# ==================================================================================================================== #
#            __     ___   _ ____  _     ____                                                                           #
#  _ __  _   \ \   / / | | |  _ \| |   |  _ \ __ _ _ __ ___  ___ _ __                                                  #
# | '_ \| | | \ \ / /| |_| | | | | |   | |_) / _` | '__/ __|/ _ \ '__|                                                 #
# | |_) | |_| |\ 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 collections import Generator
from typing import Any

from pyVHDLParser.Blocks           import BlockParserException, CommentBlock, Block
from pyVHDLParser.Blocks.Common    import IndentationBlock, LinebreakBlock, WhitespaceBlock
# from pyVHDLParser.Blocks.Document  import CommentBlock


def StripAndFuse(generator: Generator[Block, Any, None]) -> Generator[Block, Any, None]:
	iterator =  iter(generator)
	lastBlock = next(iterator)

	# don't filter the first block
	yield lastBlock

	for block in iterator:
		if isinstance(block, (IndentationBlock, CommentBlock, LinebreakBlock)):
			continue
		else:
			if (block.MultiPart == True):
				while True:
					nextBlock = next(iterator)
					if isinstance(nextBlock, (WhitespaceBlock, CommentBlock)):
						continue
					if (type(block) is not type(nextBlock)):
						raise BlockParserException("Error in multipart blocks. {0} <-> {1}".format(type(block), type(nextBlock)), None)   # TODO: review exception type

					nextBlock.StartToken.PreviousToken = block.EndToken
					block.EndToken = nextBlock.EndToken
					if (nextBlock.MultiPart == False):
						break

			block.PreviousBlock = lastBlock
			block.StartToken.PreviousToken = lastBlock.EndToken
			yield block
			lastBlock = block

def FastForward(generator: Generator[Block, Any, None]) -> Generator[Block, Any, None]:
	iterator =  iter(generator)
	# don't filter the first block
	yield next(iterator)

	for block in iterator:
		if isinstance(block, (IndentationBlock, CommentBlock, LinebreakBlock)):
			continue
		else:
			yield block
