package main

import (
	"bufio"
	"io"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"syscall"
	"time"
)

var (
	user32   = syscall.NewLazyDLL("user32.dll")
	kernel32 = syscall.NewLazyDLL("kernel32.dll")

	procGetConsoleWindow         = kernel32.NewProc("GetConsoleWindow")
	procGetCurrentThreadId       = kernel32.NewProc("GetCurrentThreadId")
	procShowWindow               = user32.NewProc("ShowWindow")
	procSetForegroundWindow      = user32.NewProc("SetForegroundWindow")
	procSetWindowPos             = user32.NewProc("SetWindowPos")
	procGetAncestor              = user32.NewProc("GetAncestor")
	procIsIconic                 = user32.NewProc("IsIconic")
	procBringWindowToTop         = user32.NewProc("BringWindowToTop")
	procGetForegroundWindow      = user32.NewProc("GetForegroundWindow")
	procGetWindowThreadProcessId = user32.NewProc("GetWindowThreadProcessId")
	procAttachThreadInput        = user32.NewProc("AttachThreadInput")
)

const (
	SW_RESTORE     = 9
	SW_SHOW        = 5
	GA_ROOTOWNER   = 3
	SWP_NOMOVE     = 0x0002
	SWP_NOSIZE     = 0x0001
	SWP_SHOWWINDOW = 0x0040
)

func getTargetWindow() uintptr {
	hwnd, _, _ := procGetConsoleWindow.Call()
	if hwnd == 0 {
		return 0
	}
	root, _, _ := procGetAncestor.Call(hwnd, GA_ROOTOWNER)
	if root != 0 {
		return root
	}
	return hwnd
}

func bringWindowToTopmost(topmost bool) {
	hwnd := getTargetWindow()
	if hwnd == 0 {
		return
	}

	// 1. 최소화되어 있는 경우 창 복원
	isMin, _, _ := procIsIconic.Call(hwnd)
	if isMin != 0 {
		procShowWindow.Call(hwnd, SW_RESTORE)
	} else {
		procShowWindow.Call(hwnd, SW_SHOW)
	}

	// 2. HWND_TOPMOST (-1) 또는 HWND_NOTOPMOST (-2) 적용
	var insertAfter uintptr
	if topmost {
		insertAfter = ^uintptr(0) // -1 (HWND_TOPMOST)
	} else {
		insertAfter = ^uintptr(1) // -2 (HWND_NOTOPMOST)
	}
	procSetWindowPos.Call(hwnd, insertAfter, 0, 0, 0, 0, SWP_NOMOVE|SWP_NOSIZE|SWP_SHOWWINDOW)

	// 3. 포커스 전환 및 최상위 활성화
	fgWnd, _, _ := procGetForegroundWindow.Call()
	if fgWnd != 0 && fgWnd != hwnd {
		fgThread, _, _ := procGetWindowThreadProcessId.Call(fgWnd, 0)
		curThread, _, _ := procGetCurrentThreadId.Call()
		if fgThread != curThread {
			procAttachThreadInput.Call(curThread, fgThread, 1)
			procSetForegroundWindow.Call(hwnd)
			procBringWindowToTop.Call(hwnd)
			procAttachThreadInput.Call(curThread, fgThread, 0)
		} else {
			procSetForegroundWindow.Call(hwnd)
			procBringWindowToTop.Call(hwnd)
		}
	} else {
		procSetForegroundWindow.Call(hwnd)
		procBringWindowToTop.Call(hwnd)
	}
}

func getPairerExePath() string {
	exePath, err := os.Executable()
	if err != nil {
		return "BlePairer.exe"
	}
	dir := filepath.Dir(exePath)
	return filepath.Join(dir, "BlePairer.exe")
}

func getDeviceDisplayName(key string) string {
	switch key {
	case "K370":
		return "LOGI K370 B"
	case "M240":
		return "LOGI M240 B"
	default:
		return key
	}
}

func runMonitor() {
	pairerExe := getPairerExePath()

	for {
		log.Println("Starting Logitech Bluetooth monitor daemon (LOGI K370 B + LOGI M240 B)...")
		cmd := exec.Command(pairerExe, "monitor")
		cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}

