#!/usr/bin/env python
# Licensed to Cloudera, Inc. under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  Cloudera, Inc. 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.

from past.builtins import cmp
from future import standard_library
standard_library.install_aliases()
from builtins import filter
from builtins import str
import functools
import logging
import re
import string
import sys
import time
import urllib.request, urllib.error, urllib.parse
import urllib.parse

from lxml import html
from urllib.parse import quote_plus

from django.http import HttpResponseRedirect
from django.utils.functional import wraps
from django.urls import reverse

from desktop.auth.backend import is_admin
from desktop.lib.django_util import JsonResponse, render_json, render, copy_query_dict
from desktop.lib.exceptions import MessageException
from desktop.lib.exceptions_renderable import PopupException
from desktop.lib.json_utils import JSONEncoderForHTML
from desktop.lib.rest.http_client import RestException
from desktop.lib.rest.resource import Resource
from desktop.log.access import access_log_level
from desktop.views import register_status_bar_view

from hadoop import cluster
from hadoop.yarn.clients import get_log_client
from hadoop.yarn import resource_manager_api as resource_manager_api

if sys.version_info[0] > 2:
  from django.utils.translation import gettext as _
else:
  from django.utils.translation import ugettext as _

LOG = logging.getLogger()


try:
  from beeswax.hive_site import hiveserver2_impersonation_enabled
except:
  LOG.warning('Hive is not enabled')
  def hiveserver2_impersonation_enabled(): return True

from jobbrowser.conf import LOG_OFFSET, SHARE_JOBS
from jobbrowser.api import get_api, ApplicationNotRunning, JobExpired
from jobbrowser.models import can_view_job, can_kill_job, LinkJobLogs
from jobbrowser.yarn_models import Application


LOG_OFFSET_BYTES = LOG_OFFSET.get()


def check_job_permission(view_func):
  """
  Ensure that the user has access to the job.
  Assumes that the wrapped function takes a 'jobid' param named 'job'.
  """
  def decorate(request, *args, **kwargs):
    jobid = kwargs['job']
    try:
      job = get_job(request, job_id=jobid)
    except ApplicationNotRunning as e:
      LOG.warning('Job %s has not yet been accepted by the RM, will poll for status.' % jobid)
      return job_not_assigned(request, jobid, request.path)

    if not SHARE_JOBS.get() and not is_admin(request.user) \
        and job.user != request.user.username and not can_view_job(request.user.username, job):
      raise PopupException(_("You don't have permission to access job %(id)s.") % {'id': jobid})
    kwargs['job'] = job
    return view_func(request, *args, **kwargs)

  return wraps(view_func)(decorate)


def get_job(request, job_id):
  try:
    job = get_api(request.user, request.jt).get_job(jobid=job_id)
  except ApplicationNotRunning as e:
    if e.job.get('state', '').lower() == 'accepted':
      rm_api = resource_manager_api.get_resource_manager(request.user)
      job = Application(e.job, rm_api)
    else:
      raise e  # Job has not yet been accepted by RM
  except JobExpired as e:
    raise PopupException(_('Job %s has expired.') % job_id, detail=_('Cannot be found on the History Server.'))
  except Exception as e:
    msg = 'Could not find job %s.'
    LOG.exception(msg % job_id)
    raise PopupException(_(msg) % job_id, detail=e)
  return job


def apps(request):
  return render('job_browser.mako', request, {
    'is_embeddable': request.GET.get('is_embeddable', False),
    'is_mini': request.GET.get('is_mini', False),
    'hiveserver2_impersonation_enabled': hiveserver2_impersonation_enabled()
  })


def job_not_assigned(request, jobid, path):
  if request.GET.get('format') == 'json':
    result = {'status': -1, 'message': ''}

    try:
      get_api(request.user, request.jt).get_job(jobid=jobid)
      result['status'] = 0
    except ApplicationNotRunning as e:
      result['status'] = 1
    except Exception as e:
      result['message'] = _('Error polling job %s: %s') % (jobid, e)

