package main

import (
	"fmt"
	"log"
	"strings"
	"time"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
	"go.bug.st/serial"
)

type UARTApp struct {
	app              fyne.App
	window           fyne.Window
	portEntry        *widget.Select
	baudEntry        *widget.Select
	lineEnding       *widget.RadioGroup
	connectButton    *widget.Button
	disconnectButton *widget.Button
	sendEntry        *widget.Entry
	sendButton       *widget.Button
	receiveText      *widget.Entry
	statusLabel      *widget.Label

	port          serial.Port
	isConnected   bool
	receiveBuffer strings.Builder
}

func main() {
	myApp := app.New()
	uartApp := &UARTApp{
		app:    myApp,
		window: myApp.NewWindow("UART Terminal"),
	}

	uartApp.createUI()
	uartApp.window.Resize(fyne.NewSize(800, 600)) // Увеличиваем начальный размер окна
	uartApp.window.ShowAndRun()
}

func (a *UARTApp) createUI() {
	// Port selection
	a.portEntry = widget.NewSelect([]string{}, nil)
	a.refreshPorts()

	// Baud rate selection
	a.baudEntry = widget.NewSelect([]string{
		"300", "600", "1200", "2400", "4800", "9600",
		"14400", "19200", "28800", "38400", "57600", "115200",
	}, nil)
	a.baudEntry.SetSelected("9600")

	// Line ending selection
	a.lineEnding = widget.NewRadioGroup([]string{"None", "CR", "LF", "CR+LF"}, nil)
	a.lineEnding.SetSelected("CR+LF")

	// Buttons
	a.connectButton = widget.NewButton("Connect", a.connect)
	a.disconnectButton = widget.NewButton("Disconnect", a.disconnect)
	a.disconnectButton.Disable()

	// Send section
	a.sendEntry = widget.NewEntry()
	a.sendEntry.SetPlaceHolder("Enter message to send")
	a.sendButton = widget.NewButton("Send", a.sendMessage)
	a.sendButton.Disable()

	// Receive section
	a.receiveText = widget.NewMultiLineEntry()
	a.receiveText.Wrapping = fyne.TextWrapOff

	// Status bar
	a.statusLabel = widget.NewLabel("Disconnected")

	// Создаем контейнер с настройками
	settingsBox := container.NewVBox(
		widget.NewLabel("Serial Port Settings"),
		container.NewHBox(widget.NewLabel("Port:"), a.portEntry, widget.NewButton("Refresh", a.refreshPorts)),
		container.NewHBox(widget.NewLabel("Baud Rate:"), a.baudEntry),
		container.NewHBox(widget.NewLabel("Line Ending:"), a.lineEnding),
		container.NewHBox(a.connectButton, a.disconnectButton),
	)

	// Контейнер для отправки сообщений
	sendBox := container.NewVBox(
		widget.NewLabel("Send Message"),
		a.sendEntry,
		a.sendButton,
	)

	// Верхняя часть (настройки + отправка)
	topSection := container.NewHSplit(
		container.NewVScroll(settingsBox),
		sendBox,
	)
	topSection.SetOffset(0.4) // Настройки занимают 40% верхней части

	// Нижняя часть (полученные данные)
	receiveBox := container.NewBorder(
		widget.NewLabel("Received Data (one message per line)"),
		nil,
		nil,
		nil,
		container.NewScroll(a.receiveText),
	)

	// Главный контейнер с правильными пропорциями
	mainContent := container.NewVSplit(
		topSection,
		receiveBox,
	)
	mainContent.SetOffset(0.3) // Верхняя часть занимает 30% высоты

	// Создаем окончательный макет с растягиванием
	finalLayout := container.NewBorder(
		nil,
		a.statusLabel,
		nil,
		nil,
		mainContent,
	)

	a.window.SetContent(finalLayout)
}

func (a *UARTApp) refreshPorts() {
	ports, err := serial.GetPortsList()
	if err != nil {
		log.Println("Error getting ports list:", err)
		return
	}

	if len(ports) == 0 {
		ports = []string{"No ports available"}
		a.portEntry.Disable()
	} else {
		a.portEntry.Enable()
	}

	a.portEntry.Options = ports
	if len(ports) > 0 && ports[0] != "No ports available" {
		a.portEntry.SetSelected(ports[0])
	}
}

func (a *UARTApp) connect() {
	if a.isConnected {
		return
	}

	portName := a.portEntry.Selected
	if portName == "" {
		a.statusLabel.SetText("Please select a port")
		return
	}

	baudRate := a.baudEntry.Selected
	if baudRate == "" {
		a.statusLabel.SetText("Please select a baud rate")
		return
	}

	mode := &serial.Mode{
		BaudRate: mustParseInt(baudRate),
	}

	port, err := serial.Open(portName, mode)
	if err != nil {
		a.statusLabel.SetText("Error opening port: " + err.Error())
		return
	}

	a.port = port
	a.isConnected = true
	a.connectButton.Disable()
	a.disconnectButton.Enable()
	a.sendButton.Enable()
	a.statusLabel.SetText("Connected to " + portName + " at " + baudRate + " baud")

	a.receiveBuffer.Reset()
	go a.readFromPort()
}

func (a *UARTApp) disconnect() {
	if !a.isConnected || a.port == nil {
		return
	}

	err := a.port.Close()
	if err != nil {
		a.statusLabel.SetText("Error closing port: " + err.Error())
	} else {
		a.statusLabel.SetText("Disconnected")
	}

	a.isConnected = false
	a.port = nil
	a.connectButton.Enable()
	a.disconnectButton.Disable()
	a.sendButton.Disable()
}

func (a *UARTApp) sendMessage() {
	if !a.isConnected || a.port == nil {
		a.statusLabel.SetText("Not connected")
		return
	}

	message := a.sendEntry.Text
	if message == "" {
		return
	}

	// Add line ending based on selection
	switch a.lineEnding.Selected {
	case "CR":
		message += "\r"
	case "LF":
		message += "\n"
	case "CR+LF":
		message += "\r\n"
	}

	_, err := a.port.Write([]byte(message))
	if err != nil {
		a.statusLabel.SetText("Send error: " + err.Error())
	} else {
		a.sendEntry.SetText("")
	}
}

func (a *UARTApp) readFromPort() {
	buf := make([]byte, 1024)
	for a.isConnected && a.port != nil {
		n, err := a.port.Read(buf)
		if err != nil {
			a.disconnect()
			a.app.Quit()
			return
		}

		if n > 0 {
			received := string(buf[:n])
			a.processReceivedData(received)
		}

		time.Sleep(100 * time.Millisecond)
	}
}

func (a *UARTApp) processReceivedData(data string) {
	// Добавляем данные в буфер
	a.receiveBuffer.WriteString(data)

	// Получаем текущий текст и добавляем новые данные с новой строки
	currentText := a.receiveText.Text
	if currentText != "" {
		currentText += "\n"
	}
	currentText += data

	// Обновляем текстовое поле в UI
	a.receiveText.SetText(currentText)

	// Прокручиваем вниз
	a.receiveText.CursorRow = len(strings.Split(currentText, "\n")) - 1
	a.receiveText.Refresh()
}

func mustParseInt(s string) int {
	var result int
	_, err := fmt.Sscanf(s, "%d", &result)
	if err != nil {
		return 9600 // default
	}
	return result
}