"""Copyright 2008 Orbitz WorldWide

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 csv
import math
import pytz
import six.moves.http_client

from datetime import datetime
from time import time
from random import shuffle
from six.moves.urllib.parse import urlencode, urlsplit, urlunsplit, parse_qs

from graphite.compat import HttpResponse
from graphite.errors import InputParameterError
from graphite.user_util import getProfileByUsername
from graphite.util import json, unpickle, pickle, msgpack, BytesIO
from graphite.storage import extractForwardHeaders
from graphite.logger import log
from graphite.render.evaluator import evaluateTarget
from graphite.render.attime import parseATTime
from graphite.functions import loadFunctions, PieFunction
from graphite.render.hashing import hashRequest, hashData
from graphite.render.glyph import GraphTypes
from graphite.tags.models import Series, Tag, TagValue, SeriesTag  # noqa # pylint: disable=unused-import

from django.http import HttpResponseServerError, HttpResponseRedirect, HttpResponseBadRequest
from django.template import Context, loader
from django.core.cache import cache
from django.core.exceptions import ObjectDoesNotExist
from django.conf import settings
from django.utils.cache import add_never_cache_headers, patch_response_headers
from six.moves import zip


loadFunctions()


def handleInputParameterError(f):
    def new_f(*args, **kwargs):
      try:
        return f(*args, **kwargs)
      except InputParameterError as e:
        return HttpResponseBadRequest('Bad Request: {err}'.format(err=e))

    return new_f


@handleInputParameterError
def renderView(request):
  start = time()
  (graphOptions, requestOptions) = parseOptions(request)
  useCache = 'noCache' not in requestOptions
  cacheTimeout = requestOptions['cacheTimeout']
  # TODO: Make that a namedtuple or a class.
  requestContext = {
    'startTime' : requestOptions['startTime'],
    'endTime' : requestOptions['endTime'],
    'now': requestOptions['now'],
    'localOnly' : requestOptions['localOnly'],
    'template' : requestOptions['template'],
    'tzinfo' : requestOptions['tzinfo'],
    'forwardHeaders': requestOptions['forwardHeaders'],
    'data' : [],
    'prefetched' : {},
    'xFilesFactor' : requestOptions['xFilesFactor'],
    'maxDataPoints' : requestOptions.get('maxDataPoints', None),
  }
  data = requestContext['data']

  response = None

  # First we check the request cache
  if useCache:
    requestKey = hashRequest(request)
    response = cache.get(requestKey)
    if response:
      log.cache('Request-Cache hit [%s]' % requestKey)
      log.rendering('Returned cached response in %.6f' % (time() - start))
      return response

    log.cache('Request-Cache miss [%s]' % requestKey)

  # Now we prepare the requested data
  if requestOptions['graphType'] == 'pie':
    for target in requestOptions['targets']:
      if target.find(':') >= 0:
        try:
          name, value = target.split(':', 1)
          value = float(value)
        except ValueError:
          raise ValueError("Invalid target '%s'" % target)
        data.append((name, value))
      else:
        seriesList = evaluateTarget(requestContext, target)

        for series in seriesList:
          func = PieFunction(requestOptions['pieMode'])
          data.append( (series.name, func(requestContext, series) or 0 ))

  elif requestOptions['graphType'] == 'line':
    # Let's see if at least our data is cached
    cachedData = None
    if useCache:
      targets = requestOptions['targets']
      startTime = requestOptions['startTime']
      endTime = requestOptions['endTime']
      dataKey = hashData(targets, startTime, endTime, requestOptions['xFilesFactor'])
      cachedData = cache.get(dataKey)
      if cachedData:
        log.cache("Data-Cache hit [%s]" % dataKey)
      else:
        log.cache("Data-Cache miss [%s]" % dataKey)

    if cachedData is not None:
      requestContext['data'] = data = cachedData
    else: # Have to actually retrieve the data now
      targets = requestOptions['targets']

      data.extend(evaluateTarget(requestContext, targets))

      if useCache:
        cache.add(dataKey, data, cacheTimeout)

    renderStart = time()

    format = requestOptions.get('format')
    if format == 'csv':
      response = renderViewCsv(requestOptions, data)
    elif format == 'json':
      response = renderViewJson(requestOptions, data)
    elif format == 'dygraph':
      response = renderViewDygraph(requestOptions, data)
    elif format == 'rickshaw':
      response = renderViewRickshaw(requestOptions, data)
    elif format == 'raw':
      response = renderViewRaw(requestOptions, data)
    elif format == 'pickle':
      response = renderViewPickle(requestOptions, data)
    elif format == 'msgpack':
      response = renderViewMsgPack(requestOptions, data)

