Scontrini-TUI-Client/main.go

package main

import (
	"fmt"
	"os"
	"strings"

	"github.com/gdamore/tcell/v2"
	"github.com/rivo/tview"
)

const (
	USB_SERIAL_PORT = "/dev/ttyUSB0"
	MAIN_WIDTH      = 240
	MAIN_HEIGHT     = 55
)

var (
	App   *tview.Application
	Pages *tview.Pages
)

func main() {
	stat, _ := os.Stdin.Stat()

	// check if data is being piped from stdin
	if (stat.Mode() & os.ModeCharDevice) == 0 {
		printFromStdIn()
	} else {
		startTui()
	}
}

func writeToPrinter(text string) {
	// move outside
	serial_port, err := os.OpenFile(USB_SERIAL_PORT, os.O_WRONLY, 0755)
	if err != nil {
		panic(err)
	}

	fmt.Fprintln(serial_port, text)
}

/**
* If text gets piped from terminal, print it
 */
func printFromStdIn() {
	text := ""
	fmt.Scanf("%s", text)
	writeToPrinter(text)
}

func startTui() {
	App = tview.NewApplication()

	print_page := createPrintPage(MAIN_WIDTH, MAIN_HEIGHT)
	pizza_page := createPizzaPage(MAIN_WIDTH, MAIN_HEIGHT)

	Pages = tview.NewPages().
		AddPage("print", print_page, true, true).
		AddPage("pizza", pizza_page, true, false)

	if err := App.SetRoot(Pages, true).Run(); err != nil {
		panic(err)
	}
}

/**
* Return a page with a TextView used to print
 */
func createPrintPage(width, height int) *tview.Grid {
	page := tview.NewGrid()

	textview := tview.NewTextView().
		SetText("[green]SCRIVI QUELLO CHE VUOI STAMPARE[white]").
		SetTextAlign(tview.AlignCenter).
		SetDynamicColors(true)
	setCommonBoxAttributes(textview.Box, "Scontrini")

	textarea := tview.NewTextArea()
	setCommonBoxAttributes(textarea.Box, "")

	print_button := tview.NewButton("Stampa").
		SetSelectedFunc(func() {
			writeToPrinter(textarea.GetText())
		})

	pizza_button := tview.NewButton("Pizza").
		SetSelectedFunc(func() {
			Pages.SwitchToPage("pizza")
		})

	// define keys and behaviour for selected events
	textarea.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
		if event.Key() == tcell.KeyTAB {
			App.SetFocus(print_button)
			return nil
		}

		return event
	})

	print_button.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
		if event.Key() == tcell.KeyTAB {
			App.SetFocus(pizza_button)
			return nil
		}

		return event
	})

	pizza_button.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
		if event.Key() == tcell.KeyTAB {
			App.SetFocus(textarea)
			return nil
		}

		return event
	})

	page.SetColumns(1/5, 1/5, 1/5, 1/5, 1/5).
		SetRows(1/5, 1/5, 1/5, 1/5, 1/5).
		AddItem(textview, 1, 1, 1, 3, 0, 0, false).
		AddItem(textarea, 2, 1, 1, 3, 0, 0, true).
		AddItem(print_button, 3, 1, 1, 1, 0, 0, false).
		AddItem(pizza_button, 3, 3, 1, 1, 0, 0, false)

	return page
}

/**
* Return a page with a Table used to print the pizza order
 */
func createPizzaPage(width, height int) *tview.Grid {
	pizza_page := tview.NewGrid()

	textview := tview.NewTextView().
		SetText("[green]STAMPA LE PIZZE[white]").
		SetTextAlign(tview.AlignCenter).
		SetDynamicColors(true)
	setCommonBoxAttributes(textview.Box, "Scontrini")

	row_index := 0

	table := tview.NewTable().
		SetBorders(true).
		InsertRow(row_index).
		InsertColumn(0).
		InsertColumn(1)
	setCommonBoxAttributes(table.Box, "")

	table.SetCellSimple(0, 0, "Quantità")
	table.SetCellSimple(0, 1, "Pizza")

	print_button := tview.NewButton("Stampa").
		SetSelectedFunc(func() {
			Pages.SwitchToPage("print")
		})

	pizza_button := tview.NewButton("Pizza").
		SetSelectedFunc(func() {
			printPizza(table)
		})

	// define keys and behaviour for selected events
	table.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
		if event.Key() == tcell.KeyTAB {
			App.SetFocus(print_button)
			return nil
		}

		if event.Key() == tcell.KeyEnter {
			row_index += 1
			table.InsertRow(row_index)
			App.Draw()
			return nil
		}

		return event
	})

	print_button.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
		if event.Key() == tcell.KeyTAB {
			App.SetFocus(pizza_button)
			return nil
		}

		return event
	})

	pizza_button.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
		if event.Key() == tcell.KeyTAB {
			App.SetFocus(table)
			return nil
		}

		return event
	})

	pizza_page.SetColumns(1/5, 1/5, 1/5, 1/5, 1/5).
		SetRows(1/5, 1/5, 1/5, 1/5, 1/5).
		AddItem(textview, 1, 1, 1, 3, 0, 0, false).
		AddItem(table, 2, 2, 1, 1, 0, 0, true).
		AddItem(print_button, 3, 1, 1, 1, 0, 0, false).
		AddItem(pizza_button, 3, 3, 1, 1, 0, 0, false)

	return pizza_page
}

/**
* Format the pizza order table and print it
 */
func printPizza(table *tview.Table) {
	// TODO
}

/**
* Create borders around the Box and add the title
 */
func setCommonBoxAttributes(box *tview.Box, title string) {
	box.SetBorder(true).
		SetTitle(strings.ToUpper(title)).
		SetBorderPadding(2, 2, 4, 4)
}