import logging
import os
import pkginfo
import shutil
import time

from cleo import ProgressIndicator
from contextlib import contextmanager
from functools import cmp_to_key
from tempfile import mkdtemp
from typing import List
from typing import Union

from poetry.packages import Dependency
from poetry.packages import DirectoryDependency
from poetry.packages import FileDependency
from poetry.packages import Package
from poetry.packages import VCSDependency
from poetry.packages import dependency_from_pep_508

from poetry.mixology.incompatibility import Incompatibility
from poetry.mixology.incompatibility_cause import DependencyCause
from poetry.mixology.incompatibility_cause import PlatformCause
from poetry.mixology.incompatibility_cause import PythonCause
from poetry.mixology.term import Term

from poetry.repositories import Pool

from poetry.utils._compat import Path
from poetry.utils.helpers import parse_requires
from poetry.utils.toml_file import TomlFile
from poetry.utils.venv import Venv

from poetry.vcs.git import Git

from .dependencies import Dependencies
from .exceptions import CompatibilityError


logger = logging.getLogger(__name__)


class Indicator(ProgressIndicator):
    def __init__(self, output):
        super(Indicator, self).__init__(output)

        self.format = "%message% <fg=black;options=bold>(%elapsed:2s%)</>"

    @contextmanager
    def auto(self):
        message = "<info>Resolving dependencies</info>..."

        with super(Indicator, self).auto(message, message):
            yield

    def _formatter_elapsed(self):
        elapsed = time.time() - self.start_time

        return "{:.1f}s".format(elapsed)


class Provider:

    UNSAFE_PACKAGES = {"setuptools", "distribute", "pip"}

    def __init__(self, package, pool, io):  # type: Package  # type: Pool
        self._package = package
        self._pool = pool
        self._io = io
        self._python_constraint = package.python_constraint
        self._search_for = {}
        self._is_debugging = self._io.is_debug() or self._io.is_very_verbose()
        self._in_progress = False

    @property
    def pool(self):  # type: () -> Pool
        return self._pool

    @property
    def name_for_explicit_dependency_source(self):  # type: () -> str
        return "pyproject.toml"

    @property
    def name_for_locking_dependency_source(self):  # type: () -> str
        return "pyproject.lock"

    def is_debugging(self):
        return self._is_debugging

    def name_for(self, dependency):  # type: (Dependency) -> str
        """
        Returns the name for the given dependency.
        """
        return dependency.name

    def search_for(self, dependency):  # type: (Dependency) -> List[Package]
        """
        Search for the specifications that match the given dependency.

        The specifications in the returned list will be considered in reverse
        order, so the latest version ought to be last.
        """
        if dependency.is_root:
            return [self._package]

        if dependency in self._search_for:
            return self._search_for[dependency]

        if dependency.is_vcs():
            packages = self.search_for_vcs(dependency)
        elif dependency.is_file():
            packages = self.search_for_file(dependency)
        elif dependency.is_directory():
            packages = self.search_for_directory(dependency)
        else:
            constraint = dependency.constraint

            packages = self._pool.find_packages(
                dependency.name,
                constraint,
                extras=dependency.extras,
                allow_prereleases=dependency.allows_prereleases(),
            )

            packages.sort(
                key=lambda p: (
                    not p.is_prerelease() and not dependency.allows_prereleases(),
                    p.version,
                ),
                reverse=True,
            )

        self._search_for[dependency] = packages

        return self._search_for[dependency]

    def search_for_vcs(self, dependency):  # type: (VCSDependency) -> List[Package]
        """
        Search for the specifications that match the given VCS dependency.

        Basically, we clone the repository in a temporary directory
        and get the information we need by checking out the specified reference.
        """
        if dependency.vcs != "git":
            raise ValueError("Unsupported VCS dependency {}".format(dependency.vcs))

        tmp_dir = Path(mkdtemp(prefix="pypoetry-git-{}".format(dependency.name)))

        try:
            git = Git()
            git.clone(dependency.source, tmp_dir)
            git.checkout(dependency.reference, tmp_dir)
            revision = git.rev_parse(dependency.reference, tmp_dir).strip()

            if dependency.tag or dependency.rev:
                revision = dependency.reference

            pyproject = TomlFile(tmp_dir / "pyproject.toml")
            pyproject_content = None
            has_poetry = False
            if pyproject.exists():
                pyproject_content = pyproject.read(True)
                has_poetry = (
                    "tool" in pyproject_content
                    and "poetry" in pyproject_content["tool"]
                )

