# 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 logging
import os.path
import textwrap
from typing import Any
from typing import List
from typing import NamedTuple
from typing import Union

import yaml

from reno import defaults

LOG = logging.getLogger(__name__)


class Opt(NamedTuple):
    name: str
    default: Any
    help: str


class Section(NamedTuple):
    name: str
    title: str
    section_level: int  # 1 represents top-level; higher values are subsctions

    @classmethod
    def from_raw_yaml(
        cls, val: List[List[Union[str, int]]]
    ) -> List["Section"]:
        result = []
        for entry in val:
            if len(entry) == 2:
                section_level = 1
            elif len(entry) == 3:
                section_level = entry[2]
                if (
                    not isinstance(section_level, int)
                    or section_level < 1
                    or section_level > 3
                ):
                    raise ValueError(
                        "The third argument for each entry in the `sections` "
                        "option config must be an integer between 1 and 3."
                        f"Invalid entry: {entry}"
                    )
            else:
                raise ValueError(
                    "Each entry in the `sections` option config must be a "
                    f"list with 2 or 3 values. Invalid entry: {entry}"
                )
            result.append(
                Section(
                    name=entry[0], title=entry[1], section_level=section_level
                )
            )
        return result

    def header_underline(self) -> str:
        symbol = {
            1: "-",
            2: "^",
            3: "~",
        }[self.section_level]
        return symbol * len(self.title)


_OPTIONS = [
    Opt('notesdir', defaults.NOTES_SUBDIR,
        textwrap.dedent("""\
        The notes subdirectory within the relnotesdir where the
        notes live.
        """)),

    Opt('allow_subdirectories', False,
        textwrap.dedent("""\
        Allow creating subdirectories under the notes subdirectory.
        """)),

    Opt('collapse_pre_releases', True,
        textwrap.dedent("""\
        Should pre-release versions be merged into the final release
        of the same number (1.0.0.0a1 notes appear under 1.0.0).
        """)),

    Opt('stop_at_branch_base', True,
        textwrap.dedent("""\
        Should the scanner stop at the base of a branch (True) or go
        ahead and scan the entire history (False)?
        """)),

    Opt('branch', None,
        textwrap.dedent("""\
        The git branch to scan. Defaults to the "current" branch
        checked out. If a stable branch is specified but does not
        exist, reno attempts to automatically convert that to an
        "end-of-life" tag. For example, ``origin/stable/liberty``
        would be converted to ``liberty-eol``.
        """)),

    Opt('default_branch', 'master',
        textwrap.dedent("""\
        The default git branch for the repository. This is the base branch that
        is treated as the root for other branches. By default this is
        ``master``.
        """)),

    Opt('earliest_version', None,
        textwrap.dedent("""\
        The earliest version to be included. This is usually the
        lowest version number, and is meant to be the oldest
        version. If unset, all versions will be scanned.
        """)),

    Opt('template', defaults.TEMPLATE.format(defaults.PRELUDE_SECTION_NAME),
        textwrap.dedent("""\
        The template used by reno new to create a note.
        """)),

    Opt('add_release_date', False,
        textwrap.dedent("""\
        Should the report include release date (True) based on
        the date of objects associated with the release tag.
        """)),

    Opt('release_tag_re',
        textwrap.dedent('''\
        ((?:v?[\\d.ab]|rc)+)  # digits, a, b, and rc cover regular and
                           # pre-releases
        '''),
        textwrap.dedent("""\
        The regex pattern used to match the repo tags representing a
        valid release version. The pattern is compiled with the
        verbose and unicode flags enabled.
        """)),

    Opt('pre_release_tag_re',
        textwrap.dedent('''\
        (?P<pre_release>\\.v?\\d+(?:[ab]|rc)+\\d*)$
        '''),
        textwrap.dedent("""\
        The regex pattern used to check if a valid release version tag
        is also a valid pre-release version. The pattern is compiled
        with the verbose and unicode flags enabled. The pattern must
        define a group called 'pre_release' that matches the
        pre-release part of the tag and any separator, e.g for
        pre-release version '12.0.0.0rc1' the default pattern will
        identify '.0rc1' as the value of the group 'pre_release'.
        """)),

    Opt('branch_name_re', 'stable/.+',
        textwrap.dedent("""\
        The pattern for names for branches that are relevant when
        scanning history to determine where to stop, to find the
        "base" of a branch. Other branches are ignored.
        """)),

    Opt('closed_branch_tag_re', '(.+)-eo[lm]',
        textwrap.dedent("""\
        The pattern for names for tags that replace closed
        branches that are relevant when scanning history to
        determine where to stop, to find the "base" of a
        branch. Other tags are ignored.
        """)),

