initial commit

pkg/reflectutil/structpopulate.go

@@ -0,0 +1,196 @@
+package reflectutil
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+// ValueGetter wraps a map[string]any and implements ValueGetter
+type ValueGetter map[string]any
+
+// Get retrieves a value from the map by key
+func (m ValueGetter) Get(key string) (any, bool) {
+	v, ok := m[key]
+	return v, ok
+}
+
+// GetFloat64 retrieves a float64 value from the map by key
+func (m ValueGetter) GetFloat64(key string) (float64, bool) {
+	v, ok := m.Get(key)
+	if !ok {
+		return 0, false
+	}
+
+	switch val := v.(type) {
+	case float64:
+		return val, true
+	case float32:
+		return float64(val), true
+	case int:
+		return float64(val), true
+	case int64:
+		return float64(val), true
+	case int32:
+		return float64(val), true
+	default:
+		return 0, false
+	}
+}
+
+// GetInt retrieves an int value from the map by key
+func (m ValueGetter) GetInt(key string) (int, bool) {
+	v, ok := m.Get(key)
+	if !ok {
+		return 0, false
+	}
+
+	switch val := v.(type) {
+	case int:
+		return val, true
+	case int64:
+		return int(val), true
+	case int32:
+		return int(val), true
+	case float64:
+		return int(val), true
+	case float32:
+		return int(val), true
+	default:
+		return 0, false
+	}
+}
+
+// GetString retrieves a string value from the map by key
+func (m ValueGetter) GetString(key string) (string, bool) {
+	v, ok := m.Get(key)
+	if !ok {
+		return "", false
+	}
+
+	switch val := v.(type) {
+	case string:
+		return val, true
+	default:
+		return "", false
+	}
+}
+
+// GetJSONTagName extracts the JSON tag name from a struct field
+func GetJSONTagName(field reflect.StructField) string {
+	tag := field.Tag.Get("json")
+	if tag == "" || tag == "-" {
+		return ""
+	}
+	// Handle cases like `json:"name,omitempty"` - take only the first part
+	if idx := strings.Index(tag, ","); idx != -1 {
+		tag = tag[:idx]
+	}
+	return tag
+}
+
+// getFloat64FromAny converts an any value to float64
+func getFloat64FromAny(v any) (float64, bool) {
+	switch val := v.(type) {
+	case float64:
+		return val, true
+	case float32:
+		return float64(val), true
+	case int:
+		return float64(val), true
+	case int64:
+		return float64(val), true
+	case int32:
+		return float64(val), true
+	default:
+		return 0, false
+	}
+}
+
+// getIntFromAny converts an any value to int
+func getIntFromAny(v any) (int, bool) {
+	switch val := v.(type) {
+	case int:
+		return val, true
+	case int64:
+		return int(val), true
+	case int32:
+		return int(val), true
+	case float64:
+		return int(val), true
+	case float32:
+		return int(val), true
+	default:
+		return 0, false
+	}
+}
+
+// getStringFromAny converts an any value to string
+func getStringFromAny(v any) (string, bool) {
+	switch val := v.(type) {
+	case string:
+		return val, true
+	default:
+		return "", false
+	}
+}
+
+// PopulateStructFromMap populates a struct from a map[string]any using reflection
+// The target must be a pointer to a struct
+func PopulateStructFromMap(m map[string]any, target interface{}) error {
+	v := reflect.ValueOf(target)
+	if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
+		return fmt.Errorf("target must be a pointer to a struct")
+	}
+
+	v = v.Elem()
+	t := v.Type()
+
+	for i := 0; i < v.NumField(); i++ {
+		field := v.Field(i)
+		fieldType := t.Field(i)
+
+		if !field.CanSet() {
+			continue
+		}
+
+		jsonTag := GetJSONTagName(fieldType)
+		if jsonTag == "" {
+			continue
+		}
+
+		mapVal, ok := m[jsonTag]
+		if !ok {
+			return fmt.Errorf("%s not found in map", jsonTag)
+		}
+
+		fieldKind := field.Kind()
+		switch fieldKind {
+		case reflect.Float64:
+			val, ok := getFloat64FromAny(mapVal)
+			if !ok {
+				return fmt.Errorf("cannot convert %s to float64 for field %s", reflect.TypeOf(mapVal), jsonTag)
+			}
+			field.SetFloat(val)
+
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			val, ok := getIntFromAny(mapVal)
+			if !ok {
+				return fmt.Errorf("cannot convert %s to int for field %s", reflect.TypeOf(mapVal), jsonTag)
+			}
+			field.SetInt(int64(val))
+
+		case reflect.String:
+			val, ok := getStringFromAny(mapVal)
+			if !ok {
+				return fmt.Errorf("cannot convert %s to string for field %s", reflect.TypeOf(mapVal), jsonTag)
+			}
+			field.SetString(val)
+
+		default:
+			return fmt.Errorf("unsupported field type %s for field %s", fieldKind, jsonTag)
+		}
+	}
+
+	return nil
+}