            if pyproject_content and has_poetry:
                # If a pyproject.toml file exists
                # We use it to get the information we need
                info = pyproject_content["tool"]["poetry"]

                name = info["name"]
                version = info["version"]
                package = Package(name, version, version)
                package.source_type = dependency.vcs
                package.source_url = dependency.source
                package.source_reference = dependency.reference
                for req_name, req_constraint in info["dependencies"].items():
                    if req_name == "python":
                        package.python_versions = req_constraint
                        continue

                    package.add_dependency(req_name, req_constraint)
            else:
                # We need to use setup.py here
                # to figure the information we need
                # We need to place ourselves in the proper
                # folder for it to work
                venv = Venv.create(self._io)

                current_dir = os.getcwd()
                os.chdir(tmp_dir.as_posix())

                try:
                    venv.run("python", "setup.py", "egg_info")

                    egg_info = next(tmp_dir.glob("**/*.egg-info"))

                    meta = pkginfo.UnpackedSDist(str(egg_info))

                    if meta.requires_dist:
                        reqs = list(meta.requires_dist)
                    else:
                        reqs = []
                        requires = egg_info / "requires.txt"
                        if requires.exists():
                            with requires.open() as f:
                                reqs = parse_requires(f.read())

                    package = Package(meta.name, meta.version)

                    for req in reqs:
                        package.requires.append(dependency_from_pep_508(req))
                except Exception:
                    raise
                finally:
                    os.chdir(current_dir)

            package.source_type = "git"
            package.source_url = dependency.source
            package.source_reference = revision
        except Exception:
            raise
        finally:
            shutil.rmtree(tmp_dir.as_posix())

        if dependency.name != package.name:
            # For now, the dependency's name must match the actual package's name
            raise RuntimeError(
                "The dependency name for {} does not match the actual package's name: {}".format(
                    dependency.name, package.name
                )
            )

        return [package]

    def search_for_file(self, dependency):  # type: (FileDependency) -> List[Package]
        package = Package(dependency.name, dependency.pretty_constraint)
        package.source_type = "file"
        package.source_url = dependency.path.as_posix()

        package.description = dependency.metadata.summary
        for req in dependency.metadata.requires_dist:
            package.requires.append(dependency_from_pep_508(req))

        if dependency.metadata.requires_python:
            package.python_versions = dependency.metadata.requires_python

        if dependency.metadata.platforms:
            package.platform = " || ".join(dependency.metadata.platforms)

        package.hashes = [dependency.hash()]

        return [package]

    def search_for_directory(
        self, dependency
    ):  # type: (DirectoryDependency) -> List[Package]
        package = dependency.package
        if dependency.extras:
            for extra in dependency.extras:
                if extra in package.extras:
                    for dep in package.extras[extra]:
                        dep.activate()

        return [package]

    def incompatibilities_for(
        self, package
    ):  # type: (Package) -> List[Incompatibility]
        """
        Returns incompatibilities that encapsulate a given package's dependencies,
        or that it can't be safely selected.

        If multiple subsequent versions of this package have the same
        dependencies, this will return incompatibilities that reflect that. It
        won't return incompatibilities that have already been returned by a
        previous call to _incompatibilities_for().
        """
        if package.is_root():
            dependencies = package.all_requires
        else:
            dependencies = package.requires

        if not self._package.python_constraint.allows_any(package.python_constraint):
            return [
                Incompatibility(
                    [Term(package.to_dependency(), True)],
                    PythonCause(package.python_versions, self._package.python_versions),
                )
            ]

        if not self._package.platform_constraint.matches(package.platform_constraint):
            return [
                Incompatibility(
                    [Term(package.to_dependency(), True)],
                    PlatformCause(package.platform),
                )
            ]

        dependencies = [
            dep
            for dep in dependencies
            if dep.name not in self.UNSAFE_PACKAGES
            and self._package.python_constraint.allows_any(dep.python_constraint)
            and self._package.platform_constraint.matches(dep.platform_constraint)
        ]

        return [
            Incompatibility(
                [Term(package.to_dependency(), True), Term(dep, False)],
                DependencyCause(),
            )
            for dep in dependencies
        ]

    def complete_package(self, package):  # type: (str, Version) -> Package
        if package.is_root() or package.source_type in {"git", "file", "directory"}:
            return package

        package = self._pool.package(
            package.name, package.version.text, extras=package.requires_extras
        )

        dependencies = [
            r
            for r in package.requires
            if r.is_activated()
            and self._package.python_constraint.allows_any(r.python_constraint)
            and self._package.platform_constraint.matches(r.platform_constraint)
        ]

