fix: 整理PrinterService——Clear错误返回+OpenPRN回退

internal/modules/printer/service/service.go

@@ -7,23 +7,18 @@ import (
 	"wails-app/internal/global"
 )
 
-// EMD807 CSN SDK DLL 路径 (x64)
 const sdkDllPath = `D:\lq\资料\停车场 道闸 车牌识别 收费机\票机自制\打印机\EMD807嵌入式热敏票据打印模组\5、SDK指令集\Win_SDK_Demo_2023_08_14\Win_SDK_Demo_2023_08_14\lib\x64\CsnPrinterLibs.dll`
 
 type PrintService struct{}
 
-func NewPrintService() *PrintService {
-	return &PrintService{}
-}
+func NewPrintService() *PrintService { return &PrintService{} }
 
-// PrintTicket 打印入场小票
 func (s *PrintService) PrintTicket(printerID uint, lotName, channelCode, plateNo string, ticketID uint, ticketNo string) error {
 	var printer dao.Printer
 	if err := global.GVA_DB.First(&printer, printerID).Error; err != nil {
 		return fmt.Errorf("打印机未配置: id=%d", printerID)
 	}
 
-	// 根据 port_name 判断连接类型
 	var err error
 	var srl *SerialPrinter
 	var usbHandle uintptr
@@ -35,43 +30,32 @@ func (s *PrintService) PrintTicket(printerID uint, lotName, channelCode, plateNo
 			defer srl.Close()
 		}
 	} else {
-		// USB → 使用 CSN SDK 直连
 		err = InitCSN(sdkDllPath)
-		if err == nil {
-			name := printer.PortName
-			// 如果配置的是 "USB" 或 "auto"，自动枚举
-			if name == "USB" || name == "auto" || name == "" {
-				name = Csn_EnumUSB()
-				if name == "" {
-					name = printer.PortName
-				}
-			}
-			// 先试 OpenUSB，失败则试 OpenPRN（Windows 打印机名）
-			usbHandle, err = csn_OpenUSB(name)
-			if err != nil {
-				usbHandle, err = csn_OpenPRN(name)
-			}
-			if err == nil {
-				useCSN = true
-				defer csn_Close(usbHandle)
-			}
+		if err != nil {
+			return fmt.Errorf("加载 CSN DLL 失败: %w (path=%s)", err, sdkDllPath)
 		}
-		if !useCSN {
-			err = fmt.Errorf("无法连接打印机: %s", printer.PortName)
+		// 尝试 OpenUSB → OpenPRN
+		name := printer.PortName
+		if name == "USB" || name == "auto" || name == "" {
+			name = Csn_EnumUSB()
 		}
-	}
-	if err != nil {
-		global.GVA_DB.Model(&printer).Update("status", "offline")
-		return fmt.Errorf("连接打印机失败: %w", err)
+		usbHandle, err = csn_OpenUSB(name)
+		if err != nil {
+			usbHandle, err = csn_OpenPRN(name)
+		}
+		if err != nil {
+			return fmt.Errorf("打开打印机失败: %w (name=%s)", err, name)
+		}
+		useCSN = true
+		defer csn_Close(usbHandle)
 	}
 
 	now := time.Now().Format("02-01-2006 15:04:05")
 	slipNo := fmt.Sprintf("%d", ticketID)
 
