add code

main.go

+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+type User struct {
+	ID       int    `json:"id"`
+	Username string `json:"username"`
+	Email    string `json:"email"`
+	Password string `json:"-"`
+}
+
+var users []User
+var lastUserID int
+
+func main() {
+	http.HandleFunc("/signup", signUp)
+	http.HandleFunc("/login", login)
+
+	log.Fatal(http.ListenAndServe(":8080", nil))
+}
+
+func signUp(w http.ResponseWriter, r *http.Request) {
+	var newUser User
+	err := json.NewDecoder(r.Body).Decode(&newUser)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(newUser.Password), bcrypt.DefaultCost)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	newUser.Password = string(hashedPassword)
+
+	lastUserID++
+	newUser.ID = lastUserID
+	users = append(users, newUser)
+
+	w.WriteHeader(http.StatusOK)
+}
+
+func login(w http.ResponseWriter, r *http.Request) {
+	var loginData struct {
+		Username string `json:"username"`
+		Password string `json:"password"`
+	}
+	err := json.NewDecoder(r.Body).Decode(&loginData)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	for _, user := range users {
+		if user.Username == loginData.Username {
+			err := bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(loginData.Password))
+			if err == nil {
+				w.WriteHeader(http.StatusOK)
+				return
+			}
+		}
+	}
+
+	http.Error(w, "Invalid username or password", http.StatusUnauthorized)
+}