#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
  Copyright © 2008-2012 Joel Schaerer
  Copyright © 2012-2014 William Ting

  * This program 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, or (at your option)
  any later version.

  * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
"""

from __future__ import print_function

from difflib import SequenceMatcher
from itertools import chain
from math import sqrt
from operator import attrgetter
from operator import itemgetter
import os
import re
import sys

if sys.version_info[0] == 3:
    ifilter = filter
    imap = map
    os.getcwdu = os.getcwd
else:
    from itertools import ifilter
    from itertools import imap

from autojump_argparse import ArgumentParser

from autojump_data import dictify
from autojump_data import entriefy
from autojump_data import Entry
from autojump_data import load
from autojump_data import save
from autojump_utils import first
from autojump_utils import get_tab_entry_info
from autojump_utils import get_pwd
from autojump_utils import has_uppercase
from autojump_utils import is_osx
from autojump_utils import is_windows
from autojump_utils import last
from autojump_utils import print_entry
from autojump_utils import print_local
from autojump_utils import print_tab_menu
from autojump_utils import sanitize
from autojump_utils import take
from autojump_utils import unico

VERSION = '22.0.0-alpha'
FUZZY_MATCH_THRESHOLD = 0.6
TAB_ENTRIES_COUNT = 9
TAB_SEPARATOR = '__'


def set_defaults():
    config = {}

    if is_osx():
        data_home = os.path.join(
                        os.path.expanduser('~'),
                        'Library',
                        'autojump')
    elif is_windows():
        data_home = os.path.join(
                        os.getenv('APPDATA'),
                        'autojump')
    else:
        data_home = os.getenv(
                'XDG_DATA_HOME',
                os.path.join(
                        os.path.expanduser('~'),
                        '.local',
                        'share',
                        'autojump'))

    config['data_path'] = os.path.join(data_home, 'autojump.txt')
    config['backup_path'] = os.path.join(data_home, 'autojump.txt.bak')
    config['tmp_path'] = os.path.join(data_home, 'data.tmp')

    return config


def parse_arguments():
    parser = ArgumentParser(
            description='Automatically jump to directory passed as an \
                    argument.',
            epilog="Please see autojump(1) man pages for full documentation.")
    parser.add_argument(
            'directory', metavar='DIRECTORY', nargs='*', default='',
            help='directory to jump to')
    parser.add_argument(
            '-a', '--add', metavar='DIRECTORY',
            help='add path')
    parser.add_argument(
            '-i', '--increase', metavar='WEIGHT', nargs='?', type=int,
            const=10, default=False,
            help='increase current directory weight')
    parser.add_argument(
            '-d', '--decrease', metavar='WEIGHT', nargs='?', type=int,
            const=15, default=False,
            help='decrease current directory weight')
    parser.add_argument(
            '--complete', action="store_true", default=False,
            help='used for tab completion')
    parser.add_argument(
            '--purge', action="store_true", default=False,
            help='remove non-existent paths from database')
    parser.add_argument(
            '-s', '--stat', action="store_true", default=False,
            help='show database entries and their key weights')
    parser.add_argument(
            '-v', '--version', action="version", version="%(prog)s v" +
            VERSION, help='show version information')

    return parser.parse_args()


def add_path(data, path, weight=10):
    """
    Add a new path or increment an existing one.

    os.path.realpath() is not used because it's preferable to use symlinks
    with resulting duplicate entries in the database than a single canonical
    path.
    """
    path = unico(path).rstrip(os.sep)
    if path == os.path.expanduser('~'):
        return data, Entry(path, 0)

    data[path] = sqrt((data.get(path, 0) ** 2) + (weight ** 2))

    return data, Entry(path, data[path])


def decrease_path(data, path, weight=15):
    """Decrease or zero out a path."""
    path = unico(path).rstrip(os.sep)
    data[path] = max(0, data.get(path, 0) - weight)
    return data, Entry(path, data[path])


