# wikiget - CLI tool for downloading files from Wikimedia sites
# Copyright (C) 2018-2023 Cody Logan
# SPDX-License-Identifier: GPL-3.0-or-later
#
# Wikiget is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Wikiget is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Wikiget. If not, see <https://www.gnu.org/licenses/>.

"""Parse download targets and batch files."""

from __future__ import annotations

import fileinput
import logging
from typing import TYPE_CHECKING
from urllib.parse import unquote, urlparse

import wikiget
from wikiget.exceptions import ParseError
from wikiget.file import File
from wikiget.validations import valid_file

if TYPE_CHECKING:
    from argparse import Namespace

logger = logging.getLogger(__name__)


def get_dest(dl: str, args: Namespace) -> File:
    """Parse the given download target for filename, destination, and site host.

    :param dl: download target (filename or URL)
    :type dl: str
    :param args: command-line arguments and their values
    :type args: argparse.Namespace
    :raises ParseError: the target was unable to be parsed as a valid file
    :return: a File object representing the target, destination, and site
    :rtype: wikiget.file.File
    """
    url = urlparse(dl)

    if url.netloc:
        filename = url.path
        site_name = url.netloc
        if args.site is not wikiget.DEFAULT_SITE:
            # this will work even if the user specifies 'commons.wikimedia.org' since
            # we're comparing objects instead of values ('is not' vs. '!=')
            logger.warning("Target is a URL; ignoring site specified with --site")
    else:
        filename = dl
        site_name = args.site

    file_match = valid_file(filename)

    # check if this is a valid file
    if file_match and file_match.group(1):
        # has File:/Image: prefix and extension
        filename = file_match.group(2)
    else:
        # no file extension and/or prefix, probably an article
        msg = f"Could not parse input '{dl}' as a file"
        raise ParseError(msg)

    filename = unquote(filename)  # remove URL encoding for special characters
    dest = args.output or filename
    return File(filename, dest, site_name)


def read_batch_file(batch_file: str) -> dict[int, str]:
    """Parse a batch file or stdin for valid input.

    The contents are returned as a dictionary with line numbers for keys and line
    contents for values. Any blank lines or lines starting with '#' are skipped.

    :param batch_file: name of the file to parse or "-" for stdin
    :type batch_file: str
    :return: a dictionary representation of the input contents
    :rtype: dict[int, str]
    """
    dl_dict = {}

    if batch_file == "-":
        logger.info("Using stdin for batch download")
    else:
        logger.info("Using file '%s' for batch download", batch_file)

    with fileinput.input(batch_file) as fd:
        # read the file into memory and process each line as we go
        for line_num, line in enumerate(fd, start=1):
            line_s = line.strip()
            # ignore blank lines and lines starting with "#" (for comments)
            if line_s and not line_s.startswith("#"):
                dl_dict[line_num] = line_s

    return dl_dict