fix: decode block header fields from Core JSON

bgld.go

@@ -112,12 +112,12 @@ type BlockHeader struct {
 	Time              int64
 	Mediantime        int64
 	Nonce             uint32
-	Bits              uint32
+	Bits              string
 	Difficulty        float64
 	Chainwork         string
 	Txes              int    `json:"nTx"`
-	Previousblockhash string `json:"omitempty"`
-	Nextblockhash     string `json:"omitempty"`
+	Previousblockhash string `json:"previousblockhash,omitempty"`
+	Nextblockhash     string `json:"nextblockhash,omitempty"`
 }
 
 func (b *Bgld) GetBlockheader(blockHash string) (*BlockHeader, error) {

blockheader_json_test.go

@@ -0,0 +1,45 @@
+package bgld
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strconv"
+	"testing"
+)
+
+func TestGetBlockheaderDecodesBitgesellCoreResponse(t *testing.T) {
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintln(w, `{"result":{"hash":"0000000000000000000000000000000000000000000000000000000000000001","confirmations":2,"height":1,"version":536870912,"versionHex":"20000000","merkleroot":"4d5e6f","time":1700000000,"mediantime":1700000000,"nonce":42,"bits":"1d00ffff","difficulty":1,"chainwork":"0000000000000000000000000000000000000000000000000000000000000002","nTx":1,"previousblockhash":"0000000000000000000000000000000000000000000000000000000000000000","nextblockhash":"0000000000000000000000000000000000000000000000000000000000000002"},"error":null,"id":1}`)
+	})
+	ts := httptest.NewServer(handler)
+	defer ts.Close()
+
+	serverURL, err := url.Parse(ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	port, err := strconv.Atoi(serverURL.Port())
+	if err != nil {
+		t.Fatal(err)
+	}
+	client, err := New(serverURL.Hostname(), port, "user", "pass", false)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	header, err := client.GetBlockheader("0000000000000000000000000000000000000000000000000000000000000001")
+	if err != nil {
+		t.Fatalf("GetBlockheader returned error: %v", err)
+	}
+	if header.Bits != "1d00ffff" {
+		t.Fatalf("Bits = %q, want %q", header.Bits, "1d00ffff")
+	}
+	if header.Previousblockhash != "0000000000000000000000000000000000000000000000000000000000000000" {
+		t.Fatalf("Previousblockhash was not decoded: %q", header.Previousblockhash)
+	}
+	if header.Nextblockhash != "0000000000000000000000000000000000000000000000000000000000000002" {
+		t.Fatalf("Nextblockhash was not decoded: %q", header.Nextblockhash)
+	}
+}