# Written by Sebastian Pipping <sebastian@pipping.org>
# Licensed under CC0 1.0 (https://creativecommons.org/publicdomain/zero/1.0/)
# 2015-05-22 16:51 UTC+2

from __future__ import print_function

import readline
import sys

from ctypes import CDLL, c_int
from ctypes.util import find_library


if sys.version_info[0] > 2:
    raw_input = input


_rl_state_flags = {                      # <readline/readline.h>
    'RL_STATE_INITIALIZING': 0x0000001,  # initializing
    'RL_STATE_INITIALIZED':  0x0000002,  # initialization done
    'RL_STATE_TERMPREPPED':  0x0000004,  # terminal is prepped
    'RL_STATE_READCMD':      0x0000008,  # reading a command key
    'RL_STATE_METANEXT':     0x0000010,  # reading input after ESC
    'RL_STATE_DISPATCHING':  0x0000020,  # dispatching to a command
    'RL_STATE_MOREINPUT':    0x0000040,  # reading more input in a command function
    'RL_STATE_ISEARCH':      0x0000080,  # doing incremental search
    'RL_STATE_NSEARCH':      0x0000100,  # doing non-inc search
    'RL_STATE_SEARCH':       0x0000200,  # doing a history search
    'RL_STATE_NUMERICARG':   0x0000400,  # reading numeric argument
    'RL_STATE_MACROINPUT':   0x0000800,  # getting input from a macro
    'RL_STATE_MACRODEF':     0x0001000,  # defining keyboard macro
    'RL_STATE_OVERWRITE':    0x0002000,  # overwrite mode
    'RL_STATE_COMPLETING':   0x0004000,  # doing completion
    'RL_STATE_SIGHANDLER':   0x0008000,  # in readline sighandler
    'RL_STATE_UNDOING':      0x0010000,  # doing an undo
    'RL_STATE_INPUTPENDING': 0x0020000,  # rl_execute_next called
    'RL_STATE_TTYCSAVED':    0x0040000,  # tty special chars saved
    'RL_STATE_CALLBACK':     0x0080000,  # using the callback interface
    'RL_STATE_VIMOTION':     0x0100000,  # reading vi motion arg
    'RL_STATE_MULTIKEY':     0x0200000,  # reading multiple-key command
    'RL_STATE_VICMDONCE':    0x0400000,  # entered vi command mode at least once
    'RL_STATE_REDISPLAYING': 0x0800000,  # updating terminal display
    'RL_STATE_DONE':         0x1000000,  # done; accepted line
}

_RL_STATE_ISEARCH = _rl_state_flags['RL_STATE_ISEARCH']
_RL_STATE_DONE = _rl_state_flags['RL_STATE_DONE']

_readline_so = CDLL(find_library('readline'))
_rl_readline_state = c_int.in_dll(_readline_so, 'rl_readline_state')


def _tell_readline_state():
    enabled_flag_names = []
    for flag_name, flag_value in sorted(_rl_state_flags.items()):
        if _rl_readline_state.value & flag_value:
            enabled_flag_names.append('%s(0x%x)' % (flag_name, flag_value))

    if not enabled_flag_names:
        enabled_flag_names.append('RL_STATE_NONE')

    print('Readline state: %s' % ' | '.join(enabled_flag_names), file=sys.stderr)


def _fix_readline_state_after_ctrl_c():
    changes_needed = False

    # Unset RL_STATE_ISEARCH flag
    if _rl_readline_state.value & _RL_STATE_ISEARCH:
        _rl_readline_state.value &= ~_RL_STATE_ISEARCH
        changes_needed = True

    # Set RL_STATE_DONE flag
    if not _rl_readline_state.value & _RL_STATE_DONE:
        _rl_readline_state.value |= _RL_STATE_DONE
        changes_needed = True

    return changes_needed

    
if __name__ == '__main__':
    readline.add_history('some command to search for')

    print('Press Ctrl+D to leave.')
    print('For the workaround to show: press <Ctrl+R> (for search), type "a", press <Ctrl+C>, press <Return>.')

    _tell_readline_state()
    while True:
        try:
            line = raw_input('> ')
            _tell_readline_state()
        except EOFError:
            print()
            _tell_readline_state()
            break
        except KeyboardInterrupt:
            print()
            _tell_readline_state()
            if _fix_readline_state_after_ctrl_c():
                print('Readline state adjusted.', file=sys.stderr)
                _tell_readline_state()
            continue

        print('You wrote "%s".' % line)