fix(legacy): parse SN-prefixed serials in M115

Fixes M115 response parsing to handle serial numbers with SN: prefix (some firmware versions report serials this way). Also standardizes A3/A4 clients to use GCodes.CmdLogin constant instead of raw M601 string.

Changes:
- FlashForgeA3Client/A4Client: Parse SN:-prefixed serial numbers
- FlashForgeA3Client/A4Client: Use GCodes.CmdLogin constant for login command
- Add test coverage for both changes

Author: GhostTypes

.pi/settings.json

@@ -0,0 +1,3 @@
+{
+  "skills": ["../.claude/skills"]
+}

src/tcpapi/FlashForgeA3Client.test.ts

@@ -24,13 +24,13 @@ describe('FlashForgeA3Client', () => {
       expect(client['port']).toBe(8899);
     });
 
-    it('should initialize connection with M601', async () => {
+    it('should initialize connection with M601 S1', async () => {
       const sendCommandSpy = vi.spyOn(client, 'sendCommandAsync');
       sendCommandSpy.mockResolvedValue('CMD M601 Received.\nok\n');
 
       const result = await client.initControl();
 
-      expect(sendCommandSpy).toHaveBeenCalledWith('~M601');
+      expect(sendCommandSpy).toHaveBeenCalledWith('~M601 S1');
       expect(result).toBe(true);
     });
 
@@ -72,6 +72,27 @@ describe('FlashForgeA3Client', () => {
 
       await expect(client.getPrinterInfo()).resolves.toBeNull();
     });
+
+    it('should parse SN-prefixed serial numbers and blank lines in M115', async () => {
+      const mockResponse = [
+        'echo: Machine Type: FlashForge Adventurer III',
+        'Machine Name: MyPrinter',
+        '',
+        'Firmware: v1.3.7',
+        'SN: SNADVA3M12345',
+        'X: 150 Y: 150 Z: 150',
+        'Tool Count: 1',
+        'Mac Address:00:11:22:33:44:55',
+        'ok',
+      ].join('\n');
+      vi.spyOn(client, 'sendCommandAsync').mockResolvedValue(mockResponse);
+
+      const info = await client.getPrinterInfo();
+
+      expect(info).not.toBeNull();
+      expect(info?.serialNumber).toBe('SNADVA3M12345');
+      expect(info?.firmware).toBe('v1.3.7');
+    });
   });
 
   describe('Print Job Control', () => {

src/tcpapi/FlashForgeA3Client.ts

@@ -119,15 +119,16 @@ export class FlashForgeA3Client extends FlashForgeTcpClient {
   }
 
   /**
-   * Initializes control by sending M601.
+   * Initializes control by sending the legacy M601 S1 login command.
    */
   public async initControl(): Promise<boolean> {
     try {
       await new Promise((resolve) => setTimeout(resolve, 500));
 
-      const response = await this.sendCommandAsync('~M601');
+      const loginCommand = GCodes.CmdLogin;
+      const response = await this.sendCommandAsync(loginCommand);
       if (response === null) {
-        console.error('A3: Failed to send M601 connection command');
+        console.error('A3: Failed to send M601 S1 login command');
         return false;
       }
 
@@ -136,7 +137,7 @@ export class FlashForgeA3Client extends FlashForgeTcpClient {
         return true;
       }
 
-      return this.isSuccessfulCommandResponse('~M601', response);
+      return this.isSuccessfulCommandResponse(loginCommand, response);
     } catch (error) {
       console.error('A3: initControl error:', error);
       return false;
@@ -170,6 +171,8 @@ export class FlashForgeA3Client extends FlashForgeTcpClient {
         info.machineName = line.replace('Machine Name:', '').trim();
       } else if (line.startsWith('Firmware:')) {
         info.firmware = line.replace('Firmware:', '').trim();
+      } else if (line.startsWith('SN:')) {
+        info.serialNumber = line.replace('SN:', '').trim();
       } else if (line.startsWith('Serial Number:')) {
         info.serialNumber = line.replace('Serial Number:', '').trim();
       } else if (line.startsWith('Tool Count:')) {

src/tcpapi/FlashForgeA4Client.test.ts

@@ -23,7 +23,7 @@ describe('FlashForgeA4Client', () => {
       expect(client['port']).toBe(8899);
     });
 
-    it('should initialize connection with the documented M601 flow', async () => {
+    it('should initialize connection with the documented M601 S1 flow', async () => {
       const sendCommandSpy = vi.spyOn(client, 'sendCommandAsync');
       vi.spyOn(client, 'startKeepAlive').mockImplementation(() => {});
       sendCommandSpy
@@ -40,7 +40,7 @@ describe('FlashForgeA4Client', () => {
         ].join('\n'));
 
       await expect(client.initControl()).resolves.toBe(true);
-      expect(sendCommandSpy).toHaveBeenNthCalledWith(1, '~M601');
+      expect(sendCommandSpy).toHaveBeenNthCalledWith(1, '~M601 S1');
       expect(sendCommandSpy).toHaveBeenNthCalledWith(2, '~M115');
     });
 
@@ -113,6 +113,24 @@ describe('FlashForgeA4Client', () => {
 
       expect(info?.serialNumber).toBe('A4SN12345');
     });
+
+    it('should accept SN-prefixed serial numbers when firmware reports them', async () => {
+      vi.spyOn(client, 'sendCommandAsync').mockResolvedValue([
+        'CMD M115 Received.',
+        'Machine Type: Flashforge Adventurer 4',
+        'Machine Name: Serial Printer',
+        'Firmware: v2.0.5 20220527',
+        'SN: A4SN67890',
+        'X: 220 Y: 200 Z: 250',
+        'Tool Count: 1',
+        'Mac Address: 00:11:22:33:44:55',
+        'ok',
+      ].join('\n'));
+
+      const info = await client.getPrinterInfo();
+
+      expect(info?.serialNumber).toBe('A4SN67890');
+    });
   });
 
   describe('Status Parsers', () => {

src/tcpapi/FlashForgeA4Client.ts

@@ -2,7 +2,7 @@
  * @fileoverview TCP client for FlashForge Adventurer 4 printers.
  *
  * Adventurer 4 Lite and Pro share the same legacy TCP protocol on port 8899.
- * This client keeps the documented M601 and M115 behavior separate from the
+ * This client keeps the legacy M601 S1 login flow and M115 behavior separate from the
  * generic legacy client while reusing the shared TCP transport and parsers.
  */
 
@@ -73,13 +73,14 @@ export class FlashForgeA4Client
   }
 
   /**
-   * Initializes control by sending the documented M601 command.
+   * Initializes control by sending the legacy M601 S1 login command.
    */
   public async initControl(): Promise<boolean> {
     try {
-      const response = await this.sendCommandAsync('~M601');
+      const loginCommand = GCodes.CmdLogin;
+      const response = await this.sendCommandAsync(loginCommand);
       if (response === null) {
-        console.error('A4: Failed to send M601 connection command');
+        console.error('A4: Failed to send M601 S1 login command');
         return false;
       }
 
@@ -88,14 +89,14 @@ export class FlashForgeA4Client
         return true;
       }
 
-      if (!this.isSuccessfulCommandResponse('~M601', response)) {
+      if (!this.isSuccessfulCommandResponse(loginCommand, response)) {
         return false;
       }
 
       await new Promise((resolve) => setTimeout(resolve, 100));
       const info = await this.getPrinterInfo();
       if (!info) {
-        console.error('A4: Failed to retrieve printer info after M601');
+        console.error('A4: Failed to retrieve printer info after M601 S1');
         return false;
       }