Automatically render wiki TOC (#19873)

Automatically add sidebar in the wiki view containing a TOC for the wiki page.
Make the TOC collapsable

Signed-off-by: Andrew Thornton <art27@cantab.net>

8 files changed, 146 insertions, 50 deletions

diff --git a/modules/markup/markdown/goldmark.go b/modules/markup/markdown/goldmark.go
index 9b6cd3aaef..1750128dec 100644
--- a/modules/markup/markdown/goldmark.go
+++ b/modules/markup/markdown/goldmark.go
@@ -27,13 +27,6 @@ import (
 
 var byteMailto = []byte("mailto:")
 
-// Header holds the data about a header.
-type Header struct {
-	Level int
-	Text  string
-	ID    string
-}
-
 // ASTTransformer is a default transformer of the goldmark tree.
 type ASTTransformer struct{}
 
@@ -42,12 +35,13 @@ func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc pa
 	metaData := meta.GetItems(pc)
 	firstChild := node.FirstChild()
 	createTOC := false
-	toc := []Header{}
+	ctx := pc.Get(renderContextKey).(*markup.RenderContext)
 	rc := &RenderConfig{
 		Meta: "table",
 		Icon: "table",
 		Lang: "",
 	}
+
 	if metaData != nil {
 		rc.ToRenderConfig(metaData)
 
@@ -56,7 +50,7 @@ func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc pa
 			node.InsertBefore(node, firstChild, metaNode)
 		}
 		createTOC = rc.TOC
-		toc = make([]Header, 0, 100)
+		ctx.TableOfContents = make([]markup.Header, 0, 100)
 	}
 
 	_ = ast.Walk(node, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
@@ -66,23 +60,20 @@ func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc pa
 
 		switch v := n.(type) {
 		case *ast.Heading:
-			if createTOC {
-				text := n.Text(reader.Source())
-				header := Header{
-					Text:  util.BytesToReadOnlyString(text),
-					Level: v.Level,
-				}
-				if id, found := v.AttributeString("id"); found {
-					header.ID = util.BytesToReadOnlyString(id.([]byte))
-				}
-				toc = append(toc, header)
-			} else {
-				for _, attr := range v.Attributes() {
-					if _, ok := attr.Value.([]byte); !ok {
-						v.SetAttribute(attr.Name, []byte(fmt.Sprintf("%v", attr.Value)))
-					}
+			for _, attr := range v.Attributes() {
+				if _, ok := attr.Value.([]byte); !ok {
+					v.SetAttribute(attr.Name, []byte(fmt.Sprintf("%v", attr.Value)))
 				}
 			}
+			text := n.Text(reader.Source())
+			header := markup.Header{
+				Text:  util.BytesToReadOnlyString(text),
+				Level: v.Level,
+			}
+			if id, found := v.AttributeString("id"); found {
+				header.ID = util.BytesToReadOnlyString(id.([]byte))
+			}
+			ctx.TableOfContents = append(ctx.TableOfContents, header)
 		case *ast.Image:
 			// Images need two things:
 			//
@@ -199,12 +190,12 @@ func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc pa
 		return ast.WalkContinue, nil
 	})
 
-	if createTOC && len(toc) > 0 {
+	if createTOC && len(ctx.TableOfContents) > 0 {
 		lang := rc.Lang
 		if len(lang) == 0 {
 			lang = setting.Langs[0]
 		}
-		tocNode := createTOCNode(toc, lang)
+		tocNode := createTOCNode(ctx.TableOfContents, lang)
 		if tocNode != nil {
 			node.InsertBefore(node, firstChild, tocNode)
 		}
diff --git a/modules/markup/markdown/markdown.go b/modules/markup/markdown/markdown.go
index 320c2f7f82..7ebdfea6c4 100644
--- a/modules/markup/markdown/markdown.go
+++ b/modules/markup/markdown/markdown.go
@@ -34,9 +34,10 @@ var (
 )
 
 var (
-	urlPrefixKey   = parser.NewContextKey()
-	isWikiKey      = parser.NewContextKey()
-	renderMetasKey = parser.NewContextKey()
+	urlPrefixKey     = parser.NewContextKey()
+	isWikiKey        = parser.NewContextKey()
+	renderMetasKey   = parser.NewContextKey()
+	renderContextKey = parser.NewContextKey()
 )
 
