# ==================================================================================================================== #
#            __     ___   _ ____  _     ____                                                                           #
#  _ __  _   \ \   / / | | |  _ \| |   |  _ \ __ _ _ __ ___  ___ _ __                                                  #
# | '_ \| | | \ \ / /| |_| | | | | |   | |_) / _` | '__/ __|/ _ \ '__|                                                 #
# | |_) | |_| |\ V / |  _  | |_| | |___|  __/ (_| | |  \__ \  __/ |                                                    #
# | .__/ \__, | \_/  |_| |_|____/|_____|_|   \__,_|_|  |___/\___|_|                                                    #
# |_|    |___/                                                                                                         #
# ==================================================================================================================== #
# Authors:                                                                                                             #
#   Patrick Lehmann                                                                                                    #
#                                                                                                                      #
# License:                                                                                                             #
# ==================================================================================================================== #
# Copyright 2017-2021 Patrick Lehmann - Boetzingen, Germany                                                            #
# Copyright 2016-2017 Patrick Lehmann - Dresden, Germany                                                               #
#                                                                                                                      #
# 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.                                                                                       #
# ==================================================================================================================== #
#
from pyTooling.Decorators             import export

from pyVHDLParser.Token               import CommentToken, CharacterToken, SpaceToken, LinebreakToken, IndentationToken, SingleLineCommentToken, MultiLineCommentToken
from pyVHDLParser.Token.Keywords      import BoundaryToken, EndToken
from pyVHDLParser.Blocks              import Block, ParserState, BlockParserException, CommentBlock
from pyVHDLParser.Blocks.Generic1     import EndOfStatementBlock
from pyVHDLParser.Blocks.Common       import LinebreakBlock, WhitespaceBlock
from pyVHDLParser.Blocks.Expression   import ExpressionBlockEndedBySemicolon


@export
class EndBlock(EndOfStatementBlock):
	pass


@export
class ReturnExpressionBlock(ExpressionBlockEndedBySemicolon):
	END_BLOCK = EndBlock


@export
class ReturnBlock(Block):
	@classmethod
	def stateReturnKeyword(cls, parserState: ParserState):
		token = parserState.Token
		if isinstance(token, CharacterToken):
			if  (token == ";"):
				parserState.NewToken =    EndToken(token)
				parserState.NewBlock =    EndBlock(parserState.LastBlock, parserState.TokenMarker, endToken=parserState.NewToken.PreviousToken)
				parserState.Pop()
				return
			elif  (token == "("):
				parserState.NewToken =    BoundaryToken(token)
				parserState.NewBlock =    cls(parserState.LastBlock, parserState.TokenMarker, endToken=parserState.NewToken.PreviousToken)
				parserState.TokenMarker = parserState.NewToken
				parserState.NextState =   EndBlock.stateError
				parserState.PushState =   ReturnExpressionBlock.stateExpression
				return
		elif isinstance(token, SpaceToken):
			parserState.NewToken =    BoundaryToken(token)
			parserState.NextState =   cls.stateWhitespace1
			return
		elif isinstance(token, (LinebreakToken, CommentToken)):
			block =                   LinebreakBlock if isinstance(token, LinebreakToken) else CommentBlock
			parserState.NewBlock =    cls(parserState.LastBlock, parserState.TokenMarker, endToken=token.PreviousToken, multiPart=True)
			_ =                       block(parserState.NewBlock, token)
			parserState.TokenMarker = None
			parserState.NextState =   cls.stateWhitespace1
			return

		raise BlockParserException("Expected ';' or whitespace after keyword RETURN.", token)

	@classmethod
	def stateWhitespace1(cls, parserState: ParserState):
		token = parserState.Token
		if (isinstance(token, CharacterToken) and  (token == ";")):
			parserState.NewToken =      EndToken(token)
			parserState.NewBlock =      EndBlock(parserState.LastBlock, parserState.TokenMarker, endToken=parserState.NewToken.PreviousToken)
			parserState.Pop()
			return
		elif isinstance(token, LinebreakToken):
			if (not (isinstance(parserState.LastBlock, CommentBlock) and isinstance(parserState.LastBlock.StartToken, MultiLineCommentToken))):
				parserState.NewBlock =    cls(parserState.LastBlock, parserState.TokenMarker, endToken=token.PreviousToken, multiPart=True)
				_ =                       LinebreakBlock(parserState.NewBlock, token)
			else:
				parserState.NewBlock =    LinebreakBlock(parserState.LastBlock, token)
			parserState.TokenMarker =   None
			return
		elif isinstance(token, CommentToken):
			parserState.NewBlock =      cls(parserState.LastBlock, parserState.TokenMarker, endToken=token.PreviousToken, multiPart=True)
			_ =                         CommentBlock(parserState.NewBlock, token)
			parserState.TokenMarker =   None
			return
		elif (isinstance(token, IndentationToken) and isinstance(token.PreviousToken, (LinebreakToken, SingleLineCommentToken))):
			return
		elif (isinstance(token, SpaceToken) and (
			isinstance(parserState.LastBlock, CommentBlock) and isinstance(parserState.LastBlock.StartToken, MultiLineCommentToken))):
			parserState.NewToken =      BoundaryToken(token)
			parserState.NewBlock =      WhitespaceBlock(parserState.LastBlock, parserState.NewToken)
			parserState.TokenMarker =   None
			return
		else:
			parserState.NewBlock =      cls(parserState.LastBlock, parserState.TokenMarker, endToken=token.PreviousToken)
			parserState.NextState =     EndBlock.stateError
			parserState.PushState =     ReturnExpressionBlock.stateExpression
			parserState.TokenMarker =   parserState.Token
			parserState.NextState(parserState)
			return
