Add new UI and sse support

api/api.go

@@ -1,42 +1,46 @@
 package api
 
 import (
+	"bytes"
 	"embed"
 	"encoding/json"
-	"fmt"
 	"io/fs"
 	"log/slog"
 	"net/http"
 
+	"github.com/a-h/templ"
+	"github.com/gevulotnetwork/devnet-explorer/api/templates"
 	"github.com/gevulotnetwork/devnet-explorer/model"
-	"github.com/julienschmidt/httprouter"
 )
 
-//go:embed all:public
-var public embed.FS
+//go:embed all:assets
+var assets embed.FS
 
 type Store interface {
 	Stats() (model.Stats, error)
+	Events() <-chan model.Event
 }
 
 type API struct {
-	r *httprouter.Router
+	r *http.ServeMux
 	s Store
 }
 
 func New(s Store) (*API, error) {
 	a := &API{
-		r: httprouter.New(),
+		r: http.NewServeMux(),
 		s: s,
 	}
 
-	publicFS, err := fs.Sub(public, "public")
+	assetsFS, err := fs.Sub(assets, "assets")
 	if err != nil {
-		return nil, fmt.Errorf("failed to create public fs: %w", err)
+		return nil, err
 	}
 
-	a.r.NotFound = http.FileServer(http.FS(publicFS))
-	a.r.GET("/api/v1/stats", a.stats)
+	a.r.Handle("GET /", templ.Handler(templates.Index()))
+	a.r.HandleFunc("GET /api/v1/stats", a.stats)
+	a.r.HandleFunc("GET /api/v1/events", a.events)
+	a.r.Handle("GET /assets/", http.StripPrefix("/assets/", http.FileServer(http.FS(assetsFS))))
 
 	return a, nil
 }
@@ -45,16 +49,54 @@ func (a *API) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	a.r.ServeHTTP(w, r)
 }
 
-func (a *API) stats(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
+func (a *API) stats(w http.ResponseWriter, r *http.Request) {
 	stats, err := a.s.Stats()
 	if err != nil {
 		slog.Error("failed to get stats", slog.Any("error", err))
 		http.Error(w, "failed to get stats", http.StatusInternalServerError)
 		return
 	}
 
-	if err := json.NewEncoder(w).Encode(stats); err != nil {
-		slog.Error("failed encode stats", slog.Any("error", err))
+	if r.Header.Get("Accept") == "application/json" {
+		if err := json.NewEncoder(w).Encode(stats); err != nil {
+			slog.Error("failed encode stats", slog.Any("error", err))
+			return
+		}
 		return
 	}
+
+	if err := templates.Stats(stats).Render(r.Context(), w); err != nil {
+		slog.Error("failed render stats", slog.Any("error", err))
+		return
+	}
+}
+
+func (a *API) events(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "text/event-stream")
+	w.Header().Set("Cache-Control", "no-cache")
+	w.Header().Set("Connection", "keep-alive")
+
+	slog.Info("client connected", slog.String("remote_addr", r.RemoteAddr))
+
+	for {
+		select {
+		case <-r.Context().Done(): // Client disconnected
+			slog.Info("client disconnected", slog.String("remote_addr", r.RemoteAddr))
+			return
+		case event, ok := <-a.s.Events():
+			if !ok {
+				return
+			}
+
+			buf := &bytes.Buffer{}
+			buf.WriteString("data: ")
+			if err := templates.Row(event).Render(r.Context(), buf); err != nil {
+				slog.Error("failed render row", slog.Any("error", err))
+				return
+			}
+			buf.WriteString("\n\n")
+			buf.WriteTo(w)
+			w.(http.Flusher).Flush()
+		}
+	}
 }