Receipt Printing Added Lol, still need to have tests mostly for the text conversion

Author: Ayidana-Aboraah

Debug/Error_Handling.go

@@ -29,8 +29,10 @@ func HandleKnownError(id int, condition bool, w fyne.Window) bool {
 	return false
 }
 
-func ShowError(state string, err error, w fyne.Window) {
+func ShowError(state string, err error, w fyne.Window) bool {
 	if err != nil {
 		dialog.ShowInformation("Oops", "Error while"+state+"\nError: "+err.Error(), w)
+		return true
 	}
+	return false
 }

Main.go

@@ -4,6 +4,7 @@ import (
 	"BronzeHermes/Database"
 	"BronzeHermes/Debug"
 	"BronzeHermes/Graph"
+	"BronzeHermes/Printer"
 	"BronzeHermes/UI"
 	unknown "BronzeHermes/Unknown"
 	"fmt"
@@ -20,6 +21,8 @@ import (
 	"fyne.io/fyne/v2/widget"
 )
 
+var printer Printer.Printer
+
 func main() {
 	a := app.NewWithID("PINKSTONE")
 	go Graph.StartServer()
@@ -42,13 +45,16 @@ func CreateWindow(a fyne.App) {
 			Database.CleanUpDeadItems()
 			Database.SaveData()
 			Database.SaveBackUp()
+			if printer.Active {
+				printer.Close()
+			}
 		},
 	)
 
 	Debug.ShowError("Loading Data", Database.LoadData(), w)
 
 	w.SetContent(container.NewVBox(container.NewAppTabs(
-		container.NewTabItem("Main", makeMainMenu(a)),
+		container.NewTabItem("Main", makeMainMenu()),
 		container.NewTabItem("Shop", makeShoppingMenu()),
 		container.NewTabItem("Inventory", Database.MakeInfoMenu(w)),
 		container.NewTabItem("Report", makeReportMenu()),
@@ -66,7 +72,7 @@ func CreateWindow(a fyne.App) {
 	w.ShowAndRun()
 }
 
-func makeMainMenu(a fyne.App) fyne.CanvasObject {
+func makeMainMenu() fyne.CanvasObject {
 	var SignInStartUp dialog.Dialog
 	var CreateUser dialog.Dialog
 	usrData := binding.NewIntList()
@@ -128,6 +134,7 @@ func makeMainMenu(a fyne.App) fyne.CanvasObject {
 		widget.NewButton("Save Backup Data", func() {
 			go Debug.ShowError("Backing up Data", Database.SaveBackUp(), w)
 		}),
+
 		widget.NewButton("Load Backup Data", func() {
 			dialog.ShowConfirm("Are you Sure?", "Are you sure you want to load the backup data?", func(b bool) {
 				if !b {
@@ -137,6 +144,64 @@ func makeMainMenu(a fyne.App) fyne.CanvasObject {
 				dialog.ShowInformation("Loaded", "Back Up Loaded", w)
 			}, w)
 		}),
+
+		widget.NewButton("Connect Printer", func() {
+			devices, idxes, err := Printer.FindUSBDevices()
+			Debug.ShowError("Looking for USB Devices", err, w)
+
+			devListData := binding.NewIntList()
+			devListData.Set(idxes)
+			devList := widget.NewListWithData(devListData,
+				func() fyne.CanvasObject {
+					return container.NewBorder(nil, nil, nil, nil, widget.NewLabel(""))
+				},
+				func(di binding.DataItem, co fyne.CanvasObject) {
+					idx, _ := di.(binding.Int).Get()
+					co.(*fyne.Container).Objects[0].(*widget.Label).SetText(devices[idx].Product)
+				})
+
+			devList.OnSelected = func(id widget.ListItemID) {
+				dialog.ShowCustomConfirm(devices[id].Product, "Select", "Close",
+					widget.NewLabel(fmt.Sprintf("ID: %d\nProduct: %s\nVender ID: %d\nManufacturer: %s\nSerial: %s\nPath: %s",
+						devices[id].ProductID, devices[id].Product, devices[id].VendorID, devices[id].Manufacturer, devices[id].Serial, devices[id].Path)), func(b bool) {
+
+						if !b {
+							return
+						}
+
+						p, e := Printer.Init(devices[id])
+
+						if Debug.ShowError("Selecting "+devices[id].Product, e, w) {
+							return
+						}
+
+						if printer.Active {
+							printer.Close()
+						}
+
+						printer = p
+					}, w)
+				devList.Unselect(id)
+			}
+
+			dialog.ShowCustom("Devices", "Close", container.NewVBox(devList), w)
+		}),
+
+		widget.NewButton("Test Printing", func() {
+			if printer.Active {
+				entry := widget.NewEntry()
+				dialog.ShowForm("", "Send", "Close", []*widget.FormItem{
+					widget.NewFormItem("Message", entry),
+				}, func(b bool) {
+					if !b {
+						return
+					}
+					printer.Print(Printer.ConvertForPrinter(entry.Text))
+				}, w)
+			} else {
+				dialog.ShowInformation("", "No Printer Connected", w)
+			}
+		}),
 	)
 }
 
