# -*- coding: utf-8 -*- #

# Copyright 2015 Google Inc. All Rights Reserved.
#
# 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.

r"""A module for console attributes, special characters and functions.

The target architectures {linux, macos, windows} support inline encoding for
all attributes except color. Windows requires win32 calls to manipulate the
console color state.

Usage:

  # Get the console attribute state.
  out = log.out
  con = console_attr.GetConsoleAttr(out=out)

  # Get the ISO 8879:1986//ENTITIES Box and Line Drawing characters.
  box = con.GetBoxLineCharacters()
  # Print an X inside a box.
  out.write(box.dr)
  out.write(box.h)
  out.write(box.dl)
  out.write('\n')
  out.write(box.v)
  out.write('X')
  out.write(box.v)
  out.write('\n')
  out.write(box.ur)
  out.write(box.h)
  out.write(box.ul)
  out.write('\n')

  # Print the bullet characters.
  for c in con.GetBullets():
    out.write(c)
  out.write('\n')

  # Print FAIL in red.
  out.write('Epic ')
  con.Colorize('FAIL', 'red')
  out.write(', my first.')

  # Print italic and bold text.
  bold = con.GetFontCode(bold=True)
  italic = con.GetFontCode(italic=True)
  normal = con.GetFontCode()
  out.write('This is {bold}bold{normal}, this is {italic}italic{normal},'
            ' and this is normal.\n'.format(bold=bold, italic=italic,
                                            normal=normal))

  # Read one character from stdin with echo disabled.
  c = con.GetRawKey()
  if c is None:
    print 'EOF\n'

  # Return the display width of a string that may contain FontCode() chars.
  display_width = con.DisplayWidth(string)

  # Reset the memoized state.
  con = console_attr.ResetConsoleAttr()

  # Print the console width and height in characters.
  width, height = con.GetTermSize()
  print 'width={width}, height={height}'.format(width=width, height=height)

  # Colorize table data cells.
  fail = console_attr.Colorizer('FAIL', 'red')
  pass = console_attr.Colorizer('PASS', 'green')
  cells = ['label', fail, 'more text', pass, 'end']
  for cell in cells;
    if isinstance(cell, console_attr.Colorizer):
      cell.Render()
    else:
      out.write(cell)
"""


from __future__ import absolute_import
from __future__ import division
from __future__ import unicode_literals

import os
import sys
import unicodedata

from googlecloudsdk.core.console import console_attr_os
from googlecloudsdk.core.util import encoding as encoding_util

import six


class BoxLineCharacters(object):
  """Box/line drawing characters.

  The element names are from ISO 8879:1986//ENTITIES Box and Line Drawing//EN:
    http://www.w3.org/2003/entities/iso8879doc/isobox.html
  """


class BoxLineCharactersUnicode(BoxLineCharacters):
  """unicode Box/line drawing characters (cp437 compatible unicode)."""
  dl = '┐'
  dr = '┌'
  h = '─'
  hd = '┬'
  hu = '┴'
  ul = '┘'
  ur = '└'
  v = '│'
  vh = '┼'
  vl = '┤'
  vr = '├'
  d_dl = '╗'
  d_dr = '╔'
  d_h = '═'
  d_hd = '╦'
  d_hu = '╩'
  d_ul = '╝'
  d_ur = '╚'
  d_v = '║'
  d_vh = '╬'
  d_vl = '╣'
  d_vr = '╠'


class BoxLineCharactersAscii(BoxLineCharacters):
  """ASCII Box/line drawing characters."""
  dl = '+'
  dr = '+'
  h = '-'
  hd = '+'
  hu = '+'
  ul = '+'
  ur = '+'
  v = '|'
  vh = '+'
  vl = '+'
  vr = '+'
  d_dl = '#'
  d_dr = '#'
  d_h = '='
  d_hd = '#'
  d_hu = '#'
  d_ul = '#'
  d_ur = '#'
  d_v = '#'
  d_vh = '#'
  d_vl = '#'
  d_vr = '#'


class ConsoleAttr(object):
  """Console attribute and special drawing characters and functions accessor.

