"""Tests for the pure ``operations.host`` layer (W2 of the web-UI plan).

Covers ``disk_status``, ``runner_status`` and ``backup_template`` — the seam
both the CLI (``monitor disk``/``monitor runner``/``template backup``) and
the future web UI import. Zero ``click``/``print`` in the module under test;
no real ``systemctl``/``tar``/``7z`` is ever invoked — everything is
monkeypatched.
"""

from __future__ import annotations

import shutil
import subprocess
from pathlib import Path
from typing import Any

import pytest

import ci_orchestrator.operations.host as host_module
from ci_orchestrator.config import BackendConfig, Config, Paths
from ci_orchestrator.operations.host import (
    BackupResult,
    DiskStatus,
    RunnerStatus,
    TemplateDeleteResult,
    backup_template,
    delete_template,
    disk_status,
    runner_status,
)


def _make_config(templates_dir: Path) -> Config:
    return Config(
        paths=Paths(
            root=templates_dir.parent,
            templates=templates_dir,
            build_vms=templates_dir.parent / "build-vms",
            artifacts=templates_dir.parent / "artifacts",
            keys=templates_dir.parent / "keys",
        ),
        backend=BackendConfig(),
    )


def _fake_usage(free_gb: float, total_gb: float = 500.0) -> shutil._ntuple_diskusage:
    gb = 1024**3
    return shutil._ntuple_diskusage(
        int(total_gb * gb), int((total_gb - free_gb) * gb), int(free_gb * gb)
    )


# ── disk_status ──────────────────────────────────────────────────────────────


def test_disk_status_normal(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
    monkeypatch.setattr(host_module.shutil, "disk_usage", lambda _p: _fake_usage(free_gb=250, total_gb=500))

    status = disk_status(tmp_path)

    assert status.path == tmp_path
    assert status.total_gb == pytest.approx(500.0, rel=1e-3)
    assert status.free_gb == pytest.approx(250.0, rel=1e-3)
    assert status.used_pct == pytest.approx(50.0, rel=1e-2)


def test_disk_status_oserror_degrades_to_zeros(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
    def _raise(_p: Any) -> Any:
        raise OSError("no such drive")

    monkeypatch.setattr(host_module.shutil, "disk_usage", _raise)

    status = disk_status(tmp_path)

    assert status == DiskStatus(path=tmp_path, total_gb=0.0, free_gb=0.0, used_pct=0.0)


# ── runner_status ────────────────────────────────────────────────────────────


class _RunResult:
    def __init__(self, stdout: str = "", returncode: int = 0) -> None:
        self.stdout = stdout
        self.returncode = returncode


def test_runner_status_active(monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setattr(host_module.shutil, "which", lambda _n: "/usr/bin/systemctl")

    def _run(cmd: list[str], **_kw: Any) -> _RunResult:
        if cmd[1] == "is-active":
            return _RunResult(stdout="active\n")
        return _RunResult(stdout="running\n")

    monkeypatch.setattr(host_module.subprocess, "run", _run)

    result = runner_status(["act-runner.service"])

    assert result == [RunnerStatus(name="act-runner.service", active=True, sub_state="running")]


def test_runner_status_inactive(monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setattr(host_module.shutil, "which", lambda _n: "/usr/bin/systemctl")

    def _run(cmd: list[str], **_kw: Any) -> _RunResult:
        if cmd[1] == "is-active":
            return _RunResult(stdout="inactive\n", returncode=3)
        return _RunResult(stdout="dead\n")

    monkeypatch.setattr(host_module.subprocess, "run", _run)

    result = runner_status(["act-runner-rust.service"])

    assert result == [RunnerStatus(name="act-runner-rust.service", active=False, sub_state="dead")]


def test_runner_status_multiple_services(monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setattr(host_module.shutil, "which", lambda _n: "/usr/bin/systemctl")

    def _run(cmd: list[str], **_kw: Any) -> _RunResult:
        name = cmd[-1]
        if cmd[1] == "is-active":
            return _RunResult(stdout="active\n" if name == "a" else "inactive\n")
        return _RunResult(stdout="running\n" if name == "a" else "dead\n")

    monkeypatch.setattr(host_module.subprocess, "run", _run)

    result = runner_status(["a", "b"])

    assert result == [
        RunnerStatus(name="a", active=True, sub_state="running"),
        RunnerStatus(name="b", active=False, sub_state="dead"),
    ]


def test_runner_status_systemctl_absent(monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setattr(host_module.shutil, "which", lambda _n: None)

    result = runner_status(["act-runner.service", "act-runner-rust.service"])

    assert result == [
        RunnerStatus(name="act-runner.service", active=False, sub_state="unknown"),
        RunnerStatus(name="act-runner-rust.service", active=False, sub_state="unknown"),
    ]


def test_runner_status_timeout_tolerated(monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setattr(host_module.shutil, "which", lambda _n: "/usr/bin/systemctl")

    def _boom(*_a: Any, **_kw: Any) -> Any:
        raise subprocess.TimeoutExpired(cmd="systemctl", timeout=10.0)

    monkeypatch.setattr(host_module.subprocess, "run", _boom)

    result = runner_status(["act-runner.service"])

    assert result == [RunnerStatus(name="act-runner.service", active=False, sub_state="unknown")]


def test_runner_status_oserror_tolerated(monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setattr(host_module.shutil, "which", lambda _n: "/usr/bin/systemctl")

    def _boom(*_a: Any, **_kw: Any) -> Any:
        raise OSError("boom")

    monkeypatch.setattr(host_module.subprocess, "run", _boom)

    result = runner_status(["svc"])

    assert result == [RunnerStatus(name="svc", active=False, sub_state="unknown")]


def test_runner_status_never_uses_shell_true(monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setattr(host_module.shutil, "which", lambda _n: "/usr/bin/systemctl")
    seen_kwargs: list[dict[str, Any]] = []

    def _run(cmd: list[str], **kw: Any) -> _RunResult:
        seen_kwargs.append(kw)
        return _RunResult(stdout="active\n")

    monkeypatch.setattr(host_module.subprocess, "run", _run)
    runner_status(["svc"])

    assert all(not kw.get("shell") for kw in seen_kwargs)