def detect_smartcase(needles):
    """
    If any needles contain an uppercase letter then use case sensitive
    searching. Otherwise use case insensitive searching.
    """
    return not any(imap(has_uppercase, needles))


def find_matches(entries, needles, check_entries=True):
    """Return an iterator to matching entries."""
    ignore_case = detect_smartcase(needles)

    try:
        pwd = os.getcwdu()
    except OSError:
        pwd = None

    # using closure and comparing vs string to prevent constantly hitting hdd
    def not_cwd(entry):
        return entry.path != pwd

    if check_entries:
        exists = lambda entry: os.path.exists(entry.path)
    else:
        exists = lambda _: True

    data = sorted(
            entries,
            key=attrgetter('weight'),
            reverse=True)

    return ifilter(
            not_cwd,
            ifilter(
                exists,
                chain(
                    match_consecutive(needles, data, ignore_case),
                    match_fuzzy(needles, data, ignore_case),
                    match_anywhere(needles, data, ignore_case),
                    # default return value so calling shell functions have an
                    # argument to `cd` to
                    [Entry('.', 0)])))


def handle_tab_completion(needle, entries):
    if not needle:
        sys.exit(0)

    tab_needle, tab_index, tab_path = get_tab_entry_info(needle, TAB_SEPARATOR)

    if tab_path:
        print_local(tab_path)
    elif tab_index:
        get_ith_path = lambda i, iterable: last(take(i, iterable)).path
        print_local(get_ith_path(
            tab_index,
            find_matches(entries, tab_needle, check_entries=False)))
    elif tab_needle:
        # found partial tab completion entry
        print_tab_menu(
                tab_needle,
                take(TAB_ENTRIES_COUNT, find_matches(
                    entries,
                    tab_needle,
                    check_entries=False)),
                TAB_SEPARATOR)
    else:
        print_tab_menu(
                needle,
                take(TAB_ENTRIES_COUNT, find_matches(
                    entries,
                    needle,
                    check_entries=False)),
                TAB_SEPARATOR)


def match_anywhere(needles, haystack, ignore_case=False):
    """
    Matches needles anywhere in the path as long as they're in the same (but
    not necessary consecutive) order.

    For example:
        needles = ['foo', 'baz']
        regex needle = r'.*foo.*baz.*'
        haystack = [
            (path="/foo/bar/baz", weight=10),
            (path="/baz/foo/bar", weight=10),
            (path="/foo/baz", weight=10)]

        result = [
            (path="/moo/foo/baz", weight=10),
            (path="/foo/baz", weight=10)]
    """
    regex_needle = '.*' + '.*'.join(needles) + '.*'
    regex_flags = re.IGNORECASE | re.UNICODE if ignore_case else re.UNICODE
    found = lambda haystack: re.search(
            regex_needle,
            haystack.path,
            flags=regex_flags)
    return ifilter(found, haystack)


def match_consecutive(needles, haystack, ignore_case=False):
    """
    Matches consecutive needles at the end of a path.

    For example:
        needles = ['foo', 'baz']
        haystack = [
            (path="/foo/bar/baz", weight=10),
            (path="/foo/baz/moo", weight=10),
            (path="/moo/foo/baz", weight=10),
            (path="/foo/baz", weight=10)]

        regex_needle = re.compile(r'''
            foo     # needle #1
            [^/]*   # all characters except os.sep zero or more times
            /       # os.sep
            [^/]*   # all characters except os.sep zero or more times
            baz     # needle #2
            [^/]*   # all characters except os.sep zero or more times
            $       # end of string
            ''')

        result = [
            (path="/moo/foo/baz", weight=10),
            (path="/foo/baz", weight=10)]
    """
    if is_windows():
        # The normal \\ separator needs to be escaped again for use in regex.
        sep = '\\\\'
    else:
        sep = os.sep
    regex_no_sep = '[^' + sep + ']*'
    regex_no_sep_end = regex_no_sep + '$'
    regex_one_sep = regex_no_sep + sep + regex_no_sep
    # can't use compiled regex because of flags
    regex_needle = regex_one_sep.join(needles) + regex_no_sep_end
    regex_flags = re.IGNORECASE | re.UNICODE if ignore_case else re.UNICODE
    found = lambda entry: re.search(
            regex_needle,
            entry.path,
            flags=regex_flags)
    return ifilter(found, haystack)


def match_fuzzy(needles, haystack, ignore_case=False):
    """
    Performs an approximate match with the last needle against the end of
    every path past an acceptable threshold (FUZZY_MATCH_THRESHOLD).