  Use GetConsoleAttr() to get a global ConsoleAttr object shared by all callers.
  Use ConsoleAttr() for abstracting multiple consoles.

  If _out is not associated with a console, or if the console properties cannot
  be determined, the default behavior is ASCII art with no attributes.

  Attributes:
    _ANSI_COLOR: The ANSI color control sequence dict.
    _ANSI_COLOR_RESET: The ANSI color reset control sequence string.
    _csi: The ANSI Control Sequence indicator string, '' if not supported.
    _encoding: The character encoding.
        ascii: ASCII art. This is the default.
        utf8: UTF-8 unicode.
        win: Windows code page 437.
    _font_bold: The ANSI bold font embellishment code string.
    _font_italic: The ANSI italic font embellishment code string.
    _get_raw_key: A function that reads one keypress from stdin with no echo.
    _out: The console output file stream.
    _term: TERM environment variable value.
    _term_size: The terminal (x, y) dimensions in characters.
  """

  _CONSOLE_ATTR_STATE = None

  _ANSI_COLOR = {
      'red': '31;1m',
      'yellow': '33;1m',
      'green': '32m',
      'blue': '34;1m'
      }
  _ANSI_COLOR_RESET = '39;0m'

  _BULLETS_UNICODE = ('▪', '◆', '▸', '▫', '◇', '▹')
  _BULLETS_WINDOWS = ('■', '≡', '∞', 'Φ', '·')  # cp437 compatible unicode
  _BULLETS_ASCII = ('o', '*', '+', '-')

  def __init__(self, encoding=None):
    """Constructor.

    Args:
      encoding: Encoding override.
        ascii -- ASCII art. This is the default.
        utf8 -- UTF-8 unicode.
        win -- Windows code page 437.
    """
    # Normalize the encoding name.
    if not encoding:
      encoding = self._GetConsoleEncoding()
    elif encoding == 'win':
      encoding = 'cp437'
    self._encoding = encoding or 'ascii'
    self._term = os.getenv('TERM', '').lower()

    # ANSI "standard" attributes.
    if self._encoding != 'ascii' and ('screen' in self._term or
                                      'xterm' in self._term):
      # Select Graphic Rendition paramaters from
      # http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
      # Italic '3' would be nice here but its not widely supported.
      self._csi = '\x1b['
      self._font_bold = '1'
      self._font_italic = '4'
    else:
      self._csi = None
      self._font_bold = ''
      self._font_italic = ''

    # Encoded character attributes.
    if self._encoding == 'utf8':
      self._box_line_characters = BoxLineCharactersUnicode()
      self._bullets = self._BULLETS_UNICODE
    elif self._encoding == 'cp437':
      self._box_line_characters = BoxLineCharactersUnicode()
      self._bullets = self._BULLETS_WINDOWS
    else:
      self._box_line_characters = BoxLineCharactersAscii()
      self._bullets = self._BULLETS_ASCII

    # OS specific attributes.
    self._get_raw_key = [console_attr_os.GetRawKeyFunction()]
    self._term_size = console_attr_os.GetTermSize()

  def _GetConsoleEncoding(self):
    """Gets the encoding as declared by the stdout stream.

    Returns:
      str, The encoding name or None if it could not be determined.
    """
    console_encoding = getattr(sys.stdout, 'encoding', None)
    if not console_encoding:
      return None
    console_encoding = console_encoding.lower()
    if 'utf-8' in console_encoding:
      return 'utf8'
    elif 'cp437' in console_encoding:
      return 'cp437'
    return None

  def Colorize(self, string, color, justify=None):
    """Generates a colorized string, optionally justified.

    Args:
      string: The string to write.
      color: The color name -- must be in _ANSI_COLOR.
      justify: The justification function, no justification if None. For
        example, justify=lambda s: s.center(10)

    Returns:
      str, The colorized string that can be printed to the console.
    """
    if justify:
      string = justify(string)
    if self._csi and color in self._ANSI_COLOR:
      return '{csi}{color_code}{string}{csi}{reset_code}'.format(
          csi=self._csi,
          color_code=self._ANSI_COLOR[color],
          reset_code=self._ANSI_COLOR_RESET,
          string=string)
    # TODO(b/35939231): Add elif self._encoding == 'cp437': code here.
    return string

  def ConvertOutputToUnicode(self, buf):
    """Converts a console output string buf to unicode.

