"""
Simple returner for CouchDB. Optional configuration
settings are listed below, along with sane defaults:

.. code-block:: yaml

    couchdb.db: 'salt'
    couchdb.url: 'http://salt:5984/'

Alternative configuration values can be used by prefacing the configuration.
Any values not found in the alternative configuration will be pulled from
the default location:

.. code-block:: yaml

    alternative.couchdb.db: 'salt'
    alternative.couchdb.url: 'http://salt:5984/'

To use the couchdb returner, append ``--return couchdb`` to the salt command. Example:

.. code-block:: bash

    salt '*' test.ping --return couchdb

To use the alternative configuration, append ``--return_config alternative`` to the salt command.

.. versionadded:: 2015.5.0

.. code-block:: bash

    salt '*' test.ping --return couchdb --return_config alternative

To override individual configuration items, append --return_kwargs '{"key:": "value"}' to the salt command.

.. versionadded:: 2016.3.0

.. code-block:: bash

    salt '*' test.ping --return couchdb --return_kwargs '{"db": "another-salt"}'

On concurrent database access
==============================

As this returner creates a couchdb document with the salt job id as document id
and as only one document with a given id can exist in a given couchdb database,
it is advised for most setups that every minion be configured to write to it own
database (the value of ``couchdb.db`` may be suffixed with the minion id),
otherwise multi-minion targeting can lead to losing output:

* the first returning minion is able to create a document in the database
* other minions fail with ``{'error': 'HTTP Error 409: Conflict'}``
"""


import logging
import time
from urllib.error import HTTPError
from urllib.request import HTTPHandler as _HTTPHandler
from urllib.request import Request as _Request
from urllib.request import build_opener as _build_opener

import salt.returners
import salt.utils.jid
import salt.utils.json

log = logging.getLogger(__name__)

# Define the module's virtual name
__virtualname__ = "couchdb"


def __virtual__():
    return __virtualname__


def _get_options(ret=None):
    """
    Get the couchdb options from salt.
    """
    attrs = {"url": "url", "db": "db"}

    _options = salt.returners.get_returner_options(
        __virtualname__, ret, attrs, __salt__=__salt__, __opts__=__opts__
    )
    if "url" not in _options:
        log.debug("Using default url.")
        _options["url"] = "http://salt:5984/"

    if "db" not in _options:
        log.debug("Using default database.")
        _options["db"] = "salt"

    return _options


def _generate_doc(ret):
    """
    Create a object that will be saved into the database based on
    options.
    """

    # Create a copy of the object that we will return.
    retc = ret.copy()

    # Set the ID of the document to be the JID.
    retc["_id"] = ret["jid"]

    # Add a timestamp field to the document
    retc["timestamp"] = time.time()

    return retc


def _request(method, url, content_type=None, _data=None):
    """
    Makes a HTTP request. Returns the JSON parse, or an obj with an error.
    """
    opener = _build_opener(_HTTPHandler)
    request = _Request(url, data=_data)
    if content_type:
        request.add_header("Content-Type", content_type)
    request.get_method = lambda: method
    try:
        handler = opener.open(request)
    except HTTPError as exc:
        return {"error": "{}".format(exc)}
    return salt.utils.json.loads(handler.read())


def returner(ret):
    """
    Take in the return and shove it into the couchdb database.
    """

    options = _get_options(ret)

    # Check to see if the database exists.
    _response = _request("GET", options["url"] + "_all_dbs")
    if options["db"] not in _response:

        # Make a PUT request to create the database.
        _response = _request("PUT", options["url"] + options["db"])

        # Confirm that the response back was simple 'ok': true.
        if "ok" not in _response or _response["ok"] is not True:
            log.error("Unable to create database '%s'", options["db"])
            log.error("Nothing logged! Lost data.")
            return
        log.info("Created database '%s'", options["db"])

    # Call _generate_doc to get a dict object of the document we're going to
    # shove into the database.
    doc = _generate_doc(ret)

    # Make the actual HTTP PUT request to create the doc.
    _response = _request(
        "PUT",
        options["url"] + options["db"] + "/" + doc["_id"],
        "application/json",
        salt.utils.json.dumps(doc),
    )

    # Sanity check regarding the response..
    if "ok" not in _response or _response["ok"] is not True:
        log.error("Unable to create document: '%s'", _response)
        log.error("Nothing logged! Lost data.")


def get_jid(jid):
    """
    Get the document with a given JID.
    """
    options = _get_options(ret=None)
    _response = _request("GET", options["url"] + options["db"] + "/" + jid)
    if "error" in _response:
        log.error("Unable to get JID '%s' : '%s'", jid, _response)
        return {}
    return {_response["id"]: _response}


def get_jids():
    """
    List all the jobs that we have..
    """
    options = _get_options(ret=None)
    _response = _request(
        "GET", options["url"] + options["db"] + "/_all_docs?include_docs=true"
    )

