EPF4: UPDATE 7

This is a direct follow-up to [UPDATE 6](https://hackmd.io/WBAtfKu3RGyUw__DFw16Fw), which is basically me reviewing the experimental code i have written prior for implementing ephemery reset using Lodestar.

The most important takeaway is that i will be creating three major code files within the [reset directory](https://github.com/AdedamolaXL/lodestar/tree/unstable/packages/ephemery/src/reset) in lodestar's ephemery package:
* `checkTestnet.ts`
* `resetTestnet.ts`
* `index.ts`

**NOTE:** `checkTestnet.ts` is a dependency on holly's [genesis implementation](https://github.com/atkinsonholly/lodestar/tree/feat/genesis/packages/ephemery/src/genesis). This is because the `checkTestnet` function as a whole is checking if a new ephemery genesis has been released based on the terminal timestamp and using that information to reset the client using the new genesis.
I will address the `checkTestnet` function in another update so as to focus solely on `resetTestnet.ts` in this one. The `index.ts` file is simply useful for importing the aforementioned functions and doesn't warrant a deep dive.

## resetTestnet.ts

async function resetTestnet(genesisRelease: string) {
    await stopClients();
    clearDataDirs();
    await downloadGenesisRelease(genesisRelease);
    await setupGenesis();
    await startClients();
}

### Priority order of important functions to execute:

#### 1. `stopClients()`
This is probably the most important part of the reset implementation problem.
* how to stop (pause) all transactions ( & any other processes ? ) on lodestar so that we can execute the functions in [(3)]() and then perform a restart with [(2)]().
* two lodestar implementation will be paused:
* the beacon-chain : lodestar's [implementation](https://github.com/ChainSafe/lodestar/tree/unstable/packages/cli/src/cmds/beacon).
* the validators : lodestar's [implementation](https://github.com/ChainSafe/lodestar/tree/unstable/packages/cli/src/cmds/validator).
* rename `stopClients()` ==> `pauseClients()`.
* add a state variable (flag) to indicate that the client has been paused
* ##### pseudocode for pauseClient():

// Define a flag to track the paused state
let isPaused = false;

// Function to pause the client
async function pauseClient() {
  if (!isPaused) {
    // Stop validating new transactions and blocks
    validator/index
    // Handle ongoing network interactions gracefully
    beacon/index
    // Set the paused flag to true
    isPaused = true;
  }
}

#### 2. `startClients()`
* confirm if a new genesis has been downloaded and created
* restart the client gracefully using updated config from the new genesis created.
* resume all processes and network interactions that were paused
* in [update6](https://hackmd.io/WBAtfKu3RGyUw__DFw16Fw) i commented that that an implementation code for starting the beacon chain will be useful and i have found it [here](https://github.com/atkinsonholly/lodestar/blob/unstable/packages/cli/src/cmds/beacon/handler.ts#L35), thanks to pk :)
* rename `startClients() ==> restartClients()`.
* ##### pseduocode for restartClients():

// Function to automatically restart the client
async function restartClient(latestGenesisRelease) {
  // Detect the trigger condition for restart (e.g: new genesis)
  chectTestnet()
  
  // If the client is currently paused, resume it first
  if (isPaused) {
    isPaused = false;
    // Resume processing and network interactions
    validator/index
    beaocn/index
  }

  // Implement logic to restart the existing client gracefully 
  beacon/handler
  
  // Update client configuration with new genesis state or other changes
  beacon/index <== latestGenesisRelease 
  // Invoke beaconHandler with the updated config to start the client
  await beaconHandler(updatedConfig);
}

// Usage examples
await pauseClient(); // Pause the client
await restartClient(latestGenesisRelease); // Restart the client with new genesis state

#### 3. `clearDataDirs() && downloadGenesisRelease(genesisRelease) && setupGenesis()`
* these functions are also dependencies that will come in from holly's [genesis implementation](https://github.com/atkinsonholly/lodestar/tree/feat/genesis/packages/ephemery/src/genesis).

**TODO:**
* In another update i will review:
* lodestar's beacon's chain [implementation](https://github.com/ChainSafe/lodestar/tree/unstable/packages/cli/src/cmds/beacon) and possibly,
* the validator [implementation](https://github.com/ChainSafe/lodestar/tree/unstable/packages/cli/src/cmds/validator) as well.