"""
Utility for locating the module (or package's __init__.py)
associated with a given console_script name
and verifying it contains the PYTHON_ARGCOMPLETE_OK marker.

Such scripts are automatically generated and cannot contain
the marker themselves, so we defer to the containing module or package.

For more information on setuptools console_scripts, see
https://setuptools.readthedocs.io/en/latest/setuptools.html#automatic-script-creation

Intended to be invoked by argcomplete's global completion function.
"""
import os
import sys

try:
    from importlib.metadata import entry_points as importlib_entry_points
    from importlib.metadata import EntryPoint
    use_entry_points_backport = False
except ImportError:
    from importlib_metadata import entry_points as importlib_entry_points  # type:ignore
    from importlib_metadata import EntryPoint # type:ignore
    use_entry_points_backport = True

from ._check_module import ArgcompleteMarkerNotFound, find
from typing import Iterable


def main():
    # Argument is the full path to the console script.
    script_path = sys.argv[1]

    # Find the module and function names that correspond to this
    # assuming it is actually a console script.
    name = os.path.basename(script_path)

    entry_points : Iterable[EntryPoint] = importlib_entry_points() # type:ignore

    # The importlib_metadata backport returns a tuple of entry point objects
    # whereas the official library returns a SelectableGroups object
    # Python 3.12+ behaves like the importlib_metadata backport
    if not use_entry_points_backport and sys.version_info < (3, 12):
        entry_points = entry_points["console_scripts"] # type:ignore

    entry_points = [ep for ep in entry_points \
            if ep.name == name and ep.group == "console_scripts" ] # type:ignore

    if not entry_points:
        raise ArgcompleteMarkerNotFound("no entry point found matching script")
    entry_point = entry_points[0]
    module_name, function_name = entry_point.value.split(":", 1)

    # Check this looks like the script we really expected.
    with open(script_path) as f:
        script = f.read()
    if "from {} import {}".format(module_name, function_name) not in script:
        raise ArgcompleteMarkerNotFound("does not appear to be a console script")
    if "sys.exit({}())".format(function_name) not in script:
        raise ArgcompleteMarkerNotFound("does not appear to be a console script")

    # Look for the argcomplete marker in the script it imports.
    with open(find(module_name, return_package=True)) as f:
        head = f.read(1024)
    if "PYTHON_ARGCOMPLETE_OK" not in head:
        raise ArgcompleteMarkerNotFound("marker not found")


if __name__ == "__main__":
    try:
        main()
    except ArgcompleteMarkerNotFound as e:
        sys.exit(str(e))
