"""
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you 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 sys
import os
import json
import  tempfile
from resource_management import *
from resource_management.libraries.functions.security_commons import build_expectations, \
  cached_kinit_executor, get_params_from_filesystem, validate_security_config_properties, \
  FILE_TYPE_XML
from resource_management.libraries.functions.version import compare_versions, \
  format_hdp_stack_version
from resource_management.libraries.functions.format import format
from resource_management.libraries.functions.check_process_status import check_process_status
from resource_management.core.exceptions import Fail
from resource_management.libraries.functions import get_klist_path

import namenode_upgrade
from hdfs_namenode import namenode
from hdfs import hdfs
import hdfs_rebalance
from utils import failover_namenode
from setup_ranger_hdfs import setup_ranger_hdfs

# hashlib is supplied as of Python 2.5 as the replacement interface for md5
# and other secure hashes.  In 2.6, md5 is deprecated.  Import hashlib if
# available, avoiding a deprecation warning under 2.6.  Import md5 otherwise,
# preserving 2.4 compatibility.
try:
  import hashlib
  _md5 = hashlib.md5
except ImportError:
  import md5
  _md5 = md5.new

class NameNode(Script):

  def get_stack_to_component(self):
    return {"HDP": "hadoop-hdfs-namenode"}

  def install(self, env):
    import params

    self.install_packages(env, params.exclude_packages)
    env.set_params(params)
    #TODO we need this for HA because of manual steps
    self.configure(env)

  def prepare_rolling_upgrade(self, env):
    namenode_upgrade.prepare_rolling_upgrade()

  def finalize_rolling_upgrade(self, env):
    namenode_upgrade.finalize_rolling_upgrade()

  def pre_rolling_restart(self, env):
    Logger.info("Executing Rolling Upgrade pre-restart")
    import params
    env.set_params(params)

    if params.version and compare_versions(format_hdp_stack_version(params.version), '2.2.0.0') >= 0:
      Execute(format("hdp-select set hadoop-hdfs-namenode {version}"))

  def start(self, env, rolling_restart=False):
    import params

    env.set_params(params)
    self.configure(env)
    setup_ranger_hdfs()
    namenode(action="start", rolling_restart=rolling_restart, env=env)

  def post_rolling_restart(self, env):
    Logger.info("Executing Rolling Upgrade post-restart")
    import params
    env.set_params(params)

    Execute("hdfs dfsadmin -report -live",
            user=params.hdfs_user
    )

  def stop(self, env, rolling_restart=False):
    import params
    env.set_params(params)

    if rolling_restart and params.dfs_ha_enabled:
      if params.dfs_ha_automatic_failover_enabled:
        failover_namenode()
      else:
        raise Fail("Rolling Upgrade - dfs.ha.automatic-failover.enabled must be enabled to perform a rolling restart")

    namenode(action="stop", rolling_restart=rolling_restart, env=env)

  def configure(self, env):
    import params

    env.set_params(params)
    hdfs()
    namenode(action="configure", env=env)
    pass

  def status(self, env):
    import status_params

    env.set_params(status_params)
    check_process_status(status_params.namenode_pid_file)
    pass

  def security_status(self, env):
    import status_params

    env.set_params(status_params)
    props_value_check = {"hadoop.security.authentication": "kerberos",
                         "hadoop.security.authorization": "true"}
    props_empty_check = ["hadoop.security.auth_to_local"]
    props_read_check = None
    core_site_expectations = build_expectations('core-site', props_value_check, props_empty_check,
                                                props_read_check)
    props_value_check = None
    props_empty_check = ['dfs.namenode.kerberos.internal.spnego.principal',
                         'dfs.namenode.keytab.file',
                         'dfs.namenode.kerberos.principal']
    props_read_check = ['dfs.namenode.keytab.file']
    hdfs_site_expectations = build_expectations('hdfs-site', props_value_check, props_empty_check,
                                                props_read_check)

    hdfs_expectations = {}
    hdfs_expectations.update(core_site_expectations)
    hdfs_expectations.update(hdfs_site_expectations)

