Add enhanced health check endpoint

- Implement comprehensive health check with database ping
- Track and report server uptime
- Return proper HTTP status codes (503 if database is down)
- Add Swagger documentation for health endpoint

cmd/api/main.go

@@ -73,8 +73,9 @@ func main() {
 	authHandlers := httpInfra.NewAuthHandlers(registerHandler, loginHandler, jwtService)
 	habitHandlers := httpInfra.NewHabitHandlers(createHandler, getTodaysHandler, getUserHabitsHandler, getHabitByIDHandler, getHabitEntriesHandler, updateHandler, archiveHandler, markHandler, unmarkHandler)
 	statsHandlers := httpInfra.NewStatsHandlers(getHabitStatsHandler)
+	healthHandlers := httpInfra.NewHealthHandlers(db.Conn())
 
-	router := httpInfra.NewRouter(cfg.CORSOrigins, habitHandlers, authHandlers, statsHandlers, jwtService)
+	router := httpInfra.NewRouter(cfg.CORSOrigins, habitHandlers, authHandlers, statsHandlers, healthHandlers, jwtService)
 
 	addr := fmt.Sprintf("%s:%s", cfg.Host, cfg.Port)
 	log.Printf("Server starting on %s", addr)

internal/infrastructure/http/health_handlers.go

@@ -0,0 +1,87 @@
+package http
+
+import (
+	"database/sql"
+	"net/http"
+	"time"
+)
+
+var startTime = time.Now()
+
+type HealthHandlers struct {
+	db *sql.DB
+}
+
+func NewHealthHandlers(db *sql.DB) *HealthHandlers {
+	return &HealthHandlers{
+		db: db,
+	}
+}
+
+type HealthResponse struct {
+	Status   string `json:"status"`
+	Database string `json:"database"`
+	Uptime   string `json:"uptime"`
+}
+
+// Health godoc
+// @Summary Health check
+// @Description Get API health status including database connectivity and uptime
+// @Tags system
+// @Produce json
+// @Success 200 {object} HealthResponse
+// @Failure 503 {object} HealthResponse
+// @Router /health [get]
+func (h *HealthHandlers) Health(w http.ResponseWriter, r *http.Request) {
+	dbStatus := "ok"
+	overallStatus := "ok"
+	statusCode := http.StatusOK
+
+	if err := h.db.Ping(); err != nil {
+		dbStatus = "error"
+		overallStatus = "degraded"
+		statusCode = http.StatusServiceUnavailable
+	}
+
+	uptime := time.Since(startTime)
+	uptimeStr := formatDuration(uptime)
+
+	response := HealthResponse{
+		Status:   overallStatus,
+		Database: dbStatus,
+		Uptime:   uptimeStr,
+	}
+
+	respondJSON(w, statusCode, response)
+}
+
+func formatDuration(d time.Duration) string {
+	d = d.Round(time.Second)
+	h := d / time.Hour
+	d -= h * time.Hour
+	m := d / time.Minute
+	d -= m * time.Minute
+	s := d / time.Second
+
+	if h > 0 {
+		return formatTime(int(h), "h") + formatTime(int(m), "m")
+	}
+	if m > 0 {
+		return formatTime(int(m), "m") + formatTime(int(s), "s")
+	}
+	return formatTime(int(s), "s")
+}
+
+func formatTime(value int, unit string) string {
+	if value == 0 {
+		return ""
+	}
+	return formatInt(value) + unit
+}
+
+func formatInt(n int) string {
+	if n < 10 {
+		return "0" + string(rune('0'+n))
+	}
+	return string(rune('0'+n/10)) + string(rune('0'+n%10))
+}

internal/infrastructure/http/router.go

@@ -15,7 +15,7 @@ import (
 	_ "apocapoc-api/docs"
 )
 
-func NewRouter(corsOrigins string, habitHandlers *HabitHandlers, authHandlers *AuthHandlers, statsHandlers *StatsHandlers, jwtService *auth.JWTService) *chi.Mux {
+func NewRouter(corsOrigins string, habitHandlers *HabitHandlers, authHandlers *AuthHandlers, statsHandlers *StatsHandlers, healthHandlers *HealthHandlers, jwtService *auth.JWTService) *chi.Mux {
 	r := chi.NewRouter()
 
 	r.Use(middleware.Logger)
@@ -34,10 +34,7 @@ func NewRouter(corsOrigins string, habitHandlers *HabitHandlers, authHandlers *A
 		httpSwagger.URL("/api/v1/docs/doc.json"),
 	))
 
-	r.Get("/api/v1/health", func(w http.ResponseWriter, r *http.Request) {
-		w.WriteHeader(http.StatusOK)
-		w.Write([]byte(`{"status":"ok"}`))
-	})
+	r.Get("/api/v1/health", healthHandlers.Health)
 
 	r.Route("/api/v1/auth", func(r chi.Router) {
 		r.Use(httprate.LimitByIP(10, 1*time.Minute))