Migrate Mobile App to the new contractkit

[mcortesi]

Expected Behavior

Use ContractKit

• [x] View functions (exchange rate, fetching balances, contract decimals)
• [ ] State changing functions

Current Behavior

Uses WalletKit

[yerdua]

blocked by:

671 - contractkit wrapper for Escrow

1042 - contractkit wrapper for GasPriceMinimum

1019 - contractkit wrapper for Attestations

[yerdua]

Missing/Incomplete wrappers

• Escrow (missing: #671)
• GasPriceMinimum (missing: #1042)
• Attestations (in-progress: #1019)

Functions from walletkit without equivalents in contractkit

• GenesisBlockUtils => gets the genesis block for a given network, downloading from google cloud storage
• StaticNodeUtils => gets the static node urls for a given network, downloading from google cloud storage
• ContractUtils.getExchangeRate => calls exchange.methods.getBuyTokenAmount and then processes the result slightly
• ContractUtils.getGasPrice => this calls GasPriceMinimum with the given currency and multiplies the result by 5
• extractAttestationCodeFromMessage => pulls an attestation code out of a message from an SMS. This looks specific to the mobile app?
• parseFromContractDecimals => It's part of erc20-utils, which are maybe useful?
• sanitizeBase64 => body of the function is: return base64String.replace(/(¿|§)/gi, '_') with a comment expressing confusion about why it's necessary
• getErc20Balance => no equivalent exists, maybe it should?
• awaitConfirmation => it calls .confirmation on the TxPromises it takes as an argument

Functions from walletkit that are Attestations contract or wrapper functions (after #1019):

• makeApproveAttestationFeeTx => attestations.approveAttestationFee
• findMatchingIssuer => attestations.findMatchingIssuer
• getActionableAttestations => attestations.getActionableAttestations
• getWalletAddress => attestations.getWalletAddress
• lookupPhoneNumbers => attesatations.lookupPhoneNumbers
• makeCompleteTx =>> attestations.complete
• makeRequestTx => attestations.request
• makeRevealTx => attestations.reveal
• makeSetAccountTx => attestations.setAccount
• validateAttestationCode => attestations.validateAttestationCode
• getDataEncryptionKey => attestations.contract.methods.getDataEncryptionKey

Renamed functions, walletkit => contractkit

• sendTransactionAsync => sendTransaction

Rough plan for migration after blockers are addressed:

1. Cache an instance of the contractkit in mobile
2. Move StaticNodeUtils + GenesisBlockUtils somewhere accessible to the mobile app, and use them in that new location
3. Replace all contract calls with contractkit contract wrapper interactions
4. Deal with all other functions with no current equivalents in contractkit

[jmrossy]

Adding some info from the mobile wallet retro meeting:

• There's a concern that using contract kit in with the app in zero-sync mode will cause all headers to be synced. (Unconfirmed)
• Sending transactions via contract kit won't work because the kit's utilities don't support zero-sync mode. For this we need local signing and gas-in-dollars by default transactions
• The current walletkit tx sending utility functions that the wallet uses make it easy to customize the logging. Just need to confirm contractkit's utilities can do the same

[jmrossy]

Another small issue to tackle before migrating: Calling contract kit class methods with redux saga effects doesn't work unless the this context is explicitly specified like so:

 const attestationsWrapper: AttestationsWrapper = yield call([
      contractKit.contracts,
      contractKit.contracts.getAttestations,
    ])

Before we fully migrate, we should find a more elegant way to call methods