# -*- coding: utf-8 -*-
# Based on py-couchdb (https://github.com/histrio/py-couchdb)

import os
import json
import uuid
import copy
import mimetypes
import warnings

from couch import utils
from couch import feedreader
from couch import exceptions as exp
from couch.resource import Resource


DEFAULT_BASE_URL = os.environ.get('COUCHDB_URL', 'http://localhost:5984/')


def _id_to_path(_id):
    if _id[:1] == "_":
        return _id.split("/", 1)
    return [_id]


def _listen_feed(object, node, feed_reader, **kwargs):
    if not callable(feed_reader):
        raise exp.UnexpectedError("feed_reader must be callable or class")

    if isinstance(feed_reader, feedreader.BaseFeedReader):
        reader = feed_reader(object)
    else:
        reader = feedreader.SimpleFeedReader()(object, feed_reader)

    # Possible options: "continuous", "longpoll"
    kwargs.setdefault("feed", "continuous")
    data = utils.force_bytes(json.dumps(kwargs.pop('data', {})))

    (resp, result) = object.resource(node).post(
        params=kwargs, data=data, stream=True)
    try:
        for line in resp.iter_lines():
            # ignore heartbeats
            if not line:
                reader.on_heartbeat()
            else:
                reader.on_message(json.loads(utils.force_text(line)))
    except exp.FeedReaderExited:
        reader.on_close()


class _StreamResponse(object):
    """
    Proxy object for python-requests stream response.

    See more on:
    http://docs.python-requests.org/en/latest/user/advanced/#streaming-requests
    """

    def __init__(self, response):
        self._response = response

    def iter_content(self, chunk_size=1, decode_unicode=False):
        return self._response.iter_content(chunk_size=chunk_size,
                                           decode_unicode=decode_unicode)

    def iter_lines(self, chunk_size=512, decode_unicode=None):
        return self._response.iter_lines(chunk_size=chunk_size,
                                         decode_unicode=decode_unicode)

    @property
    def raw(self):
        return self._response.raw

    @property
    def url(self):
        return self._response.url


class Server(object):
    """
    Class that represents a couchdb connection.

    :param verify: setup ssl verification.
    :param base_url: a full url to couchdb (can contain auth data).
    :param full_commit: If ``False``, couchdb not commits all data on a
                        request is finished.
    :param authmethod: specify a authentication method. By default "basic"
                       method is used but also exists "session" (that requires
                       some server configuration changes).

    .. versionchanged: 1.4
       Set basic auth method as default instead of session method.

    .. versionchanged: 1.5
        Add verify parameter for setup ssl verificaton

    """

    def __init__(self, base_url=DEFAULT_BASE_URL, full_commit=True,
                 authmethod="basic", verify=False):

        self.base_url, credentials = utils.extract_credentials(base_url)
        self.resource = Resource(self.base_url, full_commit,
                                 credentials=credentials,
                                 authmethod=authmethod,
                                 verify=verify)

    def __repr__(self):
        return '<CouchDB Server "{}">'.format(self.base_url)

    def __contains__(self, name):
        try:
            self.resource.head(name)
        except exp.NotFound:
            return False
        else:
            return True

    def __iter__(self):
        (r, result) = self.resource.get('_all_dbs')
        return iter(result)

    def __len__(self):
        (r, result) = self.resource.get('_all_dbs')
        return len(result)

    def info(self):
        """
        Get server info.

        :returns: dict with all data that couchdb returns.
        :rtype: dict
        """
        (r, result) = self.resource.get()
        return result

    def delete(self, name):
        """
        Delete some database.

        :param name: database name
        :raises: :py:exc:`~pycouchdb.exceptions.NotFound`
            if a database does not exists
        """

        self.resource.delete(name)

    def database(self, name):
        """
        Get a database instance.

