# Copyright 2013: Mirantis Inc.
# All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

import os

from rally import exceptions


PATH_GLOBALS = "~/.rally/globals"
ENV_ENV = "RALLY_ENV"
ENV_DEPLOYMENT = "RALLY_DEPLOYMENT"
ENV_TASK = "RALLY_TASK"
ENV_VERIFIER = "RALLY_VERIFIER"
ENV_VERIFICATION = "RALLY_VERIFICATION"
ENVVARS = (ENV_ENV, ENV_DEPLOYMENT, ENV_TASK, ENV_VERIFIER, ENV_VERIFICATION)


def _read_env_file(path, except_env=None):
    """Read the environment variable file.

    :param path: the path of the file
    :param except_env: the environment variable to avoid in the output

    :returns: the content of the original file except the line starting with
    the except_env parameter
    """
    output = []
    if os.path.exists(path):
        with open(path) as env_file:
            content = env_file.readlines()
            for line in content:
                if except_env is None or not line.startswith(f"{except_env}="):
                    output.append(line)
    return output


def _load_env_file(path):
    """Load the environment variable file into os.environ.

    :param path: the path of the file
    """
    if os.path.exists(path):
        content = _read_env_file(path)
        for line in content:
            (key, sep, value) = line.partition("=")
            os.environ[key] = value.rstrip()


def _rewrite_env_file(path, initial_content):
    """Rewrite the environment variable file.

    :param path: the path of the file
    :param initial_content: the original content of the file
    """
    with open(path, "w+") as env_file:
        for line in initial_content:
            env_file.write(line)


def _update_env_file(path, env_key, env_value):
    """Update the environment variable file.

    :param path: the path of the file
    :param env_key: the key to update
    :param env_value: the value of the property to update
    """
    output = _read_env_file(path, env_key)
    output.append("%s=%s" % (env_key, env_value))
    _rewrite_env_file(path, output)


def update_globals_file(key, value):
    """Update the globals variables file.

    :param key: the key to update
    :param value: the value to update
    """
    dir = os.path.expanduser("~/.rally/")
    if not os.path.exists(dir):
        os.makedirs(dir)
    expanded_path = os.path.join(dir, "globals")
    _update_env_file(expanded_path, key, f"{value}\n")


def clear_global(global_key):
    path = os.path.expanduser(PATH_GLOBALS)
    if os.path.exists(path):
        _update_env_file(path, global_key, "\n")
    if global_key in os.environ:
        os.environ.pop(global_key)


def clear_env():
    for envvar in ENVVARS:
        clear_global(envvar)


def get_global(global_key, do_raise=False):
    if global_key not in os.environ:
        _load_env_file(os.path.expanduser(PATH_GLOBALS))
    value = os.environ.get(global_key)
    if not value and do_raise:
        raise exceptions.InvalidArgumentsException(
            f"{global_key} env is missing"
        )
    return value


def load_globals():
    """Load persisted Rally globals (``~/.rally/globals``) into os.environ."""

    for line in _read_env_file(os.path.expanduser(PATH_GLOBALS)):
        key, _, value = line.partition("=")
        os.environ.setdefault(key, value.rstrip())

    # NOTE(boris-42): This allows smooth transition from deployment to env
    # set ENV_ENV from ENV_DEPLOYMENT and use ENV_ENV
    # This should be removed with rally env command
    if not os.environ.get(ENV_ENV) and os.environ.get(ENV_DEPLOYMENT):
        os.environ[ENV_ENV] = os.environ[ENV_DEPLOYMENT]
