feat: renderer

renderer/renderer.go

@@ -1,9 +1,78 @@
+// Package renderer provides functions for rendering Marka templates.
 package renderer
 
-func RenderFile(templatePath, jsonPath string) ([]byte, error) {
-	// TODO:
-	// 1) load aliases + template
-	// 2) validate JSON against schema (optional)
-	// 3) apply codecs to produce Markdown
-	return []byte{}, nil
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"git.max-richter.dev/max/marka/registry"
+	"git.max-richter.dev/max/marka/renderer/codec"
+	"git.max-richter.dev/max/marka/template"
+	"git.max-richter.dev/max/marka/validator"
+)
+
+const emptyBlock = "\uE000"
+
+func fixRenderedBlock(input string) string {
+	input = strings.ReplaceAll(input, "'@type':", "@type:")
+	input = strings.ReplaceAll(input, "'@context':", "@context:")
+	if len(input) == 0 {
+		return emptyBlock
+	}
+	return input
+}
+
+func RenderFile(rawJSON []byte) ([]byte, error) {
+	// 1) parse json
+	var data map[string]any
+	if err := json.Unmarshal(rawJSON, &data); err != nil {
+		return nil, fmt.Errorf("failed to parse JSON: %w", err)
+	}
+
+	// 2) extract type from "@type" Property
+	contentType, ok := data["@type"].(string)
+	if !ok || contentType == "" {
+		return nil, fmt.Errorf("JSON does not contain a valid '@type' property")
+	}
+
+	// 3) get the template from the registry
+	templateContent, err := registry.GetTemplate(contentType)
+	if err != nil {
+		return nil, fmt.Errorf("could not get template for type '%s': %w", contentType, err)
+	}
+
+	// 4) parse the template with the template package
+	compiledTemplate, err := template.CompileTemplate(templateContent)
+	if err != nil {
+		return nil, fmt.Errorf("failed to compile template for type '%s': %w", contentType, err)
+	}
+
+	// 5) validate JSON against schema
+	if schemaName, ok := data["@schema"].(string); ok {
+		if validationErr := validator.ValidateSchema(data, schemaName); validationErr != nil {
+			return nil, fmt.Errorf("failed to validate schema: %w", validationErr)
+		}
+	}
+
+	// 6) render the template with the blocks
+	var buffer bytes.Buffer
+	for _, block := range compiledTemplate {
+		renderedContent, err := codec.RenderBlock(block, data)
+		if err != nil {
+			return nil, fmt.Errorf("failed to render block for path '%s': %w", block.Path, err)
+		}
+		renderedContent = fixRenderedBlock(renderedContent)
+		buffer.WriteString(renderedContent)
+	}
+
+	outputString := buffer.String()
+	outputString = strings.ReplaceAll(outputString, "\n\n"+emptyBlock+"\n\n", "\n\n")
+	outputString = strings.ReplaceAll(outputString, emptyBlock, "")
+	if !strings.HasSuffix(outputString, "\n") {
+		outputString += "\n"
+	}
+
+	return []byte(outputString), nil
 }