/*
  stream.h - high level (serial) stream handling

  Part of grblHAL

  Copyright (c) 2019-2025 Terje Io

  grblHAL is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  grblHAL is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with grblHAL. If not, see <http://www.gnu.org/licenses/>.
*/

/*! \file
Stream I/O functions structure for the HAL.

Helper functions for saving away and restoring a stream input buffer. _Not referenced by the core._
*/

#ifndef _STREAM_H_
#define _STREAM_H_

#define ASCII_SOH  0x01
#define ASCII_STX  0x02
#define ASCII_ETX  0x03
#define ASCII_EOT  0x04
#define ASCII_ENQ  0x05
#define ASCII_ACK  0x06
#define ASCII_BS   0x08
#define ASCII_TAB  0x09
#define ASCII_LF   0x0A
#define ASCII_CR   0x0D
#define ASCII_XON  0x11
#define ASCII_XOFF 0x13
#define ASCII_NAK  0x15
#define ASCII_EOF  0x1A
#define ASCII_CAN  0x18
#define ASCII_EM   0x19
#define ASCII_ESC  0x1B
#define ASCII_DEL  0x7F
#define ASCII_EOL  "\r\n"

#ifndef RX_BUFFER_SIZE
#define RX_BUFFER_SIZE 1024 // must be a power of 2
#endif

#ifndef TX_BUFFER_SIZE
#define TX_BUFFER_SIZE 512  // must be a power of 2
#endif

#ifndef BLOCK_TX_BUFFER_SIZE
#define BLOCK_TX_BUFFER_SIZE 256
#endif

// Serial baud rate
#ifndef BAUD_RATE
#define BAUD_RATE 115200
#endif

// Value to be returned from input stream when no data is available
#ifndef SERIAL_NO_DATA
#define SERIAL_NO_DATA -1
#endif

#define BUFNEXT(ptr, buffer) ((ptr + 1) & (sizeof(buffer.data) - 1))
#define BUFCOUNT(head, tail, size) ((head >= tail) ? (head - tail) : (size - tail + head))

#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>

#include "vfs.h"

typedef enum {
    StreamType_Serial = 0,
    StreamType_MPG,
    StreamType_Bluetooth,
    StreamType_Telnet,
    StreamType_WebSocket,
    StreamType_SDCard, // deprecated, use StreamType_File instead
    StreamType_File = StreamType_SDCard,
    StreamType_Redirected,
    StreamType_Null
} stream_type_t;

typedef enum {
    StreamSuspend_Off = 0,
    StreamSuspend_Pending,
    StreamSuspend_Active
} stream_suspend_state_t;

typedef enum {
    Serial_8bit = 0,
    Serial_7bit
} serial_width_t;

typedef enum {
    Serial_StopBits1 = 0,
    Serial_StopBits1_5,
    Serial_StopBits2,
    Serial_StopBits0_5,
} serial_stopbits_t;

typedef enum {
    Serial_ParityNone = 0,
    Serial_ParityEven,
    Serial_ParityOdd,
    Serial_ParityMark,
    Serial_ParitySpace,
} serial_parity_t;

typedef union {
    uint8_t value;
    struct {
        uint8_t width    :2,
                stopbits :2,
                parity   :3,
                unused   :1;
    };
} serial_format_t;

typedef union {
    uint8_t value;
    struct {
        uint8_t dtr    :1,
                dsr    :1,
                rts    :1,
                cts    :1,
                unused :4;
    };
} serial_linestate_t;

/*! \brief Pointer to function for getting stream connected status.
\returns \a true connected, \a false otherwise.
*/
typedef bool (*stream_is_connected_ptr)(void);

/*! \brief Pointer to function for getting number of characters available or free in a stream buffer.
\returns number of characters available or free.
*/
typedef uint16_t (*get_stream_buffer_count_ptr)(void);

/*! \brief Pointer to function for reading a single character from a input stream.
\returns character or -1 if none available.
*/
typedef int32_t (*stream_read_ptr)(void);

/*! \brief Pointer to function for writing a null terminated string to the output stream.
\param s pointer to null terminated string.