    # Make sure the 'total_rows' is returned.. if not error out.
    if "total_rows" not in _response:
        log.error("Didn't get valid response from requesting all docs: %s", _response)
        return {}

    # Return the rows.
    ret = {}
    for row in _response["rows"]:
        # Because this shows all the documents in the database, including the
        # design documents, verify the id is salt jid
        jid = row["id"]
        if not salt.utils.jid.is_jid(jid):
            continue

        ret[jid] = salt.utils.jid.format_jid_instance(jid, row["doc"])

    return ret


def get_fun(fun):
    """
    Return a dict with key being minion and value
    being the job details of the last run of function 'fun'.
    """

    # Get the options..
    options = _get_options(ret=None)

    # Define a simple return object.
    _ret = {}

    # get_minions takes care of calling ensure_views for us.
    # For each minion we know about
    for minion in get_minions():

        # Make a query of the by-minion-and-timestamp view and limit the count
        # to 1.
        _response = _request(
            "GET",
            options["url"] + options["db"] + "/_design/salt/_view/by-minion-fun-times"
            'tamp?descending=true&endkey=["{0}","{1}'
            '",0]&startkey=["{0}","{1}",9999999999]&'
            "limit=1".format(minion, fun),
        )
        # Skip the minion if we got an error..
        if "error" in _response:
            log.warning(
                "Got an error when querying for last command by a minion: %s",
                _response["error"],
            )
            continue

        # Skip the minion if we didn't get any rows back. ( IE function that
        # they're looking for has a typo in it or some such ).
        if len(_response["rows"]) < 1:
            continue

        # Set the respnse ..
        _ret[minion] = _response["rows"][0]["value"]

    return _ret


def get_minions():
    """
    Return a list of minion identifiers from a request of the view.
    """
    options = _get_options(ret=None)

    # Make sure the views are valid, which includes the minions..
    if not ensure_views():
        return []

    # Make the request for the view..
    _response = _request(
        "GET", options["url"] + options["db"] + "/_design/salt/_view/minions?group=true"
    )

    # Verify that we got a response back.
    if "rows" not in _response:
        log.error("Unable to get available minions: %s", _response)
        return []

    # Iterate over the rows to build up a list return it.
    _ret = []
    for row in _response["rows"]:
        _ret.append(row["key"])
    return _ret


def ensure_views():
    """
    This function makes sure that all the views that should
    exist in the design document do exist.
    """

    # Get the options so we have the URL and DB..
    options = _get_options(ret=None)

    # Make a request to check if the design document exists.
    _response = _request("GET", options["url"] + options["db"] + "/_design/salt")

    # If the document doesn't exist, or for some reason there are not views.
    if "error" in _response:
        return set_salt_view()

    # Determine if any views are missing from the design doc stored on the
    # server..  If we come across one, simply set the salt view and return out.
    # set_salt_view will set all the views, so we don't need to continue t
    # check.
    for view in get_valid_salt_views():
        if view not in _response["views"]:
            return set_salt_view()

    # Valid views, return true.
    return True


def get_valid_salt_views():
    """
    Returns a dict object of views that should be
    part of the salt design document.
    """
    ret = {}

    ret["minions"] = {}
    ret["minions"]["map"] = "function( doc ){ emit( doc.id, null ); }"
    ret["minions"]["reduce"] = "function( keys,values,rereduce ){ return key[0]; }"

    ret["by-minion-fun-timestamp"] = {}
    ret["by-minion-fun-timestamp"][
        "map"
    ] = "function( doc ){ emit( [doc.id,doc.fun,doc.timestamp], doc ); }"
    return ret


def set_salt_view():
    """
    Helper function that sets the salt design
    document. Uses get_valid_salt_views and some hardcoded values.
    """

    options = _get_options(ret=None)

    # Create the new object that we will shove in as the design doc.
    new_doc = {}
    new_doc["views"] = get_valid_salt_views()
    new_doc["language"] = "javascript"

    # Make the request to update the design doc.
    _response = _request(
        "PUT",
        options["url"] + options["db"] + "/_design/salt",
        "application/json",
        salt.utils.json.dumps(new_doc),
    )
    if "error" in _response:
        log.warning("Unable to set the salt design document: %s", _response["error"])
        return False
    return True


def prep_jid(nocache=False, passed_jid=None):  # pylint: disable=unused-argument
    """
    Do any work necessary to prepare a JID, including sending a custom id
    """
    return passed_jid if passed_jid is not None else salt.utils.jid.gen_jid(__opts__)


def save_minions(jid, minions, syndic_id=None):  # pylint: disable=unused-argument
    """
    Included for API consistency
    """
