import os
import io
import json

import core.event
import util.algorithm

THEME_BASE_DIR=os.path.dirname(os.path.realpath(__file__))
PATHS=[
    '.',
    os.path.join(THEME_BASE_DIR, '../themes'),
    os.path.expanduser('~/.config/bumblebee-status/themes'),
]

class Theme(object):
    def __init__(self, name='default', iconset='auto', raw_data=None):
        self.name = name
        self.__widget_count = 0
        self.__previous = {}
        self.__current = {}
        if raw_data:
            self.__data = raw_data
        else:
            self.__data = self.load(name)
            for icons in self.__data['icons']:
                util.algorithm.merge(self.__data, self.load(icons, 'icons'))
            if iconset != 'auto':
                util.algorithm.merge(self.__data, self.load(iconset, 'icons'))

        core.event.register('update', self.__start)
        core.event.register('next-widget', self.__next_widget)

        for attr, default in [
            ('fg', None), ('bg', None),
            ('default-separators', True),
            ('separator-block-width', 0),
            ('separator', None),
            ('border-top', 0),
            ('border-bottom', 0),
            ('border-left', 0),
            ('border-right', 0),
        ]:
            setattr(self, attr.replace('-', '_'), lambda widget=None, default=default, attr=attr: self.__get(widget, attr, default))

    def load(self, name, subdir=''):
        for path in PATHS:
            theme_file = os.path.join(path, subdir, '{}.json'.format(name))
            if os.path.isfile(theme_file):
                with io.open(theme_file, encoding='utf-8') as data:
                    return json.load(data)
        raise RuntimeError('unable to find theme {}'.format(name))

    def __start(self):
        self.__widget_count = 0
        self.__current.clear()
        self.__previous.clear()

    def __next_widget(self):
        self.__widget_count = self.__widget_count + 1
        self.__previous = dict(self.__current)
        self.__current.clear()

    def __get(self, widget, key, default=None):
        if not widget:
            widget = core.widget.Widget('')
        if isinstance(widget, str):
            # special handling
            if widget == 'previous':
                return self.__previous.get(key, None)

        value = default

        for option in ['defaults', 'cycle']:
            if option in self.__data:
                tmp = self.__data[option]
                if isinstance(tmp, list):
                    tmp = tmp[self.__widget_count % len(tmp)]
                value = tmp.get(key, value)

        if not key in widget.state():
            for state in widget.state():
                theme = self.__get(widget, state, {})
                value = theme.get(key, value)

        self.__current[key] = value
        return value

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