# Copyright 2019 Pants project contributors (see CONTRIBUTORS.md).
# Licensed under the Apache License, Version 2.0 (see LICENSE).

from pants.backend.python.rules.pex import Pex
from pants.backend.python.rules.pex_from_target_closure import CreatePexFromTargetClosure
from pants.backend.python.targets.python_binary import PythonBinary
from pants.build_graph.address import Address
from pants.engine.addressable import Addresses
from pants.engine.legacy.graph import HydratedTarget
from pants.engine.legacy.structs import PythonBinaryAdaptor
from pants.engine.rules import UnionRule, rule
from pants.engine.selectors import Get
from pants.rules.core.binary import BinaryTarget, CreatedBinary
from pants.rules.core.strip_source_roots import SourceRootStrippedSources


@rule
async def create_python_binary(python_binary_adaptor: PythonBinaryAdaptor) -> CreatedBinary:
    # TODO(#8420) This way of calculating the entry point works but is a bit hackish.
    entry_point = None
    if hasattr(python_binary_adaptor, "entry_point"):
        entry_point = python_binary_adaptor.entry_point
    else:
        sources_snapshot = python_binary_adaptor.sources.snapshot
        if len(sources_snapshot.files) == 1:
            target = await Get[HydratedTarget](Address, python_binary_adaptor.address)
            output = await Get[SourceRootStrippedSources](HydratedTarget, target)
            root_filename = output.snapshot.files[0]
            entry_point = PythonBinary.translate_source_path_to_py_module_specifier(root_filename)

    request = CreatePexFromTargetClosure(
        addresses=Addresses((python_binary_adaptor.address,)),
        entry_point=entry_point,
        output_filename=f"{python_binary_adaptor.address.target_name}.pex",
    )

    pex = await Get[Pex](CreatePexFromTargetClosure, request)
    return CreatedBinary(digest=pex.directory_digest, binary_name=pex.output_filename)


def rules():
    return [
        UnionRule(BinaryTarget, PythonBinaryAdaptor),
        create_python_binary,
    ]