feat: renderer

validator/validator.go

@@ -0,0 +1,93 @@
+// Package validator provides a validator for the marka data.
+package validator
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"sync"
+
+	"git.max-richter.dev/max/marka/registry"
+	"github.com/santhosh-tekuri/jsonschema/v6"
+)
+
+var (
+	loadOnce    sync.Once
+	compiler    *jsonschema.Compiler
+	compileErr  error
+	schemaCache sync.Map
+)
+
+// ValidateSchema validates instance against the Schema.org JSON Schema named `schemaName`.
+// Examples: ValidateSchema(inst, "Recipe"), ValidateSchema(inst, "schema:Recipe").
+func ValidateSchema(instance any, schemaName string) error {
+	if err := ensureCompiler(); err != nil {
+		return err
+	}
+
+	ref := normalizeRef(schemaName)
+
+	if v, ok := schemaCache.Load(ref); ok {
+		if err := v.(*jsonschema.Schema).Validate(instance); err != nil {
+			return fmt.Errorf("validation failed: %w", err)
+		}
+		return nil
+	}
+
+	sch, err := compiler.Compile(ref)
+	if err != nil {
+		return fmt.Errorf("failed to compile schema %q: %w", ref, err)
+	}
+	schemaCache.Store(ref, sch)
+
+	if err := sch.Validate(instance); err != nil {
+		return fmt.Errorf("validation failed: %w", err)
+	}
+	return nil
+}
+
+func ensureCompiler() error {
+	loadOnce.Do(func() {
+		c := jsonschema.NewCompiler()
+
+		rawSchemas, err := registry.GetSchemas()
+		if err != nil {
+			compileErr = fmt.Errorf("read schema directory: %w", err)
+			return
+		}
+
+		for _, rawSchema := range rawSchemas {
+			js, err := jsonschema.UnmarshalJSON(bytes.NewReader(rawSchema))
+			if err != nil {
+				compileErr = err
+				return
+			}
+
+			id := extractID(rawSchema)
+			if err := c.AddResource(id, js); err != nil {
+				compileErr = fmt.Errorf("add resource %s: %w", id, err)
+				return
+			}
+		}
+
+		compiler = c
+	})
+	return compileErr
+}
+
+func extractID(raw []byte) string {
+	var tmp struct {
+		ID string `json:"$id"`
+	}
+	_ = json.Unmarshal(raw, &tmp)
+	return strings.TrimSpace(tmp.ID)
+}
+
+func normalizeRef(name string) string {
+	n := strings.TrimSpace(name)
+	if strings.HasPrefix(n, "schema:") || strings.HasPrefix(n, "http://") || strings.HasPrefix(n, "https://") {
+		return n
+	}
+	return "schema:" + n
+}