# Copyright (C) 2013-2020 ycmd contributors
#
# This file is part of ycmd.
#
# ycmd is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# ycmd is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with ycmd.  If not, see <http://www.gnu.org/licenses/>.

import bottle
import json
import platform
import sys
import time
import traceback
from bottle import request


from ycmd import extra_conf_store, hmac_plugin, server_state, user_options_store
from ycmd.responses import ( BuildExceptionResponse,
                             BuildCompletionResponse,
                             BuildSignatureHelpResponse,
                             BuildSignatureHelpAvailableResponse,
                             SignatureHelpAvailalability,
                             UnknownExtraConf )
from ycmd.request_wrap import RequestWrap
from ycmd.completers.completer_utils import FilterAndSortCandidatesWrap
from ycmd.utils import LOGGER, StartThread, ImportCore
ycm_core = ImportCore()


# num bytes for the request body buffer; request.json only works if the request
# size is less than this
bottle.Request.MEMFILE_MAX = 10 * 1024 * 1024

_server_state = None
_hmac_secret = bytes()
app = bottle.Bottle()
wsgi_server = None


@app.post( '/event_notification' )
def EventNotification():
  LOGGER.info( 'Received event notification' )
  request_data = RequestWrap( request.json )
  event_name = request_data[ 'event_name' ]
  LOGGER.debug( 'Event name: %s', event_name )

  event_handler = 'On' + event_name
  getattr( _server_state.GetGeneralCompleter(), event_handler )( request_data )

  filetypes = request_data[ 'filetypes' ]
  response_data = None
  if _server_state.FiletypeCompletionUsable( filetypes ):
    response_data = getattr( _server_state.GetFiletypeCompleter( filetypes ),
                             event_handler )( request_data )

  if response_data:
    return _JsonResponse( response_data )
  return _JsonResponse( {} )


@app.get( '/signature_help_available' )
def GetSignatureHelpAvailable():
  LOGGER.info( 'Received signature help available request' )
  if request.query.subserver:
    filetype = request.query.subserver
    try:
      completer = _server_state.GetFiletypeCompleter( [ filetype ] )
    except ValueError:
      return _JsonResponse( BuildSignatureHelpAvailableResponse(
        SignatureHelpAvailalability.NOT_AVAILABLE ) )
    value = completer.SignatureHelpAvailable()
    return _JsonResponse( BuildSignatureHelpAvailableResponse( value ) )
  else:
    raise RuntimeError( 'Subserver not specified' )


@app.post( '/run_completer_command' )
def RunCompleterCommand():
  LOGGER.info( 'Received command request' )
  request_data = RequestWrap( request.json )
  completer = _GetCompleterForRequestData( request_data )

  return _JsonResponse( completer.OnUserCommand(
      request_data[ 'command_arguments' ],
      request_data ) )


@app.post( '/resolve_fixit' )
def ResolveFixit():
  LOGGER.info( 'Received resolve_fixit request' )
  request_data = RequestWrap( request.json )
  completer = _GetCompleterForRequestData( request_data )

  return _JsonResponse( completer.ResolveFixit( request_data ) )


@app.post( '/completions' )
def GetCompletions():
  LOGGER.info( 'Received completion request' )
  request_data = RequestWrap( request.json )
  do_filetype_completion = _server_state.ShouldUseFiletypeCompleter(
    request_data )
  LOGGER.debug( 'Using filetype completion: %s', do_filetype_completion )

  errors = None
  completions = None

  if do_filetype_completion:
    try:
      filetype_completer = _server_state.GetFiletypeCompleter(
        request_data[ 'filetypes' ] )
      completions = filetype_completer.ComputeCandidates( request_data )
    except Exception as exception:
      if request_data[ 'force_semantic' ]:
        # user explicitly asked for semantic completion, so just pass the error
        # back
        raise

