1 files changed, 80 insertions, 0 deletions
diff --git a/src/contract.ts b/src/contract.ts
new file mode 100644
index 000000000..1aacc65dc
--- /dev/null
+++ b/src/contract.ts
@@ -0,0 +1,80 @@
+import * as Web3 from 'web3';
+import * as _ from 'lodash';
+import promisify = require('es6-promisify');
+import {SchemaValidator, schemas} from '0x-json-schemas';
+import {AbiType} from './types';
+
+export class Contract implements Web3.ContractInstance {
+    public address: string;
+    public abi: Web3.ContractAbi;
+    private contract: Web3.ContractInstance;
+    private defaults: Partial<Web3.TxData>;
+    private validator: SchemaValidator;
+    // This class instance is going to be populated with functions and events depending on the ABI
+    // and we don't know their types in advance
+    [name: string]: any;
+    constructor(web3ContractInstance: Web3.ContractInstance, defaults: Partial<Web3.TxData>) {
+        this.contract = web3ContractInstance;
+        this.address = web3ContractInstance.address;
+        this.abi = web3ContractInstance.abi;
+        this.defaults = defaults;
+        this.populateEvents();
+        this.populateFunctions();
+        this.validator = new SchemaValidator();
+    }
+    private populateFunctions(): void {
+        const functionsAbi = _.filter(this.abi, abiPart => abiPart.type === AbiType.Function);
+        _.forEach(functionsAbi, (functionAbi: Web3.MethodAbi) => {
+            if (functionAbi.constant) {
+                const cbStyleCallFunction = this.contract[functionAbi.name].call;
+                this[functionAbi.name] = {
+                    callAsync: promisify(cbStyleCallFunction, this.contract),
+                };
+            } else {
+                const cbStyleFunction = this.contract[functionAbi.name];
+                const cbStyleEstimateGasFunction = this.contract[functionAbi.name].estimateGas;
+                this[functionAbi.name] = {
+                    estimateGasAsync: promisify(cbStyleEstimateGasFunction, this.contract),
+                    sendTransactionAsync: this.promisifyWithDefaultParams(cbStyleFunction),
+                };
+            }
+        });
+    }
+    private populateEvents(): void {
+        const eventsAbi = _.filter(this.abi, abiPart => abiPart.type === AbiType.Event);
+        _.forEach(eventsAbi, (eventAbi: Web3.EventAbi) => {
+            this[eventAbi.name] = this.contract[eventAbi.name];
+        });
+    }
+    private promisifyWithDefaultParams(fn: (...args: any[]) => void): (...args: any[]) => Promise<any> {
+        const promisifiedWithDefaultParams = (...args: any[]) => {
+            const promise = new Promise((resolve, reject) => {
+                const lastArg = args[args.length - 1];
+                let txData: Partial<Web3.TxData> = {};
+                if (this.isTxData(lastArg)) {
+                    txData = args.pop();
+                }
+                txData = {
+                    ...this.defaults,
+                    ...txData,
+                };
+                const callback = (err: Error, data: any) => {
+                    if (_.isNull(err)) {
+                        resolve(data);
+                    } else {
+                        reject(err);
+                    }
+                };
+                args.push(txData);
+                args.push(callback);
+                fn.apply(this.contract, args);
+            });
+            return promise;
+        };
+        return promisifiedWithDefaultParams;
+    }
+    private isTxData(lastArg: any): boolean {
+        const isValid = this.validator.isValid(lastArg, schemas.txDataSchema);
+        return isValid;
+    }
+}