From 3536b4338b0953349dc25ab913c1b6586ee7065e Mon Sep 17 00:00:00 2001
From: Levente Batuska <mr.levente97@gmail.com>
Date: Tue, 22 Oct 2024 00:21:44 +0200
Subject: [PATCH] feat(SimpleRouter): initial version

---
 simplerouter/router.go | 155 +++++++++++++++++++++++++++++++++++++++++
 simplerouter/types.go  |  11 +++
 2 files changed, 166 insertions(+)
 create mode 100644 simplerouter/router.go
 create mode 100644 simplerouter/types.go

diff --git a/simplerouter/router.go b/simplerouter/router.go
new file mode 100644
index 0000000..0c19614
--- /dev/null
+++ b/simplerouter/router.go
@@ -0,0 +1,155 @@
+package SimpleRouter
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+)
+
+// Use this router for graceful shutdown
+func (rg *RouteGroup) StartServer(addr string) *http.Server {
+	server := &http.Server{
+		Addr:    addr,
+		Handler: rg,
+	}
+
+	go func() {
+		if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			panic(fmt.Sprintf("HTTP server error: %v", err))
+		}
+	}()
+
+	return server
+}
+
+func (rg *RouteGroup) StartWithGracefulShutdown(addr string) {
+	server := &http.Server{
+		Addr:    addr,
+		Handler: rg, // This will use your RouteGroup (with ServeMux) as the handler
+	}
+
+	// Start the server in a separate goroutine
+	go func() {
+		fmt.Println("Starting server on", addr)
+		if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			panic(fmt.Sprintf("HTTP server error: %v", err))
+		}
+	}()
+
+	// Set up signal catching for graceful shutdown (Ctrl+C, SIGINT, SIGTERM)
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+
+	// Block until a signal is received
+	<-sigChan
+
+	fmt.Println("Shutting down server...")
+
+	// Set a timeout for the shutdown process (10 seconds)
+	shutdownCtx, shutdownRelease := context.WithTimeout(context.Background(), 10*time.Second)
+	defer shutdownRelease()
+
+	// Perform graceful shutdown
+	if err := server.Shutdown(shutdownCtx); err != nil {
+		panic(fmt.Sprintf("HTTP shutdown error: %v", err))
+	}
+
+	fmt.Println("Graceful shutdown complete.")
+}
+
+// http.ListenAndServe takes a Handler interface defined as: ServeHTTP(ResponseWriter, *Request)
+func (rg *RouteGroup) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	rg.mux.ServeHTTP(w, r)
+}
+
+// / Handler returns the handler to use for the given request, ... propagate call to http library
+func (rg *RouteGroup) Handler(r *http.Request) (h http.Handler, pattern string) {
+	return rg.mux.Handler(r)
+}
+
+// Creates a new SimpleRouter with the basePath of "/"
+func SimpleRouter() *RouteGroup {
+	return &RouteGroup{mux: http.NewServeMux(), basePath: "/"}
+}
+
+// Puts middlewares on top of existing ones in order
+func (rg *RouteGroup) PushMiddleware(first Middleware, others ...Middleware) *RouteGroup {
+	rg.middlewares = append(rg.middlewares, first)
+	// append supposedly keeps the order of elements, so no extra work is needed
+	rg.middlewares = append(rg.middlewares, others...)
+	return rg
+}
+
+// Removes the top middleware and returns it to the caller
+func (rg *RouteGroup) PopMiddleware() Middleware {
+	if len(rg.middlewares) == 0 {
+		return nil
+	}
+
+	lastIndex := len(rg.middlewares) - 1
+	lastMiddleware := rg.middlewares[lastIndex]
+	rg.middlewares = rg.middlewares[:lastIndex]
+
+	return lastMiddleware
+}
+
+// applies the array of middlewares on the handler
+func (rg *RouteGroup) applyMiddlewares(handler http.Handler) http.Handler {
+	mwlen := len(rg.middlewares) - 1 // We need to start from the last element going to 0 for correct ordering
+	for i := range rg.middlewares {
+		handler = rg.middlewares[mwlen-i](handler)
+	}
+	return handler
+}
+
+func (rg *RouteGroup) registerRoute(method string, path string, handler http.HandlerFunc) {
+	if path == "/" {
+		path = rg.basePath[:len(rg.basePath)-1]
+	} else {
+		path = rg.basePath + path
+	}
+
+	fullPath := method + " " + path
+
+	rg.mux.HandleFunc(fullPath, rg.applyMiddlewares(handler).ServeHTTP)
+}
+
+func (rg *RouteGroup) HandleFunc(method string, path string, handler http.HandlerFunc) {
+	rg.registerRoute(method, path, handler)
+}
+
+func (rg *RouteGroup) Handle(method string, path string, handler http.Handler) {
+	rg.HandleFunc(method, path, handler.ServeHTTP)
+}
+
+func (rg *RouteGroup) GET(path string, handler http.Handler) {
+	rg.Handle(http.MethodGet, path, handler)
+}
+
+func (rg *RouteGroup) HEAD(path string, handler http.Handler) {
+	rg.Handle(http.MethodHead, path, handler)
+}
+
+func (rg *RouteGroup) OPTIONS(path string, handler http.Handler) {
+	rg.Handle(http.MethodOptions, path, handler)
+}
+
+func (rg *RouteGroup) POST(path string, handler http.Handler) {
+	rg.Handle(http.MethodPost, path, handler)
+}
+
+func (rg *RouteGroup) PUT(path string, handler http.Handler) {
+	rg.Handle(http.MethodPut, path, handler)
+}
+
+func (rg *RouteGroup) PATCH(path string, handler http.Handler) {
+	rg.Handle(http.MethodPatch, path, handler)
+}
+
+func (rg *RouteGroup) DELETE(path string, handler http.Handler) {
+	rg.Handle(http.MethodDelete, path, handler)
+}
diff --git a/simplerouter/types.go b/simplerouter/types.go
new file mode 100644
index 0000000..c17c6f2
--- /dev/null
+++ b/simplerouter/types.go
@@ -0,0 +1,11 @@
+package SimpleRouter
+
+import "net/http"
+
+type Middleware func(http.Handler) http.Handler
+
+type RouteGroup struct {
+	mux         *http.ServeMux // A ponter to the underlying ServeMux, this allows us to call ListenAndServe on any instance
+	basePath    string         // The current path we are defining handlers on / appending to
+	middlewares []Middleware   // Stack of middlewares that will be applied on a handler in order
+}