"""
author: deadc0de6 (https://github.com/deadc0de6)
Copyright (c) 2017, deadc0de6

utilities
"""

import subprocess
import tempfile
import os
import uuid
import fnmatch
import inspect
import importlib
import filecmp
import itertools
from shutil import rmtree, which
import json
import requests
from packaging import version

# local import
from dotdrop.logger import Logger
from dotdrop.exceptions import UnmetDependency
from dotdrop.version import __version__ as VERSION

LOG = Logger()
STAR = '*'
# the environment variable for temporary
ENV_TEMP = 'DOTDROP_TMPDIR'
# the temporary directory
TMPDIR = None

# files dotdrop refuses to remove
DONOTDELETE = [
    os.path.expanduser('~'),
    os.path.expanduser('~/.config'),
]
NOREMOVE = [os.path.normpath(p) for p in DONOTDELETE]


def run(cmd, debug=False):
    """run a command (expects a list)"""
    if debug:
        LOG.dbg('exec: {}'.format(' '.join(cmd)), force=True)
    proc = subprocess.Popen(cmd, shell=False,
                            stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
    out, _ = proc.communicate()
    ret = proc.returncode
    out = out.splitlines(keepends=True)
    lines = ''.join([x.decode('utf-8', 'replace') for x in out])
    return ret == 0, lines


def write_to_tmpfile(content):
    """write some content to a tmp file"""
    path = get_tmpfile()
    with open(path, 'wb') as file:
        file.write(content)
    return path


def shellrun(cmd, debug=False):
    """
    run a command in the shell (expects a string)
    returns True|False, output
    """
    if debug:
        LOG.dbg('shell exec: \"{}\"'.format(cmd), force=True)
    ret, out = subprocess.getstatusoutput(cmd)
    if debug:
        LOG.dbg('shell result ({}): {}'.format(ret, out), force=True)
    return ret == 0, out


def userinput(prompt, debug=False):
    """
    get user input
    return user input
    """
    if debug:
        LOG.dbg('get user input for \"{}\"'.format(prompt), force=True)
    pre = 'Please provide the value for \"{}\": '.format(prompt)
    res = input(pre)
    if debug:
        LOG.dbg('user input result: {}'.format(res), force=True)
    return res


def fastdiff(left, right):
    """fast compare files and returns True if different"""
    return not filecmp.cmp(left, right, shallow=False)


def diff(original, modified,
         diff_cmd='', debug=False):
    """compare two files, returns '' if same"""
    if not diff_cmd:
        diff_cmd = 'diff -r -u {0} {1}'

    replacements = {
        "{0}": original,
        "{original}": original,
        "{1}": modified,
        "{modified}": modified,
    }
    cmd = [replacements.get(x, x) for x in diff_cmd.split()]
    _, out = run(cmd, debug=debug)
    return out


def get_tmpdir():
    """create and return the temporary directory"""
# pylint: disable=W0603
    global TMPDIR
# pylint: enable=W0603
    if TMPDIR:
        return TMPDIR
    tmp = _get_tmpdir()
    TMPDIR = tmp
    return tmp


def _get_tmpdir():
    """create the tmpdir"""
    try:
        if ENV_TEMP in os.environ:
            tmp = os.environ[ENV_TEMP]
            tmp = os.path.expanduser(tmp)
            tmp = os.path.abspath(tmp)
            tmp = os.path.normpath(tmp)
            os.makedirs(tmp, exist_ok=True)
            return tmp
    except OSError:
        pass
    return tempfile.mkdtemp(prefix='dotdrop-')


def get_tmpfile():
    """create a temporary file"""
    tmpdir = get_tmpdir()
    return tempfile.NamedTemporaryFile(prefix='dotdrop-',
                                       dir=tmpdir, delete=False).name


def get_unique_tmp_name():
    """get a unique file name (not created)"""
    unique = str(uuid.uuid4())
    tmpdir = get_tmpdir()
    return os.path.join(tmpdir, unique)


