1 files changed, 77 insertions, 0 deletions
diff --git a/packages/contract-wrappers/src/fetchers/asset_balance_and_proxy_allowance_fetcher.ts b/packages/contract-wrappers/src/fetchers/asset_balance_and_proxy_allowance_fetcher.ts
new file mode 100644
index 000000000..023cd5ac3
--- /dev/null
+++ b/packages/contract-wrappers/src/fetchers/asset_balance_and_proxy_allowance_fetcher.ts
@@ -0,0 +1,77 @@
+// tslint:disable:no-unnecessary-type-assertion
+import { AbstractBalanceAndProxyAllowanceFetcher, assetDataUtils } from '@0xproject/order-utils';
+import { AssetProxyId, ERC20AssetData, ERC721AssetData } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import { BlockParamLiteral } from 'ethereum-types';
+
+import { ERC20TokenWrapper } from '../contract_wrappers/erc20_token_wrapper';
+import { ERC721TokenWrapper } from '../contract_wrappers/erc721_token_wrapper';
+
+export class AssetBalanceAndProxyAllowanceFetcher implements AbstractBalanceAndProxyAllowanceFetcher {
+    private readonly _erc20Token: ERC20TokenWrapper;
+    private readonly _erc721Token: ERC721TokenWrapper;
+    private readonly _stateLayer: BlockParamLiteral;
+    constructor(erc20Token: ERC20TokenWrapper, erc721Token: ERC721TokenWrapper, stateLayer: BlockParamLiteral) {
+        this._erc20Token = erc20Token;
+        this._erc721Token = erc721Token;
+        this._stateLayer = stateLayer;
+    }
+    public async getBalanceAsync(assetData: string, userAddress: string): Promise<BigNumber> {
+        const decodedAssetData = assetDataUtils.decodeAssetDataOrThrow(assetData);
+        if (decodedAssetData.assetProxyId === AssetProxyId.ERC20) {
+            const decodedERC20AssetData = decodedAssetData as ERC20AssetData;
+            const balance = await this._erc20Token.getBalanceAsync(decodedERC20AssetData.tokenAddress, userAddress, {
+                defaultBlock: this._stateLayer,
+            });
+            return balance;
+        } else {
+            const decodedERC721AssetData = decodedAssetData as ERC721AssetData;
+            const tokenOwner = await this._erc721Token.getOwnerOfAsync(
+                decodedERC721AssetData.tokenAddress,
+                decodedERC721AssetData.tokenId,
+                {
+                    defaultBlock: this._stateLayer,
+                },
+            );
+            const balance = tokenOwner === userAddress ? new BigNumber(1) : new BigNumber(0);
+            return balance;
+        }
+    }
+    public async getProxyAllowanceAsync(assetData: string, userAddress: string): Promise<BigNumber> {
+        const decodedAssetData = assetDataUtils.decodeAssetDataOrThrow(assetData);
+        if (decodedAssetData.assetProxyId === AssetProxyId.ERC20) {
+            const decodedERC20AssetData = decodedAssetData as ERC20AssetData;
+            const proxyAllowance = await this._erc20Token.getProxyAllowanceAsync(
+                decodedERC20AssetData.tokenAddress,
+                userAddress,
+                {
+                    defaultBlock: this._stateLayer,
+                },
+            );
+            return proxyAllowance;
+        } else {
+            const decodedERC721AssetData = decodedAssetData as ERC721AssetData;
+
+            const isApprovedForAll = await this._erc721Token.isProxyApprovedForAllAsync(
+                decodedERC721AssetData.tokenAddress,
+                userAddress,
+                {
+                    defaultBlock: this._stateLayer,
+                },
+            );
+            if (isApprovedForAll) {
+                return new BigNumber(this._erc20Token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS);
+            } else {
+                const isApproved = await this._erc721Token.isProxyApprovedAsync(
+                    decodedERC721AssetData.tokenAddress,
+                    decodedERC721AssetData.tokenId,
+                    {
+                        defaultBlock: this._stateLayer,
+                    },
+                );
+                const proxyAllowance = isApproved ? new BigNumber(1) : new BigNumber(0);
+                return proxyAllowance;
+            }
+        }
+    }
+}