  # if response wasn't generated above, render a graph image
  if not response:
    format = 'image'
    renderStart = time()
    response = renderViewGraph(graphOptions, requestOptions, data)

  if useCache:
    cache.add(requestKey, response, cacheTimeout)
    patch_response_headers(response, cache_timeout=cacheTimeout)
  else:
    add_never_cache_headers(response)

  log.rendering('%s rendering time %6f' % (format, time() - renderStart))
  log.rendering('Total request processing time %6f' % (time() - start))

  return response


def renderViewGraph(graphOptions, requestOptions, data):
  # We've got the data, now to render it
  graphOptions['data'] = data
  if settings.REMOTE_RENDERING: # Rendering on other machines is faster in some situations
    image = delegateRendering(requestOptions['graphType'], graphOptions, requestOptions['forwardHeaders'])
  else:
    image = doImageRender(requestOptions['graphClass'], graphOptions)

  if graphOptions['outputFormat'] == 'pdf':
    return buildResponse(image, 'application/x-pdf')

  if graphOptions['outputFormat'] == 'svg':
    if 'jsonp' in requestOptions:
      return HttpResponse(
        content="%s(%s)" % (requestOptions['jsonp'], json.dumps(image)),
        content_type='text/javascript')

    return buildResponse(image, 'image/svg+xml')

  return buildResponse(image, 'image/png')


def renderViewCsv(requestOptions, data):
  response = HttpResponse(content_type='text/csv')
  writer = csv.writer(response, dialect='excel')

  for series in data:
    for i, value in enumerate(series):
      timestamp = datetime.fromtimestamp(series.start + (i * series.step), requestOptions['tzinfo'])
      writer.writerow((series.name, timestamp.strftime("%Y-%m-%d %H:%M:%S"), value))

  return response


def renderViewJson(requestOptions, data):
  series_data = []

  if any(data):
    startTime = min([series.start for series in data])
    endTime = max([series.end for series in data])
    timeRange = endTime - startTime

    for series in data:
      if 'maxDataPoints' in requestOptions:
        maxDataPoints = requestOptions['maxDataPoints']
        if maxDataPoints == 1:
          series.consolidate(len(series))
        else:
          numberOfDataPoints = timeRange/series.step
          if maxDataPoints < numberOfDataPoints:
            valuesPerPoint = math.ceil(float(numberOfDataPoints) / float(maxDataPoints))
            secondsPerPoint = int(valuesPerPoint * series.step)
            # Nudge start over a little bit so that the consolidation bands align with each call
            # removing 'jitter' seen when refreshing.
            nudge = secondsPerPoint + (series.start % series.step) - (series.start % secondsPerPoint)
            series.start = series.start + nudge
            valuesToLose = int(nudge/series.step)
            for r in range(1, valuesToLose):
              del series[0]
            series.consolidate(valuesPerPoint)

      datapoints = series.datapoints()

      if 'noNullPoints' in requestOptions:
        datapoints = [
          point for point in datapoints
          if point[0] is not None and not math.isnan(point[0])
        ]
        if not datapoints:
          continue

      series_data.append(dict(target=series.name, tags=series.tags, datapoints=datapoints))

  output = json.dumps(series_data, indent=(2 if requestOptions.get('pretty') else None)).replace('None,', 'null,').replace('NaN,', 'null,').replace('Infinity,', '1e9999,')

  if 'jsonp' in requestOptions:
    response = HttpResponse(
      content="%s(%s)" % (requestOptions['jsonp'], output),
      content_type='text/javascript')
  else:
    response = HttpResponse(
      content=output,
      content_type='application/json')

