# -*- coding: utf-8 -*-
#
# Copyright (C) 2013-2017 Gauvain Pocentek <gauvain@pocentek.net>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser 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, see <http://www.gnu.org/licenses/>.

import copy
import importlib
import itertools
import json
import sys

import six

import gitlab
from gitlab.exceptions import *  # noqa


class jsonEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, GitlabObject):
            return obj.as_dict()
        elif isinstance(obj, gitlab.Gitlab):
            return {'url': obj._url}
        return json.JSONEncoder.default(self, obj)


class BaseManager(object):
    """Base manager class for API operations.

    Managers provide method to manage GitLab API objects, such as retrieval,
    listing, creation.

    Inherited class must define the ``obj_cls`` attribute.

    Attributes:
        obj_cls (class): class of objects wrapped by this manager.
    """

    obj_cls = None

    def __init__(self, gl, parent=None, args=[]):
        """Constructs a manager.

        Args:
            gl (gitlab.Gitlab): Gitlab object referencing the GitLab server.
            parent (Optional[Manager]): A parent manager.
            args (list): A list of tuples defining a link between the
                parent/child attributes.

        Raises:
            AttributeError: If `obj_cls` is None.
        """
        self.gitlab = gl
        self.args = args
        self.parent = parent

        if self.obj_cls is None:
            raise AttributeError("obj_cls must be defined")

    def _set_parent_args(self, **kwargs):
        args = copy.copy(kwargs)
        if self.parent is not None:
            for attr, parent_attr in self.args:
                args.setdefault(attr, getattr(self.parent, parent_attr))

        return args

    def get(self, id=None, **kwargs):
        """Get a GitLab object.

        Args:
            id: ID of the object to retrieve.
            **kwargs: Additional arguments to send to GitLab.

        Returns:
            object: An object of class `obj_cls`.

        Raises:
            NotImplementedError: If objects cannot be retrieved.
            GitlabGetError: If the server fails to perform the request.
        """
        args = self._set_parent_args(**kwargs)
        if not self.obj_cls.canGet:
            raise NotImplementedError
        if id is None and self.obj_cls.getRequiresId is True:
            raise ValueError('The id argument must be defined.')
        return self.obj_cls.get(self.gitlab, id, **args)

    def list(self, **kwargs):
        """Get a list of GitLab objects.

        Args:
            **kwargs: Additional arguments to send to GitLab.

        Returns:
            list[object]: A list of `obj_cls` objects.

        Raises:
            NotImplementedError: If objects cannot be listed.
            GitlabListError: If the server fails to perform the request.
        """
        args = self._set_parent_args(**kwargs)
        if not self.obj_cls.canList:
            raise NotImplementedError
        return self.obj_cls.list(self.gitlab, **args)

    def create(self, data, **kwargs):
        """Create a new object of class `obj_cls`.

        Args:
            data (dict): The parameters to send to the GitLab server to create
                the object. Required and optional arguments are defined in the
                `requiredCreateAttrs` and `optionalCreateAttrs` of the
                `obj_cls` class.
            **kwargs: Additional arguments to send to GitLab.

        Returns:
            object: A newly create `obj_cls` object.

        Raises:
            NotImplementedError: If objects cannot be created.
            GitlabCreateError: If the server fails to perform the request.
        """
        args = self._set_parent_args(**kwargs)
        if not self.obj_cls.canCreate:
            raise NotImplementedError
        return self.obj_cls.create(self.gitlab, data, **args)

    def delete(self, id, **kwargs):
        """Delete a GitLab object.

        Args:
            id: ID of the object to delete.