__NOTE:__ output might be buffered until an #ASCII_LF is output, this is usually done by USB or network driver code to improve throughput.
*/
typedef void (*stream_write_ptr)(const char *s);

/*! \brief Pointer to function for writing a \a n character long string to the output stream.
\param s pointer to string.
\param len number of characters to write.
*/
typedef void (*stream_write_n_ptr)(const uint8_t *s, uint16_t len);


/*! \brief Pointer to function for writing a single character to the output stream.
\param c the character to write.
*/
typedef bool (*stream_write_char_ptr)(const uint8_t c);

/*! \brief Pointer to function for extracting real-time commands from the input stream and enqueue them for processing.
This should be called by driver code prior to inserting a character into the input buffer.
\param c character to check.
\returns true if extracted, driver code should not insert the character into the input buffer if so.
*/
typedef bool (*enqueue_realtime_command_ptr)(uint8_t c);

/*! \brief Pointer to function for setting the transfer direction control signal for half-duplex connections (RS-485).
\param tx \a true when transmitting, \a false when receiving.
*/
typedef void (*stream_set_direction_ptr)(bool tx);

/*! \brief Optional, but recommended, pointer to function for enqueueing realtime command characters.
\param c character to enqueue.
\returns \a true if successfully enqueued, \a false otherwise.

__NOTE:__ Stream implementations should pass the character over the current handler registered by the set_enqueue_rt_handler().

User or plugin code should __not__ enqueue realtime command characters via this handler, it should call \a grbl.enqueue_realtime_command() instead.
*/
typedef bool (*enqueue_realtime_command2_ptr)(uint8_t c);


/*! \brief Pointer to function for setting the enqueue realtime commands handler.
\param handler a \a enqueue_realtime_command_ptr pointer to the new handler function.
\returns \a enqueue_realtime_command_ptr pointer to the replaced function.

__NOTE:__ Stream implementations should hold a pointer to the handler in a local variable and typically
set it to protocol_enqueue_realtime_command() on initialization.
*/
typedef enqueue_realtime_command_ptr (*set_enqueue_rt_handler_ptr)(enqueue_realtime_command_ptr handler);

/*! \brief Pointer to function for setting the stream format.
\param format a \a serial_format_t struct.
\returns true if successful.
*/
typedef bool (*set_format_ptr)(serial_format_t format);

/*! \brief Pointer to function for setting the stream baud rate.
\param baud_rate
\returns true if successful.
*/
typedef bool (*set_baud_rate_ptr)(uint32_t baud_rate);

/*! \brief Pointer to function for flushing a stream buffer. */
typedef void (*flush_stream_buffer_ptr)(void);

/*! \brief Pointer to function for flushing the input buffer and inserting an #ASCII_CAN character.

This function is typically called by the _enqueue_realtime_command_ handler when CMD_STOP or CMD_JOG_CANCEL character is processed.
The #ASCII_CAN character might be checked for and used by upstream code to flush any buffers it may have.
*/
typedef void (*cancel_read_buffer_ptr)(void);

/*! \brief Pointer to function for blocking reads from and restoring a input buffer.

This function is called with the _await_ parameter true on executing a tool change command (M6),
 this shall block further reading from the input buffer.
The core function stream_rx_suspend() can be called with the _await_ parameter to do this,
it will replace the _hal.stream.read_ handler with a pointer to the dummy function stream_get_null().

Reading from the input is blocked until a tool change acknowledge character #CMD_TOOL_ACK is received,
 when the driver receives this the input buffer is to be saved away and reading from the input resumed by
 restoring the _hal.stream.read_ handler with its own read character function.
Driver code can do this by calling the core function stream_rx_backup().

When the tool change is complete or a soft reset is executed the core will call this function with the _await_ parameter false,
 if the driver code called stream_rx_suspend() to block input it shall then call it again with the _await_ parameter as input to restore it.

\param await bool
\returns \a true if there is data in the buffer, \a false otherwise.
*/
typedef bool (*suspend_read_ptr)(bool await);

/*! \brief Pointer to function for disabling/enabling stream input.

Typically used to disable receive interrupts so that real-time command processing for the stream is blocked.
Usually it is desirable to block processing when another stream provides the input, but sometimes not.
E.g. when input is from a SD card real-time commands from the stream that initiated SD card streaming is needed
for handing feed-holds, overrides, soft resets etc.

\param disable \a true to disable stream, \a false to enable,
*/
typedef bool (*disable_rx_stream_ptr)(bool disable);

/*! \brief Pointer to function for handling line state changed events.

