import os
from collections.abc import MutableMapping
import shlex

from django.conf import settings as _settings
from django.core.signals import setting_changed
from django.dispatch import receiver


DEFAULTS = {
    'PIPELINE_ENABLED': not _settings.DEBUG,

    'PIPELINE_COLLECTOR_ENABLED': True,

    'PIPELINE_ROOT': _settings.STATIC_ROOT,
    'PIPELINE_URL': _settings.STATIC_URL,

    'SHOW_ERRORS_INLINE': _settings.DEBUG,

    'CSS_COMPRESSOR': 'pipeline.compressors.yuglify.YuglifyCompressor',
    'JS_COMPRESSOR': 'pipeline.compressors.yuglify.YuglifyCompressor',
    'COMPILERS': [],

    'STYLESHEETS': {},
    'JAVASCRIPT': {},

    'TEMPLATE_NAMESPACE': "window.JST",
    'TEMPLATE_EXT': ".jst",
    'TEMPLATE_FUNC': "template",
    'TEMPLATE_SEPARATOR': "_",

    'DISABLE_WRAPPER': False,
    'JS_WRAPPER': "(function() {\n%s\n}).call(this);",

    'CSSTIDY_BINARY': '/usr/bin/env csstidy',
    'CSSTIDY_ARGUMENTS': '--template=highest',

    'YUGLIFY_BINARY': '/usr/bin/env yuglify',
    'YUGLIFY_CSS_ARGUMENTS': '--terminal',
    'YUGLIFY_JS_ARGUMENTS': '--terminal',

    'YUI_BINARY': '/usr/bin/env yuicompressor',
    'YUI_CSS_ARGUMENTS': '',
    'YUI_JS_ARGUMENTS': '',

    'CLOSURE_BINARY': '/usr/bin/env closure',
    'CLOSURE_ARGUMENTS': '',

    'UGLIFYJS_BINARY': '/usr/bin/env uglifyjs',
    'UGLIFYJS_ARGUMENTS': '',
    
    'TERSER_BINARY': '/usr/bin/env terser',
    'TERSER_ARGUMENTS': '--compress',

    'CSSMIN_BINARY': '/usr/bin/env cssmin',
    'CSSMIN_ARGUMENTS': '',

    'COFFEE_SCRIPT_BINARY': '/usr/bin/env coffee',
    'COFFEE_SCRIPT_ARGUMENTS': '',

    'BABEL_BINARY': '/usr/bin/env babel',
    'BABEL_ARGUMENTS': '',

    'LIVE_SCRIPT_BINARY': '/usr/bin/env lsc',
    'LIVE_SCRIPT_ARGUMENTS': '',

    'SASS_BINARY': '/usr/bin/env sass',
    'SASS_ARGUMENTS': '',

    'STYLUS_BINARY': '/usr/bin/env stylus',
    'STYLUS_ARGUMENTS': '',

    'LESS_BINARY': '/usr/bin/env lessc',
    'LESS_ARGUMENTS': '',

    'MIMETYPES': (
        (('text/coffeescript'), ('.coffee')),
        (('text/less'), ('.less')),
        (('text/javascript'), ('.js')),
        (('text/x-sass'), ('.sass')),
        (('text/x-scss'), ('.scss'))
    ),

    'EMBED_MAX_IMAGE_SIZE': 32700,
    'EMBED_PATH': r'[/]?embed/',
}


class PipelineSettings(MutableMapping):
    """
    Container object for pipeline settings
    """
    def __init__(self, wrapped_settings):
        self.settings = DEFAULTS.copy()
        self.settings.update(wrapped_settings)

    def __getitem__(self, key):
        value = self.settings[key]
        if key.endswith(("_BINARY", "_ARGUMENTS")):
            if isinstance(value, (str,)):
                return tuple(shlex.split(value, posix=(os.name == 'posix')))
            return tuple(value)
        return value

    def __setitem__(self, key, value):
        self.settings[key] = value

    def __delitem__(self, key):
        del self.store[key]

    def __iter__(self):
        return iter(self.settings)

    def __len__(self):
        return len(self.settings)

    def __getattr__(self, name):
        return self.__getitem__(name)


settings = PipelineSettings(_settings.PIPELINE)


@receiver(setting_changed)
def reload_settings(**kwargs):
    if kwargs['setting'] == 'PIPELINE':
        settings.update(kwargs['value'])