# ================================================================================
# Copyright (c) 2018 AT&T Intellectual Property. 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.
# ============LICENSE_END=========================================================
#
# ECOMP is a trademark and service mark of AT&T Intellectual Property.
"""client to talk to consul at the standard port 8500 on localhost"""

import base64
import json
import urllib
import uuid
from datetime import datetime

import requests
from cloudify import ctx


class PoliciesOutput(object):
    """static class for store-delete policies in consul kv"""
    # it is safe to assume that consul agent is at localhost:8500 along with cloudify manager
    CONSUL_TRANSACTION_URL = "http://localhost:8500/v1/txn"

    POLICIES_EVENT = 'policies_event'

    POLICIES_FOLDER_MASK = "{0}:policies/{1}"
    MAX_OPS_PER_TXN = 64
    # MAX_VALUE_LEN = 512 * 1000

    OPERATION_SET = "set"
    OPERATION_DELETE = "delete"
    OPERATION_DELETE_FOLDER = "delete-tree"
    SERVICE_COMPONENT_NAME = "service_component_name"

    @staticmethod
    def _gen_txn_operation(verb, service_component_name, key=None, value=None):
        """returns the properly formatted operation to be used inside transaction"""
        key = PoliciesOutput.POLICIES_FOLDER_MASK.format(service_component_name, urllib.quote(key or ""))
        if value:
            return {"KV": {"Verb": verb, "Key": key, "Value": base64.b64encode(value)}}
        return {"KV": {"Verb": verb, "Key": key}}

    @staticmethod
    def _run_transaction(operation_name, txn):
        """run a single transaction of several operations at consul /txn"""
        if not txn:
            return

        response = None
        try:
            response = requests.put(PoliciesOutput.CONSUL_TRANSACTION_URL, json=txn)
        except requests.exceptions.RequestException as ex:
            ctx.logger.error("failed to {0} at {1}: {2} on txn={3}"
                .format(operation_name, PoliciesOutput.CONSUL_TRANSACTION_URL,
                        str(ex), json.dumps(txn)))
            return

        if response.status_code != requests.codes.ok:
            ctx.logger.error("failed {0} {1}: {2} text={3} txn={4} headers={5}"
                .format(operation_name, PoliciesOutput.CONSUL_TRANSACTION_URL, response.status_code,
                        response.text, json.dumps(txn),
                        json.dumps(dict(response.request.headers.items()))))
            return
        ctx.logger.info("response for {0} {1}: {2} text={3} txn={4} headers={5}"
            .format(operation_name, PoliciesOutput.CONSUL_TRANSACTION_URL, response.status_code,
                    response.text, json.dumps(txn),
                    json.dumps(dict(response.request.headers.items()))))
        return True

    @staticmethod
    def store_policies(action, policy_bodies):
        """put the policy_bodies for service_component_name into consul-kv"""
        service_component_name = ctx.instance.runtime_properties.get(PoliciesOutput.SERVICE_COMPONENT_NAME)
        if not service_component_name:
            ctx.logger.warn("failed to find service_component_name to store_policies in consul-kv")
            return False

        event = {
            "action": action,
            "timestamp": (datetime.utcnow().isoformat()[:-3] + 'Z'),
            "update_id": str(uuid.uuid4()),
            "policies_count": len(policy_bodies)
        }
        ctx.instance.runtime_properties[PoliciesOutput.POLICIES_EVENT] = event

        store_policies = [
            PoliciesOutput._gen_txn_operation(PoliciesOutput.OPERATION_SET, service_component_name,
                                              "items/" + policy_id, json.dumps(policy_body))
            for policy_id, policy_body in policy_bodies.iteritems()
        ]
        txn = [
            PoliciesOutput._gen_txn_operation(PoliciesOutput.OPERATION_DELETE_FOLDER, service_component_name),
            PoliciesOutput._gen_txn_operation(PoliciesOutput.OPERATION_SET, service_component_name, "event", json.dumps(event))
        ]
        idx_step = PoliciesOutput.MAX_OPS_PER_TXN - len(txn)
        for idx in xrange(0, len(store_policies), idx_step):
            txn += store_policies[idx : idx + idx_step]
            if not PoliciesOutput._run_transaction("store_policies", txn):
                return False
            txn = []

        PoliciesOutput._run_transaction("store_policies", txn)
        return True

    @staticmethod
    def delete_policies():
        """delete policies for service_component_name in consul-kv"""
        if PoliciesOutput.POLICIES_EVENT not in ctx.instance.runtime_properties:
            return

        service_component_name = ctx.instance.runtime_properties.get(PoliciesOutput.SERVICE_COMPONENT_NAME)
        if not service_component_name:
            ctx.logger.warn("failed to find service_component_name to delete_policies in consul-kv")
            return

        delete_policies = [
            PoliciesOutput._gen_txn_operation(PoliciesOutput.OPERATION_DELETE_FOLDER, service_component_name)
        ]
        PoliciesOutput._run_transaction("delete_policies", delete_policies)