package main

import (
	"fmt"
	"net"
	"strconv"

	"github.com/julienschmidt/httprouter"

	"git.nemunai.re/srs/adlin/libadlin"
)

func init() {
	router.GET("/api/ips", apiHandler(showIPs))
	router.GET("/api/students/:sid/ips", apiHandler(studentHandler(func(student *adlin.Student, body []byte) (interface{}, error) {
		return getStudentIPs(student), nil
	})))
}

func IPSuffix(s *adlin.Student, network net.IPNet) net.IP {
	ipshift := s.Id*4 + 7

	myIP := make(net.IP, len(network.IP))
	copy(myIP, network.IP)

	if ipshift > 254 {
		myIP[len(myIP)-2] += byte(ipshift / 254)
		ipshift = ipshift % 254
	}

	myIP[len(myIP)-1] += byte(ipshift)

	return myIP
}

func showIPs(_ httprouter.Params, body []byte) (interface{}, error) {
	r := make(map[string]map[string]string)

	students, err := adlin.GetStudents()
	if err != nil {
		return nil, err
	}

	for _, std := range students {
		sid := fmt.Sprintf("%d", std.Id)

		r[sid] = getStudentIPs(std)

		if std.MAC == nil {
			continue
		}

		r[sid]["mac"] = *std.MAC
	}

	return r, nil
}

func GetStudentTunnelIPs(student *adlin.Student) (ips []string) {
	if ts, err := student.GetActivesTunnels(); err != nil || len(ts) == 0 || ts[0].SuffixIP == 0 {
		ips = append(ips, adlin.StudentIP(student.Id, 0).String()+"1")
	} else {
		for _, t := range ts {
			ips = append(ips, t.GetStudentIP())
		}
	}
	return
}

func getStudentIPs(student *adlin.Student) (r map[string]string) {
	r = make(map[string]string)

	r["vlan0"] = IPSuffix(student, net.IPNet{IP: net.ParseIP("172.23.12.0"), Mask: net.CIDRMask(17, 32)}).String()
	r["wg0"] = IPSuffix(student, net.IPNet{IP: net.ParseIP("172.17.12.0"), Mask: net.CIDRMask(16, 32)}).String()
	r["vlan7"] = IPSuffix(student, net.IPNet{IP: net.ParseIP("172.23.142.0"), Mask: net.CIDRMask(23, 32)}).String()

	for d, ip := range GetStudentTunnelIPs(student) {
		key := "wg"
		if d > 0 {
			key += strconv.Itoa(d)
		}
		r[key] = ip
	}

	r["adn"] = student.MyAssociatedDomain()
	r["ddn"] = student.MyDelegatedDomain()

	return
}