesAndFee2 = await balances({ baseAsset, quoteAsset });
+    const amountToReceive2 = 5000;
+    const amountToBeSent2 = calculateProposeAmount(
+      balancesAndFee2.balances[quoteAsset],
+      balancesAndFee2.balances[baseAsset],
+      amountToReceive2,
+      balancesAndFee.fee
+    );
+    const traderUtxos2 = await fetchUtxos(traderWallet.address, USDT);
+    const emptyPsbt2 = Wallet.createTx();
+    const psbt2 = traderWallet.updateTx(
+      emptyPsbt2,
+      traderUtxos2,
+      amountToBeSent2,
+      amountToReceive2,
+      USDT,
+      LBTC
+    );
+    const swap2 = new Swap({ chain: 'regtest' });
+    const swapRequestSerialized2 = swap2.request({
+      assetToBeSent: USDT,
+      amountToBeSent: amountToBeSent2,
+      assetToReceive: LBTC,
+      amountToReceive: amountToReceive2,
+      psbtBase64: psbt2,
+    });
+    // 0 === Buy === receiving base_asset; 1 === sell === receiving quote_asset
+    const tradeType2 = 0;
+    const swapAcceptSerialized2: Uint8Array = await tradePropose(
+      market,
+      tradeType2,
+      swapRequestSerialized2
+    );
+
+    // trader need to check the signed inputs by the provider
+    // and add his own inputs if all is correct
+    const swapAcceptMessage2 = SwapAccept.deserializeBinary(
+      swapAcceptSerialized2
+    );
+    const transaction2 = swapAcceptMessage2.getTransaction();
+    const signedPsbt2 = traderWallet.sign(transaction2);
+
+    // Trader  adds his signed inputs to the transaction
+    const swapCompleteSerialized2 = swap2.complete({
+      message: swapAcceptSerialized2,
+      psbtBase64: signedPsbt2,
+    });
+
+    // Trader call the tradeComplete endpoint to finalize the swap
+    const txid2 = await tradeComplete(swapCompleteSerialized2);
+    expect(txid2).toBeDefined();
+    // check if market got back to be tradabale
+    const tradableMarketsAgain2 = await markets();
+    expect(tradableMarketsAgain2.length).toStrictEqual(1);
+  }, 55000);
 
   test('Calculate expected amount', () => {
     // balanceP, balanceR, amountP, fee