        Raises:
            NotImplementedError: If objects cannot be deleted.
            GitlabDeleteError: If the server fails to perform the request.
        """
        args = self._set_parent_args(**kwargs)
        if not self.obj_cls.canDelete:
            raise NotImplementedError
        self.gitlab.delete(self.obj_cls, id, **args)


class GitlabObject(object):
    """Base class for all classes that interface with GitLab."""
    #: Url to use in GitLab for this object
    _url = None
    # Some objects (e.g. merge requests) have different urls for singular and
    # plural
    _urlPlural = None
    _id_in_delete_url = True
    _id_in_update_url = True
    _constructorTypes = None

    #: Tells if GitLab-api allows retrieving single objects.
    canGet = True
    #: Tells if GitLab-api allows listing of objects.
    canList = True
    #: Tells if GitLab-api allows creation of new objects.
    canCreate = True
    #: Tells if GitLab-api allows updating object.
    canUpdate = True
    #: Tells if GitLab-api allows deleting object.
    canDelete = True
    #: Attributes that are required for constructing url.
    requiredUrlAttrs = []
    #: Attributes that are required when retrieving list of objects.
    requiredListAttrs = []
    #: Attributes that are optional when retrieving list of objects.
    optionalListAttrs = []
    #: Attributes that are optional when retrieving single object.
    optionalGetAttrs = []
    #: Attributes that are required when retrieving single object.
    requiredGetAttrs = []
    #: Attributes that are required when deleting object.
    requiredDeleteAttrs = []
    #: Attributes that are required when creating a new object.
    requiredCreateAttrs = []
    #: Attributes that are optional when creating a new object.
    optionalCreateAttrs = []
    #: Attributes that are required when updating an object.
    requiredUpdateAttrs = []
    #: Attributes that are optional when updating an object.
    optionalUpdateAttrs = []
    #: Whether the object ID is required in the GET url.
    getRequiresId = True
    #: List of managers to create.
    managers = []
    #: Name of the identifier of an object.
    idAttr = 'id'
    #: Attribute to use as ID when displaying the object.
    shortPrintAttr = None

    def _data_for_gitlab(self, extra_parameters={}, update=False,
                         as_json=True):
        data = {}
        if update and (self.requiredUpdateAttrs or self.optionalUpdateAttrs):
            attributes = itertools.chain(self.requiredUpdateAttrs,
                                         self.optionalUpdateAttrs)
        else:
            attributes = itertools.chain(self.requiredCreateAttrs,
                                         self.optionalCreateAttrs)
        attributes = list(attributes) + ['sudo', 'page', 'per_page']
        for attribute in attributes:
            if hasattr(self, attribute):
                value = getattr(self, attribute)
                # labels need to be sent as a comma-separated list
                if attribute == 'labels' and isinstance(value, list):
                    value = ", ".join(value)
                elif attribute == 'sudo':
                    value = str(value)
                data[attribute] = value

        data.update(extra_parameters)

        return json.dumps(data) if as_json else data

    @classmethod
    def list(cls, gl, **kwargs):
        """Retrieve a list of objects from GitLab.

        Args:
            gl (gitlab.Gitlab): Gitlab object referencing the GitLab server.
            per_page (int): Maximum number of items to return.
            page (int): ID of the page to return when using pagination.

        Returns:
            list[object]: A list of objects.

        Raises:
            NotImplementedError: If objects can't be listed.
            GitlabListError: If the server cannot perform the request.
        """
        if not cls.canList:
            raise NotImplementedError

        if not cls._url:
            raise NotImplementedError

        return gl.list(cls, **kwargs)

    @classmethod
    def get(cls, gl, id, **kwargs):
        """Retrieve a single object.

        Args:
            gl (gitlab.Gitlab): Gitlab object referencing the GitLab server.
            id (int or str): ID of the object to retrieve.

        Returns:
            object: The found GitLab object.