        :param name: database name
        :raises: :py:exc:`~pycouchdb.exceptions.NotFound`
            if a database does not exists

        :returns: a :py:class:`~pycouchdb.client.Database` instance
        """
        (r, result) = self.resource.head(name)
        if r.status_code == 404:
            raise exp.NotFound("Database '{0}' does not exists".format(name))

        db = Database(self.resource(name), name)
        return db

    # TODO: Config in 2.0 are applicable for nodes only
    # TODO: Reimplement when nodes endpoint will be ready
    # def config(self):
    #     pass

    def version(self):
        """
        Get the current version of a couchdb server.
        """
        (resp, result) = self.resource.get()
        return result["version"]

    # TODO: Stats in 2.0 are applicable for nodes only
    # TODO: Reimplement when nodes endpoint will be ready
    # def stats(self, name=None):
    #     pass

    def create(self, name):
        """
        Create a database.

        :param name: database name
        :raises: :py:exc:`~pycouchdb.exceptions.Conflict`
            if a database already exists
        :returns: a :py:class:`~pycouchdb.client.Database` instance
        """
        (resp, result) = self.resource.put(name)
        if resp.status_code in (200, 201):
            return self.database(name)

    def replicate(self, source, target, **kwargs):
        """
        Replicate the source database to the target one.

        .. versionadded:: 1.3

        :param source: full URL to the source database
        :param target: full URL to the target database
        """

        data = {'source': source, 'target': target}
        data.update(kwargs)

        data = utils.force_bytes(json.dumps(data))

        (resp, result) = self.resource.post('_replicate', data=data)
        return result

    def changes_feed(self, feed_reader, **kwargs):
        """
        Subscribe to changes feed of the whole CouchDB server.

        Note: this method is blocking.


        :param feed_reader: callable or :py:class:`~BaseFeedReader`
                            instance

        .. [Ref] http://docs.couchdb.org/en/1.6.1/api/server/common.html#db-updates
        .. versionadded: 1.10
        """
        object = self
        _listen_feed(object, "_db_updates", feed_reader, **kwargs)


class Database(object):
    """
    Class that represents a couchdb database.
    """

    def __init__(self, resource, name):
        self.resource = resource
        self.name = name

    def __repr__(self):
        return '<CouchDB Database "{}">'.format(self.name)

    def __contains__(self, doc_id):
        try:
            (resp, result) = self.resource.head(_id_to_path(doc_id))
            return resp.status_code < 206
        except exp.NotFound:
            return False

    def config(self):
        """
        Get database status data such as document count, update sequence etc.
        :return: dict
        """
        (resp, result) = self.resource.get()
        return result

    def __nonzero__(self):
        """Is the database available"""
        resp, _ = self.resource.head()
        return resp.status_code == 200

    def __len__(self):
        return self.config()['doc_count']

    def delete(self, doc_or_id):
        """
        Delete document by id.

        .. versionchanged:: 1.2
            Accept document or id.

        :param doc_or_id: document or id
        :raises: :py:exc:`~pycouchdb.exceptions.NotFound` if a document
                 not exists
        :raises: :py:exc:`~pycouchdb.exceptions.Conflict` if delete with
                 wrong revision.
        """

        _id = None
        if isinstance(doc_or_id, dict):
            if "_id" not in doc_or_id:
                raise ValueError("Invalid document, missing _id attr")
            _id = doc_or_id['_id']
        else:
            _id = doc_or_id

        resource = self.resource(*_id_to_path(_id))

        (r, result) = resource.head()
        (r, result) = resource.delete(
            params={"rev": r.headers["etag"].strip('"')})

    def delete_bulk(self, docs, transaction=True):
        """
        Delete a bulk of documents.

