feat: add in GhoTokenService for totalSupply & facilitator info (#444)

* feat: add in GhoTokenService and getFacilitatorBucket

* fix: typo

* feat: add in more utils for GhoTokenService

packages/contract-helpers/src/gho/GhoDiscountRateStrategyService.test.ts

@@ -30,10 +30,13 @@ describe('GhoDiscountRateStrategyService', () => {
 
   describe('Create new GhoDiscountRateStrategyService', () => {
     it('Expects to be initialized correctly', () => {
+      // Create instance
       const instance = new GhoDiscountRateStrategyService(
         correctProvider,
         DISCOUNT_RATE_STRATEGY_ADDRESS,
       );
+
+      // Assert it
       expect(instance).toBeInstanceOf(GhoDiscountRateStrategyService);
     });
   });

packages/contract-helpers/src/gho/GhoDiscountRateStrategyService.ts

@@ -3,7 +3,7 @@ import BaseService from '../commons/BaseService';
 import { GhoDiscountRateStrategy__factory } from './typechain/GhoDiscountRateStrategy__factory';
 import type { IGhoDiscountRateStrategy } from './typechain/IGhoDiscountRateStrategy';
 
-export interface GhoDiscountRateServiceInterface {
+interface IGhoDiscountRateStrategyService {
   calculateDiscountRate: (
     ghoDebtTokenBalance: BigNumberish,
     skAaveBalance: BigNumberish,
@@ -16,7 +16,7 @@ export interface GhoDiscountRateServiceInterface {
  */
 export class GhoDiscountRateStrategyService
   extends BaseService<IGhoDiscountRateStrategy>
-  implements GhoDiscountRateServiceInterface
+  implements IGhoDiscountRateStrategyService
 {
   readonly ghoDiscountRateStrategyAddress: string;
 

packages/contract-helpers/src/gho/GhoTokenService.test.ts

@@ -0,0 +1,150 @@
+import { constants, BigNumber, providers } from 'ethers';
+import { valueToWei } from '../commons/utils';
+import { GhoTokenService } from './GhoTokenService';
+import { GhoToken } from './typechain/GhoToken';
+import { GhoToken__factory } from './typechain/GhoToken__factory';
+import { IGhoToken } from './typechain/IGhoToken';
+
+jest.mock('../commons/gasStation', () => {
+  return {
+    __esModule: true,
+    estimateGasByNetwork: jest
+      .fn()
+      .mockImplementation(async () => Promise.resolve(BigNumber.from(1))),
+    estimateGas: jest.fn(async () => Promise.resolve(BigNumber.from(1))),
+  };
+});
+
+// Helper for contract call arguments
+const convertToBN = (n: string) => valueToWei(n, 18);
+
+describe('GhoTokenService', () => {
+  const GHO_TOKEN_ADDRESS = constants.AddressZero;
+  const correctProvider: providers.Provider = new providers.JsonRpcProvider();
+
+  // Mocking
+  jest
+    .spyOn(correctProvider, 'getGasPrice')
+    .mockImplementation(async () => Promise.resolve(BigNumber.from(1)));
+
+  afterEach(() => jest.clearAllMocks());
+
+  describe('Create new GhoTokenService', () => {
+    it('Expects to be initialized correctly', () => {
+      // Create Instance
+      const instance = new GhoTokenService(correctProvider, GHO_TOKEN_ADDRESS);
+
+      // Assert it
+      expect(instance).toBeInstanceOf(GhoTokenService);
+    });
+  });
+
+  describe('totalSupply', () => {
+    it('should return the total supply of GHO tokens', async () => {
+      // Create Instance
+      const contract = new GhoTokenService(correctProvider, GHO_TOKEN_ADDRESS);
+
+      // Setup
+      const mockTotalSupply = convertToBN('10000000'); // 10M
+
+      // Mock it
+      const spy = jest.spyOn(GhoToken__factory, 'connect').mockReturnValue({
+        totalSupply: async () => Promise.resolve(mockTotalSupply),
+      } as unknown as GhoToken);
+
+      // Call it
+      const result = await contract.totalSupply();
+
+      // Assert it
+      expect(spy).toHaveBeenCalled();
+      expect(spy).toBeCalledTimes(1);
+      expect(result).toEqual(mockTotalSupply);
+    });
+  });
+
+  describe('getFacilitatorsList', () => {
+    it('should return the list of facilitators as an array of addresses', async () => {
+      // Create instance
+      const contract = new GhoTokenService(correctProvider, GHO_TOKEN_ADDRESS);
+
+      // Setup
+      const faciliatorAddress1: string = constants.AddressZero;
+      const faciliatorAddress2: string = constants.AddressZero;
+      const mockFacilitatorsList: string[] = [
+        faciliatorAddress1,
+        faciliatorAddress2,
+      ];
+
+      // Mock it
+      const spy = jest.spyOn(GhoToken__factory, 'connect').mockReturnValue({
+        getFacilitatorsList: async () => Promise.resolve(mockFacilitatorsList),
+      } as unknown as GhoToken);
+
+      // Call it
+      const result = await contract.getFacilitatorsList();
+
+      // Assert it
+      expect(spy).toHaveBeenCalled();
+      expect(spy).toBeCalledTimes(1);
+      expect(result).toEqual(mockFacilitatorsList);
+    });
+  });
+
+  describe('getFacilitator', () => {
+    it('should return the facilitator instance for the provided facilitator address', async () => {
+      // Create instance
+      const contract = new GhoTokenService(correctProvider, GHO_TOKEN_ADDRESS);
+
+      // Setup
+      const faciliatorAddress: string = constants.AddressZero;
+      const mockBucket: IGhoToken.BucketStruct = {
+        maxCapacity: convertToBN('1000'),
+        level: convertToBN('500'),
+      };
+      const mockFacilitator: IGhoToken.FacilitatorStruct = {
+        bucket: mockBucket,
+        label: 'Aave Facilitator',
+      };
+
+      // Mock it
+      const spy = jest.spyOn(GhoToken__factory, 'connect').mockReturnValue({
+        getFacilitator: async () => Promise.resolve(mockFacilitator),
+      } as unknown as GhoToken);
+
+      // Call it
+      const result = await contract.getFacilitator(faciliatorAddress);
+
+      // Assert it
+      expect(spy).toHaveBeenCalled();
+      expect(spy).toBeCalledTimes(1);
+      expect(result).toEqual(mockFacilitator);
+    });
+  });
+
+  describe('getFacilitatorBucket', () => {
+    it('should return the bucket instance for the provided facilitator address', async () => {
+      // Create instance
+      const contract = new GhoTokenService(correctProvider, GHO_TOKEN_ADDRESS);
+
+      // Setup
+      const faciliatorAddress: string = constants.AddressZero;
+      const mockBucket: IGhoToken.BucketStruct = {
+        maxCapacity: convertToBN('1000'),
+        level: convertToBN('500'),
+      };
+
+      // Mock it
+      const spy = jest.spyOn(GhoToken__factory, 'connect').mockReturnValue({
+        getFacilitatorBucket: async () => Promise.resolve(mockBucket),
+      } as unknown as GhoToken);
+
+      // Call it
+      const result = await contract.getFacilitatorBucket(faciliatorAddress);
+
+      // Assert it
+      expect(spy).toHaveBeenCalled();
+      expect(spy).toBeCalledTimes(1);
+      expect(result).toEqual(mockBucket);
+    });
+  });
+});