    Mainly used for testing. Allows test comparisons in unicode while ensuring
    that unicode => encoding => unicode works.

    Args:
      buf: The console output string to convert.

    Returns:
      The console output string buf converted to unicode.
    """
    if isinstance(buf, six.text_type):
      buf = buf.encode(self._encoding)
    return six.text_type(buf, self._encoding, 'replace')

  def GetBoxLineCharacters(self):
    """Returns the box/line drawing characters object.

    The element names are from ISO 8879:1986//ENTITIES Box and Line Drawing//EN:
      http://www.w3.org/2003/entities/iso8879doc/isobox.html

    Returns:
      A BoxLineCharacters object for the console output device.
    """
    return self._box_line_characters

  def GetBullets(self):
    """Returns the bullet characters list.

    Use the list elements in order for best appearance in nested bullet lists,
    wrapping back to the first element for deep nesting. The list size depends
    on the console implementation.

    Returns:
      A tuple of bullet characters.
    """
    return self._bullets

  def GetControlSequenceIndicator(self):
    """Returns the control sequence indicator string.

    Returns:
      The conrol sequence indicator string or None if control sequences are not
      supported.
    """
    return self._csi

  def GetControlSequenceLen(self, buf):
    """Returns the control sequence length at the beginning of buf.

    Used in display width computations. Control sequences have display width 0.

    Args:
      buf: The string to check for a control sequence.

    Returns:
      The conrol sequence length at the beginning of buf or 0 if buf does not
      start with a control sequence.
    """
    if not self._csi or not buf.startswith(self._csi):
      return 0
    n = 0
    for c in buf:
      n += 1
      if c.isalpha():
        break
    return n

  def GetEncoding(self):
    """Returns the current encoding."""
    return self._encoding

  def GetFontCode(self, bold=False, italic=False):
    """Returns a font code string for 0 or more embellishments.

    GetFontCode() with no args returns the default font code string.

    Args:
      bold: True for bold embellishment.
      italic: True for italic embellishment.

    Returns:
      The font code string for the requested embellishments. Write this string
        to the console output to control the font settings.
    """
    if not self._csi:
      return ''
    codes = []
    if bold:
      codes.append(self._font_bold)
    if italic:
      codes.append(self._font_italic)
    return '{csi}{codes}m'.format(csi=self._csi, codes=';'.join(codes))

  def GetRawKey(self):
    """Reads one key press from stdin with no echo.

    Returns:
      The key name, None for EOF, <KEY-*> for function keys, otherwise a
      character.
    """
    return self._get_raw_key[0]()

  def GetTermSize(self):
    """Returns the terminal (x, y) dimensions in characters.

    Returns:
      (x, y): A tuple of the terminal x and y dimensions.
    """
    return self._term_size

  def DisplayWidth(self, buf):
    """Returns the display width of buf, handling unicode and ANSI controls.

    Args:
      buf: The string to count from.

    Returns:
      The display width of buf, handling unicode and ANSI controls.
    """
    if not isinstance(buf, six.string_types):
      # Handle non-string objects like Colorizer().
      return len(buf)
    width = 0
    max_width = 0
    i = 0
    while i < len(buf):
      if self._csi and buf[i:].startswith(self._csi):
        i += self.GetControlSequenceLen(buf[i:])
      elif buf[i] == '\n':
        # A newline incidates the start of a new line.
        # Newline characters have 0 width.
        max_width = max(width, max_width)
        width = 0
        i += 1
      else:
        width += GetCharacterDisplayWidth(buf[i])
        i += 1
    max_width = max(width, max_width)
    return max_width

  def SplitIntoNormalAndControl(self, buf):
    """Returns a list of (normal_string, control_sequence) tuples from buf.

    Args:
      buf: The input string containing one or more control sequences
        interspersed with normal strings.

