# 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.

from docutils import nodes
from docutils.parsers import rst
from docutils.parsers.rst import directives

from docutils.statemachine import ViewList
from sphinx import addnodes
from sphinx.directives import ObjectDescription
from sphinx.domains import Domain
from sphinx.domains import ObjType
from sphinx.roles import XRefRole
from sphinx.util.nodes import make_refnode
from sphinx.util.nodes import nested_parse_with_titles

from oslo_config import cfg
from oslo_config import generator
import oslo_i18n

import six


def _list_table(headers, data, title='', columns=None):
    """Build a list-table directive.

    :param add: Function to add one row to output.
    :param headers: List of header values.
    :param data: Iterable of row data, yielding lists or tuples with rows.
    """
    yield '.. list-table:: %s' % title
    yield '   :header-rows: 1'
    if columns:
        yield '   :widths: %s' % (','.join(str(c) for c in columns))
    yield ''
    yield '   - * %s' % headers[0]
    for h in headers[1:]:
        yield '     * %s' % h
    for row in data:
        yield '   - * %s' % row[0]
        for r in row[1:]:
            yield '     * %s' % r
    yield ''


def _indent(text, n=2):
    padding = ' ' * n
    return '\n'.join(padding + l for l in text.splitlines())


def _make_anchor_target(group_name, option_name):
    # We need to ensure this is unique across entire documentation
    # http://www.sphinx-doc.org/en/stable/markup/inline.html#ref-role
    target = '%s.%s' % (cfg._normalize_group_name(group_name),
                        option_name.lower())
    return target


_TYPE_DESCRIPTIONS = {
    cfg.StrOpt: 'string',
    cfg.BoolOpt: 'boolean',
    cfg.IntOpt: 'integer',
    cfg.FloatOpt: 'floating point',
    cfg.ListOpt: 'list',
    cfg.DictOpt: 'dict',
    cfg.MultiStrOpt: 'multi-valued',
    cfg.IPOpt: 'ip address',
    cfg.PortOpt: 'port number',
    cfg.HostnameOpt: 'hostname',
    cfg.URIOpt: 'URI',
    cfg.HostAddressOpt: 'host address',
    cfg._ConfigFileOpt: 'list of filenames',
    cfg._ConfigDirOpt: 'list of directory names',
}


def _get_choice_text(choice):
    if choice is None:
        return '<None>'
    elif choice == '':
        return "''"
    return six.text_type(choice)


def _format_group(app, namespace, group_name, group_obj, opt_list):
    group_name = group_name or 'DEFAULT'
    app.debug('[oslo.config] %s %s' % (namespace, group_name))

    yield '.. oslo.config:group:: %s' % group_name
    if namespace:
        yield '   :namespace: %s' % namespace
    yield ''

    if group_obj and group_obj.help:
        yield _indent(group_obj.help.rstrip())
        yield ''

    for opt in opt_list:
        opt_type = _TYPE_DESCRIPTIONS.get(type(opt),
                                          'unknown type')
        yield '.. oslo.config:option:: %s' % opt.dest
        yield ''
        yield _indent(':Type: %s' % opt_type)
        for default in generator._format_defaults(opt):
            if default:
                default = '``' + default + '``'
            yield _indent(':Default: %s' % default)
        if getattr(opt.type, 'min', None) is not None:
            yield _indent(':Minimum Value: %s' % opt.type.min)
        if getattr(opt.type, 'max', None) is not None:
            yield _indent(':Maximum Value: %s' % opt.type.max)
        if getattr(opt.type, 'choices', None):
            choices_text = ', '.join([_get_choice_text(choice)
                                      for choice in opt.type.choices])
            yield _indent(':Valid Values: %s' % choices_text)
        try:
            if opt.mutable:
                yield _indent(
                    ':Mutable: This option can be changed without restarting.'
                )
        except AttributeError as err:
            # NOTE(dhellmann): keystoneauth defines its own Opt class,
            # and neutron (at least) returns instances of those
            # classes instead of oslo_config Opt instances. The new
            # mutable attribute is the first property where the API
            # isn't supported in the external class, so we can use
            # this failure to emit a warning. See
            # https://bugs.launchpad.net/keystoneauth/+bug/1548433 for
            # more details.
            import warnings
            if not isinstance(cfg.Opt, opt):
                warnings.warn(
                    'Incompatible option class for %s (%r): %s' %
                    (opt.dest, opt.__class__, err),
                )
            else:
                warnings.warn('Failed to fully format sample for %s: %s' %
                              (opt.dest, err))
        if opt.advanced:
            yield _indent(
                ':Advanced Option: Intended for advanced users and not used')
            yield _indent(
                'by the majority of users, and might have a significant', 6)
            yield _indent(
                'effect on stability and/or performance.', 6)
        yield ''