def removepath(path, logger=None):
    """
    remove a file/directory/symlink
    if logger is defined, OSError are catched
    and printed to logger.warn instead of being forwarded
    as OSError
    """
    if not path:
        return
    if not os.path.lexists(path):
        err = 'File not found: {}'.format(path)
        if logger:
            logger.warn(err)
            return
        raise OSError(err)
    if os.path.normpath(os.path.expanduser(path)) in NOREMOVE:
        err = 'Dotdrop refuses to remove {}'.format(path)
        if logger:
            logger.warn(err)
            return
        LOG.err(err)
        raise OSError(err)
    try:
        if os.path.islink(path) or os.path.isfile(path):
            os.unlink(path)
        elif os.path.isdir(path):
            rmtree(path)
        else:
            err = 'Unsupported file type for deletion: {}'.format(path)
            raise OSError(err)
    except Exception as exc:
        err = str(exc)
        if logger:
            logger.warn(err)
            return
        raise OSError(err) from exc


def samefile(path1, path2):
    """return True if represent the same file"""
    if not os.path.exists(path1):
        return False
    if not os.path.exists(path2):
        return False
    return os.path.samefile(path1, path2)


def header():
    """return dotdrop header"""
    return 'This dotfile is managed using dotdrop'


def content_empty(string):
    """return True if is empty or only one CRLF"""
    if not string:
        return True
    if string == b'\n':
        return True
    return False


def strip_home(path):
    """properly strip $HOME from path"""
    home = os.path.expanduser('~') + os.sep
    if path.startswith(home):
        path = path[len(home):]
    return path


def must_ignore(paths, ignores, debug=False):
    """return true if any paths in list matches any ignore patterns"""
    if debug:
        LOG.dbg('must_ignore called', force=True)
    if not ignores:
        return False
    if debug:
        LOG.dbg('must ignore? \"{}\" against {}'.format(paths, ignores),
                force=True)
    ignored_negative, ignored = categorize(
        lambda ign: ign.startswith('!'), ignores)
    for path in paths:
        ignore_matches = []
        # First ignore dotfiles
        for i in ignored:
            if fnmatch.fnmatch(path, i):
                if debug:
                    LOG.dbg('ignore \"{}\" match: {}'.format(i, path),
                            force=True)
                ignore_matches.append(path)

        # Then remove any matches that actually shouldn't be ignored
        for nign in ignored_negative:
            # Each of these will start with an '!' so we need to remove that
            nign = nign[1:]
            if debug:
                msg = 'trying to match :\"{}\" with non-ignore-pattern:\"{}\"'
                LOG.dbg(msg.format(path, nign), force=True)
            if fnmatch.fnmatch(path, nign):
                if debug:
                    msg = 'negative ignore \"{}\" match: {}'.format(nign, path)
                    LOG.dbg(msg, force=True)
                try:
                    ignore_matches.remove(path)
                except ValueError:
                    LOG.warn('no files that are currently being '
                             'ignored match \"{}\". In order '
                             'for a negative ignore pattern '
                             'to work, it must match a file '
                             'that is being ignored by a '
                             'previous ignore pattern.'.format(nign)
                             )
        if ignore_matches:
            if debug:
                LOG.dbg('ignoring {}'.format(paths), force=True)
            return True
    if debug:
        LOG.dbg('NOT ignoring {}'.format(paths), force=True)
    return False


def uniq_list(a_list):
    """unique elements of a list while preserving order"""
    new = []
    if not a_list:
        return new
    for elem in a_list:
        if elem not in new:
            new.append(elem)
    return new


def patch_ignores(ignores, prefix, debug=False):
    """allow relative ignore pattern"""
    new = []
    LOG.dbg('ignores before patching: {}'.format(ignores), force=debug)
    for ignore in ignores:
        negative = ignore.startswith('!')
        if negative:
            ignore = ignore[1:]

        if os.path.isabs(ignore):
            # is absolute
            if negative:
                new.append('!' + ignore)
            else:
                new.append(ignore)
            continue
        if STAR in ignore:
            if ignore.startswith(STAR) or ignore.startswith(os.sep):
                # is glob
                if negative:
                    new.append('!' + ignore)
                else:
                    new.append(ignore)
                continue
        # patch ignore
        path = os.path.join(prefix, ignore)
        if negative:
            new.append('!' + path)
        else:
            new.append(path)
    LOG.dbg('ignores after patching: {}'.format(new), force=debug)
    return new


def get_module_functions(mod):
    """return a list of fonction from a module"""
    funcs = []
    for memb in inspect.getmembers(mod):
        name, func = memb
        if not inspect.isfunction(func):
            continue
        funcs.append((name, func))
    return funcs


def get_module_from_path(path):
    """get module from path"""
    if not path or not os.path.exists(path):
        return None
    module_name = os.path.basename(path).rstrip('.py')
    # allow any type of files
    importlib.machinery.SOURCE_SUFFIXES.append('')
    # import module
    spec = importlib.util.spec_from_file_location(module_name, path)
    mod = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(mod)
    return mod


def dependencies_met():
    """make sure all dependencies are met"""
    # check unix tools deps
    deps = ['file', 'diff']
    err = 'The tool \"{}\" was not found in the PATH!'
    for dep in deps:
        if not which(dep):
            raise UnmetDependency(err.format(dep))
    # check python deps
    err = 'missing python module \"{}\"'

