Backend: migrate ReadOnly accounts to NativeSegwit

Their public addresses would then start showing their native
segwit address (that starts with "bc1") instead of the nested
segwit one. This way they don't need to re-scan the QR code
from the coldstorage device.

In case you're wondering if there's any risk that this causes
irrecoverable funds in case you use this with a coldstorage
device that you haven't upgraded yet to NativeSegwit: this
could not happen since the JSON format is different, and then
deserialization would fail, advising the user to upgrade.

src/GWallet.Backend/Account.fs

@@ -97,14 +97,20 @@ module Account =
         failwith "OK, all accounts and cache is clear, you can disable this code block again"
 #endif
 
-        seq {
-            for currency in allCurrencies do
-                let activeKinds = [AccountKind.ReadOnly; AccountKind.Normal]
-                for kind in activeKinds do
-                    for accountFile in Config.GetAccountFiles [currency] kind do
-                        yield GetAccountFromFile accountFile currency kind
-        }
+        let allAccounts =
+            seq {
+                for currency in allCurrencies do
+                    let activeKinds = [AccountKind.ReadOnly; AccountKind.Normal]
+                    for kind in activeKinds do
+                        for accountFile in Config.GetAccountFiles [currency] kind do
+                            yield GetAccountFromFile accountFile currency kind
+            }
+
+#if NATIVE_SEGWIT
+        UtxoCoin.Account.MigrateReadOnlyAccountsToNativeSegWit allAccounts
+#endif
 
+        allAccounts
 
     let GetNormalAccountsPairingInfoForWatchWallet(): Option<WatchWalletInfo> =
         let allCurrencies = Currency.GetAll()
@@ -512,30 +518,17 @@ module Account =
         let json = SerializeSignedTransaction trans false
         File.WriteAllText(filePath, json)
 
-    let CreateReadOnlyAccounts (watchWalletInfo: WatchWalletInfo): Async<unit> = async {
-        for etherCurrency in Currency.GetAll().Where(fun currency -> currency.IsEtherBased()) do
-            do! ValidateAddress etherCurrency watchWalletInfo.EtherPublicAddress
-            let conceptAccountForReadOnlyAccount = {
-                Currency = etherCurrency
-                FileRepresentation = { Name = watchWalletInfo.EtherPublicAddress; Content = fun _ -> String.Empty }
-                ExtractPublicAddressFromConfigFileFunc = (fun file -> file.Name)
-            }
-            Config.AddAccount conceptAccountForReadOnlyAccount AccountKind.ReadOnly
-            |> ignore<FileRepresentation>
-
-        for utxoCurrency in Currency.GetAll().Where(fun currency -> currency.IsUtxo()) do
-            let address =
-                UtxoCoin.Account.GetPublicAddressFromPublicKey utxoCurrency
-                                                               (NBitcoin.PubKey(watchWalletInfo.UtxoCoinPublicKey))
-            do! ValidateAddress utxoCurrency address
-            let conceptAccountForReadOnlyAccount = {
-                Currency = utxoCurrency
-                FileRepresentation = { Name = address; Content = fun _ -> watchWalletInfo.UtxoCoinPublicKey }
-                ExtractPublicAddressFromConfigFileFunc = (fun file -> file.Name)
+    let CreateReadOnlyAccounts (watchWalletInfo: WatchWalletInfo): Async<unit> =
+        let ethJob = Ether.Account.CreateReadOnlyAccounts watchWalletInfo.EtherPublicAddress
+        let utxoJob =
+            async {
+                UtxoCoin.Account.CreateReadOnlyAccounts watchWalletInfo.UtxoCoinPublicKey
             }
-            Config.AddAccount conceptAccountForReadOnlyAccount AccountKind.ReadOnly
-            |> ignore<FileRepresentation>
-    }
+        async {
+            do!
+                Async.Parallel [ethJob; utxoJob]
+                |> Async.Ignore
+        }
 
     let Remove (account: ReadOnlyAccount) =
         Config.RemoveReadOnlyAccount account

src/GWallet.Backend/Config.fs

@@ -170,3 +170,10 @@ module Config =
 
     let RemoveReadOnlyAccount (account: ReadOnlyAccount): unit =
         RemoveAccount account
+
+    [<Literal>]
+    let private NoInitMsg = "This function never really existed, but it's here to warn you that yes, configuration needs to be initialized (e.g. for migrations) but it's done in Account.GetAllActiveAccounts() so that it's done by all frontends seamlessly (not explicitly)"
+
+    [<Obsolete "This function never really existed, but it's here to warn you that yes, configuration needs to be initialized (e.g. for migrations) but it's done in Account.GetAllActiveAccounts() so that it's done by all frontends seamlessly (not explicitly)">]
+    let Init() =
+        failwith NoInitMsg

src/GWallet.Backend/Ether/EtherAccount.fs

@@ -6,6 +6,7 @@
 open System
 open System.Numerics
 open System.Threading.Tasks
+open System.Linq
 
 open Nethereum.ABI.Decoders
 open Nethereum.Signer
@@ -154,6 +155,19 @@ module internal Account =
             raise (AddressWithInvalidChecksum(Some validCheckSumAddress))
     }
 
