# Copyright (C) 2009, 2010  Roman Zimbelmann <romanz@lavabit.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""
Colorschemes define colors for specific contexts.

Generally, this works by passing a set of keywords (strings) to
the colorscheme.get() method to receive the tuple (fg, bg, attr).
fg, bg are the foreground and background colors and attr is the attribute.
The values are specified in ranger.gui.color.

A colorscheme must...

1. be inside either of these directories:
~/.ranger/colorschemes/
path/to/ranger/colorschemes/

2. be a subclass of ranger.gui.colorscheme.ColorScheme

3. implement a use(self, context) method which returns (fg, bg, attr).
context is a struct which contains all entries of CONTEXT_KEYS,
associated with either True or False.

define which colorscheme to use by having this to your options.py:
from ranger import colorschemes
colorscheme = colorschemes.filename

If your colorscheme-file contains more than one colorscheme, specify it with:
colorscheme = colorschemes.filename.classname
"""

from ranger.ext.openstruct import ReferencedOpenStruct
from curses import color_pair
from ranger.gui.color import get_color
from ranger.gui.context import Context

class ColorScheme(object):
	"""
	This is the class that colorschemes must inherit from.

	it defines get() 
	it defines the get() method, which returns the color tuple
	which fits to the given keys.
	"""

	def __init__(self):
		self.cache = {}

	def get(self, *keys):
		"""
		Returns the (fg, bg, attr) for the given keys.

		Using this function rather than use() will cache all
		colors for faster access.
		"""
		keys = frozenset(keys)
		try:
			return self.cache[keys]

		except KeyError:
			context = Context(keys)

			# add custom error messages for broken colorschemes
			color = self.use(context)
			self.cache[keys] = color
			return color

	def get_attr(self, *keys):
		"""
		Returns the curses attribute for the specified keys

		Ready to use for curses.setattr()
		"""
		fg, bg, attr = self.get(*keys)
		return attr | color_pair(get_color(fg, bg))

	def use(self, context):
		"""
		Use the colorscheme to determine the (fg, bg, attr) tuple.
		This is a dummy function which always returns default_colors.
		Override this in your custom colorscheme!
		"""
		from ranger.gui.color import default_colors
		return default_colors