@@ -206,8 +271,8 @@ func makeShoppingMenu() fyne.CanvasObject {
 							widget.NewLabelWithStyle("PINKSTONE TRADING", fyne.TextAlignCenter, fyne.TextStyle{Bold: true}),
 							widget.NewLabelWithStyle(receipt, fyne.TextAlignCenter, fyne.TextStyle{}),
 						), func(printing bool) {
-							if printing {
-								// TODO: Send print msg to Printer & the receipt,
+							if printing && printer.Active {
+								printer.Print(Printer.ConvertForPrinter(receipt))
 							}
 						}, w)
 					}, w)

Printer/printer.go

@@ -0,0 +1,47 @@
+package Printer
+
+import (
+	"strings"
+
+	"github.com/karalabe/usb"
+)
+
+type Printer struct {
+	device usb.Device
+	Active bool
+}
+
+func FindUSBDevices() (devs []usb.DeviceInfo, out []int, err error) {
+	devs, err = usb.Enumerate(0, 0)
+	for i := range devs {
+		out = append(out, i)
+	}
+	return
+}
+
+func Init(dev usb.DeviceInfo) (printer Printer, err error) {
+	printer.device, err = dev.Open()
+	printer.Active = true
+	return
+}
+
+func (p Printer) Close() {
+	p.device.Close()
+}
+
+func (p Printer) Print(out string) {
+	p.device.Write([]byte(out))
+}
+
+func ConvertForPrinter(in string) string {
+	in = string([]byte{0x1B, '@'}) + in // Adding intialisation to the beginnning
+
+	// check for byte(183) and convert the line into Underline
+	// in = strings.replaceAll(in, string([]byte{183}), string([]byte{0x1B, }))
+
+	in = strings.ReplaceAll(in, "\n", string([]byte{0x1B, 'd', 1})) // replacing /n with line feed
+
+	in = string([]byte{0x1B, 'V', 66}) + in // add cut command
+
+	return in
+}

go.mod

@@ -5,6 +5,7 @@ go 1.18
 require (
 	fyne.io/fyne/v2 v2.1.4
 	github.com/go-echarts/go-echarts/v2 v2.2.4
+	github.com/karalabe/usb v0.0.2
 )
 
 require (

go.sum

@@ -28,6 +28,8 @@ github.com/goki/freetype v0.0.0-20181231101311-fa8a33aabaff h1:W71vTCKoxtdXgnm1E
 github.com/goki/freetype v0.0.0-20181231101311-fa8a33aabaff/go.mod h1:wfqRWLHRBsRgkp5dmbG56SA0DmVtwrF5N3oPdI8t+Aw=
 github.com/jackmordaunt/icns v0.0.0-20181231085925-4f16af745526/go.mod h1:UQkeMHVoNcyXYq9otUupF7/h/2tmHlhrS2zw7ZVvUqc=
 github.com/josephspurrier/goversioninfo v0.0.0-20200309025242-14b0ab84c6ca/go.mod h1:eJTEwMjXb7kZ633hO3Ln9mBUCOjX2+FlTljvpl9SYdE=
+github.com/karalabe/usb v0.0.2 h1:M6QQBNxF+CQ8OFvxrT90BA0qBOXymndZnk5q235mFc4=
+github.com/karalabe/usb v0.0.2/go.mod h1:Od972xHfMJowv7NGVDiWVxk2zxnWgjLlJzE+F4F7AGU=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=