// serial.h - Serial port abstraction header
//
// Wraps Windows 3.1 comm API (OpenComm, ReadComm, WriteComm, etc.)
// for use by the MSComm VBX control.

#ifndef SERIAL_H
#define SERIAL_H

#include <windows.h>

// -----------------------------------------------------------------------
// stdint types for MSVC 1.52 (no stdint.h available)
// -----------------------------------------------------------------------
#ifndef _STDINT_DEFINED
typedef short          int16_t;
typedef unsigned short uint16_t;
typedef long           int32_t;
typedef unsigned long  uint32_t;
typedef unsigned char  uint8_t;
typedef signed char    int8_t;
#define _STDINT_DEFINED
#endif

// -----------------------------------------------------------------------
// Handshaking modes
// -----------------------------------------------------------------------
#define HANDSHAKE_NONE    0
#define HANDSHAKE_XONXOFF 1
#define HANDSHAKE_RTSCTS  2
#define HANDSHAKE_BOTH    3

// -----------------------------------------------------------------------
// Flush queue selectors
// -----------------------------------------------------------------------
#define FLUSH_RX 0
#define FLUSH_TX 1

// -----------------------------------------------------------------------
// Escape function constants (mirrors EscapeCommFunction values)
// -----------------------------------------------------------------------
#define SERIAL_SETDTR    SETDTR
#define SERIAL_CLRDTR    CLRDTR
#define SERIAL_SETRTS    SETRTS
#define SERIAL_CLRRTS    CLRRTS
#define SERIAL_SETBREAK  SETBREAK
#define SERIAL_CLRBREAK  CLRBREAK

// -----------------------------------------------------------------------
// Function prototypes
// -----------------------------------------------------------------------

// Open a COM port with specified buffer sizes.
// Returns comm ID (>= 0) on success, negative on error.
int16_t serialOpen(int16_t port, int16_t inBufSize, int16_t outBufSize);

// Close an open comm port. Drops DTR and RTS before closing.
// Returns 0 on success, negative on error.
int16_t serialClose(int16_t commId);

// Configure baud, parity, data bits, stop bits from a settings string.
// settings format: "baud,parity,data,stop" (e.g., "9600,N,8,1")
// Returns 0 on success, negative on error.
int16_t serialConfigure(int16_t commId, int16_t port, const char FAR *settings);

// Apply handshaking mode to an open port.
// mode: HANDSHAKE_NONE, HANDSHAKE_XONXOFF, HANDSHAKE_RTSCTS, HANDSHAKE_BOTH
// Returns 0 on success, negative on error.
int16_t serialSetHandshaking(int16_t commId, int16_t mode);

// Apply null-discard and parity-replace settings to an open port.
// Returns 0 on success, negative on error.
int16_t serialSetOptions(int16_t commId, BOOL nullDiscard, const char FAR *parityReplace);

// Read data from receive buffer.
// Returns number of bytes read, or negative on error.
int16_t serialRead(int16_t commId, char FAR *buf, int16_t len);

// Write data to transmit buffer.
// Returns number of bytes written, or negative on error.
int16_t serialWrite(int16_t commId, const char FAR *buf, int16_t len);

// Get comm error status and buffer counts. Clears the error state.
// Returns error flags, fills stat with buffer counts.
int16_t serialGetStatus(int16_t commId, COMSTAT FAR *stat);

// Execute an escape function (DTR, RTS, break control).
// func: SERIAL_SETDTR, SERIAL_CLRDTR, SERIAL_SETRTS, etc.
// Returns 0 on success, negative on error.
int16_t serialEscape(int16_t commId, int16_t func);

// Get modem status lines via GetCommEventMask.
// Returns event mask bits (EV_CTS, EV_DSR, EV_RLSD, EV_RING).
UINT serialGetEventMask(int16_t commId, UINT mask);

// Enable WM_COMMNOTIFY messages to the specified window.
// rxThreshold: fire CN_RECEIVE when this many bytes available (-1=disable)
// txThreshold: fire CN_TRANSMIT when this much space free (-1=disable)
// Returns TRUE on success.
BOOL serialEnableNotify(int16_t commId, HWND hwnd, int16_t rxThreshold, int16_t txThreshold);

// Flush receive and/or transmit buffers.
// queue: FLUSH_RX or FLUSH_TX
// Returns 0 on success, negative on error.
int16_t serialFlush(int16_t commId, int16_t queue);

#endif // SERIAL_H