  return response


def renderViewDygraph(requestOptions, data):
  labels = ['Time']
  output = '{}'
  if data:
    datapoints = [[ts] for ts in range(data[0].start, data[0].end, data[0].step)]
    for series in data:
      labels.append(series.name)
      for i, point in enumerate(series):
        if point is None:
          point = 'null'
        elif point == float('inf'):
          point = 'Infinity'
        elif point == float('-inf'):
          point = '-Infinity'
        elif math.isnan(point):
          point = 'null'
        datapoints[i].append(point)
    line_template = '[%%s000%s]' % ''.join([', %s'] * len(data))
    lines = [line_template % tuple(points) for points in datapoints]
    output = '{"labels" : %s, "data" : [%s]}' % (json.dumps(labels), ', '.join(lines))

  if 'jsonp' in requestOptions:
    response = HttpResponse(
      content="%s(%s)" % (requestOptions['jsonp'], output),
      content_type='text/javascript')
  else:
    response = HttpResponse(
      content=output,
      content_type='application/json')

  return response


def renderViewRickshaw(requestOptions, data):
  series_data = []
  for series in data:
    timestamps = range(series.start, series.end, series.step)
    datapoints = [{'x' : x, 'y' : y} for x, y in zip(timestamps, series)]
    series_data.append( dict(target=series.name, datapoints=datapoints) )

  output = json.dumps(series_data, indent=(2 if requestOptions.get('pretty') else None))

  if 'jsonp' in requestOptions:
    response = HttpResponse(
      content="%s(%s)" % (requestOptions['jsonp'], output),
      content_type='text/javascript')
  else:
    response = HttpResponse(
      content=output,
      content_type='application/json')

  return response


def renderViewRaw(requestOptions, data):
  response = HttpResponse(content_type='text/plain')

  for series in data:
    response.write( "%s,%d,%d,%d|" % (series.name, series.start, series.end, series.step) )
    response.write( ','.join(map(repr,series)) )
    response.write('\n')

  return response


def renderViewPickle(requestOptions, data):
  response = HttpResponse(content_type='application/pickle')
  seriesInfo = [series.getInfo() for series in data]
  pickle.dump(seriesInfo, response, protocol=-1)
  return response


def renderViewMsgPack(requestOptions, data):
  response = HttpResponse(content_type='application/x-msgpack')
  seriesInfo = [series.getInfo() for series in data]
  msgpack.dump(seriesInfo, response, use_bin_type=True)
  return response


def parseOptions(request):
  queryParams = request.GET.copy()
  queryParams.update(request.POST)

  # Start with some defaults
  graphOptions = {'width' : 330, 'height' : 250}
  requestOptions = {}

  graphType = queryParams.get('graphType','line')
  if graphType not in GraphTypes:
    raise AssertionError("Invalid graphType '%s', must be one of %s"
                         % (graphType,list(GraphTypes)))
  graphClass = GraphTypes[graphType]

  # Fill in the requestOptions
  requestOptions['graphType'] = graphType
  requestOptions['graphClass'] = graphClass
  requestOptions['pieMode'] = queryParams.get('pieMode', 'average')
  cacheTimeout = int( queryParams.get('cacheTimeout', settings.DEFAULT_CACHE_DURATION) )
  requestOptions['targets'] = []
  requestOptions['forwardHeaders'] = extractForwardHeaders(request)

  # Extract the targets out of the queryParams
  mytargets = []
  # Normal format: ?target=path.1&target=path.2
  if len(queryParams.getlist('target')) > 0:
    mytargets = queryParams.getlist('target')

  # Rails/PHP/jQuery common practice format: ?target[]=path.1&target[]=path.2
  elif len(queryParams.getlist('target[]')) > 0:
    mytargets = queryParams.getlist('target[]')

