import os
from argparse import ArgumentParser, Namespace
from typing import Union

from .configuration import Configuration
from .database import Database
from .template import Template
from .builder import HTMLBuilder


def get_options() -> Namespace:
    parser = ArgumentParser(prog='pyssg',
                            description='''Static Site Generator that reads
                            Markdown files and creates HTML files.\nIf
                            [-c]onfig file is provided (or exists in default
                            location) all other options are ignored.\nFor
                            datetime formats see:
                            https://docs.python.org/3/library/datetime.html#strftime-and-strptime-format-codes''')
    parser.add_argument('-c', '--config',
                        default='$XDG_CONFIG_HOME/pyssg/pyssgrc',
                        type=str,
                        help='''config file (path) to read from; defaults to
                        '$XDG_CONFIG_HOME/pyssg/pyssgrc' ''')
    parser.add_argument('-s', '--src',
                        default='src',
                        type=str,
                        help='''src directory; handmade files, templates and
                        metadata directory; defaults to 'src' ''')
    parser.add_argument('-d', '--dst',
                        default='dst',
                        type=str,
                        help='''dst directory; generated (and transfered html)
                        files; defaults to 'dst' ''')
    parser.add_argument('-u', '--url',
                        default='',
                        type=str,
                        help='''base url without trailing slash''')
    parser.add_argument('--date-format',
                        default='%a, %b %d, %Y @ %H:%M %Z',
                        type=str,
                        help='''date format used inside pages (for creation and
                        modification times, for example); defaults to '%%a, %%b
                        %%d, %%Y @ %%H:%%M %%Z' ('Tue, Mar 16, 2021 @ 02:46 UTC',
                        for example)''')
    parser.add_argument('--list-date-format',
                        default='%b %d',
                        type=str,
                        help='''date format used for page entries in a list;
                        defaults to '%%b %%d' ('Mar 16', for example)''')
    parser.add_argument('--list-sep-date-format',
                        default='%B %Y',
                        type=str,
                        help='''date format used for the separator between page
                        entries in a list; defaults to '%%B %%Y' ('March 2021',
                        for example)''')
    parser.add_argument('-i', '--init',
                        action='store_true',
                        help='''initializes the dir structure, templates,
                        as well as the 'src' and 'dst' directories''')
    parser.add_argument('-b', '--build',
                        action='store_true',
                        help='''generates all html files and passes over
                        existing (handmade) ones''')
    parser.add_argument('-f', '--force',
                        action='store_true',
                        help='''force building all pages and not only the
                        updated ones''')

    return parser.parse_args()


def main() -> None:
    opts: dict[str, Union[str, bool]] = vars(get_options())
    conf_path: str = opts['config']
    conf_path = os.path.expandvars(conf_path)

    config: Configuration = Configuration(conf_path)
    config.read()
    config.fill_missing(opts)

    if opts['init']:
        try:
            os.mkdir(config.src)
            os.makedirs(os.path.join(config.dst, 'tag'))
        except FileExistsError:
            pass

        # write default templates
        template: Template = Template(config.src)
        template.write()
        return

    if opts['build']:
        # start the db
        db: Database = Database(os.path.join(config.src, '.files'))
        db.read()

        # read templates
        template: Template = Template(config.src)
        template.read()

        builder: HTMLBuilder = HTMLBuilder(config, template, db)
        builder.build()

        db.write()
        return