# Copyright 2012 SINA Corporation
# Copyright 2014 Cisco Systems, 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.
#

"""Extracts OpenStack config option info from module(s)."""

from __future__ import print_function

import argparse
import imp
import os
import re
import socket
import sys
import textwrap

from oslo.config import cfg
from oslo.utils import importutils
import six
import stevedore.named

STROPT = "StrOpt"
BOOLOPT = "BoolOpt"
INTOPT = "IntOpt"
FLOATOPT = "FloatOpt"
LISTOPT = "ListOpt"
DICTOPT = "DictOpt"
MULTISTROPT = "MultiStrOpt"

OPT_TYPES = {
    STROPT: 'string value',
    BOOLOPT: 'boolean value',
    INTOPT: 'integer value',
    FLOATOPT: 'floating point value',
    LISTOPT: 'list value',
    DICTOPT: 'dict value',
    MULTISTROPT: 'multi valued',
}

OPTION_REGEX = re.compile(r"(%s)" % "|".join([STROPT, BOOLOPT, INTOPT,
                                              FLOATOPT, LISTOPT, DICTOPT,
                                              MULTISTROPT]))

PY_EXT = ".py"
BASEDIR = os.path.abspath(os.path.join(os.path.dirname(__file__),
                                       "../../../../"))
WORDWRAP_WIDTH = 60


def raise_extension_exception(extmanager, ep, err):
    raise


def generate(argv):
    parser = argparse.ArgumentParser(
        description='generate sample configuration file',
    )
    parser.add_argument('-m', dest='modules', action='append')
    parser.add_argument('-l', dest='libraries', action='append')
    parser.add_argument('srcfiles', nargs='*')
    parsed_args = parser.parse_args(argv)

    mods_by_pkg = dict()
    for filepath in parsed_args.srcfiles:
        pkg_name = filepath.split(os.sep)[1]
        mod_str = '.'.join(['.'.join(filepath.split(os.sep)[:-1]),
                            os.path.basename(filepath).split('.')[0]])
        mods_by_pkg.setdefault(pkg_name, list()).append(mod_str)
    # NOTE(lzyeval): place top level modules before packages
    pkg_names = sorted(pkg for pkg in mods_by_pkg if pkg.endswith(PY_EXT))
    ext_names = sorted(pkg for pkg in mods_by_pkg if pkg not in pkg_names)
    pkg_names.extend(ext_names)

    # opts_by_group is a mapping of group name to an options list
    # The options list is a list of (module, options) tuples
    opts_by_group = {'DEFAULT': []}

    if parsed_args.modules:
        for module_name in parsed_args.modules:
            module = _import_module(module_name)
            if module:
                for group, opts in _list_opts(module):
                    opts_by_group.setdefault(group, []).append((module_name,
                                                                opts))

    # Look for entry points defined in libraries (or applications) for
    # option discovery, and include their return values in the output.
    #
    # Each entry point should be a function returning an iterable
    # of pairs with the group name (or None for the default group)
    # and the list of Opt instances for that group.
    if parsed_args.libraries:
        loader = stevedore.named.NamedExtensionManager(
            'oslo.config.opts',
            names=list(set(parsed_args.libraries)),
            invoke_on_load=False,
            on_load_failure_callback=raise_extension_exception
        )
        for ext in loader:
            for group, opts in ext.plugin():
                opt_list = opts_by_group.setdefault(group or 'DEFAULT', [])
                opt_list.append((ext.name, opts))

    for pkg_name in pkg_names:
        mods = mods_by_pkg.get(pkg_name)
        mods.sort()
        for mod_str in mods:
            if mod_str.endswith('.__init__'):
                mod_str = mod_str[:mod_str.rfind(".")]

            mod_obj = _import_module(mod_str)
            if not mod_obj:
                raise RuntimeError("Unable to import module %s" % mod_str)

            for group, opts in _list_opts(mod_obj):
                opts_by_group.setdefault(group, []).append((mod_str, opts))

    print_group_opts('DEFAULT', opts_by_group.pop('DEFAULT', []))
    for group in sorted(opts_by_group.keys()):
        print_group_opts(group, opts_by_group[group])


def _import_module(mod_str):
    try:
        if mod_str.startswith('bin.'):
            imp.load_source(mod_str[4:], os.path.join('bin', mod_str[4:]))
            return sys.modules[mod_str[4:]]
        else:
            return importutils.import_module(mod_str)
    except Exception as e:
        sys.stderr.write("Error importing module %s: %s\n" % (mod_str, str(e)))
        return None


def _is_in_group(opt, group):
    "Check if opt is in group."
    for value in group._opts.values():
        # NOTE(llu): Temporary workaround for bug #1262148, wait until
        # newly released oslo.config support '==' operator.
        if not(value['opt'] != opt):
            return True
    return False


def _guess_groups(opt, mod_obj):
    # is it in the DEFAULT group?
    if _is_in_group(opt, cfg.CONF):
        return 'DEFAULT'

