import glob
import logging
import os
import tarfile
import zipfile

from pathlib import Path
from typing import Dict
from typing import Iterator
from typing import List
from typing import Optional
from typing import Union

import pkginfo

from poetry.core.factory import Factory
from poetry.core.packages.dependency import Dependency
from poetry.core.packages.package import Package
from poetry.core.packages.project_package import ProjectPackage
from poetry.core.pyproject.toml import PyProjectTOML
from poetry.core.utils.helpers import parse_requires
from poetry.core.utils.helpers import temporary_directory
from poetry.core.version.markers import InvalidMarker
from poetry.utils.env import EnvCommandError
from poetry.utils.env import ephemeral_environment
from poetry.utils.setup_reader import SetupReader


logger = logging.getLogger(__name__)

PEP517_META_BUILD = """\
import pep517.build
import pep517.meta

path='{source}'
system=pep517.build.compat_system(path)
pep517.meta.build(source_dir=path, dest='{dest}', system=system)
"""

PEP517_META_BUILD_DEPS = ["pep517===0.8.2", "toml==0.10.1"]


class PackageInfoError(ValueError):
    def __init__(
        self, path: Union[Path, str], *reasons: Union[BaseException, str]
    ) -> None:
        reasons = (
            "Unable to determine package info for path: {}".format(str(path)),
        ) + reasons
        super(PackageInfoError, self).__init__(
            "\n\n".join(str(msg).strip() for msg in reasons if msg)
        )


class PackageInfo:
    def __init__(
        self,
        name: Optional[str] = None,
        version: Optional[str] = None,
        summary: Optional[str] = None,
        platform: Optional[str] = None,
        requires_dist: Optional[List[str]] = None,
        requires_python: Optional[str] = None,
        files: Optional[List[str]] = None,
        cache_version: Optional[str] = None,
    ):
        self.name = name
        self.version = version
        self.summary = summary
        self.platform = platform
        self.requires_dist = requires_dist
        self.requires_python = requires_python
        self.files = files or []
        self._cache_version = cache_version
        self._source_type = None
        self._source_url = None
        self._source_reference = None

    @property
    def cache_version(self) -> Optional[str]:
        return self._cache_version

    def update(self, other: "PackageInfo") -> "PackageInfo":
        self.name = other.name or self.name
        self.version = other.version or self.version
        self.summary = other.summary or self.summary
        self.platform = other.platform or self.platform
        self.requires_dist = other.requires_dist or self.requires_dist
        self.requires_python = other.requires_python or self.requires_python
        self.files = other.files or self.files
        self._cache_version = other.cache_version or self._cache_version
        return self

    def asdict(self) -> Dict[str, Optional[Union[str, List[str]]]]:
        """
        Helper method to convert package info into a dictionary used for caching.
        """
        return {
            "name": self.name,
            "version": self.version,
            "summary": self.summary,
            "platform": self.platform,
            "requires_dist": self.requires_dist,
            "requires_python": self.requires_python,
            "files": self.files,
            "_cache_version": self._cache_version,
        }

    @classmethod
    def load(cls, data: Dict[str, Optional[Union[str, List[str]]]]) -> "PackageInfo":
        """
        Helper method to load data from a dictionary produced by `PackageInfo.asdict()`.

        :param data: Data to load. This is expected to be a `dict` object output by `asdict()`.
        """
        cache_version = data.pop("_cache_version", None)
        return cls(cache_version=cache_version, **data)

    @classmethod
    def _log(cls, msg: str, level: str = "info") -> None:
        """Internal helper method to log information."""
        getattr(logger, level)("<debug>{}:</debug> {}".format(cls.__name__, msg))

    def to_package(
        self,
        name: Optional[str] = None,
        extras: Optional[List[str]] = None,
        root_dir: Optional[Path] = None,
    ) -> Package:
        """
        Create a new `poetry.core.packages.package.Package` instance using metadata from this instance.

