# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You 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 re

class Grep:

  def __init__(self):
    pass

  def grep(self, string, phrase, before, after):
    """
    Tries to find the last occurence of phrase in a given string. String should consist of lines,
    separated by line separators. String trim is performed before search.
    If occurence is found, grep () takes not more than 'before' lines above and 'after' lines below.
    If phrase is not found, returns None. Search is not case sensitive, regexps are not supported.
    """
    stripped_string = string.strip()
    lines = stripped_string.splitlines(True)
    first_occurence = None
    for index in range(len(lines)):
      line = lines[index]
      if phrase.lower() in line.lower():
        first_occurence = index
        break
    if first_occurence is None:
      return None
    bound_a = before
    if first_occurence < before:
      bound_a = first_occurence
    result = None
    if (len(lines) - first_occurence) < after:
      result = lines[first_occurence - bound_a :]
    else:
      result = lines[first_occurence - bound_a : first_occurence + after + 1]
    return "".join(result).strip()


  def tail(self, string, n):
    """
    Copies last n lines from string to result. Also, string trim is performed.
    """
    stripped_string = string.strip()
    lines = stripped_string.splitlines(True)
    if len(lines) <= n:
      return stripped_string
    else:
      length = len(lines)
      tailed = lines[length - n:]
      return "".join(tailed)

  def filterMarkup(self, string):
    """
    Filters given string from puppet colour markup done using escape codes like [0;36m
    """
    if string is None:
      result = None
    else:
      regexp = "\x1b" + r"\[[\d;]{1,4}m"
      result = re.sub(regexp, '', string)
    return result