import os
from pathlib import Path

import pytest

from knoe import knoe_conf


def _symlink_supported(tmp_path: Path) -> bool:
    try:
        target = tmp_path / "target"
        link = tmp_path / "link"
        target.write_text("x")
        os.symlink(str(target), str(link))
        return link.is_symlink()
    except Exception:
        return False


def test_layered_cfg_files_order_and_merge(tmp_path: Path):
    if not _symlink_supported(tmp_path):
        pytest.skip("symlinks not supported")

    conf_dir = tmp_path / "conf"
    env_dir = conf_dir / "dev"
    env_dir.mkdir(parents=True)

    (env_dir / "knoe.cfg").write_text(
        "[Global]\nNAMESPACE = base\nSERVICE_NAMESPACE = base-svc\n"
    )
    (env_dir / "10-first.cfg").write_text("[Global]\nNAMESPACE = first\n")
    (env_dir / "20-second.cfg").write_text("[Global]\nNAMESPACE = second\n")
    (env_dir / "gcp.cfg").write_text('project_id = "demo"\n')
    (env_dir / "prod.cfg").write_text("[Global]\nNAMESPACE = ignored\n")

    entry = conf_dir / "knoe.cfg"
    os.symlink(str(env_dir / "knoe.cfg"), str(entry))

    files = knoe_conf.layered_cfg_files(entry)
    assert files == [
        env_dir / "knoe.cfg",
        env_dir / "10-first.cfg",
        env_dir / "20-second.cfg",
    ]

    cfg = knoe_conf.load_layered_config(entry)
    assert cfg.get("Global", "NAMESPACE") == "second"
    assert cfg.get("Global", "SERVICE_NAMESPACE") == "base-svc"


def test_activate_environment_updates_symlink_and_preserves_other_env(tmp_path: Path):
    if not _symlink_supported(tmp_path):
        pytest.skip("symlinks not supported")

    conf_dir = tmp_path / "conf"
    (conf_dir / "dev").mkdir(parents=True)
    (conf_dir / "service").mkdir(parents=True)

    dev_base = conf_dir / "dev" / "knoe.cfg"
    svc_base = conf_dir / "service" / "knoe.cfg"
    dev_base.write_text("[Global]\nNAMESPACE = dev-ns\n")
    svc_base.write_text("[Global]\nNAMESPACE = service-ns\n")

    knoe_conf.activate_environment(conf_dir, "dev", create_base_if_missing=False)
    entry = conf_dir / "knoe.cfg"
    assert entry.is_symlink()
    assert entry.resolve() == dev_base

    knoe_conf.activate_environment(conf_dir, "service", create_base_if_missing=False)
    assert entry.is_symlink()
    assert entry.resolve() == svc_base

    # Ensure switching does not mutate other environments.
    assert dev_base.read_text() == "[Global]\nNAMESPACE = dev-ns\n"
    cfg = knoe_conf.load_layered_config(entry)
    assert cfg.get("Global", "NAMESPACE") == "service-ns"


def test_test_environment_defaults_not_default_namespace(tmp_path: Path):
    if not _symlink_supported(tmp_path):
        pytest.skip("symlinks not supported")

    conf_dir = tmp_path / "conf"
    knoe_conf.activate_environment(conf_dir, "test")

    entry = conf_dir / "knoe.cfg"
    cfg = knoe_conf.load_layered_config(entry)
    ns = cfg.get("Global", "NAMESPACE", fallback="")
    assert ns
    assert ns != "default"
    assert ns == "knoe-test"


@pytest.mark.parametrize(
    "mode,expected_env",
    [
        ("k3d", "dev"),
        ("k3s", "service"),
        ("k8s", "prod"),
        ("test", "test"),
    ],
)
def test_ensure_entrypoint_migrates_legacy_regular_file_based_on_mode(
    tmp_path: Path, mode: str, expected_env: str
):
    if not _symlink_supported(tmp_path):
        pytest.skip("symlinks not supported")

    conf_dir = tmp_path / "conf"
    conf_dir.mkdir(parents=True)

    legacy_text = (
        f"[Global]\nDEPLOYMENT_MODE = {mode}\nCLUSTER_ENV = {mode}-example\nNAMESPACE = ns\n"
    )
    entry = conf_dir / "knoe.cfg"
    entry.write_text(legacy_text, encoding="utf-8")

    knoe_conf.ensure_entrypoint(conf_dir)

    # Entry should now be a symlink to the inferred env base.
    assert entry.is_symlink()
    target = entry.resolve()
    assert target == conf_dir / expected_env / "knoe.cfg"
    assert target.read_text(encoding="utf-8") == legacy_text

    # Legacy should be preserved as a backup.
    backups = list(conf_dir.glob("knoe.cfg.legacy.*"))
    assert backups, "expected legacy backup to be created"
    assert any(p.read_text(encoding="utf-8") == legacy_text for p in backups)

    # All env dirs should exist after bootstrap.
    for env in knoe_conf.ENVIRONMENTS:
        assert (conf_dir / env).is_dir()