    return JsonResponse(result, encoder=JSONEncoderForHTML)
  else:
    return render('job_not_assigned.mako', request, {'jobid': jobid, 'path': path})


def jobs(request):
  user = request.POST.get('user', request.user.username)
  state = request.POST.get('state')
  text = request.POST.get('text')
  retired = request.POST.get('retired')
  time_value = request.POST.get('time_value', 7)
  time_unit = request.POST.get('time_unit', 'days')

  if request.POST.get('format') == 'json':
    try:
      # Limit number of jobs to be 1000
      jobs = get_api(request.user, request.jt).get_jobs(
          user=request.user,
          username=user,
          state=state,
          text=text,
          retired=retired,
          limit=1000,
          time_value=int(time_value),
          time_unit=time_unit
      )
    except Exception as ex:
      ex_message = str(ex)
      if 'Connection refused' in ex_message or 'standby RM' in ex_message or 'Name or service not known' in ex_message:
        response = {'status': 1, 'message': _('Resource Manager cannot be contacted or might be down.')}
        return JsonResponse(response)
      elif 'Could not connect to' in ex_message:
        raise PopupException(_('Job Tracker cannot be contacted or might be down.'))
      else:
        raise PopupException(ex)
    json_jobs = {
      'jobs': [massage_job_for_json(job, request) for job in jobs],
    }
    return JsonResponse(json_jobs, encoder=JSONEncoderForHTML)

  return render('jobs.mako', request, {
    'request': request,
    'state_filter': state,
    'user_filter': user,
    'text_filter': text,
    'retired': retired,
    'filtered': not (state == 'all' and user == '' and text == ''),
    'is_yarn': cluster.is_yarn(),
    'hiveserver2_impersonation_enabled': hiveserver2_impersonation_enabled()
  })


def massage_job_for_json(job, request=None, user=None):
  job = {
    'id': job.jobId,
    'shortId': job.jobId_short,
    'name': hasattr(job, 'jobName') and job.jobName or '',
    'status': job.status,
    'yarnStatus': hasattr(job, 'yarnStatus') and job.yarnStatus or '',
    'url': job.jobId and reverse('jobbrowser:jobbrowser.views.single_job', kwargs={'job': job.jobId}) or '',
    'logs': job.jobId and reverse('jobbrowser:jobbrowser.views.job_single_logs', kwargs={'job': job.jobId}) or '',
    'queueName': hasattr(job, 'queueName') and job.queueName or _('N/A'),
    'priority': hasattr(job, 'priority') and job.priority or _('N/A'),
    'user': job.user,
    'isRetired': job.is_retired,
    'isMR2': job.is_mr2,
    'progress': hasattr(job, 'progress') and job.progress or 0,
    'mapProgress': hasattr(job, 'mapProgress') and job.mapProgress or '',
    'reduceProgress': hasattr(job, 'reduceProgress') and job.reduceProgress or '',
    'setupProgress': hasattr(job, 'setupProgress') and job.setupProgress or '',
    'cleanupProgress': hasattr(job, 'cleanupProgress') and job.cleanupProgress or '',
    'desiredMaps': job.desiredMaps,
    'desiredReduces': job.desiredReduces,
    'applicationType': hasattr(job, 'applicationType') and job.applicationType or None,
    'type': hasattr(job, 'type') and job.type or None,
    'mapsPercentComplete': int(job.maps_percent_complete) if job.maps_percent_complete else '',
    'finishedMaps': job.finishedMaps,
    'finishedReduces': job.finishedReduces,
    'reducesPercentComplete': int(job.reduces_percent_complete) if job.reduces_percent_complete else '',
    'jobFile': hasattr(job, 'jobFile') and job.jobFile or '',
    'launchTimeMs': hasattr(job, 'launchTimeMs') and job.launchTimeMs or 0,
    'launchTimeFormatted': hasattr(job, 'launchTimeFormatted') and job.launchTimeFormatted or '',
    'startTimeMs': hasattr(job, 'startTimeMs') and job.startTimeMs or 0,
    'startTimeFormatted': hasattr(job, 'startTimeFormatted') and job.startTimeFormatted or '',
    'finishTimeMs': hasattr(job, 'finishTimeMs') and job.finishTimeMs or 0,
    'finishTimeFormatted': hasattr(job, 'finishTimeFormatted') and job.finishTimeFormatted or '',
    'durationFormatted': hasattr(job, 'durationFormatted') and job.durationFormatted or '',
    'durationMs': hasattr(job, 'durationInMillis') and job.durationInMillis or 0,
    'canKill': can_kill_job(job, request.user if request else user),
    'killUrl': job.jobId and reverse('jobbrowser:kill_job', kwargs={'job': job.jobId}) or '',
    'diagnostics': hasattr(job, 'diagnostics') and job.diagnostics or '',
  }
  return job


