import os
import re
from therandy.utils import get_closest, replace_command
from therandy.specific.brew import get_brew_path_prefix, brew_available

BREW_CMD_PATH = '/Library/Homebrew/cmd'
TAP_PATH = '/Library/Taps'
TAP_CMD_PATH = '/%s/%s/cmd'

enabled_by_default = brew_available


def _get_brew_commands(brew_path_prefix):
    """To get brew default commands on local environment"""
    brew_cmd_path = brew_path_prefix + BREW_CMD_PATH

    return [name[:-3] for name in os.listdir(brew_cmd_path)
            if name.endswith(('.rb', '.sh'))]


def _get_brew_tap_specific_commands(brew_path_prefix):
    """To get tap's specific commands
    https://github.com/Homebrew/homebrew/blob/master/Library/brew.rb#L115"""
    commands = []
    brew_taps_path = brew_path_prefix + TAP_PATH

    for user in _get_directory_names_only(brew_taps_path):
        taps = _get_directory_names_only(brew_taps_path + '/%s' % user)

        # Brew Taps's naming rule
        # https://github.com/Homebrew/homebrew/blob/master/share/doc/homebrew/brew-tap.md#naming-conventions-and-limitations
        taps = (tap for tap in taps if tap.startswith('homebrew-'))
        for tap in taps:
            tap_cmd_path = brew_taps_path + TAP_CMD_PATH % (user, tap)

            if os.path.isdir(tap_cmd_path):
                commands += (name.replace('brew-', '').replace('.rb', '')
                             for name in os.listdir(tap_cmd_path)
                             if _is_brew_tap_cmd_naming(name))

    return commands


def _is_brew_tap_cmd_naming(name):
    return name.startswith('brew-') and name.endswith('.rb')


def _get_directory_names_only(path):
    return [d for d in os.listdir(path)
            if os.path.isdir(os.path.join(path, d))]


def _brew_commands():
    brew_path_prefix = get_brew_path_prefix()
    if brew_path_prefix:
        try:
            return (_get_brew_commands(brew_path_prefix)
                    + _get_brew_tap_specific_commands(brew_path_prefix))
        except OSError:
            pass

    # Failback commands for testing (Based on Homebrew 0.9.5)
    return ['info', 'home', 'options', 'install', 'uninstall',
            'search', 'list', 'update', 'upgrade', 'pin', 'unpin',
            'doctor', 'create', 'edit']


def match(command):
    is_proper_command = ('brew' in command.script and
                         'Unknown command' in command.output)

    if is_proper_command:
        broken_cmd = re.findall(r'Error: Unknown command: ([a-z]+)',
                                command.output)[0]
        return bool(get_closest(broken_cmd, _brew_commands()))
    return False


def get_new_command(command):
    broken_cmd = re.findall(r'Error: Unknown command: ([a-z]+)',
                            command.output)[0]
    return replace_command(command, broken_cmd, _brew_commands())