  # Collect the targets
  for target in mytargets:
    requestOptions['targets'].append(target)

  template = dict()
  for key, val in queryParams.items():
    if key.startswith("template["):
      template[key[9:-1]] = val
  requestOptions['template'] = template

  if 'pickle' in queryParams:
    requestOptions['format'] = 'pickle'
  if 'rawData' in queryParams:
    requestOptions['format'] = 'raw'
  if 'format' in queryParams:
    requestOptions['format'] = queryParams['format']
    if 'jsonp' in queryParams:
      requestOptions['jsonp'] = queryParams['jsonp']

  requestOptions['pretty'] = bool(queryParams.get('pretty'))

  if 'noCache' in queryParams:
    requestOptions['noCache'] = True
  if 'maxDataPoints' in queryParams and queryParams['maxDataPoints'].isdigit():
    requestOptions['maxDataPoints'] = int(queryParams['maxDataPoints'])
  if 'noNullPoints' in queryParams:
    requestOptions['noNullPoints'] = True

  requestOptions['localOnly'] = queryParams.get('local') == '1'

  # Fill in the graphOptions
  format = requestOptions.get('format')
  if format == 'svg':
    graphOptions['outputFormat'] = 'svg'
  elif format == 'pdf':
    graphOptions['outputFormat'] = 'pdf'
  else:
    graphOptions['outputFormat'] = 'png'

  for opt in graphClass.customizable:
    if opt in queryParams:
      val = queryParams[opt]
      if (val.isdigit() or (val.startswith('-') and val[1:].isdigit())) and 'color' not in opt.lower():
        val = int(val)
      elif '.' in val and (val.replace('.','',1).isdigit() or (val.startswith('-') and val[1:].replace('.','',1).isdigit())):
        val = float(val)
      elif val.lower() in ('true','false'):
        val = val.lower() == 'true'
      elif val.lower() == 'default' or val == '':
        continue
      graphOptions[opt] = val

  tzinfo = pytz.timezone(settings.TIME_ZONE)
  if 'tz' in queryParams:
    try:
      tzinfo = pytz.timezone(queryParams['tz'])
    except pytz.UnknownTimeZoneError:
      pass
  requestOptions['tzinfo'] = tzinfo

  # Get the time interval for time-oriented graph types
  if graphType == 'line' or graphType == 'pie':
    if 'now' in queryParams:
        now = parseATTime(queryParams['now'], tzinfo)
    else:
        now = datetime.now(tzinfo)

    if 'until' in queryParams:
      untilTime = parseATTime(queryParams['until'], tzinfo, now)
    else:
      untilTime = now
    if 'from' in queryParams:
      fromTime = parseATTime(queryParams['from'], tzinfo, now)
    else:
      fromTime = parseATTime('-1d', tzinfo, now)

    startTime = min(fromTime, untilTime)
    endTime = max(fromTime, untilTime)
    assert startTime != endTime, "Invalid empty time range"

    requestOptions['startTime'] = startTime
    requestOptions['endTime'] = endTime
    timeRange = endTime - startTime
    queryTime = timeRange.days * 86400 + timeRange.seconds # convert the time delta to seconds
    if settings.DEFAULT_CACHE_POLICY and not queryParams.get('cacheTimeout'):
      timeouts = [timeout for period,timeout in settings.DEFAULT_CACHE_POLICY if period <= queryTime]
      cacheTimeout = max(timeouts or (0,))
    requestOptions['now'] = now

  if cacheTimeout == 0:
    requestOptions['noCache'] = True
  requestOptions['cacheTimeout'] = cacheTimeout

  requestOptions['xFilesFactor'] = float( queryParams.get('xFilesFactor', settings.DEFAULT_XFILES_FACTOR) )

  return (graphOptions, requestOptions)


connectionPools = {}


def connector_class_selector(https_support=False):
    return six.moves.http_client.HTTPSConnection if https_support else six.moves.http_client.HTTPConnection


