import fileinput
import logging
import os
import shutil
import subprocess as sp
import tempfile
from pathlib import Path
from typing import Iterator, NamedTuple

import pytest
from root import CLAN_CORE

from clan_cli.dirs import nixpkgs_source
from clan_cli.types import FlakeName

log = logging.getLogger(__name__)


# substitutes string sin a file.
# This can be used on the flake.nix or default.nix of a machine
def substitute(
    file: Path,
    clan_core_flake: Path | None = None,
    flake: Path = Path(__file__).parent,
) -> None:
    sops_key = str(flake.joinpath("sops.key"))
    for line in fileinput.input(file, inplace=True):
        line = line.replace("__NIXPKGS__", str(nixpkgs_source()))
        if clan_core_flake:
            line = line.replace("__CLAN_CORE__", str(clan_core_flake))
        line = line.replace("__CLAN_SOPS_KEY_PATH__", sops_key)
        line = line.replace("__CLAN_SOPS_KEY_DIR__", str(flake))
        print(line, end="")


class FlakeForTest(NamedTuple):
    name: FlakeName
    path: Path


def create_flake(
    monkeypatch: pytest.MonkeyPatch,
    temporary_home: Path,
    flake_name: FlakeName,
    clan_core_flake: Path | None = None,
    machines: list[str] = [],
    remote: bool = False,
) -> Iterator[FlakeForTest]:
    """
    Creates a flake with the given name and machines.
    The machine names map to the machines in ./test_machines
    """
    template = Path(__file__).parent / flake_name

    # copy the template to a new temporary location
    flake = temporary_home / ".local/state/clan/flake" / flake_name
    shutil.copytree(template, flake)

    # lookup the requested machines in ./test_machines and include them
    if machines:
        (flake / "machines").mkdir(parents=True, exist_ok=True)
    for machine_name in machines:
        machine_path = Path(__file__).parent / "machines" / machine_name
        shutil.copytree(machine_path, flake / "machines" / machine_name)
        substitute(flake / "machines" / machine_name / "default.nix", flake)
    # in the flake.nix file replace the string __CLAN_URL__ with the the clan flake
    # provided by get_test_flake_toplevel
    flake_nix = flake / "flake.nix"
    # this is where we would install the sops key to, when updating
    substitute(flake_nix, clan_core_flake, flake)

    if "/tmp" not in str(os.environ.get("HOME")):
        log.warning(
            f"!! $HOME does not point to a temp directory!! HOME={os.environ['HOME']}"
        )

    # TODO: Find out why test_vms_api.py fails in nix build
    # but works in pytest when this bottom line is commented out
    sp.run(
        ["git", "config", "--global", "init.defaultBranch", "main"],
        cwd=flake,
        check=True,
    )
    sp.run(["git", "init"], cwd=flake, check=True)
    sp.run(["git", "add", "."], cwd=flake, check=True)
    sp.run(["git", "config", "user.name", "clan-tool"], cwd=flake, check=True)
    sp.run(["git", "config", "user.email", "clan@example.com"], cwd=flake, check=True)
    sp.run(["git", "commit", "-a", "-m", "Initial commit"], cwd=flake, check=True)

    if remote:
        with tempfile.TemporaryDirectory():
            yield FlakeForTest(flake_name, flake)
    else:
        yield FlakeForTest(flake_name, flake)


@pytest.fixture
def test_flake(
    monkeypatch: pytest.MonkeyPatch, temporary_home: Path
) -> Iterator[FlakeForTest]:
    yield from create_flake(monkeypatch, temporary_home, FlakeName("test_flake"))


@pytest.fixture
def test_flake_with_core(
    monkeypatch: pytest.MonkeyPatch, temporary_home: Path
) -> Iterator[FlakeForTest]:
    if not (CLAN_CORE / "flake.nix").exists():
        raise Exception(
            "clan-core flake not found. This test requires the clan-core flake to be present"
        )
    yield from create_flake(
        monkeypatch,
        temporary_home,
        FlakeName("test_flake_with_core"),
        CLAN_CORE,
    )


@pytest.fixture
def test_flake_with_core_and_pass(
    monkeypatch: pytest.MonkeyPatch, temporary_home: Path
) -> Iterator[FlakeForTest]:
    if not (CLAN_CORE / "flake.nix").exists():
        raise Exception(
            "clan-core flake not found. This test requires the clan-core flake to be present"
        )
    yield from create_flake(
        monkeypatch,
        temporary_home,
        FlakeName("test_flake_with_core_and_pass"),
        CLAN_CORE,
    )