    For example:
        needles = ['foo', 'bar']
        haystack = [
            (path="/foo/bar/baz", weight=11),
            (path="/foo/baz/moo", weight=10),
            (path="/moo/foo/baz", weight=10),
            (path="/foo/baz", weight=10),
            (path="/foo/bar", weight=10)]

    result = [
            (path="/foo/bar/baz", weight=11),
            (path="/moo/foo/baz", weight=10),
            (path="/foo/baz", weight=10),
            (path="/foo/bar", weight=10)]

    This is a weak heuristic and used as a last resort to find matches.
    """
    end_dir = lambda path: last(os.path.split(path))
    if ignore_case:
        needle = last(needles).lower()
        match_percent = lambda entry: SequenceMatcher(
                a=needle,
                b=end_dir(entry.path.lower())).ratio()
    else:
        needle = last(needles)
        match_percent = lambda entry: SequenceMatcher(
                a=needle,
                b=end_dir(entry.path)).ratio()
    meets_threshold = lambda entry: match_percent(entry) >= \
        FUZZY_MATCH_THRESHOLD
    return ifilter(meets_threshold, haystack)


def purge_missing_paths(entries):
    """Remove non-existent paths from a list of entries."""
    exists = lambda entry: os.path.exists(entry.path)
    return ifilter(exists, entries)


def print_stats(data, data_path):
    for path, weight in sorted(data.items(), key=itemgetter(1)):
        print_entry(Entry(path, weight))

    print("________________________________________\n")
    print("%d:\t total weight" % sum(data.values()))
    print("%d:\t number of entries" % len(data))

    try:
        print_local(
                "%.2f:\t current directory weight" % data.get(os.getcwdu(), 0))
    except OSError:
        # current directory no longer exists
        pass

    print("\ndata:\t %s" % data_path)


def main(args):  # noqa
    config = set_defaults()
    # all arguments are mutually exclusive
    if args.add:
        save(config, first(add_path(load(config), args.add)))
    elif args.complete:
        handle_tab_completion(
                needle=first(sanitize(args.directory)),
                entries=entriefy(load(config)))
    elif args.decrease:
        data, entry = decrease_path(load(config), get_pwd(), args.decrease)
        save(config, data)
        print_entry(entry)
    elif args.increase:
        data, entry = add_path(load(config), get_pwd(), args.increase)
        save(config, data)
        print_entry(entry)
    elif args.purge:
        old_data = load(config)
        new_data = dictify(purge_missing_paths(entriefy(old_data)))
        save(config, new_data)
        print("Purged %d entries." % (len(old_data) - len(new_data)))
    elif args.stat:
        print_stats(load(config), config['data_path'])
    elif not args.directory:
        # default return value so calling shell functions have an argument
        # to `cd` to
        print_local('.')
    else:
        entries = entriefy(load(config))
        needles = sanitize(args.directory)
        tab_needle, tab_index, tab_path = \
            get_tab_entry_info(first(needles), TAB_SEPARATOR)

        if tab_path:
            print_local(tab_path)
        elif tab_index:
            get_ith_path = lambda i, iterable: last(take(i, iterable)).path
            print_local(
                    get_ith_path(tab_index, find_matches(entries, tab_needle)))
        else:
            print_local(first(find_matches(entries, needles)).path)

    return 0


if __name__ == "__main__":
    sys.exit(main(parse_arguments()))