README

Functionality

-Implementation of ERC20: Vera Token (VT) -Implementation of ERC721: AssetToken -Implementation of AssetManager Contract

Transaction flow overview

The owner of 721 Token deposits an asset worth X VT to the manager using the AssetManager->Deposit Function

AssetManager sends X VT to the Owner as a loan and the loan balance increases daily due to accumulated interest.

When the Owner pays back the loan, AssetManager sends the asset x123 back to the Owner.

Example

Bob walletB

AssetManager walletM

Bob owns 721 token x123 worth 100 VT

Bob deposits x123 to AssetManager walletM

AssetManager sends 100 VT to walletB

Daily interest is 0.05 VT

Day 1 Bob's loan balance = 100 VT

Day 2 Bob's loan balance = 100.05 VT

Day 2 Bob loan balance 100.100025 VT

When Bob pays back the balance, the asset is released.

Development

Using bash script

This script will setup the environment and build our contracts for ubuntu operating system

# Set execute permission and run the script:
chmod +x build.sh
./build.sh

Build

cargo +nightly contract build

Test

cargo +nightly test

Smart Contract Deployment

1. Upload contract metadata and wasm (.contract files) for erc20, erc721 and AssetManager

2. Instantiate erc20 and erc721 contracts first using Alice as owner. erc20 initial supply is set to 1 billion units and both contracts get 10 units endowment.

3. Instantiate assetmanager contract using Alice as owner. Erc20 and Erc721 addresses will be set to the above deployed contracts; interest rate is set to 10 (% per year); transfer rate is set to 1 million (erc20 per erc721 token) and enabled is set to true.

4. Alice, being owner of erc20 and erc721, grants approval to assetmanager calling approve and setApprovalForAll of erc20 and er721 respectively.

5. Now Bob (or any else with balance) can mint an erc721 token, grant approval to assetmanager contract to spend this token, and deposit it in the assetmanager contract in exchange for 1 million erc20 tokens. These tokens are deducted from erc20 owner account (in this case Alice).

6. There are some utility methods that can be called by anyone to check Bob's outstanding balance and interest payable etc.

7. To repay, Bob needs to grant approval to assetmanager to spend his erc20 tokens. After that, he can call withdraw method providing the token_id he is withdrawing. The assetmanager contract will deduct principal balance (1 million)+ interest from Bob's erc20 balance, deposit it in erc20 owner (Alice) and transfer erc721 token from Alice to Bob.

License

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.