#!/usr/bin/env python
#
# Copyright (C) 2011, 2012  Chiel ten Brinke <ctenbrinke@gmail.com>
#                           Google Inc.
#
# This file is part of YouCompleteMe.
#
# YouCompleteMe 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.
#
# YouCompleteMe 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 YouCompleteMe.  If not, see <http://www.gnu.org/licenses/>.

from collections import defaultdict
import os
import glob
from ycm.completers.completer import Completer
from ycm.server import responses
from ycm import utils
import urllib2
import urllib
import urlparse
import json
import logging

SERVER_NOT_FOUND_MSG = ( 'OmniSharp server binary not found at {0}. ' +
'Did you compile it? You can do so by running ' +
'"./install.sh --omnisharp-completer".' )
MIN_LINES_IN_FILE_TO_PARSE = 5
INVALID_FILE_MESSAGE = 'File is invalid.'
FILE_TOO_SHORT_MESSAGE = (
  'File is less than {0} lines long; not parsing.'.format(
    MIN_LINES_IN_FILE_TO_PARSE ) )
NO_DIAGNOSTIC_MESSAGE = 'No diagnostic for current line!'


#TODO: Handle this better than dummy classes
class CsharpDiagnostic:
  def __init__ ( self, ranges, location, location_extent, text, kind ):
    self.ranges_ = ranges
    self.location_ = location
    self.location_extent_ = location_extent
    self.text_ = text
    self.kind_ = kind


class CsharpDiagnosticRange:
  def __init__ ( self, start, end ):
    self.start_ = start
    self.end_ = end


class CsharpDiagnosticLocation:
  def __init__ ( self, line, column, filename ):
    self.line_number_ = line
    self.column_number_ = column
    self.filename_ = filename


class CsharpCompleter( Completer ):
  """
  A Completer that uses the Omnisharp server as completion engine.
  """

  subcommands = {
    'StartServer': ( lambda self, request_data: self._StartServer(
        request_data ) ),
    'StopServer': ( lambda self, request_data: self._StopServer() ),
    'RestartServer': ( lambda self, request_data: self._RestartServer(
        request_data ) ),
    'ReloadSolution': ( lambda self, request_data: self._ReloadSolution() ),
    'ServerRunning': ( lambda self, request_data: self._ServerIsRunning() ),
    'ServerReady': ( lambda self, request_data: self._ServerIsReady() ),
    'GoToDefinition': ( lambda self, request_data: self._GoToDefinition(
        request_data ) ),
    'GoToDeclaration': ( lambda self, request_data: self._GoToDefinition(
        request_data ) ),
    'GoTo': ( lambda self, request_data: self._GoToDefinition( request_data ) )
  }

  def __init__( self, user_options ):
    super( CsharpCompleter, self ).__init__( user_options )
    self._omnisharp_port = None
    self._logger = logging.getLogger( __name__ )
    self._diagnostic_store = None
    self._max_diagnostics_to_display = user_options[
      'max_diagnostics_to_display' ]


  def Shutdown( self ):
    if ( self.user_options[ 'auto_stop_csharp_server' ] and
         self._ServerIsRunning() ):
      self._StopServer()


  def SupportedFiletypes( self ):
    """ Just csharp """
    return [ 'cs' ]


  def ComputeCandidatesInner( self, request_data ):
    return [ responses.BuildCompletionData(
                completion[ 'CompletionText' ],
                completion[ 'DisplayText' ],
                completion[ 'Description' ] )
             for completion in self._GetCompletions( request_data ) ]


  def DefinedSubcommands( self ):
    return CsharpCompleter.subcommands.keys()


  def OnFileReadyToParse( self, request_data ):
    if ( not self._omnisharp_port and
         self.user_options[ 'auto_start_csharp_server' ] ):
      self._StartServer( request_data )
      return

    filename = request_data[ 'filepath' ]
    contents = request_data[ 'file_data' ][ filename ][ 'contents' ]
    if contents.count( '\n' ) < MIN_LINES_IN_FILE_TO_PARSE:
      raise ValueError( FILE_TOO_SHORT_MESSAGE )

    if not filename:
      raise ValueError( INVALID_FILE_MESSAGE )

    syntax_errors = self._GetResponse( '/syntaxerrors',
                                     self._DefaultParameters( request_data ) )

    diagnostics = [ self._SyntaxErrorToDiagnostic( x ) for x in
                    syntax_errors[ "Errors" ] ]