def massage_task_for_json(task):
  task = {
    'id': task.taskId,
    'shortId': task.taskId_short,
    'url': task.taskId and reverse('jobbrowser:jobbrowser.views.single_task', kwargs={'job': task.jobId, 'taskid': task.taskId}) or '',
    'logs': task.taskAttemptIds and reverse('jobbrowser:single_task_attempt_logs', kwargs={'job': task.jobId, 'taskid': task.taskId,
                                                                                'attemptid': task.taskAttemptIds[-1]}) or '',
    'type': task.taskType
  }
  return task


def single_spark_job(request, job):
  if request.GET.get('format') == 'json':
    json_job = {
      'job': massage_job_for_json(job, request)
    }
    return JsonResponse(json_job, encoder=JSONEncoderForHTML)
  else:
    return render('job.mako', request, {
      'request': request,
      'job': job
    })

@check_job_permission
def single_job(request, job):
  def cmp_exec_time(task1, task2):
    return cmp(task1.execStartTimeMs, task2.execStartTimeMs)

  if job.applicationType == 'SPARK':
    return single_spark_job(request, job)

  failed_tasks = job.filter_tasks(task_states=('failed',))
  recent_tasks = job.filter_tasks(task_states=('running', 'succeeded',))

  if sys.version_info[0] > 2:
    failed_tasks.sort(key=lambda task: task.execStartTimeMs)
    recent_tasks.sort(key=lambda task: task.execStartTimeMs, reverse=True)
  else:
    failed_tasks.sort(cmp_exec_time)
    recent_tasks.sort(cmp_exec_time, reverse=True)

  if request.GET.get('format') == 'json':
    json_failed_tasks = [massage_task_for_json(task) for task in failed_tasks]
    json_recent_tasks = [massage_task_for_json(task) for task in recent_tasks]
    json_job = {
      'job': massage_job_for_json(job, request),
      'failedTasks': json_failed_tasks,
      'recentTasks': json_recent_tasks
    }
    return JsonResponse(json_job, encoder=JSONEncoderForHTML)

  return render('job.mako', request, {
    'request': request,
    'job': job,
    'failed_tasks': failed_tasks and failed_tasks[:5] or [],
    'recent_tasks': recent_tasks and recent_tasks[:5] or [],
  })


@check_job_permission
def job_counters(request, job):
  return render("counters.html", request, {"counters": job.counters})


@access_log_level(logging.WARN)
@check_job_permission
def kill_job(request, job):
  if request.method != "POST":
    raise Exception(_("kill_job may only be invoked with a POST (got a %(method)s).") % {'method': request.method})

  if not can_kill_job(job, request.user):
    raise PopupException(_("Kill operation is forbidden."))

  api = get_api(request.user, request.jt)

  try:
    from jobbrowser.api import YarnApi

    if isinstance(api, YarnApi):
      api.kill_job(job.jobId)
    else:
      job.kill()
  except Exception as e:
    LOG.exception('Killing job')
    raise PopupException(e)

  cur_time = time.time()

  while time.time() - cur_time < 15:
    try:
      job = api.get_job(jobid=job.jobId)
    except Exception as e:
      LOG.warning('Failed to get job with ID %s: %s' % (job.jobId, e))
    else:
      if job.status not in ["RUNNING", "QUEUED"]:
        if request.GET.get("next"):
          return HttpResponseRedirect(request.GET.get("next"))
        elif request.GET.get("format") == "json":
          return JsonResponse({'status': 0}, encoder=JSONEncoderForHTML)
        else:
          raise MessageException("Job Killed")
    time.sleep(1)

  raise Exception(_("Job did not appear as killed within 15 seconds."))