-	// ── CSN SDK 模式 ──
 	if useCSN {
 		csn_Reset()
-		csn_Align(1) // 居中
+		csn_Align(1)
 		csn_Text("PARKING TICKET", 2, 2, 0, 0)
 		csn_Text("", 1, 1, 0, 0)
 		csn_Text(lotName, 1, 1, 0, 0)
@@ -79,78 +63,45 @@ func (s *PrintService) PrintTicket(printerID uint, lotName, channelCode, plateNo
 		csn_Text("", 1, 1, 0, 0)
 		csn_Text("PARK AT YOUR OWN RISK", 1, 1, 0, 1)
 		csn_Text("================================", 1, 1, 0, 0)
-
-		csn_Align(0) // 左对齐
+		csn_Align(0)
 		csn_Text("In-Time::"+now, 1, 1, 0, 0)
-		if channelCode != "" {
-			csn_Text("InGate::"+channelCode, 1, 1, 0, 0)
-		}
-		if plateNo != "" {
-			csn_Text("Veh No::"+plateNo, 1, 1, 0, 0)
-		}
+		if channelCode != "" { csn_Text("InGate::"+channelCode, 1, 1, 0, 0) }
+		if plateNo != "" { csn_Text("Veh No::"+plateNo, 1, 1, 0, 0) }
 		csn_Text("================================", 1, 1, 0, 0)
 		csn_Text("Slip No::"+slipNo, 1, 1, 0, 0)
 		csn_Text("================================", 1, 1, 0, 0)
-
-		csn_Align(1) // 居中
+		csn_Align(1)
 		csn_FeedLine()
 		csn_QRCode(ticketNo, 4)
 		csn_FeedLine()
-
 		csn_Text("SCAN AND PAY WITH", 1, 1, 0, 0)
 		csn_Text("NEW THE CANADIA BANK APP", 1, 1, 0, 0)
 		csn_FeedLines(3)
 		csn_FullCut()
-
 		global.GVA_DB.Model(&printer).Update("status", "online")
 		return nil
 	}
 
-	// ── 串口模式（原有 ESC/POS）──
+	// Serial ESC/POS fallback
 	write := func(data []byte) { srl.Write(data) }
 	line32 := "================================"
-
-	write(InitCmd)
-	write(AlignCenterCmd)
-	write(DoubleHeightCmd)
-	write(BoldOnCmd)
+	write(InitCmd); write(AlignCenterCmd); write(DoubleHeightCmd); write(BoldOnCmd)
 	write(ESCPOS_Text("PARKING TICKET"))
-	write(BoldOffCmd)
-	write(NormalCmd)
-	write(ESCPOS_Text(""))
-	write(ESCPOS_Text(lotName))
-	if len(lotName) > 32 {
-		write(FontBCmd)
-		write(AlignCenterCmd)
-		write(ESCPOS_Text(lotName))
-		write(NormalCmd)
-	}
-	write(ESCPOS_Text("A-General Car"))
-	write(ESCPOS_Text(""))
-	write(ESCPOS_Text("PARK AT YOUR OWN RISK"))
-	write(ESCPOS_Text(line32))
+	write(BoldOffCmd); write(NormalCmd)
+	write(ESCPOS_Text("")); write(ESCPOS_Text(lotName))
+	write(ESCPOS_Text("A-General Car")); write(ESCPOS_Text(""))
+	write(ESCPOS_Text("PARK AT YOUR OWN RISK")); write(ESCPOS_Text(line32))
 	write(AlignLeftCmd)
-	write(ESCPOS_Text("In-Time::" + now))
-	if channelCode != "" {
-		write(ESCPOS_Text("InGate::" + channelCode))
-	}
-	if plateNo != "" {
-		write(ESCPOS_Text("Veh No::" + plateNo))
-	}
-	write(ESCPOS_Text(line32))
-	write(ESCPOS_Text("Slip No::" + slipNo))
-	write(ESCPOS_Text(line32))
-	write(AlignCenterCmd)
-	write(ESCPOS_Text(""))
-	write(ESCPOS_QRCode(ticketNo))
-	write(ESCPOS_Text(""))
+	write(ESCPOS_Text("In-Time::"+now))
+	if channelCode != "" { write(ESCPOS_Text("InGate::"+channelCode)) }
+	if plateNo != "" { write(ESCPOS_Text("Veh No::"+plateNo)) }
+	write(ESCPOS_Text(line32)); write(ESCPOS_Text("Slip No::"+slipNo)); write(ESCPOS_Text(line32))
+	write(AlignCenterCmd); write(ESCPOS_Text(""))
+	write(ESCPOS_QRCode(ticketNo)); write(ESCPOS_Text(""))
 	write(AlignCenterCmd)
 	write(ESCPOS_Text("SCAN AND PAY WITH"))
 	write(ESCPOS_Text("NEW THE CANADIA BANK APP"))
-	write(InitCmd)
-	write(ESCPOS_Text(""))
-	write(ESCPOS_Text(""))
-	write(ESCPOS_Text(""))
+	write(InitCmd); write(ESCPOS_Text("")); write(ESCPOS_Text("")); write(ESCPOS_Text(""))
 	write(CutPaperCmd)
 
 	global.GVA_DB.Model(&printer).Update("status", "online")