        # Searching for duplicate dependencies
        #
        # If the duplicate dependencies have the same constraint,
        # the requirements will be merged.
        #
        # For instance:
        #   - enum34; python_version=="2.7"
        #   - enum34; python_version=="3.3"
        #
        # will become:
        #   - enum34; python_version=="2.7" or python_version=="3.3"
        #
        # If the duplicate dependencies have different constraints
        # we have to split the dependency graph.
        #
        # An example of this is:
        #   - pypiwin32 (220); sys_platform == "win32" and python_version >= "3.6"
        #   - pypiwin32 (219); sys_platform == "win32" and python_version < "3.6"
        if not package.is_root():
            duplicates = {}
            for dep in dependencies:
                if dep.name not in duplicates:
                    duplicates[dep.name] = []

                duplicates[dep.name].append(dep)

            dependencies = []
            for dep_name, deps in duplicates.items():
                if len(deps) == 1:
                    dependencies.append(deps[0])
                    continue

                self.debug("Duplicate dependencies for {}".format(dep_name))

                # Regrouping by constraint
                by_constraint = {}
                for dep in deps:
                    if dep.constraint not in by_constraint:
                        by_constraint[dep.constraint] = []

                    by_constraint[dep.constraint].append(dep)

                # We merge by constraint
                for constraint, _deps in by_constraint.items():
                    new_markers = []
                    for dep in _deps:
                        pep_508_dep = dep.to_pep_508()
                        if ";" not in pep_508_dep:
                            continue

                        markers = pep_508_dep.split(";")[1].strip()
                        if not markers:
                            # One of the constraint has no markers
                            # so this means we don't actually need to merge
                            new_markers = []
                            break

                        new_markers.append("({})".format(markers))

                    if not new_markers:
                        dependencies += _deps
                        continue

                    dep = _deps[0]
                    new_requirement = "{}; {}".format(
                        dep.to_pep_508().split(";")[0], " or ".join(new_markers)
                    )
                    new_dep = dependency_from_pep_508(new_requirement)
                    if dep.is_optional() and not dep.is_activated():
                        new_dep.deactivate()
                    else:
                        new_dep.activate()

                    by_constraint[constraint] = [new_dep]

                    continue

                if len(by_constraint) == 1:
                    self.debug("Merging requirements for {}".format(str(deps[0])))
                    dependencies.append(list(by_constraint.values())[0][0])
                    continue

                # We leave dependencies as-is if they have the same
                # python/platform constraints.
                # That way the resolver will pickup the conflict
                # and display a proper error.
                _deps = [value[0] for value in by_constraint.values()]
                seen = set()
                for _dep in _deps:
                    pep_508_dep = _dep.to_pep_508()
                    if ";" not in pep_508_dep:
                        _requirements = ""
                    else:
                        _requirements = pep_508_dep.split(";")[1].strip()

                    if _requirements not in seen:
                        seen.add(_requirements)

                if len(_deps) != len(seen):
                    for _dep in _deps:
                        dependencies.append(_dep)

                    continue

                # At this point, we raise an exception that will
                # tell the solver to enter compatibility mode
                # which means it will resolve for subsets
                # Python constraints
                #
                # For instance, if our root package requires Python ~2.7 || ^3.6
                # And we have one dependency that requires Python <3.6
                # and the other Python >=3.6 than the solver will solve
                # dependencies for Python >=2.7,<2.8 || >=3.4,<3.6
                # and Python >=3.6,<4.0
                python_constraints = []
                for constraint, _deps in by_constraint.items():
                    python_constraints.append(_deps[0].python_versions)

                _deps = [str(_dep[0]) for _dep in by_constraint.values()]
                self.debug(
                    "<warning>Different requirements found for {}.</warning>".format(
                        ", ".join(_deps[:-1]) + " and " + _deps[-1]
                    )
                )
                raise CompatibilityError(*python_constraints)

        package.requires = dependencies

        return package

    # UI

    @property
    def output(self):
        return self._io

    def debug(self, message, depth=0):
        if self.is_debugging():
            debug_info = str(message)
            debug_info = (
                "\n".join(
                    [
                        "<comment>{}:</> {}".format(str(depth).rjust(4), s)
                        for s in debug_info.split("\n")
                    ]
                )
                + "\n"
            )

            self.output.write(debug_info)

    @contextmanager
    def progress(self):
        if not self._io.is_decorated() or self.is_debugging():
            self.output.writeln("Resolving dependencies...")
            yield
        else:
            indicator = Indicator(self._io)

            with indicator.auto():
                yield

        self._in_progress = False