packages/contract-helpers/src/gho/GhoTokenService.ts

@@ -0,0 +1,75 @@
+import { BigNumber, providers } from 'ethers';
+import BaseService from '../commons/BaseService';
+import type { GhoToken } from './typechain/GhoToken';
+import { GhoToken__factory } from './typechain/GhoToken__factory';
+import type { IGhoToken } from './typechain/IGhoToken';
+
+interface IGhoTokenService {
+  totalSupply: () => Promise<BigNumber>;
+  getFacilitatorsList: () => Promise<string[]>;
+  getFacilitator: (
+    facilitatorAddress: string,
+  ) => Promise<IGhoToken.FacilitatorStruct>;
+  getFacilitatorBucket: (
+    facilitatorAddress: string,
+  ) => Promise<IGhoToken.BucketStruct>;
+}
+
+/**
+ * The service for interacting with the GhoToken.sol smart contract.
+ * This contract controls operations minting & burning the native GHO token as well as facilitator management.
+ * https://github.com/aave/gho/blob/main/src/contracts/gho/GhoToken.sol
+ */
+export class GhoTokenService
+  extends BaseService<GhoToken>
+  implements IGhoTokenService
+{
+  readonly ghoTokenAddress: string;
+
+  constructor(provider: providers.Provider, ghoTokenAddress: string) {
+    super(provider, GhoToken__factory);
+    this.ghoTokenAddress = ghoTokenAddress;
+  }
+
+  /**
+   * Gets the total supply for the GHO token. This is the sum of all facilitators' current bucket levels
+   * @returns - A BigNumber representing the total supply of GHO
+   */
+  public async totalSupply() {
+    const contract = this.getContractInstance(this.ghoTokenAddress);
+    const result = await contract.totalSupply();
+    return result;
+  }
+
+  /**
+   * Gets the full list of facilitators for the GHO token
+   * @returns - An array of facilitator addresses, which can be used for querying in more detail
+   */
+  public async getFacilitatorsList() {
+    const contract = this.getContractInstance(this.ghoTokenAddress);
+    const result = await contract.getFacilitatorsList();
+    return result;
+  }
+
+  /**
+   * Gets the instance for a given facilitator
+   * @param facilitatorAddress - The address for the currently deployed contract for the facilitator being queried
+   * @returns - The instance of the facilitator, which contains `bucket` and `label` fields
+   */
+  public async getFacilitator(facilitatorAddress: string) {
+    const contract = this.getContractInstance(this.ghoTokenAddress);
+    const result = await contract.getFacilitator(facilitatorAddress);
+    return result;
+  }
+
+  /**
+   * Gets the bucket instance for a given facilitator
+   * @param facilitatorAddress - The address for the currently deployed contract for the facilitator being queried
+   * @returns - The instance of the facilitator bucket, which contains `maxCapacity` and `level` fields
+   */
+  public async getFacilitatorBucket(facilitatorAddress: string) {
+    const contract = this.getContractInstance(this.ghoTokenAddress);
+    const result = await contract.getFacilitatorBucket(facilitatorAddress);
+    return result;
+  }
+}