from pathlib import Path
from wasabi import msg

from ..compat import symlink_to
from .. import util


def link(
    origin: ("package name or local path to model", "positional", None, str),
    link_name: ("name of shortuct link to create", "positional", None, str),
    force: ("force overwriting of existing link", "flag", "f", bool) = False,
    model_path=None,
):
    """
    Create a symlink for models within the spacy/data directory. Accepts
    either the name of a pip package, or the local path to the model data
    directory. Linking models allows loading them via spacy.load(link_name).
    """
    if util.is_package(origin):
        model_path = util.get_package_path(origin)
    else:
        model_path = Path(origin) if model_path is None else Path(model_path)
    if not model_path.exists():
        msg.fail(
            "Can't locate model data",
            f"The data should be located in {model_path}",
            exits=1,
        )
    data_path = util.get_data_path()
    if not data_path or not data_path.exists():
        spacy_loc = Path(__file__).parent.parent
        msg.fail(
            f"Can't find the spaCy data path to create model symlink",
            f"Make sure a directory `/data` exists within your spaCy "
            f"installation and try again. The data directory should be located "
            f"here: {spacy_loc}",
            exits=1,
        )
    link_path = util.get_data_path() / link_name
    if link_path.is_symlink() and not force:
        msg.fail(
            f"Link '{link_name}' already exists",
            "To overwrite an existing link, use the --force flag",
            exits=1,
        )
    elif link_path.is_symlink():  # does a symlink exist?
        # NB: It's important to check for is_symlink here and not for exists,
        # because invalid/outdated symlinks would return False otherwise.
        link_path.unlink()
    elif link_path.exists():  # does it exist otherwise?
        # NB: Check this last because valid symlinks also "exist".
        msg.fail(
            f"Can't overwrite symlink '{link_name}'",
            "This can happen if your data directory contains a directory or "
            "file of the same name.",
            exits=1,
        )
    details = f"{model_path} --> {link_path}"
    try:
        symlink_to(link_path, model_path)
    except:  # noqa: E722
        # This is quite dirty, but just making sure other errors are caught.
        msg.fail(
            f"Couldn't link model to '{link_name}'",
            "Creating a symlink in spacy/data failed. Make sure you have the "
            "required permissions and try re-running the command as admin, or "
            "use a virtualenv. You can still import the model as a module and "
            "call its load() method, or create the symlink manually.",
        )
        msg.text(details)
        raise
    msg.good("Linking successful", details)
    msg.text(f"You can now load the model via spacy.load('{link_name}')")