		stdout, err := cmd.StdoutPipe()
		if err != nil {
			log.Printf("Stdout 파이프 연결 오류: %v", err)
			time.Sleep(2 * time.Second)
			continue
		}

		stderr, err := cmd.StderrPipe()
		if err == nil {
			go io.Copy(os.Stderr, stderr)
		}

		if err := cmd.Start(); err != nil {
			log.Printf("BlePairer 실행 실패: %v", err)
			time.Sleep(2 * time.Second)
			continue
		}

		scanner := bufio.NewScanner(stdout)
		lastStatusMap := make(map[string]string)

		for scanner.Scan() {
			line := strings.TrimSpace(scanner.Text())
			if line == "" {
				continue
			}

			if strings.HasPrefix(line, "[DEBUG]") {
				log.Println(line)
			} else if strings.HasPrefix(line, "STATUS:") {
				parts := strings.Split(strings.TrimPrefix(line, "STATUS:"), ":")
				if len(parts) == 2 {
					key := parts[0]
					status := parts[1]
					devName := getDeviceDisplayName(key)

					if lastStatusMap[key] != status {
						switch status {
						case "CONNECTED":
							log.Printf("[%s] ★ 정상 연결되었습니다 (동작 중)", devName)
						case "PAIRED_WAITING":
							log.Printf("[%s] 연결 해제됨 -> 대기 모드 (재연결 또는 페어링 신호 대기)", devName)
						case "SEARCHING_FOR_PAIR":
							if key == "K370" {
								log.Printf("[%s] 등록 대기 중 (채널 버튼을 3초간 길게 누르세요)", devName)
							} else {
								log.Printf("[%s] 등록 대기 중 (마우스 전원/페어링 버튼을 누르세요)", devName)
							}
						default:
							log.Printf("[%s] 상태 변경: %s", devName, status)
						}
						lastStatusMap[key] = status
					}
				}
			} else if strings.HasPrefix(line, "DEVICE_DETECTED:") {
				parts := strings.Split(strings.TrimPrefix(line, "DEVICE_DETECTED:"), ":")
				if len(parts) >= 2 {
					key := parts[0]
					mac := parts[1]
					devName := getDeviceDisplayName(key)

					if key == "K370" {
						log.Printf("[%s] ★ 키보드 신호 포착! 창을 최상위(Topmost)로 띄웁니다... (%s)", devName, mac)
						bringWindowToTopmost(true)
					} else {
						log.Printf("[%s] ★ 마우스 신호 포착! 자동 페어링을 진행합니다... (%s)", devName, mac)
					}
				}
			} else if strings.HasPrefix(line, "PIN_REQUIRED:") {
				parts := strings.Split(strings.TrimPrefix(line, "PIN_REQUIRED:"), ":")
				if len(parts) >= 2 {
					key := parts[0]
					pin := parts[1]
					devName := getDeviceDisplayName(key)

					bringWindowToTopmost(true)
					log.Printf("======================================================")
					log.Printf("★ [%s] 페어링 번호 감지! 키보드에서 [%s] 입력 후 [Enter]를 누르세요!", devName, pin)
					log.Printf("======================================================")
				}
			} else if strings.HasPrefix(line, "PAIRED_AND_CONNECTED:") {
				parts := strings.Split(strings.TrimPrefix(line, "PAIRED_AND_CONNECTED:"), ":")
				if len(parts) >= 2 {
					key := parts[0]
					mac := parts[1]
					devName := getDeviceDisplayName(key)

					log.Printf("======================================================")
					log.Printf("[%s] ★ 블루투스 페어링 & 연결 완료! (%s)", devName, mac)
					log.Printf("======================================================")

					if key == "K370" {
						go func() {
							time.Sleep(3 * time.Second)
							bringWindowToTopmost(false)
						}()
					}
				}
			} else {
				log.Println(line)
			}
		}

		cmd.Wait()
		log.Printf("BlePairer 데몬 종료됨. 2초 후 재시작합니다...")
		time.Sleep(2 * time.Second)
	}
}

func main() {
	runMonitor()
}