        try:
            help_text = opt.help % {'default': 'the value above'}
        except (TypeError, KeyError, ValueError):
            # There is no mention of the default in the help string,
            # the string had some unknown key, or the string contained
            # invalid formatting characters
            help_text = opt.help
        if help_text:
            yield _indent(help_text)
            yield ''

        if opt.deprecated_opts:
            for line in _list_table(
                    ['Group', 'Name'],
                    ((d.group or group_name,
                      d.name or opt.dest or 'UNSET')
                     for d in opt.deprecated_opts),
                    title='Deprecated Variations'):
                yield _indent(line)
        if opt.deprecated_for_removal:
            yield _indent('.. warning::')
            if opt.deprecated_since:
                yield _indent('   This option is deprecated for removal '
                              'since %s.' % opt.deprecated_since)
            else:
                yield _indent('   This option is deprecated for removal.')
            yield _indent('   Its value may be silently ignored ')
            yield _indent('   in the future.')
            yield ''
            if opt.deprecated_reason:
                yield _indent('   :Reason: ' + opt.deprecated_reason)
            yield ''

        yield ''


def _format_option_help(app, namespaces, split_namespaces):
    """Generate a series of lines of restructuredtext.

    Format the option help as restructuredtext and return it as a list
    of lines.
    """
    opts = generator._list_opts(namespaces)

    if split_namespaces:
        for namespace, opt_list in opts:
            for group, opts in opt_list:
                if isinstance(group, cfg.OptGroup):
                    group_name = group.name
                else:
                    group_name = group
                    group = None
                if group_name is None:
                    group_name = 'DEFAULT'
                lines = _format_group(
                    app=app,
                    namespace=namespace,
                    group_name=group_name,
                    group_obj=group,
                    opt_list=opts,
                )
                for line in lines:
                    yield line
    else:
        # Merge the options from different namespaces that belong to
        # the same group together and format them without the
        # namespace.
        by_section = {}
        group_objs = {}
        for ignore, opt_list in opts:
            for group, group_opts in opt_list:
                if isinstance(group, cfg.OptGroup):
                    group_name = group.name
                else:
                    group_name = group
                    group = None
                if group_name is None:
                    group_name = 'DEFAULT'
                group_objs.setdefault(group_name, group)
                by_section.setdefault(group_name, []).extend(group_opts)
        for group_name, group_opts in sorted(by_section.items()):
            lines = _format_group(
                app=app,
                namespace=None,
                group_name=group_name,
                group_obj=group_objs.get(group_name),
                opt_list=group_opts,
            )
            for line in lines:
                yield line


class ShowOptionsDirective(rst.Directive):

    option_spec = {
        'split-namespaces': directives.flag,
        'config-file': directives.unchanged,
    }

    has_content = True

    def run(self):
        env = self.state.document.settings.env
        app = env.app

        split_namespaces = 'split-namespaces' in self.options

        config_file = self.options.get('config-file')
        if config_file:
            app.info('loading config file %s' % config_file)
            conf = cfg.ConfigOpts()
            conf.register_opts(generator._generator_opts)
            conf(
                args=['--config-file', config_file],
                project='oslo.config.sphinxext',
            )
            namespaces = conf.namespace[:]
        else:
            namespaces = [
                c.strip()
                for c in self.content
                if c.strip()
            ]

        result = ViewList()
        source_name = '<' + __name__ + '>'
        for line in _format_option_help(app, namespaces, split_namespaces):
            result.append(line, source_name)

        node = nodes.section()
        node.document = self.state.document
        nested_parse_with_titles(self.state, result, node)

        return node.children


class ConfigGroupXRefRole(XRefRole):
    "Handles :oslo.config:group: roles pointing to configuration groups."

    def __init__(self):
        super(ConfigGroupXRefRole, self).__init__(
            warn_dangling=True,
        )

    def process_link(self, env, refnode, has_explicit_title, title, target):
        # The anchor for the group link is the group name.
        return target, target


class ConfigOptXRefRole(XRefRole):
    "Handles :oslo.config:option: roles pointing to configuration options."