        Raises:
            NotImplementedError: If objects can't be retrieved.
            GitlabGetError: If the server cannot perform the request.
        """

        if cls.canGet is False:
            raise NotImplementedError
        elif cls.canGet is True:
            return cls(gl, id, **kwargs)
        elif cls.canGet == 'from_list':
            for obj in cls.list(gl, **kwargs):
                obj_id = getattr(obj, obj.idAttr)
                if str(obj_id) == str(id):
                    return obj

            raise GitlabGetError("Object not found")

    def _get_object(self, k, v, **kwargs):
        if self._constructorTypes and k in self._constructorTypes:
            cls = getattr(self._module, self._constructorTypes[k])
            return cls(self.gitlab, v, **kwargs)
        else:
            return v

    def _set_from_dict(self, data, **kwargs):
        if not hasattr(data, 'items'):
            return

        for k, v in data.items():
            # If a k attribute already exists and is a Manager, do nothing (see
            # https://github.com/python-gitlab/python-gitlab/issues/209)
            if isinstance(getattr(self, k, None), BaseManager):
                continue

            if isinstance(v, list):
                self.__dict__[k] = []
                for i in v:
                    self.__dict__[k].append(self._get_object(k, i, **kwargs))
            elif v is None:
                self.__dict__[k] = None
            else:
                self.__dict__[k] = self._get_object(k, v, **kwargs)

    def _create(self, **kwargs):
        if not self.canCreate:
            raise NotImplementedError

        json = self.gitlab.create(self, **kwargs)
        self._set_from_dict(json)
        self._from_api = True

    def _update(self, **kwargs):
        if not self.canUpdate:
            raise NotImplementedError

        json = self.gitlab.update(self, **kwargs)
        self._set_from_dict(json)

    def save(self, **kwargs):
        if self._from_api:
            self._update(**kwargs)
        else:
            self._create(**kwargs)

    def delete(self, **kwargs):
        if not self.canDelete:
            raise NotImplementedError

        if not self._from_api:
            raise GitlabDeleteError("Object not yet created")

        return self.gitlab.delete(self, **kwargs)

    @classmethod
    def create(cls, gl, data, **kwargs):
        """Create an object.

        Args:
            gl (gitlab.Gitlab): Gitlab object referencing the GitLab server.
            data (dict): The data used to define the object.

        Returns:
            object: The new object.

        Raises:
            NotImplementedError: If objects can't be created.
            GitlabCreateError: If the server cannot perform the request.
        """
        if not cls.canCreate:
            raise NotImplementedError

        obj = cls(gl, data, **kwargs)
        obj.save()

        return obj

    def __init__(self, gl, data=None, **kwargs):
        """Constructs a new object.

        Do not use this method. Use the `get` or `create` class methods
        instead.

        Args:
            gl (gitlab.Gitlab): Gitlab object referencing the GitLab server.
            data: If `data` is a dict, create a new object using the
                information. If it is an int or a string, get a GitLab object
                from an API request.
            **kwargs: Additional arguments to send to GitLab.
        """
        self._from_api = False
        #: (gitlab.Gitlab): Gitlab connection.
        self.gitlab = gl

        # store the module in which the object has been created (v3/v4) to be
        # able to reference other objects from the same module
        self._module = importlib.import_module(self.__module__)

        if (data is None or isinstance(data, six.integer_types) or
           isinstance(data, six.string_types)):
            if not self.canGet:
                raise NotImplementedError
            data = self.gitlab.get(self.__class__, data, **kwargs)
            self._from_api = True

            # the API returned a list because custom kwargs where used
            # instead of the id to request an object. Usually parameters
            # other than an id return ambiguous results. However in the
            # gitlab universe iids together with a project_id are
            # unambiguous for merge requests and issues, too.
            # So if there is only one element we can use it as our data
            # source.
            if 'iid' in kwargs and isinstance(data, list):
                if len(data) < 1:
                    raise GitlabGetError('Not found')
                elif len(data) == 1:
                    data = data[0]
                else:
                    raise GitlabGetError('Impossible! You found multiple'
                                         ' elements with the same iid.')

        self._set_from_dict(data, **kwargs)

        if kwargs:
            for k, v in kwargs.items():
                # Don't overwrite attributes returned by the server (#171)
                if k not in self.__dict__ or not self.__dict__[k]:
                    self.__dict__[k] = v

