import contextlib
import os.path
import shutil
import tarfile
from typing import Generator
from typing import Sequence
from typing import Tuple

import pre_commit.constants as C
from pre_commit.envcontext import envcontext
from pre_commit.envcontext import PatchesT
from pre_commit.envcontext import UNSET
from pre_commit.envcontext import Var
from pre_commit.hook import Hook
from pre_commit.languages import helpers
from pre_commit.prefix import Prefix
from pre_commit.util import CalledProcessError
from pre_commit.util import clean_path_on_failure
from pre_commit.util import resource_bytesio

ENVIRONMENT_DIR = 'rbenv'
get_default_version = helpers.basic_get_default_version
healthy = helpers.basic_healthy


def get_env_patch(
        venv: str,
        language_version: str,
) -> PatchesT:  # pragma: win32 no cover
    patches: PatchesT = (
        ('GEM_HOME', os.path.join(venv, 'gems')),
        ('GEM_PATH', UNSET),
        ('RBENV_ROOT', venv),
        ('BUNDLE_IGNORE_CONFIG', '1'),
        (
            'PATH', (
                os.path.join(venv, 'gems', 'bin'), os.pathsep,
                os.path.join(venv, 'shims'), os.pathsep,
                os.path.join(venv, 'bin'), os.pathsep, Var('PATH'),
            ),
        ),
    )
    if language_version != C.DEFAULT:
        patches += (('RBENV_VERSION', language_version),)
    return patches


@contextlib.contextmanager  # pragma: win32 no cover
def in_env(
        prefix: Prefix,
        language_version: str,
) -> Generator[None, None, None]:
    envdir = prefix.path(
        helpers.environment_dir(ENVIRONMENT_DIR, language_version),
    )
    with envcontext(get_env_patch(envdir, language_version)):
        yield


def _extract_resource(filename: str, dest: str) -> None:
    with resource_bytesio(filename) as bio:
        with tarfile.open(fileobj=bio) as tf:
            tf.extractall(dest)


def _install_rbenv(
        prefix: Prefix,
        version: str = C.DEFAULT,
) -> None:  # pragma: win32 no cover
    directory = helpers.environment_dir(ENVIRONMENT_DIR, version)

    _extract_resource('rbenv.tar.gz', prefix.path('.'))
    shutil.move(prefix.path('rbenv'), prefix.path(directory))

    # Only install ruby-build if the version is specified
    if version != C.DEFAULT:
        plugins_dir = prefix.path(directory, 'plugins')
        _extract_resource('ruby-download.tar.gz', plugins_dir)
        _extract_resource('ruby-build.tar.gz', plugins_dir)


def _install_ruby(
        prefix: Prefix,
        version: str,
) -> None:  # pragma: win32 no cover
    try:
        helpers.run_setup_cmd(prefix, ('rbenv', 'download', version))
    except CalledProcessError:  # pragma: no cover (usually find with download)
        # Failed to download from mirror for some reason, build it instead
        helpers.run_setup_cmd(prefix, ('rbenv', 'install', version))


def install_environment(
        prefix: Prefix, version: str, additional_dependencies: Sequence[str],
) -> None:  # pragma: win32 no cover
    additional_dependencies = tuple(additional_dependencies)
    directory = helpers.environment_dir(ENVIRONMENT_DIR, version)
    with clean_path_on_failure(prefix.path(directory)):
        # TODO: this currently will fail if there's no version specified and
        # there's no system ruby installed.  Is this ok?
        _install_rbenv(prefix, version=version)
        with in_env(prefix, version):
            # Need to call this before installing so rbenv's directories are
            # set up
            helpers.run_setup_cmd(prefix, ('rbenv', 'init', '-'))
            if version != C.DEFAULT:
                _install_ruby(prefix, version)
            # Need to call this after installing to set up the shims
            helpers.run_setup_cmd(prefix, ('rbenv', 'rehash'))
            helpers.run_setup_cmd(
                prefix, ('gem', 'build', *prefix.star('.gemspec')),
            )
            helpers.run_setup_cmd(
                prefix,
                (
                    'gem', 'install', '--no-document',
                    *prefix.star('.gem'), *additional_dependencies,
                ),
            )


def run_hook(
        hook: Hook,
        file_args: Sequence[str],
        color: bool,
) -> Tuple[int, bytes]:  # pragma: win32 no cover
    with in_env(hook.prefix, hook.language_version):
        return helpers.run_xargs(hook, hook.cmd, file_args, color=color)