    def __init__(self):
        super(ConfigOptXRefRole, self).__init__(
            warn_dangling=True,
        )

    def process_link(self, env, refnode, has_explicit_title, title, target):
        if not has_explicit_title:
            title = target
        if '.' in target:
            group, opt_name = target.split('.')
        else:
            group = 'DEFAULT'
            opt_name = target
        anchor = _make_anchor_target(group, opt_name)
        return title, anchor


class ConfigGroup(rst.Directive):

    required_arguments = 1
    optional_arguments = 0
    has_content = True
    option_spec = {
        'namespace': directives.unchanged,
    }

    def run(self):
        env = self.state.document.settings.env
        app = env.app

        group_name = self.arguments[0]
        namespace = self.options.get('namespace')

        cached_groups = env.domaindata['oslo.config']['groups']

        # Store the current group for use later in option directives
        env.temp_data['oslo.config:group'] = group_name
        app.debug('oslo.config group %s' % group_name)

        # Store the location where this group is being defined
        # for use when resolving cross-references later.
        # FIXME: This should take the source namespace into account, too
        cached_groups[group_name] = env.docname

        result = ViewList()
        source_name = '<' + __name__ + '>'

        def _add(text):
            "Append some text to the output result view to be parsed."
            result.append(text, source_name)

        if namespace:
            title = '%s: %s' % (namespace, group_name)
        else:
            title = group_name

        _add(title)
        _add('-' * len(title))
        _add('')
        for line in self.content:
            _add(line)
        node = nodes.section()
        node.document = self.state.document
        nested_parse_with_titles(self.state, result, node)

        first_child = node.children[0]

        # Compute the normalized target and set the node to have that
        # as an id
        target_name = cfg._normalize_group_name(group_name)
        first_child['ids'].append(target_name)

        indexnode = addnodes.index(entries=[])
        return [indexnode] + node.children


class ConfigOption(ObjectDescription):
    "Description of a configuration option (.. option)."

    def handle_signature(self, sig, signode):
        """Transform an option description into RST nodes."""
        optname = sig
        self.env.app.debug('oslo.config option %s' % optname)
        # Insert a node into the output showing the option name
        signode += addnodes.desc_name(optname, optname)
        signode['allnames'] = [optname]
        return optname

    def add_target_and_index(self, firstname, sig, signode):
        cached_options = self.env.domaindata['oslo.config']['options']
        # Look up the current group name from the processing context
        currgroup = self.env.temp_data.get('oslo.config:group')
        # Compute the normalized target name for the option and give
        # that to the node as an id
        target_name = _make_anchor_target(currgroup, sig)
        signode['ids'].append(target_name)
        self.state.document.note_explicit_target(signode)
        # Store the location of the option definition for later use in
        # resolving cross-references
        # FIXME: This should take the source namespace into account, too
        cached_options[target_name] = self.env.docname


class ConfigDomain(Domain):
    """oslo.config domain."""
    name = 'oslo.config'
    label = 'oslo.config'
    object_types = {
        'configoption': ObjType('configuration option', 'option'),
    }
    directives = {
        'group': ConfigGroup,
        'option': ConfigOption,
    }
    roles = {
        'option': ConfigOptXRefRole(),
        'group': ConfigGroupXRefRole(),
    }
    initial_data = {
        'options': {},
        'groups': {},
    }

    def resolve_xref(self, env, fromdocname, builder,
                     typ, target, node, contnode):
        if typ == 'option':
            group_name, option_name = target.split('.', 1)
            return make_refnode(
                builder,
                fromdocname,
                env.domaindata['oslo.config']['options'][target],
                target,
                contnode,
                option_name,
            )
        if typ == 'group':
            return make_refnode(
                builder,
                fromdocname,
                env.domaindata['oslo.config']['groups'][target],
                target,
                contnode,
                target,
            )
        return None


def setup(app):
    # NOTE(dhellmann): Try to turn off lazy translation from oslo_i18n
    # so any translated help text or deprecation messages associated
    # with configuration options are treated as regular strings
    # instead of Message objects. Unfortunately this is a bit
    # order-dependent, and so it's still possible that importing code
    # from another module such as through the autodoc features, or
    # even through the plugin scanner, will turn lazy evaluation back
    # on.
    oslo_i18n.enable_lazy(False)
    app.add_directive('show-options', ShowOptionsDirective)
    app.add_domain(ConfigDomain)