    Returns:
      A list of (normal_string, control_sequence) tuples.
    """
    if not self._csi or not buf:
      return [(buf, '')]
    seq = []
    i = 0
    while i < len(buf):
      c = buf.find(self._csi, i)
      if c < 0:
        seq.append((buf[i:], ''))
        break
      normal = buf[i:c]
      i = c + self.GetControlSequenceLen(buf[c:])
      seq.append((normal, buf[c:i]))
    return seq

  def SplitLine(self, line, width):
    """Splits line into width length chunks.

    Args:
      line: The line to split.
      width: The width of each chunk except the last which could be smaller than
        width.

    Returns:
      A list of chunks, all but the last with display width == width.
    """
    lines = []
    chunk = ''
    w = 0
    keep = False
    for normal, control in self.SplitIntoNormalAndControl(line):
      keep = True
      while True:
        n = width - w
        w += len(normal)
        if w <= width:
          break
        lines.append(chunk + normal[:n])
        chunk = ''
        keep = False
        w = 0
        normal = normal[n:]
      chunk += normal + control
    if chunk or keep:
      lines.append(chunk)
    return lines


class Colorizer(object):
  """Resource string colorizer.

  Attributes:
    _con: ConsoleAttr object.
    _color: Color name.
    _string: The string to colorize.
    _justify: The justification function, no justification if None. For example,
      justify=lambda s: s.center(10)
  """

  def __init__(self, string, color, justify=None):
    """Constructor.

    Args:
      string: The string to colorize.
      color: Color name used to index ConsoleAttr._ANSI_COLOR.
      justify: The justification function, no justification if None. For
        example, justify=lambda s: s.center(10)
    """
    self._con = GetConsoleAttr()
    self._color = color
    self._string = string
    self._justify = justify

  def __eq__(self, other):
    return self._string == six.text_type(other)

  def __ne__(self, other):
    return not self == other

  def __gt__(self, other):
    return self._string > six.text_type(other)

  def __lt__(self, other):
    return self._string < six.text_type(other)

  def __ge__(self, other):
    return not self < other

  def __le__(self, other):
    return not self > other

  def __len__(self):
    return self._con.DisplayWidth(self._string)

  def __str__(self):
    return self._string

  def Render(self, stream, justify=None):
    """Renders the string as self._color on the console.

    Args:
      stream: The stream to render the string to. The stream given here *must*
        have the same encoding as sys.stdout for this to work properly.
      justify: The justification function, self._justify if None.
    """
    stream.write(
        self._con.Colorize(self._string, self._color, justify or self._justify))


def GetConsoleAttr(encoding=None, reset=False):
  """Gets the console attribute state.

  If this is the first call or reset is True or encoding is not None and does
  not match the current encoding or out is not None and does not match the
  current out then the state is (re)initialized. Otherwise the current state
  is returned.

  This call associates the out file stream with the console. All console related
  output should go to the same stream.

  Args:
    encoding: Encoding override.
      ascii -- ASCII. This is the default.
      utf8 -- UTF-8 unicode.
      win -- Windows code page 437.
    reset: Force re-initialization if True.

  Returns:
    The global ConsoleAttr state object.
  """
  attr = ConsoleAttr._CONSOLE_ATTR_STATE  # pylint: disable=protected-access
  if not reset:
    if not attr:
      reset = True
    elif encoding and encoding != attr.GetEncoding():
      reset = True
  if reset:
    attr = ConsoleAttr(encoding=encoding)
    ConsoleAttr._CONSOLE_ATTR_STATE = attr  # pylint: disable=protected-access
  return attr


def ResetConsoleAttr(encoding=None):
  """Resets the console attribute state to the console default.

  Args:
    encoding: Reset to this encoding instead of the default.
      ascii -- ASCII. This is the default.
      utf8 -- UTF-8 unicode.
      win -- Windows code page 437.

  Returns:
    The global ConsoleAttr state object.
  """
  return GetConsoleAttr(encoding=encoding, reset=True)


def GetCharacterDisplayWidth(char):
  """Returns the monospaced terminal display width of char.

