package device

import (
	"context"
	"fmt"
	"log"
	"slices"
	"sync"
	"time"

	"gitea.sinav-lab.com/sinav/keenetic-exporter-v2/internal/config"
	"gitea.sinav-lab.com/sinav/keenetic-exporter-v2/internal/keenetic"
)

type Device struct {
	Name           string
	Client         *keenetic.Client
	SkipCollectors []string

	UpdateInterval time.Duration
	CacheTTL       time.Duration

	Cache      map[string]any
	CacheMutex sync.RWMutex
	LastUpdate time.Time

	ctx    context.Context
	cancel context.CancelFunc
	wg     sync.WaitGroup
}

type Manager struct {
	devices []*Device
	mutex   sync.RWMutex
}

func NewManager(configs []config.DeviceConfig) *Manager {
	m := &Manager{}

	for _, cfg := range configs {
		client, err := keenetic.NewClient(cfg.Address)
		if err != nil {
			log.Printf("Failed to create client for %s: %v", cfg.Name, err)
			continue
		}

		timeout, err := time.ParseDuration(cfg.Timeout)
		if err != nil {
			timeout = 10 * time.Second
		}

		ctx, cancel := context.WithTimeout(context.Background(), timeout)
		err = client.Init(ctx, cfg.Username, cfg.Password)
		cancel()

		if err != nil {
			log.Printf("Failed to initialize client for %s: %v", cfg.Name, err)
			continue
		}

		updateInterval, _ := time.ParseDuration(cfg.UpdateInterval)
		cacheTTL, _ := time.ParseDuration(cfg.CacheTTL)

		deviceCtx, deviceCancel := context.WithCancel(context.Background())
		device := &Device{
			Name:           cfg.Name,
			Client:         client,
			SkipCollectors: cfg.SkipCollectors,
			UpdateInterval: updateInterval,
			CacheTTL:       cacheTTL,
			Cache:          make(map[string]any),
			ctx:            deviceCtx,
			cancel:         deviceCancel,
		}

		m.devices = append(m.devices, device)
		log.Printf("Successfully initialized device: %s (hostname: %s)", cfg.Name, client.Hostname)

		// Запуск фонового обновления
		device.wg.Add(1)
		go device.startBackgroundUpdater()
	}

	return m
}

func (m *Manager) GetDevices() []*Device {
	m.mutex.RLock()
	defer m.mutex.RUnlock()

	result := make([]*Device, len(m.devices))
	copy(result, m.devices)
	return result
}

func (m *Manager) GetDevice(name string) (*Device, error) {
	m.mutex.RLock()
	defer m.mutex.RUnlock()

	for i := range m.devices {
		if m.devices[i].Name == name {
			return m.devices[i], nil
		}
	}
	return nil, fmt.Errorf("device %s not found", name)
}

func (m *Manager) Shutdown(ctx context.Context) error {
	m.mutex.RLock()
	devices := m.devices
	m.mutex.RUnlock()

	log.Printf("shutting down %d device(s)...", len(devices))

	// Cancel all device contexts
	for _, dev := range devices {
		if dev.cancel != nil {
			dev.cancel()
		}
	}

	// Wait for all background updaters to finish with timeout
	done := make(chan struct{})
	go func() {
		for _, dev := range devices {
			dev.wg.Wait()
		}
		close(done)
	}()

	select {
	case <-done:
		log.Println("all background updaters stopped successfully")
		return nil
	case <-ctx.Done():
		return fmt.Errorf("shutdown timeout exceeded")
	}
}

func (d *Device) startBackgroundUpdater() {
	defer d.wg.Done()

	if d.UpdateInterval <= 0 {
		return
	}

	log.Printf("starting background updater for device %s (interval: %s)", d.Name, d.UpdateInterval)

	ticker := time.NewTicker(d.UpdateInterval)
	defer ticker.Stop()

	for {
		select {
		case <-ticker.C:
			d.updateCache()

		case <-d.ctx.Done():
			log.Printf("stopping background updater for device %s", d.Name)
			return
		}
	}
}

func (d *Device) updateCache() {
	collectors := map[string]func(context.Context) (any, error){
		"system": func(ctx context.Context) (any, error) {
			return d.Client.GetSystemInfo(ctx)
		},
		"interface": func(ctx context.Context) (any, error) {
			return d.Client.GetInterfaceInfo(ctx)
		},
		"internet": func(ctx context.Context) (any, error) {
			return d.Client.GetInternetStatus(ctx)
		},
		"hotspot": func(ctx context.Context) (any, error) {
			return d.Client.GetHotspotClientInfo(ctx)
		},
		"interface_stats": func(ctx context.Context) (any, error) {
			return d.Client.GetConnectedInterfaceStats(ctx)
		},
		"process": func(ctx context.Context) (any, error) {
			return d.Client.GetProcessInfo(ctx)
		},
	}

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	updatedCount := 0
	for name, fetchFn := range collectors {
		if d.shouldSkipCollector(name) {
			continue
		}

		data, err := fetchFn(ctx)
		if err != nil {
			log.Printf("background update failed for device %s, collector %s: %v", d.Name, name, err)
			continue
		}

		d.CacheMutex.Lock()
		d.Cache[name] = data
		d.LastUpdate = time.Now()
		d.CacheMutex.Unlock()

		updatedCount++
	}

	if updatedCount > 0 {
		log.Printf("background update completed for device %s: %d collector(s) updated", d.Name, updatedCount)
	}
}

func (d *Device) shouldSkipCollector(name string) bool {
	return slices.Contains(d.SkipCollectors, name)
}