from __future__ import annotations

import contextlib
import os.path
from typing import Generator
from typing import Sequence

from pre_commit import lang_base
from pre_commit.envcontext import envcontext
from pre_commit.envcontext import PatchesT
from pre_commit.envcontext import Var
from pre_commit.errors import FatalError
from pre_commit.prefix import Prefix

ENVIRONMENT_DIR = "hs_env"
get_default_version = lang_base.basic_get_default_version
health_check = lang_base.basic_health_check
run_hook = lang_base.basic_run_hook


def get_env_patch(target_dir: str) -> PatchesT:
    bin_path = os.path.join(target_dir, "bin")
    return (("PATH", (bin_path, os.pathsep, Var("PATH"))),)


@contextlib.contextmanager
def in_env(prefix: Prefix, version: str) -> Generator[None, None, None]:
    envdir = lang_base.environment_dir(prefix, ENVIRONMENT_DIR, version)
    with envcontext(get_env_patch(envdir)):
        yield


def install_environment(
    prefix: Prefix,
    version: str,
    additional_dependencies: Sequence[str],
) -> None:
    lang_base.assert_version_default("haskell", version)
    envdir = lang_base.environment_dir(prefix, ENVIRONMENT_DIR, version)

    pkgs = [*prefix.star(".cabal"), *additional_dependencies]
    if not pkgs:
        raise FatalError("Expected .cabal files or additional_dependencies")

    bindir = os.path.join(envdir, "bin")
    os.makedirs(bindir, exist_ok=True)
    lang_base.setup_cmd(prefix, ("cabal", "update"))
    lang_base.setup_cmd(
        prefix,
        (
            "cabal",
            "install",
            "--install-method",
            "copy",
            "--installdir",
            bindir,
            *pkgs,
        ),
    )
