feat: add scim v2 service provider configuration endpoints (#9258)

# Which Problems Are Solved
* Adds support for the service provider configuration SCIM v2 endpoints

# How the Problems Are Solved
* Adds support for the service provider configuration SCIM v2 endpoints
  * `GET /scim/v2/{orgId}/ServiceProviderConfig`
  * `GET /scim/v2/{orgId}/ResourceTypes`
  * `GET /scim/v2/{orgId}/ResourceTypes/{name}`
  * `GET /scim/v2/{orgId}/Schemas`
  * `GET /scim/v2/{orgId}/Schemas/{id}`

# Additional Context
Part of #8140

Co-authored-by: Stefan Benz <46600784+stebenz@users.noreply.github.com>

internal/api/scim/schemas/schema_builder.go

@@ -0,0 +1,183 @@
+package schemas
+
+import (
+	"fmt"
+	"reflect"
+	"slices"
+	"strings"
+	"time"
+
+	"golang.org/x/text/language"
+)
+
+type SchemaBuilderArgs struct {
+	ID           ScimSchemaType
+	Name         ScimResourceTypeSingular
+	EndpointName ScimResourceTypePlural
+	Description  string
+	Resource     any
+}
+
+type fieldSchemaInfo struct {
+	Ignore    bool
+	Required  bool
+	CaseExact bool
+	Unique    bool
+}
+
+var (
+	timeType            = reflect.TypeOf(time.Time{})
+	languageTagType     = reflect.TypeOf(language.Tag{})
+	httpURLType         = reflect.TypeOf(HttpURL{})
+	writeOnlyStringType = reflect.TypeOf(WriteOnlyString(""))
+)
+
+func BuildSchema(args SchemaBuilderArgs) *ResourceSchema {
+	return &ResourceSchema{
+		Resource: &Resource{
+			Schemas: []ScimSchemaType{IdSchema},
+			ID:      string(args.ID),
+			Meta: &ResourceMeta{
+				ResourceType: SchemaResourceType,
+			},
+		},
+		ID:          args.ID,
+		Name:        args.Name,
+		PluralName:  args.EndpointName,
+		Description: args.Description,
+		Attributes:  buildSchemaAttributes(reflect.TypeOf(args.Resource)),
+	}
+}
+
+func buildSchemaAttributes(fieldType reflect.Type) []*SchemaAttribute {
+	if fieldType.Kind() == reflect.Ptr {
+		fieldType = fieldType.Elem()
+	}
+
+	if fieldType.Kind() != reflect.Struct {
+		return nil
+	}
+
+	attributes := make([]*SchemaAttribute, 0, fieldType.NumField())
+	for i := 0; i < fieldType.NumField(); i++ {
+		field := fieldType.Field(i)
+		attribute := buildAttribute(field)
+
+		if attribute != nil {
+			attributes = append(attributes, attribute)
+		}
+	}
+
+	return attributes
+}
+
+func buildAttribute(field reflect.StructField) *SchemaAttribute {
+	info := getFieldSchemaInfo(field)
+	if info.Ignore {
+		return nil
+	}
+
+	fieldType := getFieldType(field)
+	attribute := &SchemaAttribute{
+		Name:        getFieldJsonName(field),
+		Description: "For details see RFC7643",
+		Type:        getFieldAttributeType(fieldType),
+		MultiValued: isFieldMultiValued(field),
+		Required:    info.Required,
+		CaseExact:   info.CaseExact,
+		Mutability:  SchemaAttributeMutabilityReadWrite,
+		Returned:    SchemaAttributeReturnedAlways,
+		Uniqueness:  SchemaAttributeUniquenessNone,
+	}
+
+	if attribute.Type == SchemaAttributeTypeComplex {
+		attribute.SubAttributes = buildSchemaAttributes(fieldType)
+	}
+
+	if fieldType == writeOnlyStringType {
+		attribute.Returned = SchemaAttributeReturnedNever
+		attribute.Mutability = SchemaAttributeMutabilityWriteOnly
+	}
+
+	if info.Unique {
+		attribute.Uniqueness = SchemaAttributeUniquenessServer
+	}
+
+	return attribute
+}
+
+func isFieldMultiValued(field reflect.StructField) bool {
+	if field.Type.Kind() != reflect.Ptr {
+		return field.Type.Kind() == reflect.Slice
+	}
+
+	return field.Type.Elem().Kind() == reflect.Slice
+}
+
+func getFieldAttributeType(fieldType reflect.Type) SchemaAttributeType {
+	switch fieldType.Kind() { //nolint:exhaustive
+	case reflect.String:
+		return SchemaAttributeTypeString
+	case reflect.Bool:
+		return SchemaAttributeTypeBoolean
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return SchemaAttributeTypeInteger
+	case reflect.Float32, reflect.Float64:
+		return SchemaAttributeTypeDecimal
+	case reflect.Struct:
+		switch fieldType {
+		case timeType:
+			return SchemaAttributeTypeDateTime
+		case writeOnlyStringType, languageTagType, httpURLType:
+			return SchemaAttributeTypeString
+		default:
+			return SchemaAttributeTypeComplex
+		}
+	default:
+		panic(fmt.Sprintf("unsupported field type: %v", fieldType.Kind()))
+	}
+}
+
+func getFieldType(field reflect.StructField) reflect.Type {
+	fieldType := field.Type
+	if fieldType.Kind() == reflect.Ptr {
+		fieldType = fieldType.Elem()
+	}
+
+	if fieldType.Kind() == reflect.Slice || fieldType.Kind() == reflect.Array {
+		fieldType = fieldType.Elem()
+
+		if fieldType.Kind() == reflect.Ptr {
+			fieldType = fieldType.Elem()
+		}
+	}
+	return fieldType
+}
+
+func getFieldSchemaInfo(field reflect.StructField) *fieldSchemaInfo {
+	tag := field.Tag.Get("scim")
+	tagOptions := strings.Split(tag, ",")
+	return &fieldSchemaInfo{
+		Ignore:    slices.Contains(tagOptions, "ignoreInSchema"),
+		Required:  slices.Contains(tagOptions, "required"),
+		CaseExact: !slices.Contains(tagOptions, "caseInsensitive"),
+		Unique:    slices.Contains(tagOptions, "unique"),
+	}
+}
+
+func getFieldJsonName(field reflect.StructField) string {
+	jsonTag := field.Tag.Get("json")
+
+	// Skip fields explicitly excluded
+	if jsonTag == "-" {
+		return ""
+	}
+
+	// use field name as default
+	if jsonTag == "" {
+		return field.Name
+	}
+
+	// strip other options such as omitempty
+	return strings.Split(jsonTag, ",")[0]
+}