# Kredits

This repository contains all the contracts for Kredits as a [truffle framework](http://truffleframework.com/) project.

## Development

### Installation

    $ npm install

### Requirements

All requirements are defined in `package.json`.

Those can be installed globally for convenience: 
  * [truffle framework](http://truffleframework.com): `npm install -g truffle`
  * [ganache](http://truffleframework.com/ganache): `npm install -g ganache-cli`

We use following solidity contract libraries:
  * [Open Zeppelin](https://github.com/OpenZeppelin/zeppelin-solidity)

For local development it is recommended to use [ganache-cli](https://github.com/trufflesuite/ganache-cli) (or the [ganache GUI](http://truffleframework.com/ganache/) to run a local development chain.  
Using the ganache simulator no full Ethereum node is required.

We default to the port 7545 for development to not get in conflict with the default Ethereum RPC port. Have a look at `ganache-cli` for more configuration options.

Run your ganache simulator before using Kredits locally:

    $ ganache-cli -p 7545

### Truffle console

Truffle comes with a simple REPL to interact with the Smart Contracts. Have a look at the [documentation here](http://truffleframework.com/docs/getting_started/console)

NOTE: There are promisses, have a look at the examples: 

```javascript
Token.deployed().then(function(token) { 
  token.totalSupply.call().then(function(value) {
    console.log(value.toString());
  })
});
```

Also please be aware of the differences between web3.js 0.2x.x and [1.x.x](https://web3js.readthedocs.io/en/1.0/) - [web3 repo](https://github.com/ethereum/web3.js/)


## Contract Deployment

Truffle uses migration scripts to deploy contract to various networks. Have a look at the `migrations` folder for those.  
The Ethereum nodes for the different networks need to be configured in `truffle.js`.

Run the truffle migration scripts: 

    $ truffle deploy 
    $ truffle deploy --network=<network config from truffle.js>

Truffle keeps track of already executed migration scripts. To reset the migration use the `--reset` option

    $ truffle migrate --reset

Migration scripts can also be run from within `truffle console` or `truffle develop` 

To initially bootstrap a local development chain in ganache you can use the bootstrap script:

    $ npm run bootstrap (= `truffle migrate --reset && truffle exec scripts/seeds.js && npm run build-json`)


## Helper scripts

`scripts/` contains some helper scripts to interact with the contracts from the CLI. 
At some point these should be moved into a real nice CLI. 

To run these scripts use `truffle exec`. For example: `truffle exec scripts/add-proposal.js` 

### cli.js

Call any function on any contract:

    $ truffle exec scripts/cli.js <Contract Name> <Function> [<optional> <arguments>]
    
    For example: 
    $ truffle exec scripts/cli.js Operator proposalsCount

Please note that the contract name and the function are case sensitive. 

### add-contributor.js
Adds a new core contributor, creates a proposal for the new contributor and votes for that one. 

    $ truffle exec scripts/add-contributor.js <ethereum address> [<profile IPFS hash>]

### add-proposal.js
Adds a new proposal for an existing contributor

    $ truffle exec scripts/add-proposal.js <ethereum address> [<proposal IPFS hash>]

### send-funds.js
Sends funds to an address. Helpful in development mode to for example fund a metamask account.

    $ truffle exec scripts/send-funds.js <ethereum address>

### seeds.js
Run seeds defined in `config/seeds.js`.  

    $ truffle exec scripts/seeds.js 
    or 
    $ npm run seeds


## Upgradeable contracts

Some of the contracts use upgradability ideas from [zeppelinos](https://github.com/zeppelinos/labs) (see `contracts/upgradable`).

The basic idea is to have a Registry contract that knows about the current implementations and a Proxy contract that uses `delegatecall` to call the current implementation.  
That means the Proxy contract holds the storage and the address of that one does not change but the actuall implemenation is managed through the Registry. 

To deploy a new version a new contract is deployed then the version is registered (`addVersion()`) in the Registry and on the Proxy contract is "upgraded" (`upgrade()`) to the new version. 

The Registry knows about all the different contracts and implementations. Versions are stored as uint and automatically incremented for every added implementation.


### Example:

Deployment is best done using the [truffle deployer]()

1. Setup
    1. deploy the Registry 
    2. deploy the contract
    3. register the contract at the Registry: 
        `registry.addVersion('Token', Token.address)`
    4. create the Proxy: 
        `registry.createProxy('Token', 1)`
2. Update
    1. deploy a new Version of the contract
    2. register the new version at the Registry: 
        `registry.addVersion('Token', NewToken.address)`
    3. set the new implementation address on the Proxy contract:
        `registry.upgrade('Token', 2)`


## Known Issues

When resetting ganache Metamask might have an invalid transaction nonce and transactions get rejected. 
Nonces in Ethereum must be incrementing and have no gap. 

To solve this reset the metamask account (Account -> Settings -> Reset Account)