fix(client.go): correctly fetch build number info

The endpoint listed for build number data is currently broken and never updates. Using this
workaround should allow the tool to check for build number changes so it can update the cache, but
also when the endpoint is no longer broken, be easily removed.

client.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -93,10 +94,48 @@ func (client *APIClient) fetchAndDecode(endpoint string, targetType interface{})
 	return nil
 }
 
+func fetchBuildNumberData(url string) (string, error) {
+	resp, err := http.Get(url)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	return string(body), nil
+}
+
+func parseBuildNumber(data string) (int, error) {
+	if len(data) == 0 {
+		return 0, errors.New("Cannot parse empty build number data")
+	}
+	parts := strings.Split(data, " ")
+	if len(parts) == 0 {
+		return 0, errors.New("No build number data available")
+	}
+
+	firstNum, err := strconv.Atoi(parts[0])
+	if err != nil {
+		return 0, err
+	}
+	return firstNum, nil
+}
+
 func (client *APIClient) FetchBuildNumber() (Metadata, error) {
-	endpoint := "/build"
 	var metadata Metadata
-	err := client.fetchAndDecode(endpoint, &metadata)
+	buildNumberData, err := fetchBuildNumberData("http://assetcdn.101.arenanetworks.com/latest/101")
+	if err != nil {
+		return metadata, err
+	}
+	newBuild, err := parseBuildNumber(buildNumberData)
+	if err != nil {
+		return metadata, err
+	}
+	metadata.BuildNumber = newBuild
 	return metadata, err
 }
 

client_test.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestParseBuildNumber(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected int
+		err      error
+	}{
+		{"Valid input is parsed with no errors", "10", 10, nil},
+		{"Empty input data returns zero and an error", "", 0, errors.New("Cannot parse empty build number data")},
+		{"Invalid input returns zero and an error", "abc", 0, errors.New("strconv.Atoi: parsing \"abc\": invalid syntax")},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result, err := parseBuildNumber(tt.input)
+			if result != tt.expected {
+				t.Errorf("Expected %d, but got %d", tt.expected, result)
+			}
+			if err != nil && err.Error() != tt.err.Error() {
+				t.Errorf("Expected error %v, but got %v", tt.err, err)
+			}
+		})
+	}
+}