package services

import (
	"log"
	"sync"

	"github.com/robfig/cron/v3"
)

type Scheduler struct {
	cron     *cron.Cron
	entryID  cron.EntryID
	settings *SettingsManager
	modlists *ModlistManager
	steamcmd *SteamCmdManager
	mu       sync.Mutex
}

func NewScheduler(settings *SettingsManager, modlists *ModlistManager, steamcmd *SteamCmdManager) *Scheduler {
	return &Scheduler{
		cron:     cron.New(),
		settings: settings,
		modlists: modlists,
		steamcmd: steamcmd,
	}
}

func (s *Scheduler) Start() {
	s.cron.Start()
	s.Refresh()
}

func (s *Scheduler) Stop() {
	s.cron.Stop()
}

func (s *Scheduler) Refresh() {
	s.mu.Lock()
	defer s.mu.Unlock()

	if s.entryID != 0 {
		s.cron.Remove(s.entryID)
		s.entryID = 0
	}

	sett, err := s.settings.Load()
	if err != nil || sett.ScheduledUpdate == "" {
		return
	}

	id, err := s.cron.AddFunc(sett.ScheduledUpdate, s.runScheduledUpdate)
	if err != nil {
		log.Printf("scheduler: invalid cron expression %q: %v", sett.ScheduledUpdate, err)
		return
	}
	s.entryID = id
	log.Printf("scheduler: scheduled update with cron %q", sett.ScheduledUpdate)
}

func (s *Scheduler) runScheduledUpdate() {
	sett, err := s.settings.Load()
	if err != nil {
		return
	}

	if sett.SteamUser != "" && sett.SteamUser != "anonymous" {
		log.Print("scheduler: running gameserver update")
		if err := s.steamcmd.UpdateGame(sett.SteamBranch, sett.SteamUser); err != nil {
			log.Printf("scheduler: game update failed: %v", err)
		}
	}

	if sett.ActiveModlist != "" {
		ml, err := s.modlists.Get(sett.ActiveModlist)
		if err != nil {
			log.Printf("scheduler: load modlist %s: %v", sett.ActiveModlist, err)
			return
		}
		var modIDs []string
		for _, m := range ml.Mods {
			if m.Enabled {
				modIDs = append(modIDs, m.ID)
			}
		}
		if len(modIDs) > 0 {
			log.Printf("scheduler: updating %d mod(s)", len(modIDs))
			if err := s.steamcmd.DownloadMods(modIDs); err != nil {
				log.Printf("scheduler: mod update failed: %v", err)
			}
		}
	}
}