import logging
import os
import re
import sass
from grow.pods.preprocessors import base
from protorpc import messages

SUFFIXES = frozenset(['sass', 'scss'])
SUFFIX_PATTERN = re.compile('[.](' + '|'.join(map(re.escape, SUFFIXES)) + ')$')


class Config(messages.Message):
    sass_dir = messages.StringField(1)
    out_dir = messages.StringField(2)
    suffix = messages.StringField(3, default='.min.css')
    output_style = messages.StringField(4, default='compressed')
    source_comments = messages.BooleanField(5)
    image_path = messages.StringField(6)


class SassPreprocessor(base.BasePreprocessor):
    KIND = 'sass'
    Config = Config

    def run(self, build=True):
        sass_dir = os.path.abspath(os.path.join(self.root, self.config.sass_dir.lstrip('/')))
        out_dir = os.path.abspath(os.path.join(self.root, self.config.out_dir.lstrip('/')))
        self.build_directory(sass_dir, out_dir)

    def build_directory(self, sass_path, css_path, _root_sass=None, _root_css=None):
        if self.config.image_path:
            image_path = os.path.abspath(os.path.join(self.root, self.config.image_path.lstrip('/')))
        else:
            image_path = None
        _root_sass = sass_path if _root_sass is None else _root_sass
        _root_css = css_path if _root_css is None else _root_css
        result = {}
        if not os.path.isdir(css_path):
            os.makedirs(css_path)
        for name in os.listdir(sass_path):
            if not SUFFIX_PATTERN.search(name) or name.startswith('_'):
                continue
            sass_fullname = os.path.join(sass_path, name)
            if os.path.isfile(sass_fullname):
                basename = os.path.splitext(name)[0]
                css_fullname = os.path.join(css_path, basename) + self.config.suffix
                try:
                    kwargs = {
                        'filename': sass_fullname,
                        'include_paths': [_root_sass],
                        'output_style': self.config.output_style,
                    }
                    if self.config.output_style is not None:
                        kwargs['output_style'] = self.config.output_style
                    if image_path is not None:
                        kwargs['image_path'] = image_path
                    if self.config.image_path is not None:
                        kwargs['image_path'] = image_path
                    css = sass.compile(**kwargs)
                except sass.CompileError as e:
                    logging.error(str(e))
                    return result
                with open(css_fullname, 'w') as css_file:
                    if isinstance(css, unicode):
                        css = css.encode('utf-8')
                    css_file.write(css)
                result[sass_fullname] = css_fullname
            elif os.path.isdir(sass_fullname):
                css_fullname = os.path.join(css_path, name)
                subresult = self.build_directory(sass_fullname, css_fullname,
                              _root_sass, _root_css)
                result.update(subresult)
        for sass_path, out_path in result.iteritems():
            self.logger.info(
                'Compiled: {} -> {}'.format(sass_path.replace(self.root, ''),
                                           out_path.replace(self.root, '')))
        return result

    def list_watched_dirs(self):
        return [self.config.sass_dir]