Phase 2: Protocol-specific base classes for byte order enforcement

[drazisil]

Summary

Create protocol-specific base classes that enforce byte order at the type level to prevent mixing Big Endian (NPS) and Little Endian (MCOTS) protocols.

Background

From the packet architecture analysis:

• NPS Protocol (ports 7003, 8226, 8228): Uses Big Endian
• MCOTS Protocol (port 43300): Uses Little Endian
• Current issue: BytableBase.coerceValueToBuffer uses LE, but BytableMessage.htonl uses BE - this inconsistency can cause bugs

Proposed Solution

Create new base classes:

// libs/@rustymotors/binary/src/lib/NPSPacketBase.ts
export abstract class NPSPacketBase extends BytableMessage {
    protected static readonly ENDIANNESS = 'BE' as const;
    
    protected writeUInt16(buffer: Buffer, value: number, offset: number): void {
        buffer.writeUInt16BE(value, offset);
    }
    
    protected writeUInt32(buffer: Buffer, value: number, offset: number): void {
        buffer.writeUInt32BE(value, offset);
    }
}

// libs/@rustymotors/binary/src/lib/MCOTSPacketBase.ts
export abstract class MCOTSPacketBase extends BytableServerMessage {
    protected static readonly ENDIANNESS = 'LE' as const;
    
    protected writeUInt16(buffer: Buffer, value: number, offset: number): void {
        buffer.writeUInt16LE(value, offset);
    }
    
    protected writeUInt32(buffer: Buffer, value: number, offset: number): void {
        buffer.writeUInt32LE(value, offset);
    }
}

Tasks

• Create NPSPacketBase class in libs/@rustymotors/binary/
• Create MCOTSPacketBase class in libs/@rustymotors/binary/
• Fix BytableBase.coerceValueToBuffer to be protocol-aware or deprecate it
• Add tests for byte order enforcement
• Update documentation

Dependencies

• Depends on: Centralize message ID constants for protocol discoverability #2801 (Phase 1: Message ID constants)

Related

Part of the packet architecture improvement initiative. See PR #2801 for context.