Implement basic, JSON, and JSON Schema validation

internal/validate/standard_validator.go

@@ -0,0 +1,127 @@
+package validate
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/scriptorium/internal/domain"
+	"github.com/santhosh-tekuri/jsonschema/v6"
+)
+
+// StandardValidator provides basic, JSON, and JSON Schema output validation.
+type StandardValidator struct {
+	schemaBaseDir string
+}
+
+func NewStandardValidator(schemaBaseDir string) Validator {
+	return &StandardValidator{schemaBaseDir: schemaBaseDir}
+}
+
+func (v *StandardValidator) Validate(ctx context.Context, artifact *domain.Artifact, contract domain.OutputContract) (domain.ValidationResult, error) {
+	select {
+	case <-ctx.Done():
+		return domain.ValidationResult{}, ctx.Err()
+	default:
+	}
+
+	res := domain.ValidationResult{
+		Mode:           contract.ValidationMode,
+		SchemaPath:     contract.SchemaPath,
+		RepairAttempts: contract.RepairAttempts,
+	}
+
+	if artifact == nil {
+		return domain.ValidationResult{}, errors.New("artifact is required for validation")
+	}
+
+	switch contract.ValidationMode {
+	case domain.ValidationNone:
+		res.Status = domain.ValidationSkipped
+		res.IsValid = true
+		return res, nil
+	case domain.ValidationBasic:
+		if strings.TrimSpace(string(artifact.Body)) == "" {
+			res.Status = domain.ValidationFailed
+			res.IsValid = false
+			res.Errors = []string{"output is empty"}
+			return res, nil
+		}
+		res.Status = domain.ValidationPassed
+		res.IsValid = true
+		return res, nil
+	case domain.ValidationJSON:
+		_, jsonErr := parseJSON(artifact.Body)
+		if jsonErr != nil {
+			res.Status = domain.ValidationFailed
+			res.IsValid = false
+			res.Errors = []string{fmt.Sprintf("invalid JSON: %v", jsonErr)}
+			return res, nil
+		}
+		res.Status = domain.ValidationPassed
+		res.IsValid = true
+		return res, nil
+	case domain.ValidationJSONSchema:
+		instance, jsonErr := parseJSON(artifact.Body)
+		if jsonErr != nil {
+			res.Status = domain.ValidationFailed
+			res.IsValid = false
+			res.Errors = []string{fmt.Sprintf("invalid JSON: %v", jsonErr)}
+			return res, nil
+		}
+
+		schemaPath, err := v.resolveSchemaPath(contract.SchemaPath)
+		if err != nil {
+			return domain.ValidationResult{}, err
+		}
+
+		compiler := jsonschema.NewCompiler()
+		schema, err := compiler.Compile(schemaPath)
+		if err != nil {
+			return domain.ValidationResult{}, fmt.Errorf("failed to compile JSON schema %q: %w", schemaPath, err)
+		}
+
+		if err := schema.Validate(instance); err != nil {
+			res.Status = domain.ValidationFailed
+			res.IsValid = false
+			res.Errors = []string{fmt.Sprintf("json schema validation failed: %v", err)}
+			return res, nil
+		}
+
+		res.Status = domain.ValidationPassed
+		res.IsValid = true
+		return res, nil
+	default:
+		return domain.ValidationResult{}, fmt.Errorf("unsupported validation mode: %q", contract.ValidationMode)
+	}
+}
+
+func parseJSON(body []byte) (any, error) {
+	var v any
+	if err := json.Unmarshal(body, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+func (v *StandardValidator) resolveSchemaPath(schemaPath string) (string, error) {
+	if strings.TrimSpace(schemaPath) == "" {
+		return "", errors.New("schema path is required for json_schema validation")
+	}
+
+	resolved := schemaPath
+	if !filepath.IsAbs(schemaPath) {
+		resolved = filepath.Join(v.schemaBaseDir, schemaPath)
+	}
+
+	resolved = filepath.Clean(resolved)
+	if _, err := os.Stat(resolved); err != nil {
+		return "", fmt.Errorf("failed to access schema file %q: %w", resolved, err)
+	}
+
+	return resolved, nil
+}