package main

import (
	"log"
	"os"
	"os/exec"
	"sync"
	"syscall"
	"time"
)

// ScannerType identifies scanner type
type ScannerType string

const (
	ScannerBLE  ScannerType = "ble"
	ScannerWiFi ScannerType = "wifi"
)

// ScannerManager manages BLE and WiFi scanner processes
type ScannerManager struct {
	binDir string
	debug  bool

	bleCmd    *exec.Cmd
	wifiCmd   *exec.Cmd
	bleRunning  bool
	wifiRunning bool
	mu        sync.Mutex

	stopChan chan struct{}
}

// NewScannerManager creates a new scanner manager
func NewScannerManager(binDir string, debug bool) *ScannerManager {
	return &ScannerManager{
		binDir:   binDir,
		debug:    debug,
		stopChan: make(chan struct{}),
	}
}

// StartBLE starts the BLE scanner process
func (m *ScannerManager) StartBLE(zmqAddr string) error {
	m.mu.Lock()
	defer m.mu.Unlock()

	if m.bleRunning {
		return nil
	}

	binPath := m.binDir + "/ble-scanner"
	args := []string{"-zmq", zmqAddr}
	if m.debug {
		args = append(args, "-debug")
	}

	cmd := exec.Command(binPath, args...)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr

	// Set process group for clean termination
	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}

	if err := cmd.Start(); err != nil {
		return err
	}

	m.bleCmd = cmd
	m.bleRunning = true
	log.Printf("[scanner] BLE scanner started (pid=%d)", cmd.Process.Pid)

	// Monitor process
	go m.monitorProcess(ScannerBLE, cmd)

	return nil
}

// StopBLE stops the BLE scanner process
func (m *ScannerManager) StopBLE() {
	m.mu.Lock()
	defer m.mu.Unlock()

	if !m.bleRunning || m.bleCmd == nil {
		return
	}

	log.Printf("[scanner] Stopping BLE scanner...")

	// Send SIGTERM to process group
	if m.bleCmd.Process != nil {
		syscall.Kill(-m.bleCmd.Process.Pid, syscall.SIGTERM)
	}

	// Wait with timeout
	done := make(chan error, 1)
	go func() {
		done <- m.bleCmd.Wait()
	}()

	select {
	case <-done:
	case <-time.After(3 * time.Second):
		// Force kill
		if m.bleCmd.Process != nil {
			syscall.Kill(-m.bleCmd.Process.Pid, syscall.SIGKILL)
		}
	}

	m.bleRunning = false
	m.bleCmd = nil
	log.Printf("[scanner] BLE scanner stopped")
}

// StartWiFi starts the WiFi scanner process
func (m *ScannerManager) StartWiFi(zmqAddr, iface string) error {
	m.mu.Lock()
	defer m.mu.Unlock()

	if m.wifiRunning {
		return nil
	}

	binPath := m.binDir + "/wifi-scanner"
	args := []string{"-zmq", zmqAddr, "-iface", iface}
	if m.debug {
		args = append(args, "-debug")
	}

	cmd := exec.Command(binPath, args...)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}

	if err := cmd.Start(); err != nil {
		return err
	}

	m.wifiCmd = cmd
	m.wifiRunning = true
	log.Printf("[scanner] WiFi scanner started (pid=%d)", cmd.Process.Pid)

	// Monitor process
	go m.monitorProcess(ScannerWiFi, cmd)

	return nil
}

// StopWiFi stops the WiFi scanner process
func (m *ScannerManager) StopWiFi() {
	m.mu.Lock()
	defer m.mu.Unlock()

	if !m.wifiRunning || m.wifiCmd == nil {
		return
	}

	log.Printf("[scanner] Stopping WiFi scanner...")

	if m.wifiCmd.Process != nil {
		syscall.Kill(-m.wifiCmd.Process.Pid, syscall.SIGTERM)
	}

	done := make(chan error, 1)
	go func() {
		done <- m.wifiCmd.Wait()
	}()

	select {
	case <-done:
	case <-time.After(3 * time.Second):
		if m.wifiCmd.Process != nil {
			syscall.Kill(-m.wifiCmd.Process.Pid, syscall.SIGKILL)
		}
	}

	m.wifiRunning = false
	m.wifiCmd = nil
	log.Printf("[scanner] WiFi scanner stopped")
}

// IsBLERunning returns true if BLE scanner is running
func (m *ScannerManager) IsBLERunning() bool {
	m.mu.Lock()
	defer m.mu.Unlock()
	return m.bleRunning
}

// IsWiFiRunning returns true if WiFi scanner is running
func (m *ScannerManager) IsWiFiRunning() bool {
	m.mu.Lock()
	defer m.mu.Unlock()
	return m.wifiRunning
}

// StopAll stops all scanners
func (m *ScannerManager) StopAll() {
	close(m.stopChan)
	m.StopBLE()
	m.StopWiFi()
}

// monitorProcess monitors a scanner process and marks it as stopped when it exits
func (m *ScannerManager) monitorProcess(typ ScannerType, cmd *exec.Cmd) {
	err := cmd.Wait()

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

	switch typ {
	case ScannerBLE:
		m.bleRunning = false
		m.bleCmd = nil
		if err != nil {
			log.Printf("[scanner] BLE scanner exited: %v", err)
		} else {
			log.Printf("[scanner] BLE scanner exited normally")
		}
	case ScannerWiFi:
		m.wifiRunning = false
		m.wifiCmd = nil
		if err != nil {
			log.Printf("[scanner] WiFi scanner exited: %v", err)
		} else {
			log.Printf("[scanner] WiFi scanner exited normally")
		}
	}
}