    self._diagnostic_store = DiagnosticsToDiagStructure( diagnostics )

    return [ responses.BuildDiagnosticData( x ) for x in
             diagnostics[ : self._max_diagnostics_to_display ] ]


  def _SyntaxErrorToDiagnostic( self, syntax_error ):
    filename = syntax_error[ "FileName" ]

    location = CsharpDiagnosticLocation( syntax_error[ "Line" ],
                                         syntax_error[ "Column" ], filename )
    location_range = CsharpDiagnosticRange( location, location )
    return CsharpDiagnostic( list(),
                             location,
                             location_range,
                             syntax_error[ "Message" ],
                             "E" )


  def GetDetailedDiagnostic( self, request_data ):
    current_line = request_data[ 'line_num' ] + 1
    current_column = request_data[ 'column_num' ] + 1
    current_file = request_data[ 'filepath' ]

    if not self._diagnostic_store:
      raise ValueError( NO_DIAGNOSTIC_MESSAGE )

    diagnostics = self._diagnostic_store[ current_file ][ current_line ]
    if not diagnostics:
      raise ValueError( NO_DIAGNOSTIC_MESSAGE )

    closest_diagnostic = None
    distance_to_closest_diagnostic = 999

    for diagnostic in diagnostics:
      distance = abs( current_column - diagnostic.location_.column_number_ )
      if distance < distance_to_closest_diagnostic:
        distance_to_closest_diagnostic = distance
        closest_diagnostic = diagnostic

    return responses.BuildDisplayMessageResponse(
      closest_diagnostic.text_ )


  def OnUserCommand( self, arguments, request_data ):
    if not arguments:
      raise ValueError( self.UserCommandsHelpMessage() )

    command = arguments[ 0 ]
    if command in CsharpCompleter.subcommands:
      command_lamba = CsharpCompleter.subcommands[ command ]
      return command_lamba( self, request_data )
    else:
      raise ValueError( self.UserCommandsHelpMessage() )


  def DebugInfo( self ):
    if self._ServerIsRunning():
      return 'Server running at: {0}\nLogfiles:\n{1}\n{2}'.format(
        self._ServerLocation(), self._filename_stdout, self._filename_stderr )
    else:
      return 'Server is not running'


  def _StartServer( self, request_data ):
    """ Start the OmniSharp server """
    self._logger.info( 'startup' )

    self._omnisharp_port = utils.GetUnusedLocalhostPort()
    solution_files, folder = _FindSolutionFiles( request_data[ 'filepath' ] )

    if len( solution_files ) == 0:
      raise RuntimeError(
        'Error starting OmniSharp server: no solutionfile found' )
    elif len( solution_files ) == 1:
      solutionfile = solution_files[ 0 ]
    else:
      # multiple solutions found : if there is one whose name is the same
      # as the folder containing the file we edit, use this one
      # (e.g. if we have bla/Project.sln and we are editing
      # bla/Project/Folder/File.cs, use bla/Project.sln)
      filepath_components = _PathComponents( request_data[ 'filepath' ] )
      solutionpath = _PathComponents( folder )
      foldername = ''
      if len( filepath_components ) > len( solutionpath ):
          foldername = filepath_components[ len( solutionpath ) ]
      solution_file_candidates = [ sfile for sfile in solution_files
        if _GetFilenameWithoutExtension( sfile ) == foldername ]
      if len( solution_file_candidates ) == 1:
        solutionfile = solution_file_candidates[ 0 ]
      else:
        raise RuntimeError(
          'Found multiple solution files instead of one!\n{0}'.format(
            solution_files ) )

    omnisharp = os.path.join(
      os.path.abspath( os.path.dirname( __file__ ) ),
      'OmniSharpServer/OmniSharp/bin/Debug/OmniSharp.exe' )

    if not os.path.isfile( omnisharp ):
      raise RuntimeError( SERVER_NOT_FOUND_MSG.format( omnisharp ) )

    path_to_solutionfile = os.path.join( folder, solutionfile )
    # we need to pass the command to Popen as a string since we're passing
    # shell=True (as recommended by Python's doc)
    command = ( omnisharp + ' -p ' + str( self._omnisharp_port ) + ' -s ' +
                path_to_solutionfile )

    if not utils.OnWindows() and not utils.OnCygwin():
      command = 'mono ' + command

    if utils.OnCygwin():
      command = command + ' --client-path-mode Cygwin'

