Initial commit

1 files changed, 43 insertions, 0 deletions

diff --git a/internal/cms/markdown.go b/internal/cms/markdown.go
new file mode 100644
index 0000000..49149b8
--- /dev/null
+++ b/internal/cms/markdown.go
@@ -0,0 +1,43 @@
+package cms
+
+import (
+	"regexp"
+	"strings"
+)
+
+var (
+	standaloneMarkdownLink = regexp.MustCompile(`^\s*\[([^\]]+)\]\(([^)]+)\)\s*$`)
+	inlineMarkdownLink     = regexp.MustCompile(`\[([^\]]+)\]\(([^)]+)\)`)
+)
+
+func markdownToGemtext(body string) string {
+	var out []string
+	inFence := false
+
+	for _, line := range strings.Split(strings.ReplaceAll(body, "\r\n", "\n"), "\n") {
+		trimmed := strings.TrimSpace(line)
+		if strings.HasPrefix(trimmed, "```") {
+			inFence = !inFence
+			out = append(out, line)
+			continue
+		}
+		if inFence {
+			out = append(out, line)
+			continue
+		}
+		if match := standaloneMarkdownLink.FindStringSubmatch(line); match != nil {
+			out = append(out, "=> "+match[2]+" "+match[1])
+			continue
+		}
+		if strings.HasPrefix(trimmed, "- ") {
+			indent := line[:strings.Index(line, "-")]
+			line = indent + "* " + strings.TrimPrefix(trimmed, "- ")
+		}
+		line = inlineMarkdownLink.ReplaceAllString(line, "$1 ($2)")
+		line = strings.ReplaceAll(line, "**", "")
+		line = strings.ReplaceAll(line, "__", "")
+		out = append(out, line)
+	}
+
+	return strings.TrimRight(strings.Join(out, "\n"), "\n") + "\n"
+}