\param \a serial_linestate_t enum.
*/
typedef void (*on_linestate_changed_ptr)(serial_linestate_t state);

typedef union {
    uint8_t value;
    struct {
        uint8_t claimable     :1,
                claimed       :1,
                can_set_baud  :1,
                rx_only       :1,
                modbus_ready  :1,
                rts_handshake :1,
                init_ok       :1,
                unused        :1;
    };
} io_stream_flags_t;

typedef union {
    uint8_t value;
    struct {
        uint8_t webui_connected :1,
                is_usb          :1,
                linestate_event :1, //!< Set when driver supports on_linestate_changed event.
                passthru        :1, //!< Set when stream is in passthru mode.
                utf8            :1, //!< Set when stream is in UTF8 mode.
                eof             :1, //!< Set when a file stream reaches end-of-file.
                unused          :2;
    };
} io_stream_state_t;

//! Properties and handlers for stream I/O
typedef struct {
    stream_type_t type;                                     //!< Type of stream.
    uint8_t instance;                                       //!< Instance of stream type, starts from 0.
    io_stream_state_t state;                                //!< Optional status flags such as connected status.
    stream_is_connected_ptr is_connected;                   //!< Handler for getting stream connected status.
    get_stream_buffer_count_ptr get_rx_buffer_free;         //!< Handler for getting number of free characters in the input buffer.
    stream_write_ptr write;                                 //!< Handler for writing string to current output stream only.
    stream_write_ptr write_all;                             //!< Handler for writing string to all active output streams.
    stream_write_char_ptr write_char;                       //!< Handler for writing a single character to current stream only.
    enqueue_realtime_command2_ptr enqueue_rt_command;       //!< (Optional) handler for enqueueing a realtime command character.
    stream_read_ptr read;                                   //!< Handler for reading a single character from the input stream.
    flush_stream_buffer_ptr reset_read_buffer;              //!< Handler for flushing the input buffer.
    cancel_read_buffer_ptr cancel_read_buffer;              //!< Handler for flushing the input buffer and inserting an #ASCII_CAN character.
    set_enqueue_rt_handler_ptr set_enqueue_rt_handler;      //!< Handler for setting the enqueue realtime command character handler.
    suspend_read_ptr suspend_read;                          //!< Optional handler for saving away and restoring the current input buffer.
    stream_write_n_ptr write_n;                             //!< Optional handler for writing n characters to current output stream only. Required for Modbus support.
    disable_rx_stream_ptr disable_rx;                       //!< Optional handler for disabling/enabling a stream. Recommended?
    get_stream_buffer_count_ptr get_rx_buffer_count;        //!< Optional handler for getting number of characters in the input buffer.
    get_stream_buffer_count_ptr get_tx_buffer_count;        //!< Optional handler for getting number of characters in the output buffer(s). Count shall include any unsent characters in any transmit FIFO and/or transmit register. Required for Modbus/RS-485 support.
    flush_stream_buffer_ptr reset_write_buffer;             //!< Optional handler for flushing the output buffer. Any transmit FIFO shall be flushed as well. Required for Modbus/RS-485 support.
    set_baud_rate_ptr set_baud_rate;                        //!< Optional handler for setting the stream baud rate. Required for Modbus/RS-485 support, recommended for Bluetooth support.
    set_format_ptr set_format;                              //!< Optional handler for setting the stream format.
    stream_set_direction_ptr set_direction;                 //!< Optional handler for setting the transfer direction for half-duplex communication.
    on_linestate_changed_ptr on_linestate_changed;          //!< Optional handler to be called when line state changes. Set by client.
    vfs_file_t *file;                                       //!< File handle, non-null if streaming from a file.
} io_stream_t;

typedef struct {
    io_stream_state_t state;                                //!< Optional status flags such as connected status.
    io_stream_flags_t flags;                                //!< Stream capability flags.
    uint32_t baud_rate;
    serial_format_t format;
} io_stream_status_t;

typedef const io_stream_t *(*stream_claim_ptr)(uint32_t baud_rate);
typedef bool (*stream_release_ptr)(uint8_t instance);
typedef const io_stream_status_t *(*stream_get_status_ptr)(uint8_t instance);

typedef struct {
    stream_type_t type;                                     //!< Type of stream.
    uint8_t instance;                                       //!< Instance of stream type, starts from 0.
    io_stream_flags_t flags;
    stream_claim_ptr claim;
    stream_release_ptr release;
    stream_get_status_ptr get_status;                       //!< Optional handler for getting stream status, for UART streams only
} io_stream_properties_t;

typedef bool (*stream_enumerate_callback_ptr)(io_stream_properties_t const *properties, void *data);

typedef struct io_stream_details {
    uint8_t n_streams;
    io_stream_properties_t *streams;
    struct io_stream_details *next;
} io_stream_details_t;

