package common

import (
	"fmt"
	"net"
	"net/http"
)

// Display some information about this API for the default page
// TODO - static fileserver with docs
func HomeLink(w http.ResponseWriter, r *http.Request) {
	//w.WriteHeader(http.StatusNotImplemented)
	fmt.Fprintf(w, "VM Chargeback Tracking Program. API interface only. See Nathan Coad (nathan.coad@dell.com) for further details. ")
}

// Display error message for invalid requests
func HandleNotFound(w http.ResponseWriter, r *http.Request) {
	ip, err := IPFromRequest(r)
	if err != nil {
		fmt.Println("Error", err)
		http.Error(w, "VM Chargeback Tracking Program.. Invalid Path Specified.", http.StatusNotFound)
		return
	}

	fmt.Printf("Request from IP %s\n", ip.String())
	http.Error(w, "VM Chargeback Tracking Program. Invalid Path Specified.", http.StatusNotFound)
	// TODO - investigate rate limiting for invalid requests
}

// IPFromRequest extracts the user IP address from req, if present.
// @see https://blog.golang.org/context/userip/userip.go
func IPFromRequest(req *http.Request) (net.IP, error) {
	ip, _, err := net.SplitHostPort(req.RemoteAddr)
	if err != nil {
		return nil, fmt.Errorf("userip: %q is not IP:port", req.RemoteAddr)
	}

	userIP := net.ParseIP(ip)
	if userIP == nil {
		return nil, fmt.Errorf("userip: %q is not IP:port", req.RemoteAddr)
	}
	return userIP, nil
}