#
#    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.

import collections
import copy
import functools

from heat.common import exception
from heat.common.i18n import _
from heat.engine import constraints
from heat.engine import properties
from heat.engine.resources.openstack.heat import software_config as sc
from heat.engine.resources.openstack.heat import software_deployment as sd
from heat.engine import rsrc_defn
from heat.engine import support


class StructuredConfig(sc.SoftwareConfig):
    """A resource which has same logic with OS::Heat::SoftwareConfig.

    This resource is like OS::Heat::SoftwareConfig except that the config
    property is represented by a Map rather than a String.

    This is useful for configuration tools which use YAML or JSON as their
    configuration syntax. The resulting configuration is transferred,
    stored and returned by the software_configs API as parsed JSON.
    """

    support_status = support.SupportStatus(version='2014.1')

    PROPERTIES = (
        GROUP,
        CONFIG,
        OPTIONS,
        INPUTS,
        OUTPUTS
    ) = (
        sc.SoftwareConfig.GROUP,
        sc.SoftwareConfig.CONFIG,
        sc.SoftwareConfig.OPTIONS,
        sc.SoftwareConfig.INPUTS,
        sc.SoftwareConfig.OUTPUTS
    )

    properties_schema = {
        GROUP: sc.SoftwareConfig.properties_schema[GROUP],
        OPTIONS: sc.SoftwareConfig.properties_schema[OPTIONS],
        INPUTS: sc.SoftwareConfig.properties_schema[INPUTS],
        OUTPUTS: sc.SoftwareConfig.properties_schema[OUTPUTS],
        CONFIG: properties.Schema(
            properties.Schema.MAP,
            _('Map representing the configuration data structure which will '
              'be serialized to JSON format.')
        )
    }


class StructuredDeployment(sd.SoftwareDeployment):
    """A resource which has same logic with OS::Heat::SoftwareDeployment.

    A deployment resource like OS::Heat::SoftwareDeployment, but which
    performs input value substitution on the config defined by a
    OS::Heat::StructuredConfig resource.

    Some configuration tools have no concept of inputs, so the input value
    substitution needs to occur in the deployment resource. An example of this
    is the JSON metadata consumed by the cfn-init tool.

    Where the config contains {get_input: input_name} this will be substituted
    with the value of input_name in this resource's input_values. If get_input
    needs to be passed through to the substituted configuration then a
    different input_key property value can be specified.
    """

    support_status = support.SupportStatus(version='2014.1')

    PROPERTIES = (
        CONFIG,
        SERVER,
        INPUT_VALUES,
        DEPLOY_ACTIONS,
        NAME,
        SIGNAL_TRANSPORT,
        INPUT_KEY,
        INPUT_VALUES_VALIDATE
    ) = (
        sd.SoftwareDeployment.CONFIG,
        sd.SoftwareDeployment.SERVER,
        sd.SoftwareDeployment.INPUT_VALUES,
        sd.SoftwareDeployment.DEPLOY_ACTIONS,
        sd.SoftwareDeployment.NAME,
        sd.SoftwareDeployment.SIGNAL_TRANSPORT,
        'input_key',
        'input_values_validate'
    )

    _sd_ps = sd.SoftwareDeployment.properties_schema

    properties_schema = {
        CONFIG: _sd_ps[CONFIG],
        SERVER: _sd_ps[SERVER],
        INPUT_VALUES: _sd_ps[INPUT_VALUES],
        DEPLOY_ACTIONS: _sd_ps[DEPLOY_ACTIONS],
        SIGNAL_TRANSPORT: _sd_ps[SIGNAL_TRANSPORT],
        NAME: _sd_ps[NAME],
        INPUT_KEY: properties.Schema(
            properties.Schema.STRING,
            _('Name of key to use for substituting inputs during deployment.'),
            default='get_input',
        ),
        INPUT_VALUES_VALIDATE: properties.Schema(
            properties.Schema.STRING,
            _('Perform a check on the input values passed to verify that '
              'each required input has a corresponding value. '
              'When the property is set to STRICT and no value is passed, '
              'an exception is raised.'),
            default='LAX',
            constraints=[
                constraints.AllowedValues(['LAX', 'STRICT']),
            ],
        )
    }

    def empty_config(self):
        return {}

    def _build_derived_config(self, action, source,
                              derived_inputs, derived_options):
        cfg = source.get(sc.SoftwareConfig.CONFIG)
        input_key = self.properties[self.INPUT_KEY]
        check_input_val = self.properties[self.INPUT_VALUES_VALIDATE]

        inputs = dict(i.input_data() for i in derived_inputs)

        return self.parse(inputs, input_key, cfg, check_input_val)

    @staticmethod
    def get_input_key_arg(snippet, input_key):
        if len(snippet) != 1:
            return None
        fn_name, fn_arg = next(iter(snippet.items()))
        if (fn_name == input_key and isinstance(fn_arg, str)):
            return fn_arg

    @staticmethod
    def get_input_key_value(fn_arg, inputs, check_input_val='LAX'):
        if check_input_val == 'STRICT' and fn_arg not in inputs:
            raise exception.UserParameterMissing(key=fn_arg)
        return inputs.get(fn_arg)

    @staticmethod
    def parse(inputs, input_key, snippet, check_input_val='LAX'):
        parse = functools.partial(
            StructuredDeployment.parse,
            inputs,
            input_key,
            check_input_val=check_input_val)

        if isinstance(snippet, collections.abc.Mapping):
            fn_arg = StructuredDeployment.get_input_key_arg(snippet, input_key)
            if fn_arg is not None:
                return StructuredDeployment.get_input_key_value(fn_arg, inputs,
                                                                check_input_val
                                                                )

            return dict((k, parse(v)) for k, v in snippet.items())
        elif (not isinstance(snippet, str) and
              isinstance(snippet, collections.abc.Iterable)):
            return [parse(v) for v in snippet]
        else:
            return snippet


class StructuredDeploymentGroup(sd.SoftwareDeploymentGroup):
    """This resource associates a group of servers with some configuration.

    This resource works similar as OS::Heat::SoftwareDeploymentGroup, but for
    structured resources.
    """