Set up initial project structure with essential files and directories

internal/httpapp/handlers.go

@@ -0,0 +1,59 @@
+package httpapp
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+)
+
+func (a *App) handleDashboard(w http.ResponseWriter, r *http.Request) {
+	data := map[string]any{
+		"Title": "Dashboard",
+		"Build": map[string]string{
+			"version": "v0.1.0-dev",
+		},
+	}
+	a.render(w, "dashboard.html", data)
+}
+
+func (a *App) handleHealthz(w http.ResponseWriter, r *http.Request) {
+	id, _ := r.Context().Value(requestIDKey).(string)
+	resp := map[string]any{
+		"status": "ok",
+		"ts":     id, // request ID for correlation
+	}
+	writeJSON(w, http.StatusOK, resp)
+}
+
+func (a *App) handleMetrics(w http.ResponseWriter, r *http.Request) {
+	// Stub metrics (Prometheus format). We'll wire real collectors later.
+	w.Header().Set("Content-Type", "text/plain; version=0.0.4")
+	w.WriteHeader(http.StatusOK)
+	_, _ = w.Write([]byte(
+		`# HELP pluto_build_info Build info
+# TYPE pluto_build_info gauge
+pluto_build_info{version="v0.1.0-dev"} 1
+# HELP pluto_up Whether the pluto-api process is up
+# TYPE pluto_up gauge
+pluto_up 1
+`,
+	))
+}
+
+func (a *App) render(w http.ResponseWriter, name string, data any) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	// base.html defines layout; dashboard.html will invoke it via template inheritance style.
+	if err := a.tmpl.ExecuteTemplate(w, name, data); err != nil {
+		log.Printf("template render error: %v", err)
+		http.Error(w, "template render error", http.StatusInternalServerError)
+		return
+	}
+}
+
+func writeJSON(w http.ResponseWriter, code int, v any) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(code)
+	if err := json.NewEncoder(w).Encode(v); err != nil {
+		log.Printf("json encode error: %v", err)
+	}
+}