uofgcal/fetch/fetch.go

package fetch

import (
	"encoding/base64"
	"fmt"
	"net/http"
	"strings"
	"time"

	ics "github.com/arran4/golang-ical"
	"github.com/charmbracelet/log"
	cron "github.com/go-co-op/gocron/v2"
)

const calendar_url = "https://frontdoor.spa.gla.ac.uk/spacett/download/uogtimetable.ics"

var authorization string
var Scheduler *cron.Scheduler

func CollectAuth() {
	var (
		guid     string
		password string
	)
	fmt.Print("Enter your GUID: ")
	fmt.Scan(&guid)
	fmt.Print("Enter your password: ")
	fmt.Scan(&password)
	b64 := base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf("%s:%s", guid, password)))
	authorization = fmt.Sprintf("Basic %s", b64)
}

func StartScheduler() {
	// create scheduler
	Scheduler, err := cron.NewScheduler()
	if err != nil {
		log.Fatal(err)
	}

	j, err := Scheduler.NewJob(
		// every 24 hours
		cron.DurationJob(
			24*time.Hour,
		),

		// update the calendar
		cron.NewTask(
			update_calendar,
		),
	)
	if err != nil {
		log.Fatal(err)
	}

	// run job and start scheduler
	go j.RunNow()
	Scheduler.Start()
}

func update_calendar() {
	// create request
	req, err := http.NewRequest("GET", calendar_url, nil)
	if err != nil {
		log.Fatal(err)
	}
	req.Header.Set("Authorization", authorization)

	// send request
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	defer resp.Body.Close()

	// check if authentication failed
	if resp.StatusCode == 401 {
		log.Fatal("authentication failed")
	}

	// parse ics file
	calendar, err := ics.ParseCalendar(resp.Body)
	if err != nil {
		log.Fatal(err)
	}

	for _, event := range calendar.Events() {
		name := event.GetProperty(ics.ComponentPropertySummary).Value
		location := strings.TrimSpace(strings.Replace(event.GetProperty(ics.ComponentPropertyLocation).Value, "ON CAMPUS:", "", 1))
		log.Infof("%s: %s", name, location)
	}
}