Improve serach function with quick suggestions

search.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"io/fs"
 	"log"
 	"net/http"
@@ -21,7 +22,7 @@ type searchResult struct {
 
 type searchPageData struct {
 	Title        string
-	Crumbs       []crumb
+	ParentURL    string
 	EditMode     bool
 	Query        string
 	Results      []searchResult
@@ -65,7 +66,7 @@ func (h *handler) handleSearch(w http.ResponseWriter, r *http.Request) {
 	}
 	data := searchPageData{
 		Title:        title,
-		Crumbs:       []crumb{{Name: "search", URL: "/?q=" + query}},
+		ParentURL:    "/",
 		Query:        query,
 		Results:      results,
 		IndexBuiltAt: builtAt,
@@ -159,6 +160,47 @@ func scoreName(nameLower string, nameTokens []string, qLower string, qTokens []s
 	return score
 }
 
+// handleSearchSuggest serves the JSON typeahead for the header dropdown and
+// the editor's link picker. Caps results at 5; reports total so the UI can
+// surface a "show all" footer when more matches exist. Empty/whitespace query
+// is a no-op (200 with empty results), not a 400 — every keystroke fires this.
+func (h *handler) handleSearchSuggest(w http.ResponseWriter, r *http.Request) {
+	if !h.checkAuth(w, r) {
+		return
+	}
+	query := strings.TrimSpace(r.URL.Query().Get("q"))
+	type suggestResult struct {
+		Name string `json:"name"`
+		Path string `json:"path"`
+		URL  string `json:"url"`
+	}
+	type suggestResp struct {
+		Query   string          `json:"query"`
+		Results []suggestResult `json:"results"`
+		Total   int             `json:"total"`
+	}
+	resp := suggestResp{Query: query, Results: []suggestResult{}}
+	if query != "" {
+		all, _ := searchWiki(query)
+		resp.Total = len(all)
+		limit := 5
+		if len(all) < limit {
+			limit = len(all)
+		}
+		for i := 0; i < limit; i++ {
+			resp.Results = append(resp.Results, suggestResult{
+				Name: all[i].Name,
+				Path: all[i].Path,
+				URL:  all[i].URL,
+			})
+		}
+	}
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	if err := json.NewEncoder(w).Encode(resp); err != nil {
+		log.Printf("search suggest encode error: %v", err)
+	}
+}
+
 // handleReindex rebuilds the folder index synchronously and returns 204.
 // The frontend reloads the page on success. Serialized via buildMu so a
 // double-click waits rather than running two walks in parallel.