choose

#!/usr/bin/env python
# coding: utf-8
# Copyright (c) 2012-2014 Christian Geier and contributors
#
# 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.
"""simple chooser program

reads lines from stdin, lets user choose one line in an urwid (ncurses like)
interface, prints it to stdout and exits. Input will be aligned to tabs '\t'.
It does read and write directly into the currently active tty, thus working
like this: `get_data | choose | process_data`
"""
from __future__ import print_function

import os
import re
import sys

import urwid


def get_terminal_size():
    """ taken from
    http://stackoverflow.com/questions/566746/566752#566752
    by user Johannes Weiss http://stackoverflow.com/users/55925/johannes-weiss
    """
    env = os.environ

    def ioctl_GWINSZ(filedesc):
        try:
            import fcntl
            import termios
            import struct
            con_props = struct.unpack('hh', fcntl.ioctl(filedesc,
                                                        termios.TIOCGWINSZ,
                                                        '1234'))
        except IOError:
            return None
        return con_props
    con_props = ioctl_GWINSZ(0) or ioctl_GWINSZ(1) or ioctl_GWINSZ(2)
    if not con_props:
        try:
            filedesc = os.open(os.ctermid(), os.O_RDONLY)
            con_props = ioctl_GWINSZ(filedesc)
            os.close(filedesc)
        except IOError:
            pass
    if not con_props:
        try:
            con_props = (env['LINES'], env['COLUMNS'])
        except:
            con_props = (25, 80)
    return int(con_props[1]), int(con_props[0])


def get_terminal_size_wrapper():
    """wrapper function, if we are on py3.3+ it will use the build in function,
    otherwise our own"""
    try:
        # python3.3+
        import shutil
        termsize = shutil.get_terminal_size()
        return termsize.columns, termsize.lines
    except AttributeError:
        return get_terminal_size()


def select_entry(names, header_text=''):
    """interactive href selector (urwid based)

    returns: href
    return type: string
    """
    class SelText(urwid.Text):
        """Selectable Text, saving index"""
        def __init__(self, text):
            urwid.Text.__init__(self, text)
            self.orig_text = text
            self.selected = False

        @classmethod
        def selectable(cls):
            """needs to be implemented"""
            return True

        def keypress(self, _, key):
            """needs to be implemented"""
            if key == 'enter':
                raise Selected(self.orig_text)
            return key

    class Selected(Exception):
        """used for signalling that an item was chosen in urwid"""
        def __init__(self, exit_token=None):
            self.exit_token = exit_token

    class MyFrame(urwid.Frame):
        def __init__(self, filterfun=None, backtrackfun=None, *args, **kwargs):
            self._filter = filterfun
            self._backtrack = backtrackfun
            super(MyFrame, self).__init__(*args, **kwargs)

        def keypress(self, size, key):
            if key not in ['enter', 'esc', 'down', 'up', 'left', 'right', 'backspace', 'delete']:
                out = self._footer.keypress([1], key=key)
                self._filter(self.footer.text)
                return out
            elif key == 'backspace':
                self._backtrack()
                out = self._footer.keypress([1], key=key)
            else:
                return super(MyFrame, self).keypress(size, key)

    class MySimpleListWalker(urwid.SimpleListWalker):
        original_content = None
        _out = list()

        def filter_regex(self, string):
            start, end = '', ''
            self._out.append(list())
            string = string.lower()
            if len(string) and string[0] == '^':
                string = string[1:]
                start = '^'
            if len(string) and string[-1] == '$':
                string = string[:-1]
                end = '$'
            if string[0] in '\'"':
                quote = string[0]
                string = string[1:]
            else:
                quote = False

            if quote and string and string[-1] == quote:
                regex = start + '.*' + string[:-1] + '.*' + end
            else:
                regex = start + '.*'.join(string) + end

            regex = re.compile(regex)
            length = len(self.contents)
            for num, line in enumerate(self.contents[::-1]):
                text = line.original_widget.text.decode('utf-8').lower().strip()
                if not regex.search(text):
                    self._out[-1].append(self.contents.pop(length - num - 1))

        def backtrack(self):
            if len(self._out) and isinstance(self._out[-1], list):
                self.contents.extend(self._out.pop())

    if len(names) is 1:
        return names[0]
    if names == list():
        return None
    name_list = list()

    for one in names:
        name_list.append(SelText(one))
    palette = [
        ('header', 'white', 'black'),
        ('reveal focus', 'black', 'dark cyan', 'standout'),
    ]
    content = MySimpleListWalker(
        [urwid.AttrMap(w, None, 'reveal focus') for w in name_list])

    listbox = urwid.ListBox(content)
    header = urwid.Text(header_text, wrap='clip')
    head = urwid.AttrMap(header, 'header')
    foot = urwid.Edit()
    top = MyFrame(content.filter_regex, content.backtrack, listbox, head, footer=foot)

    def keystroke(input):
        """used for urwid test
        to be removed
        """
        if input in ['q', 'esc']:
            raise urwid.ExitMainLoop()

    loop = urwid.MainLoop(top, palette, unhandled_input=keystroke)
    try:
        loop.run()
    except Selected as error:
        return error.exit_token


def do_it(choice):
    width, _ = get_terminal_size_wrapper()

    def get_lengths(choice):
        """return max lengths of strings in 'columns' """
        # list() for python3 compat.
        return list(map(max, list(zip(*[map(len, one) for one in choice]))))

    # main work is done here
    choice = choice.split('\n')[:-1]  # last line is always empty
    choice = [one.split('\t') for one in choice]

    # make sure all have elements have the same number of elements
    number_elements = max([len(one) for one in choice])
    for ind, _ in enumerate(choice):
        while len(choice[ind]) < number_elements:
            choice[ind].append('')

    lengths = get_lengths(choice)
    number_columns = len(lengths)
    number_splits = number_columns - 1

    while sum(lengths) + number_splits > width:
        missing = width - sum(lengths) - number_splits
        number_offenders = 0
        for length in lengths:
            if length > width / number_columns + number_splits:
                number_offenders = number_offenders + 1
        for ind, length in enumerate(lengths):
            if length > width / number_columns + number_splits:
                lengths[ind] = lengths[ind] + missing / number_offenders
                break

    # set length of column[i] to length[i], either clip or extent
    choice = [[s[:length].ljust(length + 1) for s, length in list(zip(wahl, lengths))] for wahl in choice]

    choice = [''.join(elemente) for elemente in choice]
    out = select_entry(
        choice, header_text=(
            u'Navigate by pressing ↑ and ↓, search (fuzzy) by entering letters, '
            'select by pressing Enter')
    )
    return out


class StreamTo(object):
    def __init__(self, stdout='/dev/tty', stdin='/dev/tty'):
        self._stdout = stdout
        self._stdin = stdin

    def __enter__(self):
        self.old_out = sys.stdout
        self.old_in = sys.stdin
        sys.__stdout__ = sys.stdout = open(self._stdout, 'w')
        sys.__stdin__ = sys.stdin = open(self._stdin)
        os.dup2(sys.stdin.fileno(), 0)
        os.dup2(sys.stdout.fileno(), 1)

    def __exit__(self, exc_type, exc_value, traceback):
        sys.stdout.flush()
        sys.stdin.close()
        sys.stdout.close()
        sys.__stdout__ = sys.stdout = self.old_out
        sys.__stdin__ = sys.stdin = self.old_in


if __name__ == "__main__":
    choice = sys.stdin.read()
    with StreamTo():
        choice = do_it(choice)
    if choice is not None:
        sys.stderr.write(choice + '\n')