# ── backup_template ─────────────────────────────────────────────────────────


def test_backup_template_missing_template_dir_errors(tmp_path: Path) -> None:
    templates = tmp_path / "templates"
    templates.mkdir()
    config = _make_config(templates)

    result = backup_template(config, "NoSuchTemplate")

    assert result.ok is False
    assert result.archive_path is None
    assert result.error is not None
    assert "NoSuchTemplate" in result.error or "not found" in result.error.lower()


def test_backup_template_dry_run_does_not_compress(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
    templates = tmp_path / "templates"
    tmpl_dir = templates / "WinBuild2025"
    tmpl_dir.mkdir(parents=True)
    config = _make_config(templates)

    calls: list[tuple[Path, Path]] = []
    monkeypatch.setattr(host_module, "_compress_7z", lambda src, dst: calls.append((src, dst)))

    result = backup_template(config, "WinBuild2025", dry_run=True)

    assert result.ok is True
    assert result.template == "WinBuild2025"
    assert result.archive_path is not None
    assert result.error is None
    assert calls == [], "dry_run must not compress"
    assert not result.archive_path.exists()


def test_backup_template_success_mocked_archive_step(
    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
) -> None:
    templates = tmp_path / "templates"
    tmpl_dir = templates / "WinBuild2025"
    tmpl_dir.mkdir(parents=True)
    config = _make_config(templates)

    def _fake_compress(src: Path, dst: Path) -> None:
        dst.parent.mkdir(parents=True, exist_ok=True)
        dst.write_bytes(b"archive")

    monkeypatch.setattr(host_module, "_compress_7z", _fake_compress)

    result = backup_template(config, "WinBuild2025")

    assert result == BackupResult(
        template="WinBuild2025", archive_path=result.archive_path, ok=True, error=None
    )
    assert result.archive_path is not None
    assert result.archive_path.exists()


def test_backup_template_archive_failure_reported(
    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
) -> None:
    templates = tmp_path / "templates"
    tmpl_dir = templates / "WinBuild2025"
    tmpl_dir.mkdir(parents=True)
    config = _make_config(templates)

    def _boom(_src: Path, _dst: Path) -> None:
        raise subprocess.CalledProcessError(1, ["7z"])

    monkeypatch.setattr(host_module, "_compress_7z", _boom)

    result = backup_template(config, "WinBuild2025")

    assert result.ok is False
    assert result.archive_path is None
    assert result.error is not None


def test_backup_template_never_calls_real_vmrun_or_7z(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
    """Guard: without mocking ``_compress_7z`` this would try to run real ``7z``."""
    templates = tmp_path / "templates"
    tmpl_dir = templates / "WinBuild2025"
    tmpl_dir.mkdir(parents=True)
    config = _make_config(templates)

    called: list[bool] = []

    def _fake(_src: Path, _dst: Path) -> None:
        called.append(True)

    monkeypatch.setattr(host_module, "_compress_7z", _fake)
    backup_template(config, "WinBuild2025")

    assert called == [True]


# ── delete_template ─────────────────────────────────────────────────────────


def test_delete_template_missing_template_dir_errors(tmp_path: Path) -> None:
    templates = tmp_path / "templates"
    templates.mkdir()
    config = _make_config(templates)

    result = delete_template(config, "NoSuchTemplate")

    assert result == TemplateDeleteResult(
        template="NoSuchTemplate", ok=False, error=result.error
    )
    assert result.error is not None
    assert "NoSuchTemplate" in result.error or "not found" in result.error.lower()


def test_delete_template_dry_run_does_not_remove_the_directory(tmp_path: Path) -> None:
    templates = tmp_path / "templates"
    tmpl_dir = templates / "WinBuild2025"
    tmpl_dir.mkdir(parents=True)
    (tmpl_dir / "WinBuild2025.vmx").write_text("config.version = \"8\"")
    config = _make_config(templates)

    result = delete_template(config, "WinBuild2025", dry_run=True)

    assert result == TemplateDeleteResult(template="WinBuild2025", ok=True, error=None)
    assert tmpl_dir.is_dir()


def test_delete_template_removes_the_whole_directory(tmp_path: Path) -> None:
    templates = tmp_path / "templates"
    tmpl_dir = templates / "WinBuild2025"
    tmpl_dir.mkdir(parents=True)
    (tmpl_dir / "WinBuild2025.vmx").write_text("config.version = \"8\"")
    config = _make_config(templates)

    result = delete_template(config, "WinBuild2025")

    assert result == TemplateDeleteResult(template="WinBuild2025", ok=True, error=None)
    assert not tmpl_dir.exists()


def test_delete_template_removal_failure_reported(
    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
) -> None:
    templates = tmp_path / "templates"
    tmpl_dir = templates / "WinBuild2025"
    tmpl_dir.mkdir(parents=True)
    config = _make_config(templates)

    def _boom(_path: Path) -> None:
        raise OSError("device busy")

    monkeypatch.setattr(shutil, "rmtree", _boom)

    result = delete_template(config, "WinBuild2025")

    assert result.ok is False
    assert result.error is not None
    assert tmpl_dir.is_dir()