package main

import (
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"strings"
	"time"
)

// types

const (
	baseURL = "https://unifi.freifunk-troisdorf.de/v2.1"
	iso8601 = "2006-01-02T15:04:05-0700"
)

// flags
var token = flag.String("token", "", "Defines the x-auth-token")

func main() {
	// parse all flags
	flag.Parse()

	// check if token is set
	if *token == "" {
		log.Fatalln("Please specify an API token via the flag '-token'")
	}

	log.Println("starting...")

	// Variables for runtime
	var links []link
	var nodes []node

	d, err := getDevices()
	if err != nil {
		log.Fatalln(err)
	}

	// API CALL 1
	log.Println("calling API 1")
	var u []unifiAPIResponse
	err = callUnifiAPI("/devices", &u)
	if err != nil {
		log.Fatalln(err)
	}

	for i := range d.Devices {
		var dev unifiAPIResponse
		var currentDevice device
		for j := range u {
			if strings.ToUpper(u[j].Identification.MAC) == strings.ToUpper(d.Devices[i].MAC) {
				dev = u[j]
				currentDevice = d.Devices[i]
			}
		}

		var isOnline bool = false
		if dev.Overview.Status == "active" {
			isOnline = true
		}
		// END OF API CALL 1

		// API CALL 2
		log.Println("calling API 2 for device", d.Devices[i].Name)
		var details unifiAPIDetails
		callUnifiAPI("/devices/erouters/"+dev.Identification.ID, &details)
		// END OF API CALL 2

		// API CALL 3
		log.Println("calling API 3 for device", d.Devices[i].Name)
		var airmaxes []unifiAPIAirmax
		callUnifiAPI("/devices/airmaxes/"+dev.Identification.ID+"/stations", &airmaxes)
		// check if remote mac address is part of our published network
		for i := range airmaxes {
			if isRemoteMACpublished(airmaxes[i].DeviceIdentification.MAC, d.Devices) == true {
				links = addLink(dev, airmaxes[i], links)
			}
		}
		// END OF API CALL 3

		// Get info from json file (static)
		nodes = append(nodes, node{
			Firstseen:      dev.Overview.CreatedAt.Format(iso8601),
			Lastseen:       dev.Overview.LastSeen.Format(iso8601),
			IsOnline:       isOnline,
			IsGateway:      false,
			Clients:        0,
			ClientsWifi24:  0,
			ClientsWifi5:   0,
			ClientsOther:   0,
			RootFSUsage:    0,
			LoadAVG:        details.Overview.CPU / 100,
			MemoryUsage:    details.Overview.RAM / 100,
			Uptime:         dev.Identification.Started.Format(iso8601),
			GatewayNexthop: currentDevice.GatewayNexthop,
			Gateway:        currentDevice.Gateway,
			Location:       currentDevice.Location,
			NodeID:         strings.ReplaceAll(dev.Identification.MAC, ":", ""),
			MAC:            dev.Identification.MAC,
			Adresses:       getAddresses(details.IPAddress),
			Domain:         currentDevice.Domain,
			Hostname:       "[RiFu] " + details.Identification.Name,
			Owner:          "Freifunk Rhein-Sieg",
			Firmware: firmware{
				Base:    "Ubiquiti - Stock",
				Release: details.Firmware.Current,
			},
			Autoupdater: autoupdater{
				Enabled: false,
				Branch:  "stable",
			},
			NProc: 1,
			Model: details.Identification.Model,
		})
	}

	// assemble final struct
	o := output{
		Timestamp: time.Now().Format(iso8601),
		Nodes:     nodes,
		Links:     links,
	}

	// create file output
	log.Println("writing json file")
	writeJSONtoFile(o)

	// we're done here
	log.Println("...done")
}

func getDevices() (devices, error) {
	// get devices from JSON file
	jsonFile, err := os.Open("devices.json")
	if err != nil {
		return devices{}, errors.New("can't open devices.json")
	}
	defer jsonFile.Close()

	// read file to bytes
	byteValue, _ := ioutil.ReadAll(jsonFile)

	// variable for d
	var d devices
	// unmarshal to struct
	json.Unmarshal(byteValue, &d)
	return d, nil
}

func callUnifiAPI(url string, i interface{}) error {
	request, err := http.NewRequest(http.MethodGet, baseURL+url, nil)
	if err != nil {
		return errors.New(fmt.Sprint("can't set request", baseURL+url))
	}
	request.Header.Set("x-auth-token", *token)
	client := &http.Client{}
	response, err := client.Do(request)
	if err != nil {
		return fmt.Errorf("can't get request %s with x-auth-token %s", baseURL+url, *token)
	}

	data, err := ioutil.ReadAll(response.Body)
	defer response.Body.Close()
	if err != nil {
		return fmt.Errorf("can't read response body: %+v", response.Body)
	}
	// try to fetch errors
	var a apiResponse
	json.Unmarshal(data, &a)

	if a.StatusCode != 0 {
		return fmt.Errorf("got following errorcode from API: %d %s %s", a.StatusCode, a.Error, a.Message)
	}

	// no error occurred, unmarshal to struct
	json.Unmarshal(data, &i)
	return nil
}

func isRemoteMACpublished(mac string, devices []device) bool {
	for i := range devices {
		if devices[i].MAC == mac {
			return true
		}
	}
	return false
}

func addLink(dev unifiAPIResponse, airmaxes unifiAPIAirmax, links []link) []link {
	for i := range links {
		if links[i].SourceAddr == airmaxes.DeviceIdentification.MAC {
			// link already exists
			return links
		}
	}
	links = append(links, link{
		Type:       "wifi",
		Source:     strings.ReplaceAll(dev.Identification.MAC, ":", ""),
		Target:     strings.ReplaceAll(airmaxes.DeviceIdentification.MAC, ":", ""),
		SourceTQ:   airmaxes.Statistics.LinkScore,
		TargetTQ:   airmaxes.Statistics.LinkScore,
		SourceAddr: dev.Identification.MAC,
		TargetAddr: airmaxes.DeviceIdentification.MAC,
	})
	return links
}

func writeJSONtoFile(o output) error {
	file, err := json.MarshalIndent(o, "", "  ")
	if err != nil {
		return fmt.Errorf("can't marshal to json: %+v", o)
	}

	// write to file
	err = ioutil.WriteFile("example.json", file, 0644)
	if err != nil {
		return fmt.Errorf("can't write to json file example.json")
	}
	return nil
}

func getAddresses(ip string) []string {
	var adresses []string
	adresses = append(adresses, strings.Split(ip, "/")[0])
	return adresses
}