 type limitWriter struct {
@@ -67,6 +68,7 @@ func newParserContext(ctx *markup.RenderContext) parser.Context {
 	pc.Set(urlPrefixKey, ctx.URLPrefix)
 	pc.Set(isWikiKey, ctx.IsWiki)
 	pc.Set(renderMetasKey, ctx.Metas)
+	pc.Set(renderContextKey, ctx)
 	return pc
 }
 
diff --git a/modules/markup/markdown/toc.go b/modules/markup/markdown/toc.go
index 9d11b771f7..fec45103e5 100644
--- a/modules/markup/markdown/toc.go
+++ b/modules/markup/markdown/toc.go
@@ -8,12 +8,13 @@ import (
 	"fmt"
 	"net/url"
 
+	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/translation/i18n"
 
 	"github.com/yuin/goldmark/ast"
 )
 
-func createTOCNode(toc []Header, lang string) ast.Node {
+func createTOCNode(toc []markup.Header, lang string) ast.Node {
 	details := NewDetails()
 	summary := NewSummary()
 
diff --git a/modules/markup/renderer.go b/modules/markup/renderer.go
index cf8b9bace7..53ecbfce2b 100644
--- a/modules/markup/renderer.go
+++ b/modules/markup/renderer.go
@@ -33,18 +33,26 @@ func Init() {
 	}
 }
 
+// Header holds the data about a header.
+type Header struct {
+	Level int
+	Text  string
+	ID    string
+}
+
 // RenderContext represents a render context
 type RenderContext struct {
-	Ctx           context.Context
-	Filename      string
-	Type          string
-	IsWiki        bool
-	URLPrefix     string
-	Metas         map[string]string
-	DefaultLink   string
-	GitRepo       *git.Repository
-	ShaExistCache map[string]bool
-	cancelFn      func()
+	Ctx             context.Context
+	Filename        string
+	Type            string
+	IsWiki          bool
+	URLPrefix       string
+	Metas           map[string]string
+	DefaultLink     string
+	GitRepo         *git.Repository
+	ShaExistCache   map[string]bool
+	cancelFn        func()
+	TableOfContents []Header
 }
 
 // Cancel runs any cleanup functions that have been registered for this Ctx
diff --git a/modules/templates/helper.go b/modules/templates/helper.go
index cc0fed7442..ef7b70c09f 100644
--- a/modules/templates/helper.go
+++ b/modules/templates/helper.go
@@ -18,6 +18,7 @@ import (
 	"reflect"
 	"regexp"
 	"runtime"
+	"strconv"
 	"strings"
 	texttmpl "text/template"
 	"time"
@@ -390,6 +391,66 @@ func NewFuncMap() []template.FuncMap {
 		"Join":        strings.Join,
 		"QueryEscape": url.QueryEscape,
 		"DotEscape":   DotEscape,
+		"Iterate": func(arg interface{}) (items []uint64) {
+			count := uint64(0)
+			switch val := arg.(type) {
+			case uint64:
+				count = val
+			case *uint64:
+				count = *val
+			case int64:
+				if val < 0 {
+					val = 0
+				}
+				count = uint64(val)
+			case *int64:
+				if *val < 0 {
+					*val = 0
+				}
+				count = uint64(*val)
+			case int:
+				if val < 0 {
+					val = 0
+				}
+				count = uint64(val)
+			case *int:
+				if *val < 0 {
+					*val = 0
+				}
+				count = uint64(*val)
+			case uint:
+				count = uint64(val)
+			case *uint:
+				count = uint64(*val)
+			case int32:
+				if val < 0 {
+					val = 0
+				}
+				count = uint64(val)
+			case *int32:
+				if *val < 0 {
+					*val = 0
+				}
+				count = uint64(*val)
+			case uint32:
+				count = uint64(val)
+			case *uint32:
+				count = uint64(*val)
+			case string:
+				cnt, _ := strconv.ParseInt(val, 10, 64)
+				if cnt < 0 {
+					cnt = 0
+				}
+				count = uint64(cnt)
+			}
+			if count <= 0 {
+				return items
+			}
+			for i := uint64(0); i < count; i++ {
+				items = append(items, i)
+			}
+			return items
+		},
 	}}
 }
 
diff --git a/routers/web/repo/wiki.go b/routers/web/repo/wiki.go
index 77f60a1dfa..f4aabbf480 100644
--- a/routers/web/repo/wiki.go
+++ b/routers/web/repo/wiki.go
@@ -280,6 +280,8 @@ func renderViewPage(ctx *context.Context) (*git.Repository, *git.TreeEntry) {
 		ctx.Data["footerPresent"] = false
 	}
 