        :param name: Name to use for the package, if not specified name from this instance is used.
        :param extras: Extras to activate for this package.
        :param root_dir:  Optional root directory to use for the package. If set, dependency strings
            will be parsed relative to this directory.
        """
        name = name or self.name

        if not self.version:
            # The version could not be determined, so we raise an error since it is mandatory.
            raise RuntimeError(
                "Unable to retrieve the package version for {}".format(name)
            )

        package = Package(
            name=name,
            version=self.version,
            source_type=self._source_type,
            source_url=self._source_url,
            source_reference=self._source_reference,
        )
        package.description = self.summary
        package.root_dir = root_dir
        package.python_versions = self.requires_python or "*"
        package.files = self.files

        if root_dir or (self._source_type in {"directory"} and self._source_url):
            # this is a local poetry project, this means we can extract "richer" requirement information
            # eg: development requirements etc.
            poetry_package = self._get_poetry_package(path=root_dir or self._source_url)
            if poetry_package:
                package.extras = poetry_package.extras
                package.requires = poetry_package.requires
                return package

        seen_requirements = set()

        for req in self.requires_dist or []:
            try:
                # Attempt to parse the PEP-508 requirement string
                dependency = Dependency.create_from_pep_508(req, relative_to=root_dir)
            except InvalidMarker:
                # Invalid marker, We strip the markers hoping for the best
                req = req.split(";")[0]
                dependency = Dependency.create_from_pep_508(req, relative_to=root_dir)
            except ValueError:
                # Likely unable to parse constraint so we skip it
                self._log(
                    "Invalid constraint ({}) found in {}-{} dependencies, "
                    "skipping".format(req, package.name, package.version),
                    level="warning",
                )
                continue

            if dependency.in_extras:
                # this dependency is required by an extra package
                for extra in dependency.in_extras:
                    if extra not in package.extras:
                        # this is the first time we encounter this extra for this package
                        package.extras[extra] = []

                    package.extras[extra].append(dependency)

            req = dependency.to_pep_508(with_extras=True)

            if req not in seen_requirements:
                package.requires.append(dependency)
                seen_requirements.add(req)

        return package

    @classmethod
    def _from_distribution(
        cls, dist: Union[pkginfo.BDist, pkginfo.SDist, pkginfo.Wheel]
    ) -> "PackageInfo":
        """
        Helper method to parse package information from a `pkginfo.Distribution` instance.

        :param dist: The distribution instance to parse information from.
        """
        requirements = None

        if dist.requires_dist:
            requirements = list(dist.requires_dist)
        else:
            requires = Path(dist.filename) / "requires.txt"
            if requires.exists():
                with requires.open(encoding="utf-8") as f:
                    requirements = parse_requires(f.read())

        info = cls(
            name=dist.name,
            version=dist.version,
            summary=dist.summary,
            platform=dist.supported_platforms,
            requires_dist=requirements,
            requires_python=dist.requires_python,
        )

        info._source_type = "file"
        info._source_url = Path(dist.filename).resolve().as_posix()

        return info

    @classmethod
    def _from_sdist_file(cls, path: Path) -> "PackageInfo":
        """
        Helper method to parse package information from an sdist file. We attempt to first inspect the
        file using `pkginfo.SDist`. If this does not provide us with package requirements, we extract the
        source and handle it as a directory.

        :param path: The sdist file to parse information from.
        """
        info = None

        try:
            info = cls._from_distribution(pkginfo.SDist(str(path)))
        except ValueError:
            # Unable to determine dependencies
            # We pass and go deeper
            pass
        else:
            if info.requires_dist is not None:
                # we successfully retrieved dependencies from sdist metadata
                return info

        # Still not dependencies found
        # So, we unpack and introspect
        suffix = path.suffix

        if suffix == ".zip":
            context = zipfile.ZipFile
        else:
            if suffix == ".bz2":
                suffixes = path.suffixes
                if len(suffixes) > 1 and suffixes[-2] == ".tar":
                    suffix = ".tar.bz2"
            else:
                suffix = ".tar.gz"

            context = tarfile.open

        with temporary_directory() as tmp:
            tmp = Path(tmp)
            with context(path.as_posix()) as archive:
                archive.extractall(tmp.as_posix())

            # a little bit of guess work to determine the directory we care about
            elements = list(tmp.glob("*"))

            if len(elements) == 1 and elements[0].is_dir():
                sdist_dir = elements[0]
            else:
                sdist_dir = tmp / path.name.rstrip(suffix)
                if not sdist_dir.is_dir():
                    sdist_dir = tmp

            # now this is an unpacked directory we know how to deal with
            new_info = cls.from_directory(path=sdist_dir)

        if not info:
            return new_info

        return info.update(new_info)

    @staticmethod
    def has_setup_files(path: Path) -> bool:
        return any((path / f).exists() for f in SetupReader.FILES)

    @classmethod
    def from_setup_files(cls, path: Path) -> "PackageInfo":
        """
        Mechanism to parse package information from a `setup.[py|cfg]` file. This uses the implementation
        at `poetry.utils.setup_reader.SetupReader` in order to parse the file. This is not reliable for
        complex setup files and should only attempted as a fallback.