        .. versionadded:: 1.2

        :param docs: list of docs
        :raises: :py:exc:`~pycouchdb.exceptions.Conflict` if a delete
                 is not success
        :returns: raw results from server
        """

        _docs = copy.copy(docs)
        for doc in _docs:
            if "_deleted" not in doc:
                doc["_deleted"] = True

        data = utils.force_bytes(json.dumps({"docs": _docs}))
        params = {"all_or_nothing": "true" if transaction else "false"}
        (resp, results) = self.resource.post(
            "_bulk_docs", data=data, params=params)

        for result, doc in zip(results, _docs):
            if "error" in result:
                raise exp.Conflict("one or more docs are not saved")

        return results

    def get(self, doc_id, params=None, **kwargs):
        """
        Get a document by id.

        .. versionadded: 1.5
            Now the prefered method to pass params is via **kwargs
            instead of params argument. **params** argument is now
            deprecated and will be deleted in future versions.

        :param doc_id: document id
        :raises: :py:exc:`~pycouchdb.exceptions.NotFound` if a document
                 not exists

        :returns: document (dict)
        """

        if params:
            warnings.warn("params parameter is now deprecated in favor to"
                          "**kwargs usage.", DeprecationWarning)

        if params is None:
            params = {}

        params.update(kwargs)

        (resp, result) = self.resource(*_id_to_path(doc_id)).get(params=params)
        return result

    def save(self, doc, batch=False):
        """
        Save or update a document.

        .. versionchanged:: 1.2
            Now returns a new document instead of modify the original.

        :param doc: document
        :param batch: allow batch=ok inserts (default False)
        :raises: :py:exc:`~pycouchdb.exceptions.Conflict` if save with wrong
                 revision.
        :returns: doc
        """

        _doc = copy.copy(doc)
        if "_id" not in _doc:
            _doc['_id'] = uuid.uuid4().hex

        if batch:
            params = {'batch': 'ok'}
        else:
            params = {}

        data = utils.force_bytes(json.dumps(_doc))
        (resp, result) = self.resource(_doc['_id']).put(
            data=data, params=params)

        if resp.status_code == 409:
            raise exp.Conflict(result['reason'])

        if "rev" in result and result["rev"] is not None:
            _doc["_rev"] = result["rev"]

        return _doc

    def save_bulk(self, docs, try_setting_ids=True, transaction=True):
        """
        Save a bulk of documents.

        .. versionchanged:: 1.2
            Now returns a new document list instead of modify the original.

        :param docs: list of docs
        :param try_setting_ids: if ``True``, we loop through docs and generate/set
                            an id in each doc if none exists
        :param transaction: if ``True``, couchdb do a insert in transaction
                            model.
        :returns: docs
        """

        _docs = copy.deepcopy(docs)

        # Insert _id field if it not exists and try_setting_ids is true
        if try_setting_ids:
            for doc in _docs:
                if "_id" not in doc:
                    doc["_id"] = uuid.uuid4().hex

        data = utils.force_bytes(json.dumps({"docs": _docs}))
        params = {"all_or_nothing": "true" if transaction else "false"}

        (resp, results) = self.resource.post("_bulk_docs", data=data,
                                             params=params)

        for result, doc in zip(results, _docs):
            if "rev" in result:
                doc['_rev'] = result['rev']

        return _docs

    def all(self, wrapper=None, flat=None, as_list=False, **kwargs):
        """
        Execute a builtin view for get all documents.

        :param wrapper: wrap result into a specific class.
        :param as_list: return a list of results instead of a
            default lazy generator.
        :param flat: get a specific field from a object instead
            of a complete object.

        .. versionadded: 1.4
           Add as_list parameter.
           Add flat parameter.

        :returns: generator object
        """

        params = {"include_docs": "true"}
        params.update(kwargs)

        data = None

        if "keys" in params:
            data = {"keys": params.pop("keys")}
            data = utils.force_bytes(json.dumps(data))

        params = utils.encode_view_options(params)
        if data:
            (resp, result) = self.resource.post(
                "_all_docs", params=params, data=data)
        else:
            (resp, result) = self.resource.get("_all_docs", params=params)

        if wrapper is None:
            def wrapper(doc): return doc

        if flat is not None:
            def wrapper(doc): return doc[flat]

        def _iterate():
            for row in result["rows"]:
                yield wrapper(row)