        # Special handling for api-objects that don't have id-number in api
        # responses. Currently only Labels and Files
        if not hasattr(self, "id"):
            self.id = None

    def _set_manager(self, var, cls, attrs):
        manager = cls(self.gitlab, self, attrs)
        setattr(self, var, manager)

    def __getattr__(self, name):
        # build a manager if it doesn't exist yet
        for var, cls, attrs in self.managers:
            if var != name:
                continue
            # Build the full class path if needed
            if isinstance(cls, six.string_types):
                cls = getattr(self._module, cls)
            self._set_manager(var, cls, attrs)
            return getattr(self, var)

        raise AttributeError(name)

    def __str__(self):
        return '%s => %s' % (type(self), str(self.__dict__))

    def __repr__(self):
        return '<%s %s:%s>' % (self.__class__.__name__,
                               self.idAttr,
                               getattr(self, self.idAttr))

    def display(self, pretty):
        if pretty:
            self.pretty_print()
        else:
            self.short_print()

    def short_print(self, depth=0):
        """Print the object on the standard output (verbose).

        Args:
            depth (int): Used internaly for recursive call.
        """
        id = self.__dict__[self.idAttr]
        print("%s%s: %s" % (" " * depth * 2, self.idAttr, id))
        if self.shortPrintAttr:
            print("%s%s: %s" % (" " * depth * 2,
                                self.shortPrintAttr.replace('_', '-'),
                                self.__dict__[self.shortPrintAttr]))

    @staticmethod
    def _get_display_encoding():
        return sys.stdout.encoding or sys.getdefaultencoding()

    @staticmethod
    def _obj_to_str(obj):
        if isinstance(obj, dict):
            s = ", ".join(["%s: %s" %
                          (x, GitlabObject._obj_to_str(y))
                          for (x, y) in obj.items()])
            return "{ %s }" % s
        elif isinstance(obj, list):
            s = ", ".join([GitlabObject._obj_to_str(x) for x in obj])
            return "[ %s ]" % s
        elif six.PY2 and isinstance(obj, six.text_type):
            return obj.encode(GitlabObject._get_display_encoding(), "replace")
        else:
            return str(obj)

    def pretty_print(self, depth=0):
        """Print the object on the standard output (verbose).

        Args:
            depth (int): Used internaly for recursive call.
        """
        id = self.__dict__[self.idAttr]
        print("%s%s: %s" % (" " * depth * 2, self.idAttr, id))
        for k in sorted(self.__dict__.keys()):
            if k in (self.idAttr, 'id', 'gitlab'):
                continue
            if k[0] == '_':
                continue
            v = self.__dict__[k]
            pretty_k = k.replace('_', '-')
            if six.PY2:
                pretty_k = pretty_k.encode(
                    GitlabObject._get_display_encoding(), "replace")
            if isinstance(v, GitlabObject):
                if depth == 0:
                    print("%s:" % pretty_k)
                    v.pretty_print(1)
                else:
                    print("%s: %s" % (pretty_k, v.id))
            elif isinstance(v, BaseManager):
                continue
            else:
                if hasattr(v, __name__) and v.__name__ == 'Gitlab':
                    continue
                v = GitlabObject._obj_to_str(v)
                print("%s%s: %s" % (" " * depth * 2, pretty_k, v))

    def json(self):
        """Dump the object as json.

        Returns:
            str: The json string.
        """
        return json.dumps(self, cls=jsonEncoder)

    def as_dict(self):
        """Dump the object as a dict."""
        return {k: v for k, v in six.iteritems(self.__dict__)
                if (not isinstance(v, BaseManager) and not k[0] == '_')}

    def __eq__(self, other):
        if type(other) is type(self):
            return self.as_dict() == other.as_dict()
        return False

    def __ne__(self, other):
        return not self.__eq__(other)


class SaveMixin(object):
    """Mixin for RESTObject's that can be updated."""
    def save(self, **kwargs):
        """Saves the changes made to the object to the server.