    Opt('branch_name_prefix', 'stable/',
        textwrap.dedent("""\
        The prefix to add to tags for closed branches
        to restore the old branch name to allow sorting
        to place the tag in the proper place in history.
        For example, OpenStack turns "mitaka-eol" into
        "stable/mitaka" by removing the "-eol" suffix
        via closed_branch_tag_re and setting the prefix
        to "stable/".
        """)),

    Opt('branch_sort_re', 'stable/([0-9].*)',
        textwrap.dedent("""\
        By default branches are sorted alphabetically, except
        for branches matching this pattern, those will be sorted
        with branch_sort_prefix inserted in order to accomodate
        the way OpenStack stable branches are named and sorted.
        """)),

    Opt('branch_sort_prefix', 'stable/zzz',
        textwrap.dedent("""\
        The prefix to add to names of branches matched
        by branch_sort_re. This allows OpenStack branches
        to be sorted according to the current release
        naming scheme. Set to "stable/" in order to
        restore plain alphabetic ordering.
        """)),

    Opt('sections',
        [
            ['features', 'New Features'],
            ['issues', 'Known Issues'],
            ['upgrade', 'Upgrade Notes'],
            ['deprecations', 'Deprecation Notes'],
            ['critical', 'Critical Issues'],
            ['security', 'Security Issues'],
            ['fixes', 'Bug Fixes'],
            ['other', 'Other Notes'],
        ],
        textwrap.dedent("""\
        The identifiers and names of permitted sections in the
        release notes, in the order in which the final report will
        be generated. A prelude section will always be automatically
        inserted before the first element of this list.

        You can optionally include a number from 1 to 3 at the
        end of the list to mark the entry as a subsection. By default,
        each section has the number 1, which represents a top-level
        section. Use 2 and 3 for subsections and subsubsections.
        For example, ``['features', 'New Features', 1]``,
        ``['features_command_line', 'Command Line', 2]``,
        and ``['features_command_line_ios', 'iOS', 3]``. The order of this
        option matters; define subsections right after their ancestor
        sections.

        Warning: you should check that ``semver_major``, ``semver_minor``,
        and ``semver_patch`` includes the relevant section names,
        including subsections.
        """)),

    Opt('prelude_section_name', defaults.PRELUDE_SECTION_NAME,
        textwrap.dedent("""\
        The name of the prelude section in the note template. This
        allows users to rename the section to, for example,
        'release_summary' or 'project_wide_general_announcements',
        which is displayed in titlecase in the report after
        replacing underscores with spaces.
        """)),

    Opt('ignore_null_merges', True,
        textwrap.dedent("""\
        When this option is set to True, any merge commits with no
        changes and in which the second or later parent is tagged
        are considered "null-merges" that bring the tag information
        into the current branch but nothing else.

        OpenStack used to use null-merges to bring final release
        tags from stable branches back into the master branch. This
        confuses the regular traversal because it makes that stable
        branch appear to be part of master and/or the later stable
        branch. This option allows us to ignore those.
        """)),

    Opt('ignore_notes', [],
        textwrap.dedent("""\
        Note files to be ignored. It's useful to be able to ignore a
        file if it is edited on the wrong branch. Notes should be
        specified by their filename or UID.

        Setting the option in the main configuration file makes it
        apply to all branches. To ignore a note in the HTML build, use
        the ``ignore-notes`` parameter to the ``release-notes`` sphinx
        directive.
        """)),

    Opt('unreleased_version_title', '',
        textwrap.dedent("""\
        The title to use for any notes that do not appear in a
        released version. If this option is unset, the development
        version number is used (for example, ``3.0.0-3``).
        """)),
    Opt('encoding', None,
        textwrap.dedent("""\
        The character encoding to use when opening note files. If not
        specified it will be dependent on the system running reno (whatever
        'locale.getpreferredencoding()' returns. This takes in a string
        name that will be passed to the encoding kwarg for open(), so any
        codec or alias from stdlib's codec module is valid.
        """)),

    Opt('semver_major', ['upgrade'],
        textwrap.dedent("""\
        The sections that indicate release notes triggering major version
        updates for the next release, from X.Y.Z to X+1.0.0.
        """)),
    Opt('semver_minor', ['features'],
        textwrap.dedent("""\
        The sections that indicate release notes triggering minor version
        updates for the next release, from X.Y.Z to X.Y+1.0.
        """)),
    Opt('semver_patch', ['fixes'],
        textwrap.dedent("""\
        The sections that indicate release notes triggering patch version
        updates for the next release, from X.Y.Z to X.Y.Z+1.
        """)),
]


class Config:

