input-remapper/keymapper/dev/macros.py

#!/usr/bin/python3
# -*- coding: utf-8 -*-
# key-mapper - GUI for device specific keyboard mappings
# Copyright (C) 2020 sezanzeb <proxima@hip70890b.de>
#
# This file is part of key-mapper.
#
# key-mapper 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.
#
# key-mapper 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 key-mapper.  If not, see <https://www.gnu.org/licenses/>.


"""Executes more complex patterns of keystrokes.

To keep it short on the UI, the available functions are one-letter long.

The global functions actually perform the stuff and always return macro
instances that can then be further chained.

the outermost macro (in the examples below the one created by 'r',
'r' and 'w') will be started, which triggers a chain reaction to execute
all of the configured stuff.

Examples
--------
r(3, k('a').w(10)): 'a' <10ms> 'a' <10ms> 'a'
r(2, k('a').k('-')).k('b'): 'a' '-' 'a' '-' 'b'
w(1000).m('SHIFT_L', r(2, k('a'))).w(10).k('b'): <1s> 'A' 'A' <10ms> 'b'
"""


import time
import re
import random

from keymapper.logger import logger


class _Macro:
    """Supports chaining and preparing actions."""
    def __init__(self, handler):
        """Create a macro instance that can be populated with tasks.

        Parameters
        ----------
        handler : func
            A function that accepts keycodes as the first parameter and the
            key-press state as the second. 1 for down and 0 for up. The
            macro will write to this function once executed with `.run()`.
        """
        self.tasks = []
        self.handler = handler

    def run(self):
        """Run the macro."""
        for task in self.tasks:
            # TODO async, don't block the rest of the application
            task()

    def stop(self):
        """Stop the macro."""
        # TODO

    def modify(self, modifier, macro):
        """Do stuff while a modifier is activated.

        Parameters
        ----------
        modifier : str
        macro : _Macro
        """
        self.tasks.append(lambda: self.handler(modifier, 1))
        self.tasks.append(macro.run)
        self.tasks.append(lambda: self.handler(modifier, 0))
        return self

    def repeat(self, repeats, macro):
        """Repeat actions.

        Parameters
        ----------
        repeats : int
        macro : _Macro
        """
        for _ in range(repeats):
            self.tasks.append(macro.run)
        return self

    def keycode(self, character):
        """Write the character."""
        self.tasks.append(lambda: self.handler(character, 1))
        self.tasks.append(lambda: self.handler(character, 0))
        return self

    def wait(self, min, max=None):
        """Wait a random time in milliseconds"""
        # TODO random
        self.tasks.append(lambda: time.sleep(min / 1000))
        return self


def _extract_params(inner):
    """Extract parameters from the inner contents of a call.

    Parameters
    ----------
    inner : string
        for example 'r, r(2, k(a))' should result in ['r', 'r(2, k(a)']
    """
    inner = inner.strip()
    brackets = 0
    params = []
    start = 0
    for position, char in enumerate(inner):
        if char == '(':
            brackets += 1
        if char == ')':
            brackets -= 1
        if (char == ',') and brackets == 0:
            # , potentially starts another parameter, but only if
            # the current brackets are all closed.
            params.append(inner[start:position].strip())
            # skip the comma
            start = position + 1

    if brackets == 0 and start != len(inner):
        # one last parameter
        params.append(inner[start:].strip())

    return params


def _parse_recurse(macro, handler, macro_instance=None, depth=0):
    """Handle a subset of the macro, e.g. one parameter or function call.

    Parameters
    ----------
    macro : string
        Just like parse
    handler : function
        passed to _Macro constructors
    macro_instance : _Macro or None
        A macro instance to add tasks to
    depth : int
        For logging and debugging purposes
    """
    # to anyone who knows better about compilers and thinks this is horrible:
    # please make a pull request. Because it probably is.
    # not using eval for security reasons ofc. And this syntax doesn't need
    # string quotes for its params.
    # If this gets more complicated than that I'd rather make a macro
    # editor GUI and store them as json.
    assert isinstance(macro, str)
    assert callable(handler)
    assert isinstance(depth, int)

    if macro_instance is None:
        macro_instance = _Macro(handler)
    else:
        assert isinstance(macro_instance, _Macro)

    macro = macro.strip()
    logger.spam('%sinput %s', '  ' * depth, macro)
    space = '  ' * depth

    # is it another macro?
    call_match = re.match(r'^(\w+)\(.+?', macro)
    call = call_match[1] if call_match else None
    if call is not None:
        # available functions in the macro
        functions = {
            'm': macro_instance.modify,
            'r': macro_instance.repeat,
            'k': macro_instance.keycode,
            'w': macro_instance.wait
        }

        if functions.get(call) is None:
            logger.error(f'Unknown function %s', call)

        # get all the stuff inbetween
        brackets = 0
        position = 0
        for char in macro:
            position += 1

            if char == '(':
                brackets += 1
                continue

            if char == ')':
                brackets -= 1
                if brackets < 0:
                    logger.error(f'There is one ")" too much at %s', position)
                    return
                if brackets == 0:
                    # the closing bracket of the call
                    break

        if brackets != 0:
            logger.error(f'There are %s closing brackets missing', brackets)

        inner = macro[2:position - 1]

        # split "3, k(a).w(10)" into parameters
        string_params = _extract_params(inner)
        logger.spam('%scalls %s with %s', space, call, string_params)
        # evaluate the params
        params = [
            _parse_recurse(param.strip(), handler, None, depth + 1)
            for param in string_params
        ]

        logger.spam('%scalling %s with %s', space, call, params)
        functions[call](*params)

        # is after this another call? Chain it to the macro_instance
        if len(macro) > position and macro[position] == '.':
            chain = macro[position + 1:]
            logger.spam('%sfollowed by %s', space, chain)
            _parse_recurse(chain, handler, macro_instance, depth)

        return macro_instance
    else:
        # probably a parameter for an outer function
        try:
            macro = int(macro)
        except ValueError:
            pass
        return macro


def parse(macro, handler):
    """parse and generate a _Macro that can be run as often as you want.

    Parameters
    ----------
    macro : string
        "r(3, k(a).w(10))"
        "r(2, k(a).k(-)).k(b)"
        "w(1000).m(SHIFT_L, r(2, k(a))).w(10, 20).k(b)"
    handler : func
        A function that accepts keycodes as the first parameter and the
        key-press state as the second. 1 for down and 0 for up. The
        macro will write to this function once executed with `.run()`.
    """
    try:
        return _parse_recurse(macro, handler)
    except Exception as e:
        logger.error('Failed to parse macro "%s": %s', macro, e)
        return None