    filename_format = os.path.join( utils.PathToTempDir(),
                                   'omnisharp_{port}_{sln}_{std}.log' )

    self._filename_stdout = filename_format.format(
        port=self._omnisharp_port, sln=solutionfile, std='stdout' )
    self._filename_stderr = filename_format.format(
        port=self._omnisharp_port, sln=solutionfile, std='stderr' )

    with open( self._filename_stderr, 'w' ) as fstderr:
      with open( self._filename_stdout, 'w' ) as fstdout:
        # shell=True is needed for Windows so OmniSharp does not spawn
        # in a new visible window
        utils.SafePopen( command, stdout=fstdout, stderr=fstderr, shell=True )

    self._logger.info( 'Starting OmniSharp server' )


  def _StopServer( self ):
    """ Stop the OmniSharp server """
    self._GetResponse( '/stopserver' )
    self._omnisharp_port = None
    self._logger.info( 'Stopping OmniSharp server' )


  def _RestartServer ( self, request_data ):
    """ Restarts the OmniSharp server """
    if self._ServerIsRunning():
      self._StopServer()
    return self._StartServer( request_data )


  def _ReloadSolution( self ):
    """ Reloads the solutions in the OmniSharp server """
    self._logger.info( 'Reloading Solution in OmniSharp server' )
    return self._GetResponse( '/reloadsolution' )


  def _GetCompletions( self, request_data ):
    """ Ask server for completions """
    completions = self._GetResponse( '/autocomplete',
                                     self._DefaultParameters( request_data ) )
    return completions if completions != None else []


  def _GoToDefinition( self, request_data ):
    """ Jump to definition of identifier under cursor """
    definition = self._GetResponse( '/gotodefinition',
                                    self._DefaultParameters( request_data ) )
    if definition[ 'FileName' ] != None:
      return responses.BuildGoToResponse( definition[ 'FileName' ],
                                          definition[ 'Line' ] - 1,
                                          definition[ 'Column' ] - 1 )
    else:
      raise RuntimeError( 'Can\'t jump to definition' )


  def _DefaultParameters( self, request_data ):
    """ Some very common request parameters """
    parameters = {}
    parameters[ 'line' ] = request_data[ 'line_num' ] + 1
    parameters[ 'column' ] = request_data[ 'column_num' ] + 1
    filepath = request_data[ 'filepath' ]
    parameters[ 'buffer' ] = request_data[ 'file_data' ][ filepath ][
      'contents' ]
    parameters[ 'filename' ] = filepath
    return parameters


  def _ServerIsRunning( self ):
    """ Check if our OmniSharp server is running """
    try:
      return bool( self._omnisharp_port and
                  self._GetResponse( '/checkalivestatus', silent = True ) )
    except:
      return False


  def _ServerIsReady( self ):
    """ Check if our OmniSharp server is ready """
    try:
      return bool( self._omnisharp_port and
                   self._GetResponse( '/checkreadystatus', silent = True ) )
    except:
      return False


  def _ServerLocation( self ):
    return 'http://localhost:' + str( self._omnisharp_port )


  def _GetResponse( self, handler, parameters = {}, silent = False ):
    """ Handle communication with server """
    # TODO: Replace usage of urllib with Requests
    target = urlparse.urljoin( self._ServerLocation(), handler )
    parameters = urllib.urlencode( parameters )
    response = urllib2.urlopen( target, parameters )
    return json.loads( response.read() )


def _FindSolutionFiles( filepath ):
  """ Find solution files by searching upwards in the file tree """
  folder = os.path.dirname( filepath )
  solutionfiles = glob.glob1( folder, '*.sln' )
  while not solutionfiles:
    lastfolder = folder
    folder = os.path.dirname( folder )
    if folder == lastfolder:
      break
    solutionfiles = glob.glob1( folder, '*.sln' )
  return solutionfiles, folder


def _PathComponents( path ):
  path_components = []
  while True:
    path, folder = os.path.split( path )
    if folder:
      path_components.append( folder )
    else:
      if path:
        path_components.append( path )
      break
  path_components.reverse()
  return path_components


def _GetFilenameWithoutExtension( path ):
    return os.path.splitext( os.path.basename ( path ) )[ 0 ]


def DiagnosticsToDiagStructure( diagnostics ):
  structure = defaultdict( lambda : defaultdict( list ) )
  for diagnostic in diagnostics:
    structure[ diagnostic.location_.filename_ ][
      diagnostic.location_.line_number_ ].append( diagnostic )
  return structure