+    let internal CreateReadOnlyAccounts (etherPublicAddress: string) =
+        async {
+            for etherCurrency in Currency.GetAll().Where(fun currency -> currency.IsEtherBased()) do
+                do! ValidateAddress etherCurrency etherPublicAddress
+                let conceptAccountForReadOnlyAccount = {
+                    Currency = etherCurrency
+                    FileRepresentation = { Name = etherPublicAddress; Content = fun _ -> String.Empty }
+                    ExtractPublicAddressFromConfigFileFunc = (fun file -> file.Name)
+                }
+                Config.AddAccount conceptAccountForReadOnlyAccount AccountKind.ReadOnly
+                |> ignore<FileRepresentation>
+        }
+
     let private GetTransactionCount (currency: Currency) (publicAddress: string): Async<int64> = async {
         let! result = Ether.Server.GetTransactionCount currency publicAddress
         let value = result.Value

src/GWallet.Backend/UtxoCoin/UtxoCoinAccount.fs

@@ -621,11 +621,12 @@ module Account =
         else
             addressOrUrl,None
 
+    let BITCOIN_ADDRESS_BECH32_PREFIX = "bc1"
+
     let internal ValidateAddress (currency: Currency) (address: string) =
         if String.IsNullOrEmpty address then
             raise <| ArgumentNullException "address"
 
-        let BITCOIN_ADDRESS_BECH32_PREFIX = "bc1"
         let LITECOIN_ADDRESS_BECH32_PREFIX = "ltc1"
 
         let utxoCoinValidAddressPrefixes =
@@ -683,6 +684,49 @@ module Account =
         | :? FormatException ->
             raise (AddressWithInvalidChecksum None)
 
+    let internal CreateReadOnlyAccounts (utxoPublicKey: string) =
+        for utxoCurrency in Currency.GetAll().Where(fun currency -> currency.IsUtxo()) do
+            let address =
+                GetPublicAddressFromPublicKey
+                    utxoCurrency
+                    (NBitcoin.PubKey utxoPublicKey)
+            ValidateAddress utxoCurrency address
+            let conceptAccountForReadOnlyAccount = {
+                Currency = utxoCurrency
+                FileRepresentation = { Name = address; Content = fun _ -> utxoPublicKey }
+                ExtractPublicAddressFromConfigFileFunc = (fun file -> file.Name)
+            }
+            Config.AddAccount conceptAccountForReadOnlyAccount AccountKind.ReadOnly
+            |> ignore<FileRepresentation>
+
+#if NATIVE_SEGWIT
+    let internal MigrateReadOnlyAccountsToNativeSegWit (allAccounts: seq<IAccount>): unit =
+        let utxoAccountsToMigrate =
+            seq {
+                for utxoAccount in allAccounts.Where(fun acc -> acc.Currency.IsUtxo()) do
+                    match utxoAccount with
+                    | :? ReadOnlyAccount as readOnlyAccount ->
+                        let accountFile = readOnlyAccount.AccountFile
+                        if not (accountFile.Name.StartsWith BITCOIN_ADDRESS_BECH32_PREFIX) then
+                            yield readOnlyAccount
+                    | _ -> ()
+            }
+
+        let utxoPublicKeys =
+            seq {
+                for utxoReadOnlyAccount in utxoAccountsToMigrate do
+                    let accountFile = utxoReadOnlyAccount.AccountFile
+                    let utxoPublicKey = accountFile.Content()
+                    yield utxoPublicKey
+            } |> Set.ofSeq
+
+        for utxoPublicKey in utxoPublicKeys do
+            CreateReadOnlyAccounts utxoPublicKey
+
+        for utxoReadOnlyAccount in utxoAccountsToMigrate do
+            Config.RemoveReadOnlyAccount utxoReadOnlyAccount
+#endif
+
     let GetSignedTransactionDetails<'T when 'T :> IBlockchainFeeInfo>(rawTransaction: string)
                                                                      (currency: Currency)
                                                                          : ITransactionDetails =