@check_job_permission
def job_executor_logs(request, job, attempt_index=0, name='syslog', offset=LOG_OFFSET_BYTES):
  response = {'status': -1}
  try:
    log = ''
    if job.status not in ('NEW', 'SUBMITTED', 'ACCEPTED'):
      log = job.history_server_api.download_executors_logs(request, job, name, offset)
    response['status'] = 0
    response['log'] = LinkJobLogs._make_hdfs_links(log)
  except Exception as e:
    response['log'] = _('Failed to retrieve executor log: %s' % e)

  return JsonResponse(response)


@check_job_permission
def job_attempt_logs(request, job, attempt_index=0):
  return render("job_attempt_logs.mako", request, {
    "attempt_index": attempt_index,
    "job": job,
    "log_offset": LOG_OFFSET_BYTES
  })


@check_job_permission
def job_attempt_logs_json(request, job, attempt_index=0, name='syslog', offset=LOG_OFFSET_BYTES, is_embeddable=False):
  """For async log retrieval as Yarn servers are very slow"""
  log_link = None
  response = {'status': -1}

  try:
    jt = get_api(request.user, request.jt)
    app = jt.get_application(job.jobId)

    if app['applicationType'] == 'MAPREDUCE':
      if app['finalStatus'] in ('SUCCEEDED', 'FAILED', 'KILLED'):
        attempt_index = int(attempt_index)
        if not job.job_attempts['jobAttempt']:
          response = {'status': 0, 'log': _('Job has no tasks')}
        else:
          attempt = job.job_attempts['jobAttempt'][attempt_index]

          log_link = attempt['logsLink']
          # Reformat log link to use YARN RM, replace node addr with node ID addr
          log_link = log_link.replace(attempt['nodeHttpAddress'], attempt['nodeId'])
      elif app['state'] == 'RUNNING':
        log_link = app['amContainerLogs']
    elif app.get('amContainerLogs'):
      log_link = app.get('amContainerLogs')
  except (KeyError, RestException) as e:
    raise KeyError(_("Cannot find job attempt '%(id)s'.") % {'id': job.jobId}, e)
  except Exception as e:
    raise Exception(_("Failed to get application for job %s: %s") % (job.jobId, e))

  if log_link:
    link = '/%s/' % name
    params = {
      'doAs': request.user.username
    }

    if offset != 0:
      params['start'] = offset

    root = Resource(get_log_client(log_link), urllib.parse.urlsplit(log_link)[2], urlencode=False)
    api_resp = None

    try:
      api_resp = root.get(link, params=params)
      log = html.fromstring(api_resp, parser=html.HTMLParser()).xpath('/html/body/table/tbody/tr/td[2]')[0].text_content()

      response['status'] = 0
      response['log'] = LinkJobLogs._make_hdfs_links(log, is_embeddable)
    except Exception as e:
      response['log'] = _('Failed to retrieve log: %s' % e)
      try:
        debug_info = '\nLog Link: %s' % log_link
        if api_resp:
          debug_info += '\nHTML Response: %s' % response
        response['debug'] = debug_info
        LOG.error(debug_info)
      except:
        LOG.exception('failed to create debug info')

  return JsonResponse(response)


@check_job_permission
def job_single_logs(request, job, offset=LOG_OFFSET_BYTES):
  """
  Try to smartly detect the most useful task attempt (e.g. YarnV2, failed task) and get its MR logs.
  """
  def cmp_exec_time(task1, task2):
    return cmp(task1.execStartTimeMs, task2.execStartTimeMs)

  if job.applicationType == 'SPARK':
    return job.history_server_api.download_logs(job.app)