+	ctx.Data["toc"] = rctx.TableOfContents
+
 	// get commit count - wiki revisions
 	commitsCount, _ := wikiRepo.FileCommitsCount("master", pageFilename)
 	ctx.Data["CommitCount"] = commitsCount
diff --git a/templates/repo/wiki/view.tmpl b/templates/repo/wiki/view.tmpl
index 04faa90b9e..3189ed64ca 100644
--- a/templates/repo/wiki/view.tmpl
+++ b/templates/repo/wiki/view.tmpl
@@ -64,20 +64,39 @@
 				<p>{{.FormatWarning}}</p>
 			</div>
 		{{end}}
-		<div class="ui {{if .sidebarPresent}}grid equal width{{end}}" style="margin-top: 1rem;">
-			<div class="ui {{if .sidebarPresent}}eleven wide column{{end}} segment markup wiki-content-main">
+		<div class="ui {{if or .sidebarPresent .toc}}grid equal width{{end}}" style="margin-top: 1rem;">
+			<div class="ui {{if or .sidebarPresent .toc}}eleven wide column{{end}} segment markup wiki-content-main">
 				{{template "repo/unicode_escape_prompt" dict "EscapeStatus" .EscapeStatus "root" $}}
 				{{.content | Safe}}
 			</div>
-			{{if .sidebarPresent}}
+			{{if or .sidebarPresent .toc}}
 			<div class="column" style="padding-top: 0;">
-				<div class="ui segment wiki-content-sidebar">
-					{{if and .CanWriteWiki (not .Repository.IsMirror)}}
-						<a class="ui right floated muted" href="{{.RepoLink}}/wiki/_Sidebar?action=_edit" aria-label="{{.i18n.Tr "repo.wiki.edit_page_button"}}">{{svg "octicon-pencil"}}</a>
-					{{end}}
-					{{template "repo/unicode_escape_prompt" dict "EscapeStatus" .sidebarEscapeStatus "root" $}}
-					{{.sidebarContent | Safe}}
-				</div>
+				{{if .toc}}
+					<div class="ui segment wiki-content-toc">
+						<details open>
+							<summary>
+								<div class="ui header">{{.i18n.Tr "toc"}}</div>
+							</summary>
+							{{$level := 0}}
+							{{range .toc}}
+								{{if lt $level .Level}}{{range Iterate (Subtract .Level $level)}}<ul>{{end}}{{end}}
+								{{if gt $level .Level}}{{range Iterate (Subtract $level .Level)}}</ul>{{end}}{{end}}
+								{{$level = .Level}}
+								<li><a href="#{{.ID}}">{{.Text}}</a></li>
+							{{end}}
+							{{range Iterate $level}}</ul>{{end}}
+						</details>
+					</div>
+				{{end}}
+				{{if .sidebarPresent}}
+					<div class="ui segment wiki-content-sidebar">
+						{{if and .CanWriteWiki (not .Repository.IsMirror)}}
+							<a class="ui right floated muted" href="{{.RepoLink}}/wiki/_Sidebar?action=_edit" aria-label="{{.i18n.Tr "repo.wiki.edit_page_button"}}">{{svg "octicon-pencil"}}</a>
+						{{end}}
+						{{template "repo/unicode_escape_prompt" dict "EscapeStatus" .sidebarEscapeStatus "root" $}}
+						{{.sidebarContent | Safe}}
+					</div>
+				{{end}}
 			</div>
 			{{end}}
 		</div>
diff --git a/web_src/less/_repository.less b/web_src/less/_repository.less
index 0cae04d115..d73cb90330 100644
--- a/web_src/less/_repository.less
+++ b/web_src/less/_repository.less
@@ -3088,6 +3088,18 @@ td.blob-excerpt {
   }
 }
 
+.wiki-content-toc {
+  > ul > li {
+    margin-bottom: 4px;
+  }
+
+  ul {
+    margin: 0;
+    list-style: none;
+    padding-left: 1em;
+  }
+}
+
 /* fomantic's last-child selector does not work with hidden last child */
 .ui.buttons .unescape-button {
   border-top-right-radius: .28571429rem;