        :param path: Path to `setup.py` file
        """
        if not cls.has_setup_files(path):
            raise PackageInfoError(
                path, "No setup files (setup.py, setup.cfg) was found."
            )

        try:
            result = SetupReader.read_from_directory(path)
        except Exception as e:
            raise PackageInfoError(path, e)

        python_requires = result["python_requires"]
        if python_requires is None:
            python_requires = "*"

        requires = ""
        for dep in result["install_requires"]:
            requires += dep + "\n"

        if result["extras_require"]:
            requires += "\n"

        for extra_name, deps in result["extras_require"].items():
            requires += "[{}]\n".format(extra_name)

            for dep in deps:
                requires += dep + "\n"

            requires += "\n"

        requirements = parse_requires(requires)

        info = cls(
            name=result.get("name"),
            version=result.get("version"),
            summary=result.get("description", ""),
            requires_dist=requirements or None,
            requires_python=python_requires,
        )

        if not (info.name and info.version) and not info.requires_dist:
            # there is nothing useful here
            raise PackageInfoError(
                path,
                "No core metadata (name, version, requires-dist) could be retrieved.",
            )

        return info

    @staticmethod
    def _find_dist_info(path: Path) -> Iterator[Path]:
        """
        Discover all `*.*-info` directories in a given path.

        :param path: Path to search.
        """
        pattern = "**/*.*-info"
        # Sometimes pathlib will fail on recursive symbolic links, so we need to workaround it
        # and use the glob module instead. Note that this does not happen with pathlib2
        # so it's safe to use it for Python < 3.4.
        directories = glob.iglob(path.joinpath(pattern).as_posix(), recursive=True)

        for d in directories:
            yield Path(d)

    @classmethod
    def from_metadata(cls, path: Path) -> Optional["PackageInfo"]:
        """
        Helper method to parse package information from an unpacked metadata directory.

        :param path: The metadata directory to parse information from.
        """
        if path.suffix in {".dist-info", ".egg-info"}:
            directories = [path]
        else:
            directories = cls._find_dist_info(path=path)

        for directory in directories:
            try:
                if directory.suffix == ".egg-info":
                    dist = pkginfo.UnpackedSDist(directory.as_posix())
                elif directory.suffix == ".dist-info":
                    dist = pkginfo.Wheel(directory.as_posix())
                else:
                    continue
                break
            except ValueError:
                continue
        else:
            try:
                # handle PKG-INFO in unpacked sdist root
                dist = pkginfo.UnpackedSDist(path.as_posix())
            except ValueError:
                return

        info = cls._from_distribution(dist=dist)
        if info:
            return info

    @classmethod
    def from_package(cls, package: Package) -> "PackageInfo":
        """
        Helper method to inspect a `Package` object, in order to generate package info.

        :param package: This must be a poetry package instance.
        """
        requires = {dependency.to_pep_508() for dependency in package.requires}

        for extra_requires in package.extras.values():
            for dependency in extra_requires:
                requires.add(dependency.to_pep_508())

        return cls(
            name=package.name,
            version=str(package.version),
            summary=package.description,
            platform=package.platform,
            requires_dist=list(requires),
            requires_python=package.python_versions,
            files=package.files,
        )

    @staticmethod
    def _get_poetry_package(path: Path) -> Optional[ProjectPackage]:
        # Note: we ignore any setup.py file at this step
        # TODO: add support for handling non-poetry PEP-517 builds
        if PyProjectTOML(path.joinpath("pyproject.toml")).is_poetry_project():
            return Factory().create_poetry(path).package

    @classmethod
    def _pep517_metadata(cls, path: Path) -> "PackageInfo":
        """
        Helper method to use PEP-517 library to build and read package metadata.