  task = None

  failed_tasks = job.filter_tasks(task_states=('failed',))
  if sys.version_info[0] > 2:
    failed_tasks.sort(key=functools.cmp_to_key(cmp_exec_time))
  else:
    failed_tasks.sort(cmp_exec_time)
  if failed_tasks:
    task = failed_tasks[0]
    if not task.taskAttemptIds and len(failed_tasks) > 1: # In some cases the last task ends up without any attempt
      task = failed_tasks[1]
  else:
    task_states = ['running', 'succeeded']
    if job.is_mr2:
      task_states.append('scheduled')
    recent_tasks = job.filter_tasks(task_states=task_states, task_types=('map', 'reduce',))
    if sys.version_info[0] > 2:
      recent_tasks.sort(key=functools.cmp_to_key(cmp_exec_time), reverse=True)
    else:
      recent_tasks.sort(cmp_exec_time, reverse=True)
    if recent_tasks:
      task = recent_tasks[0]

  if task is None or not task.taskAttemptIds:
    if request.GET.get('format') == 'link':
      params = {'job': job.jobId, 'offset': offset}
    else:
      raise PopupException(_("No tasks found for job %(id)s.") % {'id': job.jobId})
  else:
    params = {'job': job.jobId, 'taskid': task.taskId, 'attemptid': task.taskAttemptIds[-1], 'offset': offset}

  if request.GET.get('format') == 'link':
    return JsonResponse(params)
  else:
    return single_task_attempt_logs(request, **params)


@check_job_permission
def tasks(request, job):
  """
  We get here from /jobs/job/tasks?filterargs, with the options being:
    page=<n>            - Controls pagination. Defaults to 1.
    tasktype=<type>     - Type can be one of hadoop.job_tracker.VALID_TASK_TYPES
                          ("map", "reduce", "job_cleanup", "job_setup")
    taskstate=<state>   - State can be one of hadoop.job_tracker.VALID_TASK_STATES
                          ("succeeded", "failed", "running", "pending", "killed")
    tasktext=<text>     - Where <text> is a string matching info on the task
  """
  ttypes = request.GET.get('tasktype')
  tstates = request.GET.get('taskstate')
  ttext = request.GET.get('tasktext')
  pagenum = int(request.GET.get('page', 1))
  pagenum = pagenum > 0 and pagenum or 1

  filters = {
    'task_types': ttypes and set(ttypes.split(',')) or None,
    'task_states': tstates and set(tstates.split(',')) or None,
    'task_text': ttext,
    'pagenum': pagenum,
  }

  jt = get_api(request.user, request.jt)

  task_list = jt.get_tasks(job.jobId, **filters)

  filter_params = copy_query_dict(request.GET, ('tasktype', 'taskstate', 'tasktext')).urlencode()

  return render("tasks.mako", request, {
    'request': request,
    'filter_params': filter_params,
    'job': job,
    'task_list': task_list,
    'tasktype': ttypes,
    'taskstate': tstates,
    'tasktext': ttext
  })


@check_job_permission
def single_task(request, job, taskid):
  jt = get_api(request.user, request.jt)

  job_link = jt.get_job_link(job.jobId)
  task = job_link.get_task(taskid)

  return render("task.mako", request, {
    'task': task,
    'joblnk': job_link
  })

@check_job_permission
def single_task_attempt(request, job, taskid, attemptid):
  jt = get_api(request.user, request.jt)

  job_link = jt.get_job_link(job.jobId)
  task = job_link.get_task(taskid)

  try:
    attempt = task.get_attempt(attemptid)
  except (KeyError, RestException) as e:
    raise PopupException(_("Cannot find attempt '%(id)s' in task") % {'id': attemptid}, e)

  return render("attempt.mako", request, {
      "attempt": attempt,
      "taskid": taskid,
      "joblnk": job_link,
      "task": task
    })