        Args:
            **kwargs: Extra option to send to the server (e.g. sudo)

        The object is updated to match what the server returns.
        """
        updated_data = {}
        required, optional = self.manager.get_update_attrs()
        for attr in required:
            # Get everything required, no matter if it's been updated
            updated_data[attr] = getattr(self, attr)
        # Add the updated attributes
        updated_data.update(self._updated_attrs)

        # class the manager
        obj_id = self.get_id()
        server_data = self.manager.update(obj_id, updated_data, **kwargs)
        self._updated_attrs = {}
        self._attrs.update(server_data)


class RESTObject(object):
    """Represents an object built from server data.

    It holds the attributes know from te server, and the updated attributes in
    another. This allows smart updates, if the object allows it.

    You can redefine ``_id_attr`` in child classes to specify which attribute
    must be used as uniq ID. None means that the object can be updated without
    ID in the url.
    """
    _id_attr = 'id'

    def __init__(self, manager, attrs):
        self.__dict__.update({
            'manager': manager,
            '_attrs': attrs,
            '_updated_attrs': {},
        })

    def __getattr__(self, name):
        try:
            return self.__dict__['_updated_attrs'][name]
        except KeyError:
            try:
                return self.__dict__['_attrs'][name]
            except KeyError:
                raise AttributeError(name)

    def __setattr__(self, name, value):
        self.__dict__['_updated_attrs'][name] = value

    def __str__(self):
        data = self._attrs.copy()
        data.update(self._updated_attrs)
        return '%s => %s' % (type(self), data)

    def __repr__(self):
        if self._id_attr :
            return '<%s %s:%s>' % (self.__class__.__name__,
                                   self._id_attr,
                                   self.get_id())
        else:
            return '<%s>' % self.__class__.__name__

    def get_id(self):
        if self._id_attr is None:
            return None
        return getattr(self, self._id_attr)


class RESTObjectList(object):
    """Generator object representing a list of RESTObject's.

    This generator uses the Gitlab pagination system to fetch new data when
    required.

    Note: you should not instanciate such objects, they are returned by calls
    to RESTManager.list()

    Args:
        manager: Manager to attach to the created objects
        obj_cls: Type of objects to create from the json data
        _list: A GitlabList object
    """
    def __init__(self, manager, obj_cls, _list):
        self.manager = manager
        self._obj_cls = obj_cls
        self._list = _list

    def __iter__(self):
        return self

    def __len__(self):
        return len(self._list)

    def __next__(self):
        return self.next()

    def next(self):
        data = self._list.next()
        return self._obj_cls(self.manager, data)


class GetMixin(object):
    def get(self, id, **kwargs):
        """Retrieve a single object.

        Args:
            id (int or str): ID of the object to retrieve
            **kwargs: Extra data to send to the Gitlab server (e.g. sudo)

        Returns:
            object: The generated RESTObject.

        Raises:
            GitlabGetError: If the server cannot perform the request.
        """
        path = '%s/%s' % (self._path, id)
        server_data = self.gitlab.http_get(path, **kwargs)
        return self._obj_cls(self, server_data)


class GetWithoutIdMixin(object):
    def get(self, **kwargs):
        """Retrieve a single object.

        Args:
            **kwargs: Extra data to send to the Gitlab server (e.g. sudo)

        Returns:
            object: The generated RESTObject.

        Raises:
            GitlabGetError: If the server cannot perform the request.
        """
        server_data = self.gitlab.http_get(self._path, **kwargs)
        return self._obj_cls(self, server_data)


class ListMixin(object):
    def list(self, **kwargs):
        """Retrieves a list of objects.

        Args:
            **kwargs: Extra data to send to the Gitlab server (e.g. sudo).
                      If ``all`` is passed and set to True, the entire list of
                      objects will be returned.

        Returns:
            RESTObjectList: Generator going through the list of objects, making
                            queries to the server when required.
                            If ``all=True`` is passed as argument, returns
                            list(RESTObjectList).
        """

        obj = self.gitlab.http_list(self._path, **kwargs)
        if isinstance(obj, list):
            return [self._obj_cls(self, item) for item in obj]
        else:
            return RESTObjectList(self, self._obj_cls, obj)


class GetFromListMixin(ListMixin):
    def get(self, id, **kwargs):
        """Retrieve a single object.

