"""
Utilities aimed to help achieve mostly basic tasks.
"""

import datetime
import logging
import os
import re
import time
import urllib.request

import mercurial.url
from pygments import highlight
from pygments.formatters import TerminalFormatter
from pygments.lexers import ClassNotFound, guess_lexer_for_filename

from kallithea.lib.vcs import backends
from kallithea.lib.vcs.exceptions import RepositoryError, VCSError
from kallithea.lib.vcs.utils import safe_str
from kallithea.lib.vcs.utils.paths import abspath


ALIASES = ['hg', 'git']


def get_scm(path, search_up=False, explicit_alias=None):
    """
    Returns one of alias from ``ALIASES`` (in order of precedence same as
    shortcuts given in ``ALIASES``) and top working dir path for the given
    argument. If no scm-specific directory is found or more than one scm is
    found at that directory, ``VCSError`` is raised.

    :param search_up: if set to ``True``, this function would try to
      move up to parent directory every time no scm is recognized for the
      currently checked path. Default: ``False``.
    :param explicit_alias: can be one of available backend aliases, when given
      it will return given explicit alias in repositories under more than one
      version control, if explicit_alias is different than found it will raise
      VCSError
    """
    if not os.path.isdir(path):
        raise VCSError("Given path %s is not a directory" % path)

    while True:
        found_scms = [(scm, path) for scm in get_scms_for_path(path)]
        if found_scms or not search_up:
            break
        newpath = abspath(path, '..')
        if newpath == path:
            break
        path = newpath

    if len(found_scms) > 1:
        for scm in found_scms:
            if scm[0] == explicit_alias:
                return scm
        raise VCSError('More than one [%s] scm found at given path %s'
                       % (', '.join((x[0] for x in found_scms)), path))

    if len(found_scms) == 0:
        raise VCSError('No scm found at given path %s' % path)

    return found_scms[0]


def get_scms_for_path(path):
    """
    Returns all scm's found at the given path. If no scm is recognized
    - empty list is returned.

    :param path: path to directory which should be checked. May be callable.

    :raises VCSError: if given ``path`` is not a directory
    """
    if hasattr(path, '__call__'):
        path = path()
    if not os.path.isdir(path):
        raise VCSError("Given path %r is not a directory" % path)

    result = []
    for key in ALIASES:
        # find .hg / .git
        dirname = os.path.join(path, '.' + key)
        if os.path.isdir(dirname):
            result.append(key)
            continue
        # find rm__.hg / rm__.git too - left overs from old method for deleting
        dirname = os.path.join(path, 'rm__.' + key)
        if os.path.isdir(dirname):
            return result
        # We still need to check if it's not bare repository as
        # bare repos don't have working directories
        try:
            backends.get_backend(key)(path)
            result.append(key)
            continue
        except RepositoryError:
            # Wrong backend
            pass
        except VCSError:
            # No backend at all
            pass
    return result


def get_highlighted_code(name, code, type='terminal'):
    """
    If pygments are available on the system
    then returned output is colored. Otherwise
    unchanged content is returned.
    """
    try:
        lexer = guess_lexer_for_filename(name, code)
        formatter = TerminalFormatter()
        content = highlight(code, lexer, formatter)
    except ClassNotFound:
        logging.debug("Couldn't guess Lexer, will not use pygments.")
        content = code
    return content


def parse_changesets(text):
    """
    Returns dictionary with *start*, *main* and *end* ids.

    Examples::

        >>> parse_changesets('aaabbb')
        {'start': None, 'main': 'aaabbb', 'end': None}
        >>> parse_changesets('aaabbb..cccddd')
        {'start': 'aaabbb', 'end': 'cccddd', 'main': None}

    """
    text = text.strip()
    CID_RE = r'[a-zA-Z0-9]+'
    if '..' not in text:
        m = re.match(r'^(?P<cid>%s)$' % CID_RE, text)
        if m:
            return {
                'start': None,
                'main': text,
                'end': None,
            }
    else:
        RE = r'^(?P<start>%s)?\.{2,3}(?P<end>%s)?$' % (CID_RE, CID_RE)
        m = re.match(RE, text)
        if m:
            result = m.groupdict()
            result['main'] = None
            return result
    raise ValueError("IDs not recognized")


def parse_datetime(text):
    """
    Parses given text and returns ``datetime.datetime`` instance or raises
    ``ValueError``.

    :param text: string of desired date/datetime or something more verbose,
      like *yesterday*, *2weeks 3days*, etc.
    """

    text = text.strip().lower()

    INPUT_FORMATS = (
        '%Y-%m-%d %H:%M:%S',
        '%Y-%m-%d %H:%M',
        '%Y-%m-%d',
        '%m/%d/%Y %H:%M:%S',
        '%m/%d/%Y %H:%M',
        '%m/%d/%Y',
        '%m/%d/%y %H:%M:%S',
        '%m/%d/%y %H:%M',
        '%m/%d/%y',
    )
    for format in INPUT_FORMATS:
        try:
            return datetime.datetime(*time.strptime(text, format)[:6])
        except ValueError:
            pass

    # Try descriptive texts
    if text == 'tomorrow':
        future = datetime.datetime.now() + datetime.timedelta(days=1)
        args = future.timetuple()[:3] + (23, 59, 59)
        return datetime.datetime(*args)
    elif text == 'today':
        return datetime.datetime(*datetime.datetime.today().timetuple()[:3])
    elif text == 'now':
        return datetime.datetime.now()
    elif text == 'yesterday':
        past = datetime.datetime.now() - datetime.timedelta(days=1)
        return datetime.datetime(*past.timetuple()[:3])
    else:
        days = 0
        matched = re.match(
            r'^((?P<weeks>\d+) ?w(eeks?)?)? ?((?P<days>\d+) ?d(ays?)?)?$', text)
        if matched:
            groupdict = matched.groupdict()
            if groupdict['days']:
                days += int(matched.groupdict()['days'])
            if groupdict['weeks']:
                days += int(matched.groupdict()['weeks']) * 7
            past = datetime.datetime.now() - datetime.timedelta(days=days)
            return datetime.datetime(*past.timetuple()[:3])

    raise ValueError('Wrong date: "%s"' % text)


def get_dict_for_attrs(obj, attrs):
    """
    Returns dictionary for each attribute from given ``obj``.
    """
    data = {}
    for attr in attrs:
        data[attr] = getattr(obj, attr)
    return data

def get_urllib_request_handlers(url_obj):
    handlers = []
    test_uri, authinfo = url_obj.authinfo()

    if authinfo:
        # authinfo is a tuple (realm, uris, user, password) where 'uris' itself
        # is a tuple of URIs.
        # If url_obj is obtained via mercurial.util.url, the obtained authinfo
        # values will be bytes, e.g.
        #    (None, (b'http://127.0.0.1/repo', b'127.0.0.1'), b'user', b'pass')
        # However, urllib expects strings, not bytes, so we must convert them.

        # create a password manager
        passmgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()
        passmgr.add_password(
            safe_str(authinfo[0]) if authinfo[0] else None, # realm
            tuple(safe_str(x) for x in authinfo[1]),        # uris
            safe_str(authinfo[2]),                          # user
            safe_str(authinfo[3]),                          # password
        )

        handlers.extend((mercurial.url.httpbasicauthhandler(passmgr),
                         mercurial.url.httpdigestauthhandler(passmgr)))

    return test_uri, handlers