@check_job_permission
def single_task_attempt_logs(request, job, taskid, attemptid, offset=LOG_OFFSET_BYTES):
  jt = get_api(request.user, request.jt)

  job_link = jt.get_job_link(job.jobId)
  task = job_link.get_task(taskid)

  try:
    attempt = task.get_attempt(attemptid)
  except (KeyError, RestException) as e:
    raise KeyError(_("Cannot find attempt '%(id)s' in task") % {'id': attemptid}, e)

  first_log_tab = 0

  try:
    # Add a diagnostic log
    if hasattr(task, 'job') and hasattr(task.job, 'diagnostics'):
      diagnostic_log = task.job.diagnostics
    elif job_link.is_mr2:
      diagnostic_log = attempt.diagnostics
    else:
      diagnostic_log = ", ".join(task.diagnosticMap[attempt.attemptId])
    logs = [diagnostic_log]
    # Add remaining logs
    logs += [section.strip() for section in attempt.get_task_log(offset=offset)]
    log_tab = [i for i, log in enumerate(logs) if log]
    if log_tab:
      first_log_tab = log_tab[0]
  except urllib.error.URLError:
    logs = [_("Failed to retrieve log. TaskTracker not ready.")] * 4

  context = {
      "attempt": attempt,
      "taskid": taskid,
      "joblnk": job_link,
      "task": task,
      "logs": logs,
      "logs_list": attempt.get_log_list(),
      "first_log_tab": first_log_tab,
  }

  if request.GET.get('format') == 'python':
    return context
  else:
    context['logs'] = [LinkJobLogs._make_links(log) for i, log in enumerate(logs)]

  if request.GET.get('format') == 'json':
    response = {
      "logs": context['logs'],
      "logsList": context['logs_list'],
      "isRunning": job.status.lower() in ('running', 'pending', 'prep')
    }
    return JsonResponse(response)
  else:
    return render("attempt_logs.mako", request, context)

@check_job_permission
def task_attempt_counters(request, job, taskid, attemptid):
  """
  We get here from /jobs/jobid/tasks/taskid/attempts/attemptid/counters
  (phew!)
  """
  job_link = JobLinkage(request.jt, job.jobId)
  task = job_link.get_task(taskid)
  attempt = task.get_attempt(attemptid)
  counters = {}
  if attempt:
    counters = attempt.counters
  return render("counters.html", request, {'counters': counters})

@access_log_level(logging.WARN)
def kill_task_attempt(request, attemptid):
  """
  We get here from /jobs/jobid/tasks/taskid/attempts/attemptid/kill
  TODO: security
  """
  ret = request.jt.kill_task_attempt(request.jt.thriftattemptid_from_string(attemptid))
  return render_json({})

def trackers(request):
  """
  We get here from /trackers
  """
  trackers = get_tasktrackers(request)

  return render("tasktrackers.mako", request, {'trackers': trackers})

def single_tracker(request, trackerid):
  jt = get_api(request.user, request.jt)

  try:
    tracker = jt.get_tracker(trackerid)
  except Exception as e:
    raise PopupException(_('The tracker could not be contacted.'), detail=e)
  return render("tasktracker.mako", request, {'tracker': tracker})

def container(request, node_manager_http_address, containerid):
  jt = get_api(request.user, request.jt)

  try:
    tracker = jt.get_tracker(node_manager_http_address, containerid)
  except Exception as e:
    # TODO: add a redirect of some kind
    raise PopupException(_('The container disappears as soon as the job finishes.'), detail=e)
  return render("container.mako", request, {'tracker': tracker})


def clusterstatus(request):
  """
  We get here from /clusterstatus
  """
  return render("clusterstatus.html", request, Cluster(request.jt))

def queues(request):
  """
  We get here from /queues
  """
  return render("queues.html", request, {"queuelist": request.jt.queues()})

@check_job_permission
def set_job_priority(request, job):
  """
  We get here from /jobs/job/setpriority?priority=PRIORITY
  """
  priority = request.GET.get("priority")
  jid = request.jt.thriftjobid_from_string(job.jobId)
  request.jt.set_job_priority(jid, ThriftJobPriority._NAMES_TO_VALUES[priority])
  return render_json({})

CONF_VARIABLE_REGEX = r"\$\{(.+)\}"

def make_substitutions(conf):
  """
  Substitute occurences of ${foo} with conf[foo], recursively, in all the values
  of the conf dict.

