package main

import (
	"encoding/json"
	"net/http"
)

type ApiError struct {
	Message string `json:"message"`
	Err     error  `json:"error"`
	Status  int
}

func (a *ApiError) Error() string {
	return a.Message
}

type Server struct {
	addr string
	mux  *http.ServeMux
}

func NewServer(addr string) *Server {
	return &Server{
		addr: addr,
		mux:  http.NewServeMux(),
	}
}

func (s *Server) Handle(pattern string, handler func(w http.ResponseWriter, r *http.Request) error) {
	s.mux.HandleFunc(pattern, func(w http.ResponseWriter, r *http.Request) {
		err := handler(w, r)
		if err != nil {
			if e, ok := err.(*ApiError); ok {
				var nestedErr *string
				if e.Err != nil {
					nestedErr = new(e.Err.Error())
				}
				s.JSON(w, map[string]any{
					"message": e.Message,
					"error":   nestedErr,
				}, e.Status)
			} else {
				s.JSON(w, map[string]any{
					"message": "something bad happened",
					"error":   err.Error(),
				}, 500)
			}
		}
	})
}

func (s *Server) JSON(w http.ResponseWriter, data any, status int) error {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	return json.NewEncoder(w).Encode(data)
}

func (s *Server) Error(msg string, err error, status int) error {
	return &ApiError{
		Message: msg,
		Err:     err,
		Status:  status,
	}
}

func (s *Server) ListenAndServe() error {
	return http.ListenAndServe(s.addr, s.mux)
}