package main

import (
	"context"
	"flag"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"jukebox_maker/internal/api"
	"jukebox_maker/internal/config"
	"jukebox_maker/internal/copier"
	"jukebox_maker/internal/db"
	"jukebox_maker/internal/disk"
	"jukebox_maker/internal/task"
	"jukebox_maker/internal/watcher"
)

func main() {
	configPath := flag.String("config", "/config/config.json", "path to config file")
	addr := flag.String("addr", ":8080", "HTTP listen address")
	mediaPath := flag.String("media", "/media", "path to media source directory")
	mountPath := flag.String("mount", "/mnt/usb", "path to USB mount point")
	flag.Parse()

	cfg, err := config.Load(*configPath)
	if err != nil {
		log.Fatalf("load config: %v", err)
	}

	taskStore := task.NewStore()
	cp := copier.New(taskStore)

	var activeDB *db.DB
	var activeDiskID string

	openDiskDB := func(info disk.DiskInfo) {
		if activeDiskID == info.DiskID {
			return // already open for this disk
		}
		if activeDB != nil {
			activeDB.Close()
			activeDB = nil
			activeDiskID = ""
		}
		d, err := db.Open(disk.DBPath(info.MountPath))
		if err != nil {
			log.Printf("open disk DB: %v", err)
			return
		}
		activeDB = d
		activeDiskID = info.DiskID
		cp.SetDB(d)
		log.Printf("disk DB opened for %s", info.DiskID)
	}

	closeDiskDB := func() {
		if activeDB != nil {
			activeDB.Close()
			activeDB = nil
			activeDiskID = ""
			cp.SetDB(nil)
			log.Println("disk DB closed")
		}
	}

	w := watcher.New(*mountPath, 5*time.Second, func(ev watcher.DiskEvent) {
		log.Printf("disk: %s -> %s", ev.Prev, ev.Info.State)
		switch ev.Info.State {
		case disk.DiskKnown:
			openDiskDB(ev.Info)
			if ev.Prev != disk.DiskKnown && cfg.AutoCopy {
				triggerAutoCopy(cp, cfg, ev.Info, *mediaPath)
			}
		case disk.DiskAbsent:
			closeDiskDB()
		}
	})

	// Open DB immediately if disk already connected at startup
	{
		info, _ := disk.Probe(*mountPath)
		if info.State == disk.DiskKnown {
			openDiskDB(info)
		}
	}

	srv, err := api.New(api.Deps{
		Config:     cfg,
		ConfigPath: *configPath,
		Watcher:    w,
		Copier:     cp,
		Tasks:      taskStore,
		MediaPath:  *mediaPath,
		MountPath:  *mountPath,
	})
	if err != nil {
		log.Fatalf("init server: %v", err)
	}

	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()

	go w.Run(ctx)

	httpSrv := &http.Server{Addr: *addr, Handler: srv}
	go func() {
		log.Printf("jukebox_maker listening on %s", *addr)
		if err := httpSrv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatalf("http: %v", err)
		}
	}()

	<-ctx.Done()
	log.Println("shutting down…")
	shutCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	httpSrv.Shutdown(shutCtx)
	closeDiskDB()
}

func triggerAutoCopy(cp *copier.Copier, cfg *config.Config, info disk.DiskInfo, mediaPath string) {
	var sources []string
	for _, s := range cfg.Sources {
		if s.Enabled {
			sources = append(sources, s.Path)
		}
	}
	if len(sources) == 0 {
		return
	}
	go func() {
		_, err := cp.Start(context.Background(), copier.Options{
			DiskID:         info.DiskID,
			MountPath:      info.MountPath,
			MediaPath:      mediaPath,
			EnabledSources: sources,
			ReserveFreeGB:  cfg.ReserveFreeGB,
			OverwriteMode:  cfg.OverwriteMode,
			FileSelectMode: cfg.FileSelectMode,
		})
		if err != nil {
			log.Printf("auto-copy: %v", err)
		}
	}()
}