Initial commit

gmi2html.go

@@ -0,0 +1,135 @@
+package gmi2html
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"net/url"
+	"regexp"
+	"strings"
+)
+
+// Based on https://geminiprotocol.net/docs/gemtext-specification.gmi
+
+// Gmi2html converts Gemini text to HTML with proper escaping and wraps it in a container with typography-focused CSS
+func Gmi2html(text string, title string) string {
+	content := convertGeminiContent(text)
+
+	// Handle any template errors with container
+	var buffer bytes.Buffer
+	err := containerTmpl.Execute(&buffer, struct {
+		Title   string
+		Content template.HTML
+	}{
+		Title:   title,
+		Content: template.HTML(content), // Content already properly escaped in convertGeminiContent
+	})
+	if err != nil {
+		fmt.Printf("Error executing container template: %s\n", err)
+		return ""
+	}
+
+	return buffer.String()
+}
+
+// convertGeminiContent converts Gemini text to HTML with proper escaping
+func convertGeminiContent(text string) string {
+	lines := strings.Split(text, "\n")
+	var buffer bytes.Buffer
+	normalMode := true
+
+	for _, line := range lines {
+		switch {
+		case strings.HasPrefix(line, "=>"):
+			handleLinkLine(&buffer, line)
+		case strings.HasPrefix(line, "```"):
+			normalMode = !normalMode
+			// Don't output the ``` line
+		case strings.HasPrefix(line, "###"):
+			content := strings.TrimSpace(strings.TrimPrefix(line, "###"))
+			err := h3Tmpl.Execute(&buffer, content)
+			if err != nil {
+				return ""
+			}
+		case strings.HasPrefix(line, "##"):
+			content := strings.TrimSpace(strings.TrimPrefix(line, "##"))
+			err := h2Tmpl.Execute(&buffer, content)
+			if err != nil {
+				return ""
+			}
+		case strings.HasPrefix(line, "#"):
+			content := strings.TrimSpace(strings.TrimPrefix(line, "#"))
+			err := h1Tmpl.Execute(&buffer, content)
+			if err != nil {
+				return ""
+			}
+		case strings.HasPrefix(line, "*"):
+			content := strings.TrimSpace(strings.TrimPrefix(line, "*"))
+			err := listItemTmpl.Execute(&buffer, content)
+			if err != nil {
+				return ""
+			}
+		case strings.HasPrefix(line, ">"):
+			content := strings.TrimSpace(strings.TrimPrefix(line, ">"))
+			err := blockquoteTmpl.Execute(&buffer, content)
+			if err != nil {
+				return ""
+			}
+		default:
+			if normalMode {
+				err := textLineTmpl.Execute(&buffer, line)
+				if err != nil {
+					return ""
+				}
+			} else {
+				err := preformattedTmpl.Execute(&buffer, line)
+				if err != nil {
+					return ""
+				}
+			}
+		}
+	}
+
+	return buffer.String()
+}
+
+// handleLinkLine parses and renders a link line
+func handleLinkLine(buffer *bytes.Buffer, linkLine string) {
+	url, description, err := parseGeminiLink(linkLine)
+	if err != nil {
+		fmt.Printf("Error parsing gemini link line: %s\n", err)
+		return
+	}
+
+	err = linkTmpl.Execute(buffer, struct {
+		URL, Description string
+	}{url, description})
+	if err != nil {
+		return
+	}
+}
+
+// parseGeminiLink extracts URL and description from a link line
+func parseGeminiLink(linkLine string) (string, string, error) {
+	re := regexp.MustCompile(`^=>[ \t]+(\S+)([ \t]+.*)?`)
+	matches := re.FindStringSubmatch(linkLine)
+	if len(matches) == 0 {
+		return "", "", fmt.Errorf("error parsing link line: no regexp match for line %s", linkLine)
+	}
+
+	urlStr := matches[1]
+
+	// Check: Unescape the URL if escaped
+	_, err := url.QueryUnescape(urlStr)
+	if err != nil {
+		return "", "", fmt.Errorf("error parsing link line: %w input '%s'", err, linkLine)
+	}
+
+	// Set description to URL if not provided
+	description := urlStr
+	if len(matches) > 2 && strings.TrimSpace(matches[2]) != "" {
+		description = strings.TrimSpace(matches[2])
+	}
+
+	return urlStr, description, nil
+}