        :param path: Path to package source to build and read metadata for.
        """
        info = None
        try:
            info = cls.from_setup_files(path)
            if all([info.version, info.name, info.requires_dist]):
                return info
        except PackageInfoError:
            pass

        with ephemeral_environment(pip=True, wheel=True, setuptools=True) as venv:
            # TODO: cache PEP 517 build environment corresponding to each project venv
            dest_dir = venv.path.parent / "dist"
            dest_dir.mkdir()

            try:
                venv.run_pip(
                    "install",
                    "--disable-pip-version-check",
                    "--ignore-installed",
                    *PEP517_META_BUILD_DEPS
                )
                venv.run(
                    "python",
                    "-",
                    input_=PEP517_META_BUILD.format(
                        source=path.as_posix(), dest=dest_dir.as_posix()
                    ),
                )
                return cls.from_metadata(dest_dir)
            except EnvCommandError as e:
                # something went wrong while attempting pep517 metadata build
                # fallback to egg_info if setup.py available
                cls._log("PEP517 build failed: {}".format(e), level="debug")
                setup_py = path / "setup.py"
                if not setup_py.exists():
                    raise PackageInfoError(
                        path,
                        e,
                        "No fallback setup.py file was found to generate egg_info.",
                    )

                cwd = Path.cwd()
                os.chdir(path.as_posix())
                try:
                    venv.run("python", "setup.py", "egg_info")
                    return cls.from_metadata(path)
                except EnvCommandError as fbe:
                    raise PackageInfoError(
                        path, "Fallback egg_info generation failed.", fbe
                    )
                finally:
                    os.chdir(cwd.as_posix())

        if info:
            cls._log(
                "Falling back to parsed setup.py file for {}".format(path), "debug"
            )
            return info

        # if we reach here, everything has failed and all hope is lost
        raise PackageInfoError(path, "Exhausted all core metadata sources.")

    @classmethod
    def from_directory(cls, path: Path, disable_build: bool = False) -> "PackageInfo":
        """
        Generate package information from a package source directory. If `disable_build` is not `True` and
        introspection of all available metadata fails, the package is attempted to be build in an isolated
        environment so as to generate required metadata.

        :param path: Path to generate package information from.
        :param disable_build: If not `True` and setup reader fails, PEP 517 isolated build is attempted in
            order to gather metadata.
        """
        project_package = cls._get_poetry_package(path)
        if project_package:
            info = cls.from_package(project_package)
        else:
            info = cls.from_metadata(path)

            if not info or info.requires_dist is None:
                try:
                    if disable_build:
                        info = cls.from_setup_files(path)
                    else:
                        info = cls._pep517_metadata(path)
                except PackageInfoError:
                    if not info:
                        raise

                    # we discovered PkgInfo but no requirements were listed

        info._source_type = "directory"
        info._source_url = path.as_posix()

        return info

    @classmethod
    def from_sdist(cls, path: Path) -> "PackageInfo":
        """
        Gather package information from an sdist file, packed or unpacked.

        :param path: Path to an sdist file or unpacked directory.
        """
        if path.is_file():
            return cls._from_sdist_file(path=path)

        # if we get here then it is neither an sdist instance nor a file
        # so, we assume this is an directory
        return cls.from_directory(path=path)

    @classmethod
    def from_wheel(cls, path: Path) -> "PackageInfo":
        """
        Gather package information from a wheel.

        :param path: Path to wheel.
        """
        try:
            return cls._from_distribution(pkginfo.Wheel(str(path)))
        except ValueError:
            return PackageInfo()

    @classmethod
    def from_bdist(cls, path: Path) -> "PackageInfo":
        """
        Gather package information from a bdist (wheel etc.).

        :param path: Path to bdist.
        """
        if isinstance(path, (pkginfo.BDist, pkginfo.Wheel)):
            cls._from_distribution(dist=path)

        if path.suffix == ".whl":
            return cls.from_wheel(path=path)

        try:
            return cls._from_distribution(pkginfo.BDist(str(path)))
        except ValueError as e:
            raise PackageInfoError(path, e)

    @classmethod
    def from_path(cls, path: Path) -> "PackageInfo":
        """
        Gather package information from a given path (bdist, sdist, directory).

        :param path: Path to inspect.
        """
        try:
            return cls.from_bdist(path=path)
        except PackageInfoError:
            return cls.from_sdist(path=path)
