feat: add getbalance

Signed-off-by: Lorenz Herzberger <[email protected]>

README.md

@@ -2,9 +2,33 @@
 
 ## Example usage
 
-### Reissue Asset
+### GetBalance
+```golang
+package main
 
+import (
+	"fmt"
+	"log"
+
+	elementsrpc "github.com/rddl-network/elements-rpc"
+)
+
+func main() {
+	res, err := elementsrpc.GetBalance("http://user:[email protected]:18891/wallet/foowallet", []string{})
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println(res)
+}
 ```
+Output:
+```
+map[bitcoin:0]
+```
+
+### Reissue Asset
+
+```golang
 package main
 
 import (
@@ -36,7 +60,7 @@ Output:
 ### Send To Address
 
 
-```
+```golang
 package main
 
 import (
@@ -74,7 +98,7 @@ Output:
 ```
 
 ### Wallet management
-```
+```golang
 package main
 
 import (
@@ -113,7 +137,7 @@ Output:
 
 ### Complex Example
 
-```
+```golang
 package main
 
 import (

types/const.go

@@ -27,4 +27,5 @@ var (
 	MethodWalletpassphrase             = "walletpassphrase"
 	MethodListWallets                  = "listwallets"
 	MethodListReceivedByAddress        = "listreceivedbyaddress"
+	MethodGetBalance                   = "getbalance"
 )

types/wallet.go

@@ -89,3 +89,5 @@ type ListReceivedByAddressResult struct {
 
 type WalletpassphraseResult struct {
 }
+
+type GetBalanceResult map[string]float64

wallet.go

@@ -162,3 +162,15 @@ func ListReceivedByAddress(url string, params []string) (listReceivedByAddressRe
 	}
 	return
 }
+
+func GetBalance(url string, params []string) (getBalanceResult types.GetBalanceResult, err error) {
+	result, err := SendRequest(url, types.MethodGetBalance, params)
+	if err != nil {
+		return
+	}
+	err = json.Unmarshal(result, &getBalanceResult)
+	if err != nil {
+		return
+	}
+	return
+}