        if as_list:
            return list(_iterate())
        return _iterate()

    def cleanup(self):
        """
        Execute a cleanup operation.
        """
        (r, result) = self.resource('_view_cleanup').post()
        return result

    def commit(self):
        """
        Send commit message to server.
        """
        (resp, result) = self.resource.post('_ensure_full_commit')
        return result

    def compact(self):
        """
        Send compact message to server. Compacting write-heavy databases
        should be avoided, otherwise the process may not catch up with
        the writes. Read load has no effect.
        """
        (r, result) = self.resource("_compact").post()
        return result

    def compact_view(self, ddoc):
        """
        Execute compact over design view.

        :raises: :py:exc:`~pycouchdb.exceptions.NotFound`
            if a view does not exists.
        """
        (r, result) = self.resource("_compact", ddoc).post()
        return result

    def revisions(self, doc_id, status='available', params=None, **kwargs):
        """
        Get all revisions of one document.

        :param doc_id: document id
        :param status: filter of revision status, set empty to list all
        :raises: :py:exc:`~pycouchdb.exceptions.NotFound`
            if a view does not exists.

        :returns: generator object
        """
        if params:
            warnings.warn("params parameter is now deprecated in favor to"
                          "**kwargs usage.", DeprecationWarning)

        if params is None:
            params = {}

        params.update(kwargs)

        if not params.get('revs_info'):
            params['revs_info'] = 'true'

        resource = self.resource(doc_id)
        (resp, result) = resource.get(params=params)
        if resp.status_code == 404:
            raise exp.NotFound("Document id `{0}` not found".format(doc_id))

        for rev in result['_revs_info']:
            if status and rev['status'] == status:
                yield self.get(doc_id, rev=rev['rev'])
            elif not status:
                yield self.get(doc_id, rev=rev['rev'])

    def delete_attachment(self, doc, filename):
        """
        Delete attachment by filename from document.

        .. versionchanged:: 1.2
            Now returns a new document instead of modify the original.

        :param doc: document dict
        :param filename: name of attachment.
        :raises: :py:exc:`~pycouchdb.exceptions.Conflict`
            if save with wrong revision.
        :returns: doc
        """

        _doc = copy.deepcopy(doc)
        resource = self.resource(_doc['_id'])

        (resp, result) = resource.delete(
            filename, params={'rev': _doc['_rev']})
        if resp.status_code == 404:
            raise exp.NotFound("filename {0} not found".format(filename))

        if resp.status_code > 205:
            raise exp.Conflict(result['reason'])

        _doc['_rev'] = result['rev']
        try:
            del _doc['_attachments'][filename]

            if not _doc['_attachments']:
                del _doc['_attachments']
        except KeyError:
            pass

        return _doc

    def get_attachment(self, doc, filename, stream=False, **kwargs):
        """
        Get attachment by filename from document.

        :param doc: document dict
        :param filename: attachment file name.
        :param stream: setup streaming output (default: False)

        .. versionchanged: 1.5
            Add stream parameter for obtain very large attachments
            without load all file to the memory.

        :returns: binary data or
        """

        params = {"rev": doc["_rev"]}
        params.update(kwargs)

        r, result = self.resource(doc['_id']).get(filename, stream=stream,
                                                  params=params)
        if stream:
            return _StreamResponse(r)

        return r.content

    def put_attachment(self, doc, content, filename=None, content_type=None):
        """
        Put a attachment to a document.

        .. versionchanged:: 1.2
            Now returns a new document instead of modify the original.