# pylint: disable=C0415
    # python-magic
    try:
        import magic
        assert magic
        if not hasattr(magic, 'from_file'):
            LOG.warn(err.format('python-magic'))
    except ImportError:
        LOG.warn(err.format('python-magic'))

    # docopt
    try:
        from docopt import docopt
        assert docopt
    except ImportError as exc:
        raise Exception(err.format('docopt')) from exc

    # jinja2
    try:
        import jinja2
        assert jinja2
    except ImportError as exc:
        raise Exception(err.format('jinja2')) from exc

    # ruamel.yaml
    try:
        from ruamel.yaml import YAML
        assert YAML
    except ImportError as exc:
        raise Exception(err.format('ruamel.yaml')) from exc
# pylint: enable=C0415


def mirror_file_rights(src, dst):
    """mirror file rights of src to dst (can rise exc)"""
    if not os.path.exists(src) or not os.path.exists(dst):
        return
    rights = get_file_perm(src)
    os.chmod(dst, rights)


def get_umask():
    """return current umask value"""
    cur = os.umask(0)
    os.umask(cur)
    # return 0o777 - cur
    return cur


def get_default_file_perms(path, umask):
    """get default rights for a file"""
    base = 0o666
    if os.path.isdir(path):
        base = 0o777
    return base - umask


def get_file_perm(path):
    """return file permission"""
    return os.stat(path).st_mode & 0o777


def chmod(path, mode, debug=False):
    """change mode of file"""
    if debug:
        LOG.dbg('chmod {} {}'.format(oct(mode), path), force=True)
    os.chmod(path, mode)
    return get_file_perm(path) == mode


def adapt_workers(options, logger):
    """adapt number of workers if safe/dry"""
    if options.safe and options.workers > 1:
        logger.warn('workers set to 1 when --force is not used')
        options.workers = 1
    if options.dry and options.workers > 1:
        logger.warn('workers set to 1 when --dry is used')
        options.workers = 1


def categorize(function, iterable):
    """separate an iterable into elements for which
    function(element) is true for each element and
    for which function(element) is false for each
    element"""
    return (tuple(filter(function, iterable)),
            tuple(itertools.filterfalse(function, iterable)))


def debug_list(title, elems, debug):
    """pretty print list"""
    if not debug:
        return
    LOG.dbg('{}:'.format(title), force=debug)
    for elem in elems:
        LOG.dbg('\t- {}'.format(elem), force=debug)


def debug_dict(title, elems, debug):
    """pretty print dict"""
    if not debug:
        return
    LOG.dbg('{}:'.format(title), force=debug)
    for k, val in elems.items():
        if isinstance(val, list):
            LOG.dbg('\t- \"{}\":'.format(k), force=debug)
            for i in val:
                LOG.dbg('\t\t- {}'.format(i), force=debug)
        else:
            LOG.dbg('\t- \"{}\": {}'.format(k, val), force=debug)


def check_version():
    """check dotdrop version on github and compare with current"""
    url = 'https://api.github.com/repos/deadc0de6/dotdrop/releases/latest'
    req = requests.get(url, timeout=1)
    if not req:
        return
    try:
        latest = req.json()['name']
    except json.decoder.JSONDecodeError:
        return
    except ValueError:
        return
    if latest.startswith('v'):
        latest = latest[1:]
    if version.parse(VERSION) < version.parse(latest):
        msg = 'A new version of dotdrop is available ({})'
        LOG.warn(msg.format(latest))


def pivot_path(path, newdir, striphome=False, logger=None):
    """change path to be under newdir"""
    if logger:
        logger.dbg('pivot new dir: \"{}\"'.format(newdir))
        logger.dbg('strip home: {}'.format(striphome))
    if striphome:
        path = strip_home(path)
    sub = path.lstrip(os.sep)
    new = os.path.join(newdir, sub)
    if logger:
        logger.dbg('pivot \"{}\" to \"{}\"'.format(path, new))
    return new