docs: serve from a directory

tools/docs/docs.go

@@ -0,0 +1,181 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+
+	"github.com/Depado/bfchroma/v2"
+	bhtml "github.com/alecthomas/chroma/v2/formatters/html"
+	"github.com/alecthomas/chroma/v2/styles"
+	"github.com/russross/blackfriday/v2"
+)
+
+func writeDocs(src, out string) error {
+	b := new(bytes.Buffer)
+	err := buildDocs(b, src)
+	if err != nil {
+		return fmt.Errorf("failed building documentation %v", err)
+	}
+	return os.WriteFile(filepath.Join(out, "index.html"), b.Bytes(), 0600)
+}
+
+func buildDocs(w io.Writer, dir string) error {
+	var idx int
+	id := func() int {
+		idx++
+		return idx
+	}
+	var b bytes.Buffer
+	m := Model{
+		Domain: domain,
+		Track:  track,
+		CSS:    style,
+		JS:     script,
+		Logo:   LOGO,
+		Icon:   Icon,
+	}
+	var positions []int
+	seen := make(map[string]struct{})
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		return err
+	}
+	for _, entry := range entries {
+		if entry.IsDir() {
+			continue
+		}
+		path := filepath.Join(dir, entry.Name())
+		if filepath.Ext(path) != ".md" {
+			return nil
+		}
+		data, err := os.ReadFile(path)
+		if err != nil {
+			return err
+		}
+		b.Reset()
+		items := renderPage(&b, id, seen, data)
+		name := filepath.Base(path)
+		order, name, _ := strings.Cut(name, "-")
+		i, err := strconv.Atoi(order)
+		if err != nil {
+			return err
+		}
+		positions = append(positions, i)
+		x := Menu{
+			ID:    items[0].ID,
+			Text:  items[0].Text,
+			Items: items[1:],
+		}
+		if len(items) > 0 {
+			x.ID = items[0].ID
+		}
+		m.Menus = append(m.Menus, x)
+		m.Pages = append(m.Pages, template.HTML(b.String()))
+	}
+	x := &ms{indices: positions, m: &m}
+	sort.Sort(x)
+	return page.Execute(w, m)
+}
+
+type ms struct {
+	indices []int
+	m       *Model
+}
+
+var _ sort.Interface = (*ms)(nil)
+
+func (m *ms) Len() int {
+	return len(m.indices)
+}
+
+func (m *ms) Less(i, j int) bool {
+	return m.indices[i] < m.indices[j]
+}
+
+func (m *ms) Swap(i, j int) {
+	m.indices[i], m.indices[j] = m.indices[j], m.indices[i]
+	m.m.Menus[i], m.m.Menus[j] = m.m.Menus[j], m.m.Menus[i]
+	m.m.Pages[i], m.m.Pages[j] = m.m.Pages[j], m.m.Pages[i]
+}
+
+func renderPage(w io.Writer, id func() int, seen map[string]struct{}, text []byte) (o []Item) {
+	m := blackfriday.New(
+		blackfriday.WithExtensions(blackfriday.CommonExtensions),
+	)
+	r := &bfchroma.Renderer{
+		Base: blackfriday.NewHTMLRenderer(blackfriday.HTMLRendererParameters{
+			Flags: blackfriday.CommonHTMLFlags,
+		}),
+		Style:      styles.SolarizedLight,
+		Autodetect: true,
+	}
+	r.Formatter = bhtml.New(r.ChromaOptions...)
+	ast := m.Parse(text)
+	var inHeading bool
+	var lastNode *blackfriday.Node
+	ast.Walk(func(node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
+		if node.Type == blackfriday.Heading && !node.HeadingData.IsTitleblock {
+			inHeading = entering
+			if entering {
+				lastNode = node
+			}
+			return blackfriday.GoToNext
+		}
+		if inHeading {
+			switch lastNode.HeadingData.Level {
+			case 1, 2:
+				lastNode.HeadingData.HeadingID = toLink(id, seen, string(node.Literal))
+				o = append(o, Item{
+					ID:   lastNode.HeadingData.HeadingID,
+					Text: string(node.Literal),
+				})
+			}
+		}
+		return blackfriday.GoToNext
+	})
+
+	ast.Walk(func(node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
+		return r.RenderNode(w, node, entering)
+	})
+	return
+}
+
+func toLink(id func() int, seen map[string]struct{}, txt string) string {
+	txt = strings.Replace(txt, " ", "-", -1)
+	txt = strings.ToLower(txt)
+	_, ok := seen[txt]
+	if !ok {
+		seen[txt] = struct{}{}
+		return txt
+	}
+	return fmt.Sprintf("%d-%s", id(), txt)
+}
+
+type Item struct {
+	ID   string
+	Text string
+}
+
+type Model struct {
+	Domain string
+	Track  string
+	CSS    template.CSS
+	Logo   template.HTMLAttr
+	Icon   template.HTMLAttr
+	JS     []template.JS
+	Menus  []Menu
+	Pages  []template.HTML
+}
+
+type Menu struct {
+	ID    string
+	Text  string
+	Items []Item
+}