    security_params = get_params_from_filesystem(status_params.hadoop_conf_dir,
                                                 {'core-site.xml': FILE_TYPE_XML,
                                                  'hdfs-site.xml': FILE_TYPE_XML})
    if 'core-site' in security_params and 'hadoop.security.authentication' in security_params['core-site'] and \
        security_params['core-site']['hadoop.security.authentication'].lower() == 'kerberos':
      result_issues = validate_security_config_properties(security_params, hdfs_expectations)
      if not result_issues:  # If all validations passed successfully
        try:
          # Double check the dict before calling execute
          if ( 'hdfs-site' not in security_params
               or 'dfs.namenode.keytab.file' not in security_params['hdfs-site']
               or 'dfs.namenode.kerberos.principal' not in security_params['hdfs-site']):
            self.put_structured_out({"securityState": "UNSECURED"})
            self.put_structured_out(
              {"securityIssuesFound": "Keytab file or principal are not set property."})
            return
          cached_kinit_executor(status_params.kinit_path_local,
                                status_params.hdfs_user,
                                security_params['hdfs-site']['dfs.namenode.keytab.file'],
                                security_params['hdfs-site']['dfs.namenode.kerberos.principal'],
                                status_params.hostname,
                                status_params.tmp_dir)
          self.put_structured_out({"securityState": "SECURED_KERBEROS"})
        except Exception as e:
          self.put_structured_out({"securityState": "ERROR"})
          self.put_structured_out({"securityStateErrorInfo": str(e)})
      else:
        issues = []
        for cf in result_issues:
          issues.append("Configuration file %s did not pass the validation. Reason: %s" % (cf, result_issues[cf]))
        self.put_structured_out({"securityIssuesFound": ". ".join(issues)})
        self.put_structured_out({"securityState": "UNSECURED"})
    else:
      self.put_structured_out({"securityState": "UNSECURED"})


  def decommission(self, env):
    import params

    env.set_params(params)
    namenode(action="decommission")
    pass


  def rebalancehdfs(self, env):
    import params
    env.set_params(params)

    name_node_parameters = json.loads( params.name_node_params )
    threshold = name_node_parameters['threshold']
    _print("Starting balancer with threshold = %s\n" % threshold)

    rebalance_env = {'PATH': params.hadoop_bin_dir}

    if params.security_enabled:
      # Create the kerberos credentials cache (ccache) file and set it in the environment to use
      # when executing HDFS rebalance command. Use the md5 hash of the combination of the principal and keytab file
      # to generate a (relatively) unique cache filename so that we can use it as needed.
      # TODO: params.tmp_dir=/var/lib/ambari-agent/data/tmp. However hdfs user doesn't have access to this path.
      # TODO: Hence using /tmp
      ccache_file_name = "hdfs_rebalance_cc_" + _md5(format("{hdfs_principal_name}|{hdfs_user_keytab}")).hexdigest()
      ccache_file_path = os.path.join(tempfile.gettempdir(), ccache_file_name)
      rebalance_env['KRB5CCNAME'] = ccache_file_path

      # If there are no tickets in the cache or they are expired, perform a kinit, else use what
      # is in the cache
      klist_cmd = format("{klist_path_local} -s {ccache_file_path}")
      kinit_cmd = format("{kinit_path_local} -c {ccache_file_path} -kt {hdfs_user_keytab} {hdfs_principal_name}")
      if os.system(klist_cmd) != 0:
        Execute(kinit_cmd, user=params.hdfs_user)

    def calculateCompletePercent(first, current):
      return 1.0 - current.bytesLeftToMove/first.bytesLeftToMove


    def startRebalancingProcess(threshold, rebalance_env):
      rebalanceCommand = format('hdfs --config {hadoop_conf_dir} balancer -threshold {threshold}')
      return as_user(rebalanceCommand, params.hdfs_user, env=rebalance_env)

    command = startRebalancingProcess(threshold, rebalance_env)

    basedir = os.path.join(env.config.basedir, 'scripts')
    if(threshold == 'DEBUG'): #FIXME TODO remove this on PROD
      basedir = os.path.join(env.config.basedir, 'scripts', 'balancer-emulator')
      command = ['python','hdfs-command.py']

    _print("Executing command %s\n" % command)

    parser = hdfs_rebalance.HdfsParser()

    def handle_new_line(line):
      _print('[balancer] %s' % (line))
      pl = parser.parseLine(line)
      if pl:
        res = pl.toJson()
        res['completePercent'] = calculateCompletePercent(parser.initialLine, pl)

        self.put_structured_out(res)
      elif parser.state == 'PROCESS_FINISED' :
        _print('[balancer] %s' % ('Process is finished' ))
        self.put_structured_out({'completePercent' : 1})
        return

    Execute(command,
            on_new_line = handle_new_line,
            logoutput = False,
    )

    if params.security_enabled and os.path.exists(ccache_file_path):
      # Delete the kerberos credentials cache (ccache) file
      os.remove(ccache_file_path)

def _print(line):
  sys.stdout.write(line)
  sys.stdout.flush()

if __name__ == "__main__":
  NameNode().execute()