  Assumptions:
    - monospaced display
    - ambiguous or unknown chars default to width 1
    - ASCII control char width is 1 => don't use this for control chars

  Args:
    char: The character to determine the display width of.

  Returns:
    The monospaced terminal display width of char: either 0, 1, or 2.
  """
  if not isinstance(char, six.text_type):
    # Non-unicode chars have width 1. Don't use this function on control chars.
    return 1

  # Normalize to avoid special cases.
  char = unicodedata.normalize('NFC', char)

  if unicodedata.combining(char) != 0:
    # Modifies the previous character and does not move the cursor.
    return 0
  elif unicodedata.category(char) == 'Cf':
    # Unprintable formatting char.
    return 0
  elif unicodedata.east_asian_width(char) in 'FW':
    # Fullwidth or Wide chars take 2 character positions.
    return 2
  else:
    # Don't use this function on control chars.
    return 1


def SafeText(data, encoding=None, escape=True):
  br"""Converts the data to a text string compatible with the given encoding.

  This works the same way as Decode() below except it guarantees that any
  characters in the resulting text string can be re-encoded using the given
  encoding (or GetConsoleAttr().GetEncoding() if None is given). This means
  that the string will be safe to print to sys.stdout (for example) without
  getting codec exceptions if the user's terminal doesn't support the encoding
  used by the source of the text.

  Args:
    data: Any bytes, string, or object that has str() or unicode() methods.
    encoding: The encoding name to ensure compatibility with. Defaults to
      GetConsoleAttr().GetEncoding().
    escape: Replace unencodable characters with a \uXXXX or \xXX equivalent if
      True. Otherwise replace unencodable characters with an appropriate unknown
      character, '?' for ASCII, and the unicode unknown replacement character
      \uFFFE for unicode.

  Returns:
    A text string representation of the data, but modified to remove any
    characters that would result in an encoding exception with the target
    encoding. In the worst case, with escape=False, it will contain only ?
    characters.
  """
  if data is None:
    return 'None'
  encoding = encoding or GetConsoleAttr().GetEncoding()
  string = encoding_util.Decode(data, encoding=encoding)

  try:
    # No change needed if the string encodes to the output encoding.
    string.encode(encoding)
    return string
  except UnicodeError:
    # The string does not encode to the output encoding. Encode it with error
    # handling then convert it back into a text string (which will be
    # guaranteed to only contain characters that can be encoded later.
    return (string
            .encode(encoding, 'backslashreplace' if escape else 'replace')
            .decode(encoding))


def EncodeToBytes(data):
  r"""Encode data to bytes.

  The primary use case is for base64/mime style 7-bit ascii encoding where the
  encoder input must be bytes. "safe" means that the conversion always returns
  bytes and will not raise codec exceptions.

  If data is text then an 8-bit ascii encoding is attempted, then the console
  encoding, and finally utf-8.

  Args:
    data: Any bytes, string, or object that has str() or unicode() methods.

  Returns:
    A bytes string representation of the data.
  """
  if data is None:
    return b''
  if isinstance(data, bytes):
    # Already bytes - our work is done.
    return data

  # Coerce to text that will be converted to bytes.
  s = six.text_type(data)

  try:
    # Assume the text can be directly converted to bytes (8-bit ascii).
    return s.encode('iso-8859-1')
  except UnicodeEncodeError:
    pass

  try:
    # Try the output encoding.
    return s.encode(GetConsoleAttr().GetEncoding())
  except UnicodeEncodeError:
    pass

  # Punt to utf-8.
  return s.encode('utf-8')


def Decode(data, encoding=None):
  """Converts the given string, bytes, or object to a text string.

  Args:
    data: Any bytes, string, or object that has str() or unicode() methods.
    encoding: A suggesting encoding used to decode. If this encoding doesn't
      work, other defaults are tried. Defaults to
      GetConsoleAttr().GetEncoding().

  Returns:
    A text string representation of the data.
  """
  encoding = encoding or GetConsoleAttr().GetEncoding()
  return encoding_util.Decode(data, encoding=encoding)
