View switching feature

render.go

@@ -4,10 +4,12 @@ import (
 	"bytes"
 	"fmt"
 	"html/template"
+	"net/url"
 	"os"
 	"path"
 	"sort"
 	"strings"
+	"time"
 
 	"github.com/yuin/goldmark"
 	"github.com/yuin/goldmark/extension"
@@ -31,6 +33,13 @@ func initMarkdown(root string) {
 type entry struct {
 	Icon            template.HTML
 	Name, URL, Meta string
+	// ThumbURL is set for thumbnailable files; the thumbnail view renders an
+	// <img> when it is non-empty and falls back to Icon otherwise.
+	ThumbURL string
+	// modTime/size carry the raw sort keys; the template only reads the
+	// formatted Meta string.
+	modTime time.Time
+	size    int64
 }
 
 type pageData struct {
@@ -45,15 +54,68 @@ type pageData struct {
 	RawContent     string
 	Content        template.HTML
 	Entries        []entry
+	View           string // listing view style: "list" or "thumbnail"
+	Sort           string // listing sort key: "name" / "modified" / "size"
+	Order          string // listing sort order: "asc" / "desc"
 	SpecialContent template.HTML
 	SidebarWidget  template.HTML
 	SuppressTOC    bool
 	RenderMS       int64
 }
 
-// pageSettings holds the parsed contents of a .page-settings file.
+// Allowed values for the listing view settings. Unknown values in the file or
+// a POST body fall back to the first (default) value of each set.
+const (
+	viewList      = "list"
+	viewThumbnail = "thumbnail"
+
+	sortName     = "name"
+	sortModified = "modified"
+	sortSize     = "size"
+
+	orderAsc  = "asc"
+	orderDesc = "desc"
+)
+
+// pageSettings holds the parsed contents of a .page-settings file. View, Sort,
+// and Order are always valid once parsed (defaults applied on read).
 type pageSettings struct {
-	Type string
+	Type  string
+	View  string
+	Sort  string
+	Order string
+}
+
+// viewSettings returns the listing view/sort/order, applying defaults when the
+// receiver is nil (no .page-settings file).
+func (s *pageSettings) viewSettings() (view, sortKey, order string) {
+	if s == nil {
+		return viewList, sortName, orderAsc
+	}
+	return s.View, s.Sort, s.Order
+}
+
+func validateView(v string) string {
+	if v == viewThumbnail {
+		return viewThumbnail
+	}
+	return viewList
+}
+
+func validateSort(v string) string {
+	switch v {
+	case sortModified, sortSize:
+		return v
+	default:
+		return sortName
+	}
+}
+
+func validateOrder(v string) string {
+	if v == orderDesc {
+		return orderDesc
+	}
+	return orderAsc
 }
 
 var (
@@ -117,7 +179,7 @@ func parentURL(urlPath string) string {
 	return parent + "/"
 }
 
-func listEntries(fsPath, urlPath string) []entry {
+func listEntries(fsPath, urlPath, sortKey, order string) []entry {
 	entries, err := os.ReadDir(fsPath)
 	if err != nil {
 		return nil
@@ -136,30 +198,36 @@ func listEntries(fsPath, urlPath string) []entry {
 		entryURL := path.Join(urlPath, name)
 		if e.IsDir() {
 			folders = append(folders, entry{
-				Icon: iconFolder,
-				Name: name,
-				URL:  entryURL + "/",
-				Meta: info.ModTime().Format("2006-01-02"),
+				Icon:    iconFolder,
+				Name:    name,
+				URL:     entryURL + "/",
+				Meta:    info.ModTime().Format("2006-01-02"),
+				modTime: info.ModTime(),
 			})
 		} else {
 			if name == "index.md" {
 				continue // rendered above, don't list it
 			}
-			files = append(files, entry{
-				Icon: fileIcon(name),
-				Name: name,
-				URL:  entryURL,
-				Meta: formatSize(info.Size()) + " · " + info.ModTime().Format("2006-01-02"),
-			})
+			f := entry{
+				Icon:    fileIcon(name),
+				Name:    name,
+				URL:     entryURL,
+				Meta:    formatSize(info.Size()) + " · " + info.ModTime().Format("2006-01-02"),
+				modTime: info.ModTime(),
+				size:    info.Size(),
+			}
+			if hasThumbnail(name) {
+				f.ThumbURL = thumbURL(path.Join(urlPath, url.PathEscape(name)), 300)
+			}
+			files = append(files, f)
 		}
 	}
 
-	sort.Slice(folders, func(i, j int) bool {
-		return strings.ToLower(folders[i].Name) < strings.ToLower(folders[j].Name)
-	})
-	sort.Slice(files, func(i, j int) bool {
-		return strings.ToLower(files[i].Name) < strings.ToLower(files[j].Name)
-	})
+	// Folders always sort by name regardless of the chosen key (they have no
+	// meaningful byte size); files honor the chosen key. The chosen order
+	// applies to both groups.
+	sortEntries(folders, sortName, order)
+	sortEntries(files, sortKey, order)
 
 	// `..` row mirrors the header Up button so the listing itself is
 	// navigable without reaching for the header on mobile. Prepended after
@@ -177,6 +245,42 @@ func listEntries(fsPath, urlPath string) []entry {
 	return out
 }
 
+// sortEntries sorts a single group (folders or files) in place by the given
+// key, breaking ties on case-insensitive name, then reverses for descending
+// order. The stable sort keeps the name tiebreak meaningful.
+func sortEntries(group []entry, sortKey, order string) {
+	sort.SliceStable(group, func(i, j int) bool {
+		a, b := group[i], group[j]
+		cmp := 0
+		switch sortKey {
+		case sortModified:
+			if a.modTime.Before(b.modTime) {
+				cmp = -1
+			} else if a.modTime.After(b.modTime) {
+				cmp = 1
+			}
+		case sortSize:
+			if a.size < b.size {
+				cmp = -1
+			} else if a.size > b.size {
+				cmp = 1
+			}
+		}
+		if cmp == 0 {
+			an, bn := strings.ToLower(a.Name), strings.ToLower(b.Name)
+			if an < bn {
+				cmp = -1
+			} else if an > bn {
+				cmp = 1
+			}
+		}
+		if order == orderDesc {
+			return cmp > 0
+		}
+		return cmp < 0
+	})
+}
+
 func readIcon(name string) template.HTML {
 	b, _ := assets.ReadFile("assets/icons/" + name + ".svg")
 	return template.HTML(strings.TrimSpace(string(b)))