Internet computer ledger utility supporting 2 step transfer (separate sign and send)

ledger.did

type ICPTs = record {
     e8s : nat64;
};

type Duration = record {
    secs: nat64;
    nanos: nat32;
};

type TimeStamp = record {
    timestamp_nanos: nat64;
};

type ArchiveOptions = record {
    node_max_memory_size_bytes: opt nat32;
    max_message_size_bytes: opt nat32;
    controller_id: principal;
};

type BlockHeight = nat64;
type Memo = nat64;
type AccountIdentifier = text;
type SubAccount = vec nat8;

type Transfer = variant {
    Burn: record {
        from: AccountIdentifier;
        amount: ICPTs;
    };
    Mint: record {
        to: AccountIdentifier;
        amount: ICPTs;
    };
    Send: record {
        from: AccountIdentifier;
        to: AccountIdentifier;
        amount: ICPTs;
    };
};

type Transaction = record {
    transfer: Transfer;
    memo: Memo;
    created_at: BlockHeight;
};

type SendArgs = record {
    memo: Memo;
    amount: ICPTs;
    fee: ICPTs;
    from_subaccount: opt SubAccount;
    to: AccountIdentifier;
    created_at_time: opt TimeStamp;
};

type NotifyCanisterArgs = record {
    block_height: BlockHeight;
    max_fee: ICPTs;
    from_subaccount: opt SubAccount;
    to_canister: principal;
    to_subaccount: opt SubAccount;
};

type AccountBalanceArgs = record {
    account: AccountIdentifier;
};

type LedgerCanisterInitPayload = record {
    minting_account: AccountIdentifier;
    initial_values: vec record {AccountIdentifier; ICPTs};
    max_message_size_bytes: opt nat32;
    transaction_window: opt Duration;
    archive_options: opt ArchiveOptions;
    send_whitelist: vec record {principal};
}

service: (LedgerCanisterInitPayload) -> {
  send_dfx : (SendArgs) -> (BlockHeight);
  notify_dfx: (NotifyCanisterArgs) -> ();
  account_balance_dfx : (AccountBalanceArgs) -> (ICPTs) query;
}

ledger.sh

set -euo pipefail
USAGE="$0 [balance|transfer|sign|send] ...

Sub-command:
    balance <account_id>
    transfer <amount> <account_id>
    sign <amount> <account_id> <output_file>
    send <file>
    
Note that amount must be specified as ICP in decimal, not e8s.
"

FEE=${FEE:-0.0001}
DFX="dfx canister --no-wallet --network=ic"
DFX_VERSION=$(dfx --version | sed -e 's/dfx //')
test -n "$DFX_VERSION" || (echo "Unable to get dfx version number." && exit 1)
test -f "${LEDGER_DID:-}" || (echo "Cannot find ledger.did. Please specify it in the environment variable LEDGER_DID." && exit 1)

prepare() {
    PROJ_DIR=$(mktemp -td dfx-transfer-XXXXXXXX)
    test -d "$PROJ_DIR" || exit 1
    cp "$LEDGER_DID" "$PROJ_DIR/ledger.did" || exit 1

    cat >"$PROJ_DIR/dfx.json" <<END
{
  "version": 1,
  "dfx": "$DFX_VERSION",
  "canisters": {
    "ledger":{ "build": "", "wasm": "", "type": "custom", "candid": "leger.did" }
  },
  "defaults": { "build": { "packtool": "" } },
  "networks": {}
}
END
    cat >"$PROJ_DIR/canister_ids.json" <<END
{ "ledger": { "ic": "ryjl3-tyaaa-aaaaa-aaaba-cai" } }
END

    pushd "$PROJ_DIR"
}

cleanup() {
    popd
    rm -rf "$PROJ_DIR"
}

get_balance() {
    prepare
    local account=${1:-$(dfx ledger account-id)}
    local result=$($DFX call ledger account_balance_dfx --type idl "(record { account = \"$account\" })")
    local balance=$(echo "$result"| sed -e 's/.*= \([^ ]*\).*/\1/' -e 's/_//g')
    printf "%08d" "$balance" | sed -e 's/\(.*\)\(........\)$/\1.\2/'
}

transfer_args() {
    local amount=$(printf "%.8f" "$1" | sed -e 's/\.//')
    local fee=$(printf "%.8f" "$FEE" | sed -e 's/\.//')
    local account=$2
    echo "(record {
          memo = 0 : nat64;
          amount = record { e8s = $amount : nat64 };
          fee = record { e8s = $fee : nat64 };
          to = \"$account\";
          created_at_time = record { timestamp_nanos = $(date +%s)000000000 : nat64 }
        })"
}

transfer_balance() {
    local args=$(transfer_args "$1" "$2")
    prepare
    $DFX call ledger send_dfx --type idl "$args"
    cleanup
}

sign_transfer() {
    local args=$(transfer_args "$1" "$2")
    local outfile="$(realpath $3)"
    prepare
    $DFX sign ledger send_dfx --file "$outfile" --type idl "$args"
    cleanup
}

send_transfer() {
    local infile="$(realpath $1)"
    prepare
    local request_id=$($DFX send "$infile")
    echo
    echo "Request ID: $request_id"
    # Cannot do the following because signer needs to sign rqeuest-status on AG setup first.
    # $DFX request-status "$request_id" ledger
    cleanup
}

case "${1:-}" in
"balance") get_balance "${2:-}" ;;
"transfer")
    test "$#" -eq "3" || (echo "$USAGE" && exit 1)
    transfer_balance "$2" "$3"
    ;;
"sign")
    test "$#" -eq "4" || (echo "$USAGE" && exit 1)
    sign_transfer "$2" "$3" "$4"
    ;;
"send")
    test "$#" -eq "2" || (echo "$USAGE" && exit 1)
    send_transfer "$2"
    ;;
*) echo "$USAGE" ;;
esac