# Copyright 2014 Pex project contributors.
# Licensed under the Apache License, Version 2.0 (see LICENSE).

from __future__ import absolute_import

import ast
import os

from pex.common import open_zip, safe_mkdtemp
from pex.dist_metadata import (
    CallableEntryPoint,
    Distribution,
    DistributionType,
    ModuleEntryPoint,
    NamedEntryPoint,
)
from pex.executables import is_python_script
from pex.installed_wheel import InstalledWheel
from pex.pep_503 import ProjectName
from pex.sysconfig import SCRIPT_DIR, script_name
from pex.typing import TYPE_CHECKING, cast
from pex.wheel import Wheel

if TYPE_CHECKING:
    from typing import Dict, Iterable, Optional, Union

    import attr  # vendor:skip
else:
    from pex.third_party import attr


@attr.s(frozen=True)
class DistributionScript(object):
    @classmethod
    def find(
        cls,
        dist,  # type: Distribution
        name,  # type: str
    ):
        # type: (...) -> Optional[DistributionScript]
        if dist.type is DistributionType.WHEEL:
            script_path = Wheel.load(dist.location).data_path("scripts", script_name(name))
            with open_zip(dist.location) as zfp:
                try:
                    zfp.getinfo(script_path)
                except KeyError:
                    return None
        elif dist.type is DistributionType.INSTALLED:
            script_path = InstalledWheel.load(dist.location).stashed_path(
                SCRIPT_DIR, script_name(name)
            )
            if not os.path.isfile(script_path):
                return None
        else:
            raise ValueError(
                "Can only probe .whl files and installed wheel chroots for scripts; "
                "given sdist: {sdist}".format(sdist=dist.location)
            )
        return cls(dist=dist, path=script_path)

    dist = attr.ib()  # type: Distribution
    path = attr.ib()  # type: str

    def read_contents(self, path_hint=None):
        # type: (Optional[str]) -> bytes
        path = path_hint or self._maybe_extract()
        with open(path, "rb") as fp:
            return fp.read()

    def python_script(self):
        # type: () -> Optional[ast.AST]
        path = self._maybe_extract()
        if not is_python_script(path, check_executable=False):
            return None

        return cast(
            ast.AST,
            compile(self.read_contents(path_hint=path), path, "exec", flags=0, dont_inherit=1),
        )

    def _maybe_extract(self):
        # type: () -> str
        if self.dist.type is not DistributionType.WHEEL:
            return self.path

        with open_zip(self.dist.location) as zfp:
            chroot = safe_mkdtemp()
            zfp.extract(self.path, chroot)
            return os.path.join(chroot, self.path)


def get_script_from_distributions(
    name,  # type: str
    dists,  # type: Iterable[Distribution]
):
    # type: (...) -> Optional[DistributionScript]
    for dist in dists:
        distribution_script = DistributionScript.find(dist, name)
        if distribution_script:
            return distribution_script
    return None


@attr.s(frozen=True)
class DistributionEntryPoint(object):
    dist = attr.ib()  # type: Distribution
    name = attr.ib()  # type: str
    entry_point = attr.ib()  # type: Union[ModuleEntryPoint, CallableEntryPoint]

    def render_description(self):
        # type: () -> str
        return "console script {name} = {entry_point} in {dist}".format(
            name=self.name, entry_point=self.entry_point, dist=self.dist
        )


def get_entry_point_from_console_script(
    script,  # type: str
    dists,  # type: Iterable[Distribution]
):
    # type: (...) -> Optional[DistributionEntryPoint]
    # Check all distributions for the console_script "script". De-dup by dist key to allow for a
    # duplicate console script IFF the distribution is platform-specific and this is a
    # multi-platform pex.
    def get_entrypoint(
        dist,  # type: Distribution
        gui=False,  # type: bool
    ):
        # type: (...) -> Optional[NamedEntryPoint]
        return dist.get_entry_map().get("gui_scripts" if gui else "console_scripts", {}).get(script)

    entries = {}  # type: Dict[ProjectName, DistributionEntryPoint]
    for dist in dists:
        named_entry_point = get_entrypoint(dist) or get_entrypoint(dist, gui=True)
        if named_entry_point is not None:
            entries[dist.metadata.project_name] = DistributionEntryPoint(
                dist=dist, name=named_entry_point.name, entry_point=named_entry_point.entry_point
            )

    if len(entries) > 1:
        raise RuntimeError(
            "Ambiguous script specification {script} matches multiple entry points:\n\t"
            "{entry_points}".format(
                script=script,
                entry_points="\n\t".join(
                    "{entry_point} from {dist}".format(
                        entry_point=dist_entry_point.entry_point, dist=dist_entry_point.dist
                    )
                    for dist_entry_point in entries.values()
                ),
            )
        )

    dist_entry_point = None
    if entries:
        dist_entry_point = next(iter(entries.values()))
    return dist_entry_point
