Separate code/README rendering and unsafe to their own packages

3 files changed, 87 insertions, 0 deletions

diff --git a/render/chroma.go b/render/chroma.go
new file mode 100644
index 0000000..c7d64ec
--- /dev/null
+++ b/render/chroma.go
@@ -0,0 +1,35 @@
+package render
+
+import (
+	"bytes"
+	"html/template"
+
+	chromaHTML "github.com/alecthomas/chroma/v2/formatters/html"
+	chromaLexers "github.com/alecthomas/chroma/v2/lexers"
+	chromaStyles "github.com/alecthomas/chroma/v2/styles"
+)
+
+func Highlight(filename, content string) template.HTML {
+	lexer := chromaLexers.Match(filename)
+	if lexer == nil {
+		lexer = chromaLexers.Fallback
+	}
+
+	iterator, err := lexer.Tokenise(nil, content)
+	if err != nil {
+		return template.HTML("<pre>Error tokenizing file: " + err.Error() + "</pre>") //#nosec G203`
+	}
+
+	var buf bytes.Buffer
+	style := chromaStyles.Get("autumn")
+	formatter := chromaHTML.New(
+		chromaHTML.WithClasses(true),
+		chromaHTML.TabWidth(8),
+	)
+
+	if err := formatter.Format(&buf, style, iterator); err != nil {
+		return template.HTML("<pre>Error formatting file: " + err.Error() + "</pre>") //#nosec G203
+	}
+
+	return template.HTML(buf.Bytes()) //#nosec G203
+}
diff --git a/render/escape.go b/render/escape.go
new file mode 100644
index 0000000..44c56f3
--- /dev/null
+++ b/render/escape.go
@@ -0,0 +1,11 @@
+package render
+
+import (
+	"html"
+	"html/template"
+)
+
+// EscapeHTML just escapes a string and wraps it in [template.HTML].
+func EscapeHTML(s string) template.HTML {
+	return template.HTML(html.EscapeString(s)) //#nosec G203
+}
diff --git a/render/readme.go b/render/readme.go
new file mode 100644
index 0000000..1a153fb
--- /dev/null
+++ b/render/readme.go
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+
+package render
+
+import (
+	"bytes"
+	"html"
+	"html/template"
+	"strings"
+
+	"github.com/microcosm-cc/bluemonday"
+	"github.com/niklasfasching/go-org/org"
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/extension"
+	"go.lindenii.runxiyu.org/forge/misc"
+)
+
+var markdownConverter = goldmark.New(goldmark.WithExtensions(extension.GFM))
+
+// renderReadme renders and sanitizes README content from a byte slice and filename.
+func Readme(data []byte, filename string) (string, template.HTML) {
+	switch strings.ToLower(filename) {
+	case "readme":
+		return "README", template.HTML("<pre>" + html.EscapeString(misc.BytesToString(data)) + "</pre>") //#nosec G203
+	case "readme.md":
+		var buf bytes.Buffer
+		if err := markdownConverter.Convert(data, &buf); err != nil {
+			return "Error fetching README", EscapeHTML("Unable to render README: " + err.Error())
+		}
+		return "README.md", template.HTML(bluemonday.UGCPolicy().SanitizeBytes(buf.Bytes())) //#nosec G203
+	case "readme.org":
+		htmlStr, err := org.New().Parse(strings.NewReader(misc.BytesToString(data)), filename).Write(org.NewHTMLWriter())
+		if err != nil {
+			return "Error fetching README", EscapeHTML("Unable to render README: " + err.Error())
+		}
+		return "README.org", template.HTML(bluemonday.UGCPolicy().Sanitize(htmlStr)) //#nosec G203
+	default:
+		return filename, template.HTML("<pre>" + html.EscapeString(misc.BytesToString(data)) + "</pre>") //#nosec G203
+	}
+}