    _OPTS = {o.name: o for o in _OPTIONS}

    @classmethod
    def get_default(cls, opt):
        """Return the default for an option."""
        try:
            return cls._OPTS[opt].default
        except KeyError:
            raise ValueError('unknown option name %r' % (opt,))

    def __init__(self, reporoot, relnotesdir=None):
        """Instantiate a Config object

        :param str reporoot:
            The root directory of the repository.
        :param str relnotesdir:
            The directory containing release notes. Defaults to
            'releasenotes'.
        """
        self.reporoot = reporoot
        if relnotesdir is None:
            relnotesdir = defaults.RELEASE_NOTES_SUBDIR
        self.relnotesdir = relnotesdir
        # Initialize attributes from the defaults.
        self.override(**{o.name: o.default for o in _OPTIONS})

        self._contents = {}
        self._load_file()

    def _load_file(self):
        filenames = [
            os.path.join(self.reporoot, self.relnotesdir, 'config.yaml'),
            os.path.join(self.reporoot, 'reno.yaml')]

        for filename in filenames:
            LOG.debug('looking for configuration file %s', filename)
            if os.path.isfile(filename):
                break
        else:
            self._report_missing_config_files(filenames)
            return

        try:
            with open(filename, 'r') as fd:
                self._contents = yaml.safe_load(fd)
            LOG.info('loaded configuration file %s', filename)
        except IOError as err:
            self._report_failure_config_file(filename, err)
        else:
            if self._contents:
                self.override(**self._contents)

    def _report_missing_config_files(self, filenames):
        # NOTE(dhellmann): This is extracted so we can mock it for
        # testing.
        LOG.info('no configuration file in: %s', ', '.join(filenames))

    def _report_failure_config_file(self, filename, err):
        # NOTE(dhellmann): This is extracted so we can mock it for
        # testing.
        LOG.warning('did not load config file %s: %s', filename, err)

    def _rename_prelude_section(self, **kwargs):
        key = 'prelude_section_name'
        if key in kwargs and kwargs[key] != self._OPTS[key].default:
            new_prelude_name = kwargs[key]

            self.template = defaults.TEMPLATE.format(new_prelude_name)

    def override(self, **kwds):
        """Set the values of the named configuration options.

        Take the values of the keyword arguments as the current value
        of the same option, regardless of whether a value is already
        present.

        """
        # Replace prelude section name if it has been changed.
        self._rename_prelude_section(**kwds)

        for name, val in kwds.items():
            if name not in self._OPTS:
                LOG.warning('ignoring unknown configuration value %r = %r',
                            name, val)
            else:
                if name == "sections":
                    val = Section.from_raw_yaml(val)
                setattr(self, name, val)

    def override_from_parsed_args(self, parsed_args):
        """Set the values of the configuration options from parsed CLI args.

        This method assumes that the DEST values for the command line
        arguments are named the same as the configuration options.

        """
        arg_values = {
            o.name: getattr(parsed_args, o.name)
            for o in _OPTIONS
            if getattr(parsed_args, o.name, None) is not None
        }
        if arg_values:
            LOG.info('[config] updating from command line options')
            self.override(**arg_values)

    @property
    def reporoot(self):
        return self._reporoot

    # Ensure that the 'reporoot' value always only ends in one '/'.
    @reporoot.setter
    def reporoot(self, value):
        self._reporoot = value.rstrip('/') + '/'

    @property
    def notespath(self):
        """The path in the repo where notes are kept.

        .. important::

           This does not take ``reporoot`` into account. You need to add this
           manually if required.
        """
        return os.path.join(self.relnotesdir, self.notesdir)

    @property
    def options(self):
        """Get all configuration options as a dict.

        Returns the actual configuration options after overrides.
        """
        options = {
            o.name: getattr(self, o.name)
            for o in _OPTIONS
        }
        return options

# def parse_config_into(parsed_arguments):

#         """Parse the user config onto the namespace arguments.

#     :param parsed_arguments:
#         The result of calling :meth:`argparse.ArgumentParser.parse_args`.
#     :type parsed_arguments:
#         argparse.Namespace
#     """
#     config_path = get_config_path(parsed_arguments.relnotesdir)
#     config_values = read_config(config_path)

#     for key in config_values.keys():
#         try:
#             getattr(parsed_arguments, key)
#         except AttributeError:
#             LOG.info('Option "%s" does not apply to this particular command.'
#                      '. Ignoring...', key)
#             continue
#         setattr(parsed_arguments, key, config_values[key])

#     parsed_arguments._config = config_values