        Args:
            id (int or str): ID of the object to retrieve
            **kwargs: Extra data to send to the Gitlab server (e.g. sudo)

        Returns:
            object: The generated RESTObject.

        Raises:
            GitlabGetError: If the server cannot perform the request.
        """
        gen = self.list()
        for obj in gen:
            if str(obj.get_id()) == str(id):
                return obj


class RetrieveMixin(ListMixin, GetMixin):
    pass


class CreateMixin(object):
    def _check_missing_attrs(self, data):
        required, optional = self.get_create_attrs()
        missing = []
        for attr in required:
            if attr not in data:
                missing.append(attr)
                continue
        if missing:
            raise AttributeError("Missing attributes: %s" % ", ".join(missing))

    def get_create_attrs(self):
        """Returns the required and optional arguments.

        Returns:
            tuple: 2 items: list of required arguments and list of optional
                   arguments for creation (in that order)
        """
        if hasattr(self, '_create_attrs'):
            return (self._create_attrs['required'],
                    self._create_attrs['optional'])
        return (tuple(), tuple())

    def create(self, data, **kwargs):
        """Created a new object.

        Args:
            data (dict): parameters to send to the server to create the
                         resource
            **kwargs: Extra data to send to the Gitlab server (e.g. sudo)

        Returns:
            RESTObject: a new instance of the manage object class build with
                        the data sent by the server
        """
        self._check_missing_attrs(data)
        if hasattr(self, '_sanitize_data'):
            data = self._sanitize_data(data, 'create')
        server_data = self.gitlab.http_post(self._path, post_data=data, **kwargs)
        return self._obj_cls(self, server_data)


class UpdateMixin(object):
    def _check_missing_attrs(self, data):
        required, optional = self.get_update_attrs()
        missing = []
        for attr in required:
            if attr not in data:
                missing.append(attr)
                continue
        if missing:
            raise AttributeError("Missing attributes: %s" % ", ".join(missing))

    def get_update_attrs(self):
        """Returns the required and optional arguments.

        Returns:
            tuple: 2 items: list of required arguments and list of optional
                   arguments for update (in that order)
        """
        if hasattr(self, '_update_attrs'):
            return (self._update_attrs['required'],
                    self._update_attrs['optional'])
        return (tuple(), tuple())

    def update(self, id=None, new_data={}, **kwargs):
        """Update an object on the server.

        Args:
            id: ID of the object to update (can be None if not required)
            new_data: the update data for the object
            **kwargs: Extra data to send to the Gitlab server (e.g. sudo)

        Returns:
            dict: The new object data (*not* a RESTObject)
        """

        if id is None:
            path = self._path
        else:
            path = '%s/%s' % (self._path, id)

        self._check_missing_attrs(new_data)
        if hasattr(self, '_sanitize_data'):
            data = self._sanitize_data(new_data, 'update')
        server_data = self.gitlab.http_put(self._path, post_data=data,
                                           **kwargs)
        return server_data


class DeleteMixin(object):
    def delete(self, id, **kwargs):
        """Deletes an object on the server.

        Args:
            id: ID of the object to delete
            **kwargs: Extra data to send to the Gitlab server (e.g. sudo)
        """
        path = '%s/%s' % (self._path, id)
        self.gitlab.http_delete(path, **kwargs)


class CRUDMixin(GetMixin, ListMixin, CreateMixin, UpdateMixin, DeleteMixin):
    pass


class RESTManager(object):
    """Base class for CRUD operations on objects.

    Derivated class must define ``_path`` and ``_obj_cls``.

    ``_path``: Base URL path on which requests will be sent (e.g. '/projects')
    ``_obj_cls``: The class of objects that will be created
    """

    _path = None
    _obj_cls = None

    def __init__(self, gl, parent_attrs={}):
        self.gitlab = gl
        self._parent_attrs = {}  # for nested managers