'''
Code Input
==========

.. versionadded:: 1.5.0

.. image:: images/codeinput.jpg

.. note::

    This widget requires ``pygments`` package to run. Install it with ``pip``.

The :class:`CodeInput` provides a box of editable highlighted text like the one
shown in the image.

It supports all the features provided by the :class:`~kivy.uix.textinput` as
well as code highlighting for `languages supported by pygments
<http://pygments.org/docs/lexers/>`_ along with `KivyLexer` for
:mod:`kivy.lang` highlighting.

Usage example
-------------

To create a CodeInput with highlighting for `KV language`::

    from kivy.uix.codeinput import CodeInput
    from kivy.extras.highlight import KivyLexer
    codeinput = CodeInput(lexer=KivyLexer())

To create a CodeInput with highlighting for `Cython`::

    from kivy.uix.codeinput import CodeInput
    from pygments.lexers import CythonLexer
    codeinput = CodeInput(lexer=CythonLexer())

'''

__all__ = ('CodeInput', )

from pygments import highlight
from pygments import lexers
from pygments import styles
from pygments.formatters import BBCodeFormatter

from kivy.uix.textinput import TextInput
from kivy.core.text.markup import MarkupLabel as Label
from kivy.cache import Cache
from kivy.properties import ObjectProperty, OptionProperty
from kivy.utils import get_hex_from_color, get_color_from_hex
from kivy.uix.behaviors import CodeNavigationBehavior

Cache_get = Cache.get
Cache_append = Cache.append

# TODO: color chooser for keywords/strings/...


class CodeInput(CodeNavigationBehavior, TextInput):
    '''CodeInput class, used for displaying highlighted code.
    '''

    lexer = ObjectProperty(None)
    '''This holds the selected Lexer used by pygments to highlight the code.


    :attr:`lexer` is an :class:`~kivy.properties.ObjectProperty` and
    defaults to `PythonLexer`.
    '''

    style_name = OptionProperty(
        'default', options=list(styles.get_all_styles())
    )
    '''Name of the pygments style to use for formatting.

    :attr:`style_name` is an :class:`~kivy.properties.OptionProperty`
    and defaults to ``'default'``.

    '''

    style = ObjectProperty(None)
    '''The pygments style object to use for formatting.

    When ``style_name`` is set, this will be changed to the
    corresponding style object.

    :attr:`style` is a :class:`~kivy.properties.ObjectProperty` and
    defaults to ``None``

    '''

    def __init__(self, **kwargs):
        stylename = kwargs.get('style_name', 'default')
        style = kwargs['style'] if 'style' in kwargs \
            else styles.get_style_by_name(stylename)
        self.formatter = BBCodeFormatter(style=style)
        self.lexer = lexers.PythonLexer()
        self.text_color = '#000000'
        self._label_cached = Label()
        self.use_text_color = True

        super(CodeInput, self).__init__(**kwargs)

        self._line_options = kw = self._get_line_options()
        self._label_cached = Label(**kw)
        # use text_color as foreground color
        text_color = kwargs.get('foreground_color')
        if text_color:
            self.text_color = get_hex_from_color(text_color)
        # set foreground to white to allow text colors to show
        # use text_color as the default color in bbcodes
        self.use_text_color = False
        self.foreground_color = [1, 1, 1, .999]
        if not kwargs.get('background_color'):
            self.background_color = [.9, .92, .92, 1]

    def on_style_name(self, *args):
        self.style = styles.get_style_by_name(self.style_name)
        self.background_color = get_color_from_hex(self.style.background_color)
        self._trigger_refresh_text()

    def on_style(self, *args):
        self.formatter = BBCodeFormatter(style=self.style)
        self._trigger_update_graphics()

    def _create_line_label(self, text, hint=False):
        # Create a label from a text, using line options
        ntext = text.replace(u'\n', u'').replace(u'\t', u' ' * self.tab_width)
        if self.password and not hint:  # Don't replace hint_text with *
            ntext = u'*' * len(ntext)
        ntext = self._get_bbcode(ntext)
        kw = self._get_line_options()
        cid = u'{}\0{}\0{}'.format(ntext, self.password, kw)
        texture = Cache_get('textinput.label', cid)

        if texture is None:
            # FIXME right now, we can't render very long line...
            # if we move on "VBO" version as fallback, we won't need to
            # do this.
            # try to find the maximum text we can handle
            label = Label(text=ntext, **kw)