From 834de42a3fd5b68c859f9585fcc14e9710ab1472 Mon Sep 17 00:00:00 2001
From: some <some@somehole.com>
Date: Tue, 8 Oct 2024 18:58:08 -0400
Subject: [PATCH] Add Router

---
 router.go | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 router.go

diff --git a/router.go b/router.go
new file mode 100644
index 0000000..0b29fab
--- /dev/null
+++ b/router.go
@@ -0,0 +1,67 @@
+package router
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+type Route struct {
+	pattern  string
+	required bool
+}
+
+type Router struct {
+	*http.ServeMux
+	routes map[Route]*server
+}
+
+func NewRouter(mux *http.ServeMux, requiredRoutes []string) (ro *Router) {
+	if mux == nil {
+		mux = http.NewServeMux()
+	}
+	ro = &Router{
+		ServeMux: mux,
+		routes:   make(map[Route]*server),
+	}
+	for _, pattern := range requiredRoutes {
+		ro.routes[Route{pattern: pattern, required: true}] = &server{}
+	}
+	return
+}
+
+func (ro *Router) Register(pattern string, server *server) (err error) {
+	if !strings.HasPrefix(pattern, "/") {
+		return fmt.Errorf("missing preceding slash in pattern (%s)", pattern)
+	}
+	if server == nil {
+		return fmt.Errorf("server must be set in register")
+	}
+	srv, required := ro.routes[Route{pattern: pattern, required: true}]
+	if !required {
+		srv, _ = ro.routes[Route{pattern: pattern, required: false}]
+	}
+	if srv != nil {
+		return fmt.Errorf("too many routes for same pattern (%s)", pattern)
+	}
+	srv = server
+	ro.ServeMux.Handle(string(pattern), srv)
+	return
+}
+
+func (ro *Router) Validate() (err error) {
+	for route, server := range ro.routes {
+		if route.required && server == nil {
+			err = fmt.Errorf("missing required route for pattern (%s)", route.pattern)
+			return
+		}
+	}
+	return
+}
+
+func (ro *Router) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if err := ro.Validate(); err != nil {
+		panic(err)
+	}
+	ro.ServeMux.ServeHTTP(w, r)
+}