        :param doc: document dict.
        :param content: the content to upload, either a file-like object or
            bytes
        :param filename: the name of the attachment file; if omitted, this
                         function tries to get the filename from the file-like
                         object passed as the `content` argument value
        :raises: :py:exc:`~pycouchdb.exceptions.Conflict`
            if save with wrong revision.
        :raises: ValueError
        :returns: doc
        """

        if filename is None:
            if hasattr(content, 'name'):
                filename = os.path.basename(content.name)
            else:
                raise ValueError('no filename specified for attachment')

        if content_type is None:
            content_type = ';'.join(
                filter(None, mimetypes.guess_type(filename)))

        headers = {"Content-Type": content_type}
        resource = self.resource(doc['_id'])

        (resp, result) = resource.put(
            filename, data=content, params={'rev': doc['_rev']}, headers=headers)

        if resp.status_code < 206:
            return self.get(doc["_id"])

        raise exp.Conflict(result['reason'])

    def one(self, name, flat=None, wrapper=None, **kwargs):
        """
        Execute a design document view query and returns a first
        result.

        :param name: name of the view (eg: docidname/viewname).
        :param wrapper: wrap result into a specific class.
        :param flat: get a specific field from a object instead
            of a complete object.

        .. versionadded: 1.4

        :returns: object or None
        """

        params = {"limit": 1}
        params.update(kwargs)

        path = utils._path_from_name(name, '_view')
        data = None

        if "keys" in params:
            data = {"keys": params.pop('keys')}

        if data:
            data = utils.force_bytes(json.dumps(data))

        params = utils.encode_view_options(params)
        result = list(self._query(self.resource(*path), wrapper=wrapper,
                                  flat=flat, params=params, data=data))

        return result[0] if len(result) > 0 else None

    def _query(self, resource, data=None, params=None, headers=None,
               flat=None, wrapper=None):

        if data is None:
            (resp, result) = resource.get(params=params, headers=headers)
        else:
            (resp, result) = resource.post(
                data=data, params=params, headers=headers)

        if wrapper is None:
            def wrapper(row): return row

        if flat is not None:
            def wrapper(row): return row[flat]

        for row in result["rows"]:
            yield wrapper(row)

    def query(self, name, wrapper=None, flat=None, as_list=False, **kwargs):
        """
        Execute a design document view query.

        :param name: name of the view (eg: docidname/viewname).
        :param wrapper: wrap result into a specific class.
        :param as_list: return a list of results instead of a
            default lazy generator.
        :param flat: get a specific field from a object instead
            of a complete object.

        .. versionadded: 1.4
           Add as_list parameter.
           Add flat parameter.

        :returns: generator object
        """
        params = copy.copy(kwargs)
        path = utils._path_from_name(name, '_view')
        data = None

        if "keys" in params:
            data = {"keys": params.pop('keys')}

        if data:
            data = utils.force_bytes(json.dumps(data))

        params = utils.encode_view_options(params)
        result = self._query(self.resource(*path), wrapper=wrapper,
                             flat=flat, params=params, data=data)

        if as_list:
            return list(result)
        return result

    def changes_feed(self, feed_reader, **kwargs):
        """
        Subscribe to changes feed of couchdb database.

        Note: this method is blocking.


        :param feed_reader: callable or :py:class:`~BaseFeedReader`
                            instance

        .. versionadded: 1.5
        """

        object = self
        _listen_feed(object, "_changes", feed_reader, **kwargs)

    def changes_list(self, **kwargs):
        """
        Obtain a list of changes from couchdb.

        .. versionadded: 1.5
        """

        (resp, result) = self.resource("_changes").get(params=kwargs)
        return result['last_seq'], result['results']

    def find(self, selector, wrapper=None, **kwargs):
        """
        Execute Mango querys using _find.

        :param selector: data to search
        :param wrapper: wrap result into a specific class.

        """
        path = '_find'
        data = utils.force_bytes(json.dumps(selector))

        (resp, result) = self.resource.post(path, data=data, params=kwargs)

        if wrapper is None:
            def wrapper(doc): return doc

        for doc in result["docs"]:
            yield wrapper(doc)

    def index(self, index_doc, **kwargs):
        path = '_index'
        data = utils.force_bytes(json.dumps(index_doc))

        (resp, result) = self.resource.post(path, data=data, params=kwargs)

        return result