import os
from typing import Optional, Dict
from datetime import datetime, timedelta
from szurubooru import config, rest
from szurubooru.func import auth, posts, users, util


_cache_time = None  # type: Optional[datetime]
_cache_result = None  # type: Optional[int]


def _get_disk_usage() -> int:
    global _cache_time, _cache_result  # pylint: disable=global-statement
    threshold = timedelta(hours=48)
    now = datetime.utcnow()
    if _cache_time and _cache_time > now - threshold:
        assert _cache_result is not None
        return _cache_result
    total_size = 0
    for dir_path, _, file_names in os.walk(config.config['data_dir']):
        for file_name in file_names:
            file_path = os.path.join(dir_path, file_name)
            total_size += os.path.getsize(file_path)
    _cache_time = now
    _cache_result = total_size
    return total_size


@rest.routes.get('/info/?')
def get_info(
        ctx: rest.Context, _params: Dict[str, str] = {}) -> rest.Response:
    post_feature = posts.try_get_current_post_feature()
    ret = {
        'postCount': posts.get_post_count(),
        'diskUsage': _get_disk_usage(),
        'serverTime': datetime.utcnow(),
        'config': {
            'name': config.config['name'],
            'userNameRegex': config.config['user_name_regex'],
            'passwordRegex': config.config['password_regex'],
            'tagNameRegex': config.config['tag_name_regex'],
            'tagCategoryNameRegex': config.config['tag_category_name_regex'],
            'defaultUserRank': config.config['default_rank'],
            'enableSafety': config.config['enable_safety'],
            'contactEmail': config.config['contact_email'],
            'canSendMails': bool(config.config['smtp']['host']),
            'privileges':
                util.snake_case_to_lower_camel_case_keys(
                    config.config['privileges']),
        },
    }
    if auth.has_privilege(ctx.user, 'posts:view:featured'):
        ret['featuredPost'] = (
            posts.serialize_post(post_feature.post, ctx.user)
            if post_feature else None)
        ret['featuringUser'] = (
            users.serialize_user(post_feature.user, ctx.user)
            if post_feature else None)
        ret['featuringTime'] = post_feature.time if post_feature else None
    return ret
