package device

import (
	"fmt"
	"log"
	"sync"

	"visiona-local/server/internal/driver"
	"visiona-local/server/internal/driver/kneron"
	"visiona-local/server/pkg/logger"
)

type Manager struct {
	registry       *DriverRegistry
	sessions       map[string]*DeviceSession
	eventBus       chan DeviceEvent
	scriptPath     string
	logBroadcaster *logger.Broadcaster
	mu             sync.RWMutex
}

func NewManager(registry *DriverRegistry, scriptPath string) *Manager {
	return &Manager{
		registry:   registry,
		sessions:   make(map[string]*DeviceSession),
		eventBus:   make(chan DeviceEvent, 100),
		scriptPath: scriptPath,
	}
}

// SetLogBroadcaster attaches a log broadcaster so that Kneron driver
// and bridge logs are forwarded to the frontend.
func (m *Manager) SetLogBroadcaster(b *logger.Broadcaster) {
	m.logBroadcaster = b
	// Also set on any already-registered kneron drivers.
	m.mu.RLock()
	defer m.mu.RUnlock()
	for _, s := range m.sessions {
		if kd, ok := s.Driver.(*kneron.KneronDriver); ok {
			kd.SetLogBroadcaster(b)
		}
	}
}

func (m *Manager) Start() {
	// Detect real Kneron devices (KL520, KL720, etc.) via Python bridge.
	devices := kneron.DetectDevices(m.scriptPath)
	if len(devices) == 0 {
		log.Println("No Kneron devices detected")
		return
	}

	m.mu.Lock()
	defer m.mu.Unlock()
	for _, info := range devices {
		d := kneron.NewKneronDriver(info, m.scriptPath)
		if m.logBroadcaster != nil {
			d.SetLogBroadcaster(m.logBroadcaster)
		}
		m.sessions[info.ID] = NewSession(d)
		log.Printf("Registered Kneron device: %s (%s, type=%s)", info.Name, info.ID, info.Type)
	}
}

// Rescan re-detects connected Kneron devices. New devices are registered,
// removed devices are cleaned up, and existing devices are left untouched.
func (m *Manager) Rescan() []driver.DeviceInfo {
	detected := kneron.DetectDevices(m.scriptPath)

	// Build a set of detected device IDs.
	detectedIDs := make(map[string]driver.DeviceInfo, len(detected))
	for _, info := range detected {
		detectedIDs[info.ID] = info
	}

	m.mu.Lock()
	defer m.mu.Unlock()

	// Remove devices that are no longer present.
	for id, s := range m.sessions {
		if _, exists := detectedIDs[id]; !exists {
			log.Printf("Device removed: %s", id)
			s.Driver.Disconnect()
			delete(m.sessions, id)
		}
	}

	// Add newly detected devices.
	for _, info := range detected {
		if _, exists := m.sessions[info.ID]; !exists {
			d := kneron.NewKneronDriver(info, m.scriptPath)
			if m.logBroadcaster != nil {
				d.SetLogBroadcaster(m.logBroadcaster)
			}
			m.sessions[info.ID] = NewSession(d)
			log.Printf("Registered Kneron device: %s (%s, type=%s)", info.Name, info.ID, info.Type)
		}
	}

	// Return current list.
	devices := make([]driver.DeviceInfo, 0, len(m.sessions))
	for _, s := range m.sessions {
		devices = append(devices, s.Driver.Info())
	}
	return devices
}

func (m *Manager) ListDevices() []driver.DeviceInfo {
	m.mu.RLock()
	defer m.mu.RUnlock()
	devices := make([]driver.DeviceInfo, 0, len(m.sessions))
	for _, s := range m.sessions {
		devices = append(devices, s.Driver.Info())
	}
	return devices
}

func (m *Manager) GetDevice(id string) (*DeviceSession, error) {
	m.mu.RLock()
	defer m.mu.RUnlock()
	s, ok := m.sessions[id]
	if !ok {
		return nil, fmt.Errorf("device not found: %s", id)
	}
	return s, nil
}

func (m *Manager) Connect(id string) error {
	s, err := m.GetDevice(id)
	if err != nil {
		return err
	}
	if err := s.Driver.Connect(); err != nil {
		return err
	}
	m.eventBus <- DeviceEvent{Event: "updated", Device: s.Driver.Info()}
	return nil
}

func (m *Manager) Disconnect(id string) error {
	s, err := m.GetDevice(id)
	if err != nil {
		return err
	}
	if err := s.Driver.Disconnect(); err != nil {
		return err
	}
	m.eventBus <- DeviceEvent{Event: "updated", Device: s.Driver.Info()}
	return nil
}

func (m *Manager) Events() <-chan DeviceEvent {
	return m.eventBus
}