log.py

''' Configurable asynchronous logger using second core as context for writing to REPL, file and/or screen

    Copyright (c) 2025 Harm Lammers
    
    The dependency on the `display` module is optional: the Log class also works if `display.py` is missing, but only for logging to file.
    For logging to display this module is set up to work with the Cybo-Drummer hardware (https://github.com/HLammers/cybo-drummer), which
    uses an ILI9225 display, connected as defined in the constant definitions below. To make this work with another screen the `_DisplayMonitor`
    class needs to be rewritten to use different display drivers.

    MIT licence:

    Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the
    "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish,
    distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to
    the following conditions:

    The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
'''

import machine
import asyncio
from collections import deque

from singleton import singleton
from context import Context
try:
    from display import Display, DISPLAY_W, DISPLAY_H
    display_missing = False
except:
    display_missing = True # allow the display module to be missing (to allow only logging to file)

_LOG_BUF_LEN  = const(32)

# Diplay configuration
_DSP_BAUTRATE = const(50_000_000)
_DSP_SPI      = const(0)  # SPI controller
_DSP_PIN_RS   = const(20) # RS (register selection) pin GPIO number
_DSP_PIN_RST  = const(21) # RST (reset) pin GPIO number
_DSP_PIN_LED  = const(17) # LED (backlight) pin GPIO number

_ROW_H        = const(9)
_ROWS         = const(19) # DISPLAY_H // _ROW_H
_COLS         = const(27) # DISPLAY_W // 8
_TOP_MARGIN   = const(3)  # (_ROW_H - 8) // 2 + (DISPLAY_H - _ROWS * _ROW_H)

@singleton
class Log:
    ''' `asyncio`-compatible singleton logger which prints the message and can be configured to write to file and/or monitor

    Args:
        to_file (bool, optional): Write logs to log file if `True`; defaults to `False`
        to_monitor (bool, optional): Write logs to display if `True`; defaults to `True` (which is overruled if the `display` import failed)
        file_name (str, optional): File name for log file; defaults to '/log.txt'
    '''
    def __init__(self, to_file: bool = False, to_monitor: bool = True, file_name: str = '/log.txt') -> None:
        self.to_file = to_file
        if display_missing: to_monitor = False # overrule if the `display` import failed
        self.to_monitor = to_monitor
        self.file_name = file_name
        if to_file:
            open(file_name, 'w').close()
        if to_monitor:
            self._monitor = _DisplayMonitor()
            self._monitor_task = None
        self._core_1 = Context()
        self._deque = deque((), _LOG_BUF_LEN)
        self._put_flag = asyncio.ThreadSafeFlag()

    def write(self, msg: str|bytes|bytearray) -> None:
        ''' Write message to logger buffer to be logged synchronously

        Args:
            msg (str | bytes | bytearray): Message to write to logger
        '''
        _deque = self._deque
        if len(_deque) >= _LOG_BUF_LEN:
            print('LOG BUF FULL, NOT LOGGED:', str(msg))
            return
        _deque.append(msg)
        _put_flag = self._put_flag
        _put_flag.set()
    
    def sync_write(self, msg: str|bytes|bytearray) -> None:
        ''' Write message to logger synchronously (flushes to screen immediately and blocks until completed)

        Args:
            msg (str | bytes | bytearray): Message to write to logger
        '''
        print(msg if type(msg) == str else msg.decode('ascii')) # pyright: ignore[reportAttributeAccessIssue]
        if self.to_monitor:
            _monitor = self._monitor
            _monitor.write(msg, True)
        if self.to_file:
            _log_to_file(self.file_name, msg)

    async def run(self) -> None:
        ''' `asyncio` task to read from log buffer and print, write to file and/or show on display whenever data is available '''
        _deque = self._deque
        to_monitor = self.to_monitor
        if to_monitor:
            _monitor = self._monitor
            self._monitor_task = asyncio.create_task(_monitor.run())
            _monitor_write = _monitor.write
        _write_to_file = _log_to_file
        to_file = self.to_file
        file_name = self.file_name
        _core_1 = self._core_1
        _sleep = asyncio.sleep
        while True:
            while not _deque:
                await self._put_flag.wait()     
            msg = _deque.popleft()
            print(msg if type(msg) == str else msg.decode('ascii'))
            if to_monitor:
                await _core_1.assign(_monitor_write, msg)
            if to_file:
                await _core_1.assign(_write_to_file, file_name, msg)
            await _sleep(0)

    def deinit(self) -> None:
        ''' Stop second core context, switch off display and cancel display monitor task '''
        self._core_1.deinit()
        if self.to_monitor:
            self._monitor.deinit()
            if (_task := self._monitor_task) is not None: _task.cancel()

def _log_to_file(file_name, msg: str|bytes|bytearray) -> None:
    ''' Write message to file

    Args:
        file_name (str): File name for log file; defaults to '/log.txt'
        msg (str | bytes | bytearray): Message to write to file
    '''
    with open(file_name, 'a') as f:
        f.write(msg)
        f.write(b'\n')

@singleton
class _DisplayMonitor:
    ''' Singleton writer for displaying log messages on ILI9225 screen '''

    def __init__(self) -> None:
        self._display = Display(_DSP_SPI, _DSP_BAUTRATE, machine.Pin(_DSP_PIN_RS), machine.Pin(_DSP_PIN_RST),
                                machine.Pin(_DSP_PIN_LED, mode=machine.Pin.OUT))
        self._line_buf = bytearray(_COLS)
        self.row = 0
        self._redraw = asyncio.Event()

    def write(self, text: str|bytes|bytearray, sync: bool = False) -> None:
        ''' Write text to display asynchronously or synchronously; word wraps text to multiple lines if necessary

        Args:
            text (str | bytes | bytearray): Text to display
            sync (bool, optional): Synchronously show screen update if `True`; set redraw screen flag to synchronously show screen update if
            `False`; defaults to `False`
        '''
        if type(text) is not str:
            text = text.decode('ascii') # pyright: ignore[reportAttributeAccessIssue]
        _display = self._display
        row = self.row
        _DISPLAY_W = DISPLAY_W
        _DISPLAY_H = DISPLAY_H
        if len(text) <= _COLS:
            line = text
        else:
            words = text.split()
            line = ''
            for word in words:
                if (len_line := len(line)) + len(word) + (0 if len_line == 0 else 1) <= _COLS:
                    line += ('' if len_line == 0 else ' ') + word
                else:
                    _display.text(line, 0, row * _ROW_H + _TOP_MARGIN, 0xFFFF)
                    row += 1
                    if row == _ROWS:
                        _display.scroll(0, -_ROW_H)
                        _display.fill_rect(0, _DISPLAY_H - _ROW_H, _DISPLAY_W, _ROW_H, 0)
                        row = _ROWS - 1
                    line = word
        if line:
            _display.text(line, 0, row * _ROW_H + _TOP_MARGIN, 0xFFFF)
            row += 1
            if row == _ROWS:
                _display.scroll(0, -_ROW_H)
                _display.fill_rect(0, _DISPLAY_H - _ROW_H, _DISPLAY_W, _ROW_H, 0)
                row = _ROWS - 1
        self.row = row
        if sync:
            _display.show()
        else:
            self._redraw.set()

    async def run(self) -> None:
        ''' `asyncio` task to flush display buffer to screen whenever the redraw screen flag is set '''
        _redraw = self._redraw.wait
        _clear = self._redraw.clear
        _draw_screen = self._display.async_show
        while True:
            await _redraw()
            _clear()
            await _draw_screen()

    def deinit(self) -> None:
        ''' Turn display off '''
        self._display.off()