    # what other groups is it in?
    for value in cfg.CONF.values():
        if isinstance(value, cfg.CONF.GroupAttr):
            if _is_in_group(opt, value._group):
                return value._group.name

    raise RuntimeError(
        "Unable to find group for option %s, "
        "maybe it's defined twice in the same group?"
        % opt.name
    )


def _list_opts(obj):
    def is_opt(o):
        return (isinstance(o, cfg.Opt) and
                not isinstance(o, cfg.SubCommandOpt))

    opts = list()
    for attr_str in dir(obj):
        attr_obj = getattr(obj, attr_str)
        if is_opt(attr_obj):
            opts.append(attr_obj)
        elif (isinstance(attr_obj, list) and
              all(map(lambda x: is_opt(x), attr_obj))):
            opts.extend(attr_obj)

    ret = {}
    for opt in opts:
        ret.setdefault(_guess_groups(opt, obj), []).append(opt)
    return ret.items()


def print_group_opts(group, opts_by_module):
    print("[%s]" % group)
    print('')
    for mod, opts in opts_by_module:
        print('#')
        print('# Options defined in %s' % mod)
        print('#')
        print('')
        for opt in opts:
            _print_opt(opt)
        print('')


def _get_my_ip():
    try:
        csock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        csock.connect(('8.8.8.8', 80))
        (addr, port) = csock.getsockname()
        csock.close()
        return addr
    except socket.error:
        return None


def _sanitize_default(name, value):
    """Set up a reasonably sensible default for pybasedir, my_ip and host."""
    if value.startswith(sys.prefix):
        # NOTE(jd) Don't use os.path.join, because it is likely to think the
        # second part is an absolute pathname and therefore drop the first
        # part.
        value = os.path.normpath("/usr/" + value[len(sys.prefix):])
    elif value.startswith(BASEDIR):
        return value.replace(BASEDIR, '/usr/lib/python/site-packages')
    elif BASEDIR in value:
        return value.replace(BASEDIR, '')
    elif value == _get_my_ip():
        return '10.0.0.1'
    elif value in (socket.gethostname(), socket.getfqdn()) and 'host' in name:
        return 'nova'
    elif value.strip() != value:
        return '"%s"' % value
    return value


def _print_opt(opt):
    opt_name, opt_default, opt_help = opt.dest, opt.default, opt.help
    if not opt_help:
        sys.stderr.write('WARNING: "%s" is missing help string.\n' % opt_name)
        opt_help = ""
    opt_type = None
    try:
        opt_type = OPTION_REGEX.search(str(type(opt))).group(0)
    except (ValueError, AttributeError) as err:
        sys.stderr.write("%s\n" % str(err))
        sys.exit(1)
    opt_help = u'%s (%s)' % (opt_help,
                             OPT_TYPES[opt_type])
    print('#', "\n# ".join(textwrap.wrap(opt_help, WORDWRAP_WIDTH)))
    if opt.deprecated_opts:
        for deprecated_opt in opt.deprecated_opts:
            if deprecated_opt.name:
                deprecated_group = (deprecated_opt.group if
                                    deprecated_opt.group else "DEFAULT")
                print('# Deprecated group/name - [%s]/%s' %
                      (deprecated_group,
                       deprecated_opt.name))
    try:
        if opt_default is None:
            print('#%s=<None>' % opt_name)
        elif opt_type == STROPT:
            assert(isinstance(opt_default, six.string_types))
            print('#%s=%s' % (opt_name, _sanitize_default(opt_name,
                                                          opt_default)))
        elif opt_type == BOOLOPT:
            assert(isinstance(opt_default, bool))
            print('#%s=%s' % (opt_name, str(opt_default).lower()))
        elif opt_type == INTOPT:
            assert(isinstance(opt_default, int) and
                   not isinstance(opt_default, bool))
            print('#%s=%s' % (opt_name, opt_default))
        elif opt_type == FLOATOPT:
            assert(isinstance(opt_default, float))
            print('#%s=%s' % (opt_name, opt_default))
        elif opt_type == LISTOPT:
            assert(isinstance(opt_default, list))
            print('#%s=%s' % (opt_name, ','.join(opt_default)))
        elif opt_type == DICTOPT:
            assert(isinstance(opt_default, dict))
            opt_default_strlist = [str(key) + ':' + str(value)
                                   for (key, value) in opt_default.items()]
            print('#%s=%s' % (opt_name, ','.join(opt_default_strlist)))
        elif opt_type == MULTISTROPT:
            assert(isinstance(opt_default, list))
            if not opt_default:
                opt_default = ['']
            for default in opt_default:
                print('#%s=%s' % (opt_name, default))
        print('')
    except Exception:
        sys.stderr.write('Error in option "%s"\n' % opt_name)
        sys.exit(1)


def main():
    generate(sys.argv[1:])

if __name__ == '__main__':
    main()