def delegateRendering(graphType, graphOptions, headers=None):
  if headers is None:
    headers = {}
  start = time()
  postData = graphType + '\n' + pickle.dumps(graphOptions)
  servers = settings.RENDERING_HOSTS[:] #make a copy so we can shuffle it safely
  shuffle(servers)
  connector_class = connector_class_selector(settings.INTRACLUSTER_HTTPS)
  for server in servers:
    start2 = time()
    try:
      # Get a connection
      try:
        pool = connectionPools[server]
      except KeyError: #happens the first time
        pool = connectionPools[server] = set()
      try:
        connection = pool.pop()
      except KeyError: #No available connections, have to make a new one
        connection = connector_class(server)
        connection.timeout = settings.REMOTE_RENDER_CONNECT_TIMEOUT
      # Send the request
      try:
        connection.request('POST','/render/local/', postData, headers)
      except six.moves.http_client.CannotSendRequest:
        connection = connector_class(server) #retry once
        connection.timeout = settings.REMOTE_RENDER_CONNECT_TIMEOUT
        connection.request('POST', '/render/local/', postData, headers)
      # Read the response
      try: # Python 2.7+, use buffering of HTTP responses
        response = connection.getresponse(buffering=True)
      except TypeError:  # Python 2.6 and older
        response = connection.getresponse()
      assert response.status == 200, "Bad response code %d from %s" % (response.status,server)
      contentType = response.getheader('Content-Type')
      imageData = response.read()
      assert contentType == 'image/png', "Bad content type: \"%s\" from %s" % (contentType,server)
      assert imageData, "Received empty response from %s" % server
      # Wrap things up
      log.rendering('Remotely rendered image on %s in %.6f seconds' % (server,time() - start2))
      log.rendering('Spent a total of %.6f seconds doing remote rendering work' % (time() - start))
      pool.add(connection)
      return imageData
    except Exception:
      log.exception("Exception while attempting remote rendering request on %s" % server)
      log.rendering('Exception while remotely rendering on %s wasted %.6f' % (server,time() - start2))
      continue


def renderLocalView(request):
  try:
    start = time()
    reqParams = BytesIO(request.body)
    graphType = reqParams.readline().strip()
    optionsPickle = reqParams.read()
    reqParams.close()
    graphClass = GraphTypes[graphType]
    options = unpickle.loads(optionsPickle)
    image = doImageRender(graphClass, options)
    log.rendering("Delegated rendering request took %.6f seconds" % (time() -  start))
    response = buildResponse(image)
    add_never_cache_headers(response)
    return response
  except Exception:
    log.exception("Exception in graphite.render.views.rawrender")
    return HttpResponseServerError()


def renderMyGraphView(request,username,graphName):
  profile = getProfileByUsername(username)
  if not profile:
    return errorPage("No such user '%s'" % username)
  try:
    graph = profile.mygraph_set.get(name=graphName)
  except ObjectDoesNotExist:
    return errorPage("User %s doesn't have a MyGraph named '%s'" % (username,graphName))

  request_params = request.GET.copy()
  request_params.update(request.POST)
  if request_params:
    url_parts = urlsplit(graph.url)
    query_string = url_parts[3]
    if query_string:
      url_params = parse_qs(query_string)
      # Remove lists so that we can do an update() on the dict
      for param, value in url_params.items():
        if isinstance(value, list) and param != 'target':
          url_params[param] = value[-1]
      url_params.update(request_params)
      # Handle 'target' being a list - we want duplicate &target params out of it
      url_param_pairs = []
      for key,val in url_params.items():
        if isinstance(val, list):
          for v in val:
            url_param_pairs.append( (key,v) )
        else:
          url_param_pairs.append( (key,val) )

      query_string = urlencode(url_param_pairs)
    url = urlunsplit(url_parts[:3] + (query_string,) + url_parts[4:])
  else:
    url = graph.url
  return HttpResponseRedirect(url)


def doImageRender(graphClass, graphOptions):
  pngData = BytesIO()
  t = time()
  img = graphClass(**graphOptions)
  img.output(pngData)
  log.rendering('Rendered PNG in %.6f seconds' % (time() - t))
  imageData = pngData.getvalue()
  pngData.close()
  return imageData


def buildResponse(imageData, content_type="image/png"):
  return HttpResponse(imageData, content_type=content_type)


def errorPage(message):
  template = loader.get_template('500.html')
  context = Context(dict(message=message))
  return HttpResponseServerError( template.render(context) )