// The following structures and functions are not referenced in the core code, may be used by drivers

typedef struct {
    volatile uint_fast16_t head;
    volatile uint_fast16_t tail;
    volatile bool rts_state;
    bool overflow;
    bool backup;
    uint8_t data[RX_BUFFER_SIZE];
} stream_rx_buffer_t;

typedef struct {
    volatile uint_fast16_t head;
    volatile uint_fast16_t tail;
    uint8_t data[TX_BUFFER_SIZE];
} stream_tx_buffer_t;

typedef struct {
    uint_fast16_t length;
    uint_fast16_t max_length;
    uint8_t *s;
    uint8_t data[BLOCK_TX_BUFFER_SIZE];
} stream_block_tx_buffer_t;

// double buffered tx stream
typedef struct {
    uint_fast16_t length;
    uint_fast16_t max_length;
    uint8_t *s;
    bool use_tx2data;
    uint8_t data[BLOCK_TX_BUFFER_SIZE];
    uint8_t data2[BLOCK_TX_BUFFER_SIZE];
} stream_block_tx_buffer2_t;

#ifdef __cplusplus
extern "C" {
#endif

static inline bool stream_is_uart (stream_type_t type)
{
    return type == StreamType_Serial || type == StreamType_Bluetooth;
}

/*! \brief Dummy function for reading data from a virtual empty input buffer.
\returns always -1 as there is no data available.
*/
int32_t stream_get_null (void);

/*! \brief Function for blocking reads from or restoring an input buffer.
\param rxbuffer pointer to a stream_rx_buffer_t.
\param suspend when true _hal.stream.read_ is changed to stream_get_null(), if false it is restored if already saved.
\returns true if there is data in the buffer, false otherwise.
*/
 bool stream_rx_suspend (stream_rx_buffer_t *rxbuffer, bool suspend);

 stream_suspend_state_t stream_is_rx_suspended (void);

bool stream_mpg_register (const io_stream_t *stream, bool rx_only, stream_write_char_ptr write_char);

/*! \brief Function for enabling/disabling input from a secondary input stream.
\param on \a true if switching input to mpg stream, \a false when restoring original input.
\returns \a true when succsessful, \a false otherwise.
*/
bool stream_mpg_enable (bool on);

void stream_mpg_set_mode (void *data);

bool stream_mpg_check_enable (uint8_t c);

bool stream_buffer_all (uint8_t c);

bool stream_tx_blocking (void);

bool stream_enqueue_realtime_command (uint8_t c);

void stream_register_streams (io_stream_details_t *details);

bool stream_enumerate_streams (stream_enumerate_callback_ptr callback, void *data);

bool stream_connect (const io_stream_t *stream);

bool stream_connect_instance (uint8_t instance, uint32_t baud_rate);

void stream_disconnect (const io_stream_t *stream);

bool stream_connected (void);

void stream_set_defaults (const io_stream_t *stream, uint32_t baud_rate);

const io_stream_t *stream_get_base (void);

io_stream_flags_t stream_get_flags (io_stream_t stream);

const io_stream_status_t *stream_get_uart_status (uint8_t instance);

const io_stream_t *stream_null_init (uint32_t baud_rate);

io_stream_t const *stream_open_instance (uint8_t instance, uint32_t baud_rate, stream_write_char_ptr rx_handler, const char *description);
bool stream_close (io_stream_t const *stream);
bool stream_set_description (const io_stream_t *stream, const char *description);

void debug_printf(const char *fmt, ...);

#if defined(DEBUG) || defined(DEBUGOUT)
#define DEBUG_PRINT 1
#ifdef DEBUGOUT
void debug_write (const char *s);
void debug_writeln (const char *s);
bool debug_stream_init (void);
#endif
#else
#define DEBUG_PRINT 0
#endif

#define debug_print(fmt, ...) \
   do { if(DEBUG_PRINT) debug_printf(fmt, __VA_ARGS__); } while(0)

#ifdef __cplusplus
}
#endif

#endif