      # store the error to be returned with results from the identifier
      # completer
      LOGGER.exception( 'Exception from semantic completer (using general)' )
      stack = traceback.format_exc()
      errors = [ BuildExceptionResponse( exception, stack ) ]

  if not completions and not request_data[ 'force_semantic' ]:
    completions = _server_state.GetGeneralCompleter().ComputeCandidates(
      request_data )

  return _JsonResponse(
      BuildCompletionResponse( completions if completions else [],
                               request_data[ 'start_column' ],
                               errors = errors ) )


@app.post( '/signature_help' )
def GetSignatureHelp():
  LOGGER.info( 'Received signature help request' )
  request_data = RequestWrap( request.json )

  if not _server_state.FiletypeCompletionUsable( request_data[ 'filetypes' ],
                                                 silent = True ):
    return _JsonResponse( BuildSignatureHelpResponse( None ) )

  errors = None
  signature_info = None

  try:
    filetype_completer = _server_state.GetFiletypeCompleter(
      request_data[ 'filetypes' ] )
    signature_info = filetype_completer.ComputeSignatures( request_data )
  except Exception as exception:
    LOGGER.exception( 'Exception from semantic completer during sig help' )
    errors = [ BuildExceptionResponse( exception, traceback.format_exc() ) ]

  # No fallback for signature help. The general completer is unlikely to be able
  # to offer anything of for that here.
  return _JsonResponse(
      BuildSignatureHelpResponse( signature_info, errors = errors ) )


@app.post( '/filter_and_sort_candidates' )
def FilterAndSortCandidates():
  LOGGER.info( 'Received filter & sort request' )
  # Not using RequestWrap because no need and the requests coming in aren't like
  # the usual requests we handle.
  request_data = request.json

  return _JsonResponse( FilterAndSortCandidatesWrap(
    request_data[ 'candidates' ],
    request_data[ 'sort_property' ],
    request_data[ 'query' ],
    _server_state.user_options[ 'max_num_candidates' ] ) )


@app.get( '/healthy' )
def GetHealthy():
  LOGGER.info( 'Received health request' )
  if request.query.subserver:
    filetype = request.query.subserver
    completer = _server_state.GetFiletypeCompleter( [ filetype ] )
    return _JsonResponse( completer.ServerIsHealthy() )
  return _JsonResponse( True )


@app.get( '/ready' )
def GetReady():
  LOGGER.info( 'Received ready request' )
  if request.query.subserver:
    filetype = request.query.subserver
    completer = _server_state.GetFiletypeCompleter( [ filetype ] )
    return _JsonResponse( completer.ServerIsReady() )
  return _JsonResponse( True )


@app.post( '/semantic_completion_available' )
def FiletypeCompletionAvailable():
  LOGGER.info( 'Received filetype completion available request' )
  return _JsonResponse( _server_state.FiletypeCompletionAvailable(
      RequestWrap( request.json )[ 'filetypes' ] ) )


@app.post( '/defined_subcommands' )
def DefinedSubcommands():
  LOGGER.info( 'Received defined subcommands request' )
  completer = _GetCompleterForRequestData( RequestWrap( request.json ) )

  return _JsonResponse( completer.DefinedSubcommands() )


@app.post( '/detailed_diagnostic' )
def GetDetailedDiagnostic():
  LOGGER.info( 'Received detailed diagnostic request' )
  request_data = RequestWrap( request.json )
  completer = _GetCompleterForRequestData( request_data )

  return _JsonResponse( completer.GetDetailedDiagnostic( request_data ) )


@app.post( '/load_extra_conf_file' )
def LoadExtraConfFile():
  LOGGER.info( 'Received extra conf load request' )
  request_data = RequestWrap( request.json, validate = False )
  extra_conf_store.Load( request_data[ 'filepath' ], force = True )

  return _JsonResponse( True )


@app.post( '/ignore_extra_conf_file' )
def IgnoreExtraConfFile():
  LOGGER.info( 'Received extra conf ignore request' )
  request_data = RequestWrap( request.json, validate = False )
  extra_conf_store.Disable( request_data[ 'filepath' ] )

  return _JsonResponse( True )


