#!/usr/bin/env python

"""
A simple script to download a course by name from ILIAS.
"""

import argparse
import logging
import sys
from pathlib import Path, PurePath
from typing import Optional
from urllib.parse import urlparse

from PFERD import Pferd
from PFERD.authenticators import KeyringAuthenticator, UserPassAuthenticator
from PFERD.cookie_jar import CookieJar
from PFERD.ilias import (IliasCrawler, IliasElementType,
                         KitShibbolethAuthenticator)
from PFERD.logging import PrettyLogger, enable_logging
from PFERD.organizer import (ConflictType, FileConflictResolution,
                             FileConflictResolver, resolve_prompt_user)
from PFERD.transform import sanitize_windows_path
from PFERD.utils import to_path

_LOGGER = logging.getLogger("sync_url")
_PRETTY = PrettyLogger(_LOGGER)


def _extract_credentials(file_path: Optional[str],
                         username: Optional[str], password: Optional[str]) -> UserPassAuthenticator:
    if not file_path:
        return UserPassAuthenticator("KIT ILIAS Shibboleth", username, password)

    if not Path(file_path).exists():
        _PRETTY.error("Credential file does not exist")
        sys.exit(1)

    with open(file_path, "r") as file:
        first_line = file.read().splitlines()[0]
        read_name, *read_password = first_line.split(":", 1)

        name = read_name if read_name else None
        password = read_password[0] if read_password else None
        return UserPassAuthenticator("KIT ILIAS Shibboleth", username=name, password=password)


def _resolve_remote_first(_path: PurePath, _conflict: ConflictType) -> FileConflictResolution:
    return FileConflictResolution.DESTROY_EXISTING


def _resolve_local_first(_path: PurePath, _conflict: ConflictType) -> FileConflictResolution:
    return FileConflictResolution.KEEP_EXISTING


def _resolve_no_delete(_path: PurePath, conflict: ConflictType) -> FileConflictResolution:
    # Update files
    if conflict == ConflictType.FILE_OVERWRITTEN:
        return FileConflictResolution.DESTROY_EXISTING
    if conflict == ConflictType.MARKED_FILE_OVERWRITTEN:
        return FileConflictResolution.DESTROY_EXISTING
    # But do not delete them
    return FileConflictResolution.KEEP_EXISTING


def main() -> None:
    enable_logging(name="sync_url")

    parser = argparse.ArgumentParser()
    parser.add_argument("--test-run", action="store_true")
    parser.add_argument('-c', '--cookies', nargs='?', default=None, help="File to store cookies in")
    parser.add_argument('-u', '--username', nargs='?', default=None, help="Username for Ilias")
    parser.add_argument('-p', '--password', nargs='?', default=None, help="Password for Ilias")
    parser.add_argument('--credential-file', nargs='?', default=None,
                        help="Path to a file containing credentials for Ilias. The file must have "
                        "one line in the following format: '<user>:<password>'")
    parser.add_argument("-k", "--keyring", action="store_true",
                        help="Use the system keyring service for authentication")
    parser.add_argument('--no-videos', action="store_true", help="Don't download videos")
    parser.add_argument('--local-first', action="store_true",
                        help="Don't prompt for confirmation, keep existing files")
    parser.add_argument('--remote-first', action="store_true",
                        help="Don't prompt for confirmation, delete and overwrite local files")
    parser.add_argument('--no-delete', action="store_true",
                        help="Don't prompt for confirmation, overwrite local files, don't delete")
    parser.add_argument('url', help="URL to the course page")
    parser.add_argument('folder', nargs='?', default=None, help="Folder to put stuff into")
    args = parser.parse_args()

    cookie_jar = CookieJar(to_path(args.cookies) if args.cookies else None)
    session = cookie_jar.create_session()

    if args.keyring:
        if not args.username:
            _PRETTY.error("Keyring auth selected but no --username passed!")
            return
        inner_auth: UserPassAuthenticator = KeyringAuthenticator(
            "KIT ILIAS Shibboleth", username=args.username, password=args.password
        )
    else:
        inner_auth = _extract_credentials(args.credential_file, args.username, args.password)

    username, password = inner_auth.get_credentials()
    authenticator = KitShibbolethAuthenticator(inner_auth)

    url = urlparse(args.url)

    crawler = IliasCrawler(url.scheme + '://' + url.netloc, session,
                           authenticator, lambda x, y: True)

    cookie_jar.load_cookies()

    if args.folder is None:
        element_name = crawler.find_element_name(args.url)
        if not element_name:
            print("Error, could not get element name. Please specify a folder yourself.")
            return
        folder = sanitize_windows_path(Path(element_name.replace("/", "-").replace("\\", "-")))
        cookie_jar.save_cookies()
    else:
        folder = Path(args.folder)

    # files may not escape the pferd_root with relative paths
    # note: Path(Path.cwd, Path(folder)) == Path(folder) if it is an absolute path
    pferd_root = Path(Path.cwd(), Path(folder)).parent
    # Folder might be a *PurePath* at this point
    target = Path(folder).resolve().name
    pferd = Pferd(pferd_root, test_run=args.test_run)

    def dir_filter(_: Path, element: IliasElementType) -> bool:
        if args.no_videos:
            return element not in [IliasElementType.VIDEO_FILE, IliasElementType.VIDEO_FOLDER]
        return True

    if args.local_first:
        file_conflict_resolver: FileConflictResolver = _resolve_local_first
    elif args.no_delete:
        file_conflict_resolver = _resolve_no_delete
    elif args.remote_first:
        file_conflict_resolver = _resolve_remote_first
    else:
        file_conflict_resolver = resolve_prompt_user

    pferd.enable_logging()

    # fetch
    pferd.ilias_kit_folder(
        target=target,
        full_url=args.url,
        cookies=args.cookies,
        dir_filter=dir_filter,
        username=username,
        password=password,
        file_conflict_resolver=file_conflict_resolver,
        transform=sanitize_windows_path
    )

    pferd.print_summary()


if __name__ == "__main__":
    main()