# Authors:
#     Endi S. Dewata <edewata@redhat.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the Lesser GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser 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.
#
# Copyright (C) 2013 Red Hat, Inc.
# All rights reserved.
#
"""
Module containing utility functions and classes for the Dogtag python code
"""


from __future__ import absolute_import
import os
import shutil
from shutil import Error
try:
    from shutil import WindowsError  # pylint: disable=E0611
except ImportError:
    WindowsError = None

import subprocess

DEFAULT_PKI_ENV_LIST = [
    '/usr/share/pki/etc/pki.conf',
    '/etc/pki/pki.conf',
]


def copy(source, dest):
    """
    Copy a file or a folder and its contents.
    """

    # remove trailing slashes
    if source[-1] == '/':
        source = source[:-1]
    if dest[-1] == '/':
        dest = dest[:-1]

    sourceparent = os.path.dirname(source)
    destparent = os.path.dirname(dest)

    copydirs(sourceparent, destparent)

    if os.path.isfile(source):
        copyfile(source, dest)

    else:
        for sourcepath, _, filenames in os.walk(source):

            relpath = sourcepath[len(source):]
            destpath = dest + relpath
            if destpath == '':
                destpath = '/'

            copydirs(sourcepath, destpath)

            for filename in filenames:
                sourcefile = os.path.join(sourcepath, filename)
                targetfile = os.path.join(destpath, filename)
                copyfile(sourcefile, targetfile)


def copyfile(source, dest, overwrite=True):
    """
    Copy a file or link while preserving its attributes.
    """

    # if dest already exists and not overwriting, do nothing
    if os.path.exists(dest) and not overwrite:
        return

    if os.path.islink(source):
        target = os.readlink(source)
        os.symlink(target, dest)

        stat = os.lstat(source)
        os.lchown(dest, stat.st_uid, stat.st_gid)

    else:
        shutil.copyfile(source, dest)

        stat = os.stat(source)
        os.utime(dest, (stat.st_atime, stat.st_mtime))
        os.chmod(dest, stat.st_mode)
        os.chown(dest, stat.st_uid, stat.st_gid)


def copydirs(source, dest):
    """
    Copy a folder and its parents while preserving their attributes.
    """

    if os.path.exists(dest):
        return

    destparent = os.path.dirname(dest)

    if not os.path.exists(destparent):
        sourceparent = os.path.dirname(source)
        copydirs(sourceparent, destparent)

    os.mkdir(dest)

    stat = os.stat(source)
    os.utime(dest, (stat.st_atime, stat.st_mtime))
    os.chmod(dest, stat.st_mode)
    os.chown(dest, stat.st_uid, stat.st_gid)


def chown(path, uid, gid):
    """
    Change ownership of a folder and its contents.
    """

    os.chown(path, uid, gid)

    for item in os.listdir(path):
        itempath = os.path.join(path, item)

        if os.path.isfile(itempath):
            os.chown(itempath, uid, gid)
        elif os.path.isdir(itempath):
            chown(itempath, uid, gid)


def customize_file(input_file, output_file, params):
    """
    Customize a file with specified parameters.
    """

    with open(input_file) as infile, open(output_file, 'w') as outfile:
        for line in infile:
            for src, target in params.items():
                line = line.replace(src, target)
            outfile.write(line)


def load_properties(filename, properties):

    with open(filename) as f:

        lines = f.read().splitlines()

        for index, line in enumerate(lines):

            line = line.strip()

            if not line or line.startswith('#'):
                continue

            parts = line.split('=', 1)

            if len(parts) < 2:
                raise Exception('Missing delimiter in %s line %d' %
                                (filename, index + 1))

            name = parts[0].strip()
            value = parts[1].strip()
            properties[name] = value


def store_properties(filename, properties):

    with open(filename, 'w') as f:

        for name, value in properties.items():
            line = '%s=%s\n' % (name, value)
            f.write(line)


def copytree(src, dst, symlinks=False, ignore=None):
    """
    Recursively copy a directory tree using copy2().

    PATCH:  This code was copied from 'shutil.py' and patched to
            allow 'The destination directory to already exist.'

    If exception(s) occur, an Error is raised with a list of reasons.

    If the optional symlinks flag is true, symbolic links in the
    source tree result in symbolic links in the destination tree; if
    it is false, the contents of the files pointed to by symbolic
    links are copied.

    The optional ignore argument is a callable. If given, it
    is called with the `src` parameter, which is the directory
    being visited by copytree(), and `names` which is the list of
    `src` contents, as returned by os.listdir():

        callable(src, names) -> ignored_names

    Since copytree() is called recursively, the callable will be
    called once for each directory that is copied. It returns a
    list of names relative to the `src` directory that should
    not be copied.

    Consider this example code rather than the ultimate tool.
    """
    names = os.listdir(src)
    if ignore is not None:
        ignored_names = ignore(src, names)
    else:
        ignored_names = set()

    # PATCH:  ONLY execute 'os.makedirs(dst)' if the top-level
    #         destination directory does NOT exist!
    if not os.path.exists(dst):
        os.makedirs(dst)
    errors = []
    for name in names:
        if name in ignored_names:
            continue
        srcname = os.path.join(src, name)
        dstname = os.path.join(dst, name)
        try:
            if symlinks and os.path.islink(srcname):
                linkto = os.readlink(srcname)
                os.symlink(linkto, dstname)
            elif os.path.isdir(srcname):
                copytree(srcname, dstname, symlinks, ignore)
            else:
                # Will raise a SpecialFileError for unsupported file types
                shutil.copy2(srcname, dstname)
        # catch the Error from the recursive copytree so that we can
        # continue with other files
        except Error as err:
            errors.extend(err.args[0])
        except EnvironmentError as why:
            errors.append((srcname, dstname, str(why)))
    try:
        shutil.copystat(src, dst)
    except OSError as why:
        if WindowsError is not None and isinstance(why, WindowsError):
            # Copying file access times may fail on Windows
            pass
        else:
            errors.extend((src, dst, str(why)))
    if errors:
        raise Error(errors)


def read_environment_files(env_file_list=None):
    if env_file_list is None:
        env_file_list = DEFAULT_PKI_ENV_LIST

    file_command = ' && '.join(
        'source {}'.format(env_file) for env_file in env_file_list)
    file_command += ' && env'

    command = [
        'bash',
        '-c',
        file_command
    ]

    env_vals = subprocess.check_output(command).decode('utf-8').split('\n')

    for env_val in env_vals:
        (key, _, value) = env_val.partition("=")
        os.environ[key] = value