  Note that the Java code may also substitute Java properties in, which
  this code does not have.
  """
  r = re.compile(CONF_VARIABLE_REGEX)
  def sub(s, depth=0):
    # Malformed / malicious confs could make this loop infinitely
    if depth > 100:
      logging.warn("Max recursion depth exceeded when substituting jobconf value: %s" % s)
      return s
    m = r.search(s)
    if m:
      for g in [g for g in m.groups() if g in conf]:
        substr = "${%s}" % g
        s = s.replace(substr, sub(conf[g], depth+1))
    return s

  for k, v in list(conf.items()):
    conf[k] = sub(v)
  return conf

##################################
## Helper functions

def get_shorter_id(hadoop_job_id):
  return "_".join(hadoop_job_id.split("_")[-2:])


def format_counter_name(s):
  """
  Makes counter/config names human readable:
  FOOBAR_BAZ -> "Foobar Baz"
  foo_barBaz -> "Foo Bar Baz"
  """
  def splitCamels(s):
    """ Convert "fooBar" to "foo bar" """
    return re.sub(r'[a-z][A-Z]',
                  lambda x: x.group(0)[0] + " " + x.group(0)[1].lower(),
                  s)

  return string.capwords(re.sub('_', ' ', splitCamels(s)).lower())


def get_state_link(request, option=None, val='', VALID_OPTIONS=("state", "user", "text", "taskstate")):
  """
    constructs the query string for the state of the current query for the jobs page.
    pass in the request, and an optional option/value pair; these are used for creating
    links to turn on the filter, while preserving the other present settings.
  """
  states = []
  val = quote_plus(val)

  assert option is None or option in VALID_OPTIONS

  states = dict()
  for o in VALID_OPTIONS:
    if o in request.GET:
      states[o] = request.GET[o]
  if option is not None:
    states[option] = val

  return "&".join(["%s=%s" % (key, quote_plus(value)) for key, value in states.items()])


## All Unused below

# DEAD?
def dock_jobs(request):
  username = request.user.username
  matching_jobs = get_job_count_by_state(request, username)
  return render("jobs_dock_info.mako", request, {
    'jobs': matching_jobs
  }, force_template=True)
register_status_bar_view(dock_jobs)


def get_tasktrackers(request):
  """
  Return a ThriftTaskTrackerStatusList object containing all task trackers
  """
  return [Tracker(tracker) for tracker in request.jt.all_task_trackers().trackers]


def get_single_job(request, jobid):
  """
  Returns the job which matches jobid.
  """
  return Job.from_id(jt=request.jt, jobid=jobid)


def get_job_count_by_state(request, username):
  """
  Returns the number of comlpeted, running, and failed jobs for a user.
  """
  res = {
    'completed': 0,
    'running': 0,
    'failed': 0,
    'killed': 0,
    'all': 0
  }

  jobcounts = request.jt.get_job_count_by_user(username)
  res['completed'] = jobcounts.nSucceeded
  res['running'] = jobcounts.nPrep + jobcounts.nRunning
  res['failed'] = jobcounts.nFailed
  res['killed'] = jobcounts.nKilled
  res['all'] = res['completed'] + res['running'] + res['failed'] + res['killed']
  return res


def jobbrowser(request):
  """
  jobbrowser.jsp - a - like.
  """
  # TODO(bc): Is this view even reachable?
  def check_job_state(state):
    return lambda job: job.status == state

  status = request.jt.cluster_status()
  alljobs = [] #get_matching_jobs(request)
  runningjobs = list(filter(check_job_state('RUNNING'), alljobs))
  completedjobs = list(filter(check_job_state('COMPLETED'), alljobs))
  failedjobs = list(filter(check_job_state('FAILED'), alljobs))
  killedjobs = list(filter(check_job_state('KILLED'), alljobs))
  jobqueues = request.jt.queues()

  return render("jobbrowser.html", request, {
      "clusterstatus": status,
      "queues": jobqueues,
      "alljobs": alljobs,
      "runningjobs": runningjobs,
      "failedjobs": failedjobs,
      "killedjobs": killedjobs,
      "completedjobs": completedjobs
  })
