feat: bootstrap foundation application

apps/server/internal/markdown/renderer.go

@@ -0,0 +1,168 @@
+package markdown
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"regexp"
+	"slices"
+	"strings"
+
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/extension"
+	"github.com/yuin/goldmark/parser"
+	"github.com/yuin/goldmark/renderer/html"
+)
+
+var (
+	tagPattern = regexp.MustCompile(`(^|[\s(])#([a-zA-Z0-9_-]+)\b`)
+)
+
+type Result struct {
+	HTML  template.HTML
+	Title string
+	Tags  []string
+}
+
+type Renderer struct {
+	markdown goldmark.Markdown
+}
+
+func NewRenderer() *Renderer {
+	return &Renderer{
+		markdown: goldmark.New(
+			goldmark.WithExtensions(
+				extension.GFM,
+				extension.Footnote,
+				extension.DefinitionList,
+				extension.Table,
+				extension.Strikethrough,
+				extension.TaskList,
+				extension.Typographer,
+			),
+			goldmark.WithParserOptions(
+				parser.WithAutoHeadingID(),
+			),
+			goldmark.WithRendererOptions(
+				html.WithHardWraps(),
+				html.WithXHTML(),
+			),
+		),
+	}
+}
+
+func (r *Renderer) Render(content []byte) (Result, error) {
+	title := extractTitle(string(content))
+	tags := extractTags(string(content))
+	prepared := preprocess(string(content))
+
+	var output bytes.Buffer
+	if err := r.markdown.Convert([]byte(prepared), &output); err != nil {
+		return Result{}, fmt.Errorf("render markdown: %w", err)
+	}
+
+	return Result{
+		HTML:  template.HTML(output.String()),
+		Title: title,
+		Tags:  tags,
+	}, nil
+}
+
+func preprocess(input string) string {
+	lines := strings.Split(input, "\n")
+	for index, line := range lines {
+		line = rewriteWikiLinks(line)
+		line = normalizeAdmonition(line)
+		lines[index] = line
+	}
+	return strings.Join(lines, "\n")
+}
+
+func rewriteWikiLinks(line string) string {
+	var builder strings.Builder
+	remaining := line
+
+	for {
+		start := strings.Index(remaining, "[[")
+		if start == -1 {
+			builder.WriteString(remaining)
+			return builder.String()
+		}
+
+		end := strings.Index(remaining[start+2:], "]]")
+		if end == -1 {
+			builder.WriteString(remaining)
+			return builder.String()
+		}
+
+		builder.WriteString(remaining[:start])
+		label := strings.TrimSpace(remaining[start+2 : start+2+end])
+		if label == "" {
+			builder.WriteString(remaining[start : start+2+end+2])
+		} else {
+			builder.WriteString(fmt.Sprintf("[%s](/docs/%s)", label, slugify(label)))
+		}
+
+		remaining = remaining[start+2+end+2:]
+	}
+}
+
+func normalizeAdmonition(line string) string {
+	switch {
+	case strings.HasPrefix(line, "> [!NOTE]"):
+		return strings.Replace(line, "> [!NOTE]", "> **Note:**", 1)
+	case strings.HasPrefix(line, "> [!TIP]"):
+		return strings.Replace(line, "> [!TIP]", "> **Tip:**", 1)
+	case strings.HasPrefix(line, "> [!WARNING]"):
+		return strings.Replace(line, "> [!WARNING]", "> **Warning:**", 1)
+	default:
+		return line
+	}
+}
+
+func extractTitle(content string) string {
+	for _, line := range strings.Split(content, "\n") {
+		if strings.HasPrefix(line, "# ") {
+			return strings.TrimSpace(strings.TrimPrefix(line, "# "))
+		}
+	}
+	return "Untitled"
+}
+
+func extractTags(content string) []string {
+	matches := tagPattern.FindAllStringSubmatch(content, -1)
+	tags := make([]string, 0, len(matches))
+	seen := make(map[string]struct{}, len(matches))
+	for _, match := range matches {
+		if len(match) < 3 {
+			continue
+		}
+		tag := match[2]
+		if _, exists := seen[tag]; exists {
+			continue
+		}
+		seen[tag] = struct{}{}
+		tags = append(tags, tag)
+	}
+	slices.Sort(tags)
+	return tags
+}
+
+func slugify(value string) string {
+	value = strings.ToLower(strings.TrimSpace(value))
+	var builder strings.Builder
+	lastDash := false
+	for _, r := range value {
+		switch {
+		case r >= 'a' && r <= 'z', r >= '0' && r <= '9':
+			builder.WriteRune(r)
+			lastDash = false
+		default:
+			if !lastDash {
+				builder.WriteByte('-')
+				lastDash = true
+			}
+		}
+	}
+	return strings.Trim(builder.String(), "-")
+}