@app.post( '/debug_info' )
def DebugInfo():
  LOGGER.info( 'Received debug info request' )
  request_data = RequestWrap( request.json )

  has_clang_support = ycm_core.HasClangSupport()
  clang_version = ycm_core.ClangVersion() if has_clang_support else None

  filepath = request_data[ 'filepath' ]
  try:
    extra_conf_path = extra_conf_store.ModuleFileForSourceFile( filepath )
    is_loaded = bool( extra_conf_path )
  except UnknownExtraConf as error:
    extra_conf_path = error.extra_conf_file
    is_loaded = False

  response = {
    'python': {
      'executable': sys.executable,
      'version': platform.python_version()
    },
    'clang': {
      'has_support': has_clang_support,
      'version': clang_version
    },
    'extra_conf': {
      'path': extra_conf_path,
      'is_loaded': is_loaded
    },
    'completer': None
  }

  try:
    response[ 'completer' ] = _GetCompleterForRequestData(
        request_data ).DebugInfo( request_data )
  except Exception:
    LOGGER.exception( 'Error retrieving completer debug info' )

  return _JsonResponse( response )


@app.post( '/shutdown' )
def Shutdown():
  LOGGER.info( 'Received shutdown request' )
  ServerShutdown()

  return _JsonResponse( True )


@app.post( '/receive_messages' )
def ReceiveMessages():
  # Receive messages is a "long-poll" handler.
  # The client makes the request with a long timeout (1 hour).
  # When we have data to send, we send it and close the socket.
  # The client then sends a new request.
  request_data = RequestWrap( request.json )
  try:
    completer = _GetCompleterForRequestData( request_data )
  except Exception:
    # No semantic completer for this filetype, don't requery. This is not an
    # error.
    return _JsonResponse( False )

  return _JsonResponse( completer.PollForMessages( request_data ) )


# The type of the param is Bottle.HTTPError
def ErrorHandler( httperror ):
  body = _JsonResponse( BuildExceptionResponse( httperror.exception,
                                                httperror.traceback ) )
  hmac_plugin.SetHmacHeader( body, _hmac_secret )
  return body


# For every error Bottle encounters it will use this as the default handler
app.default_error_handler = ErrorHandler


def _JsonResponse( data ):
  bottle.response.set_header( 'Content-Type', 'application/json' )
  return json.dumps( data,
                     separators = ( ',', ':' ),
                     default = _UniversalSerialize )


def _UniversalSerialize( obj ):
  try:
    serialized = obj.__dict__.copy()
    serialized[ 'TYPE' ] = type( obj ).__name__
    return serialized
  except AttributeError:
    return str( obj )


def _GetCompleterForRequestData( request_data ):
  completer_target = request_data.get( 'completer_target', None )

  if completer_target == 'identifier':
    return _server_state.GetGeneralCompleter().GetIdentifierCompleter()
  elif completer_target == 'filetype_default' or not completer_target:
    return _server_state.GetFiletypeCompleter( request_data[ 'filetypes' ] )
  else:
    return _server_state.GetFiletypeCompleter( [ completer_target ] )


def ServerShutdown():
  def Terminator():
    if wsgi_server:
      wsgi_server.Shutdown()

  # Use a separate thread to let the server send the response before shutting
  # down.
  StartThread( Terminator )


def ServerCleanup():
  if _server_state:
    _server_state.Shutdown()
    extra_conf_store.Shutdown()


def SetHmacSecret( hmac_secret ):
  global _hmac_secret
  _hmac_secret = hmac_secret


def UpdateUserOptions( options ):
  global _server_state

  if not options:
    return

  # This should never be passed in, but let's try to remove it just in case.
  options.pop( 'hmac_secret', None )
  user_options_store.SetAll( options )
  _server_state = server_state.ServerState( options )


def KeepSubserversAlive( check_interval_seconds ):
  def Keepalive( check_interval_seconds ):
    while True:
      time.sleep( check_interval_seconds )

      LOGGER.debug( 'Keeping subservers alive' )
      loaded_completers = _server_state.GetLoadedFiletypeCompleters()
      for completer in loaded_completers:
        completer.ServerIsHealthy()

  StartThread( Keepalive, check_interval_seconds )
