"""ORCH-110 TC-01 / TC-02: process-group tree-kill of orchestrator-spawned pytest.

Covers D1 (FR-2 / BR-3 / AC-4): a timeout in ``merge_gate.retest_branch`` /
``coverage_gate.measure_coverage`` must tree-kill the WHOLE subprocess subtree
(children + grandchildren) — the orphan-leak root cause of the ORCH-109 incident —
not just the direct child.

Fully deterministic and offline:
  * TC-01 runs a REAL throwaway process that spawns a long-sleeping grandchild via
    ``sys.executable`` (always present), then asserts the grandchild is dead after a
    ``run_in_process_group`` timeout — the concrete "no orphan survives" proof.
  * TC-01b / TC-02 assert the two call sites delegate to ``run_in_process_group``
    with the right tree-kill kwargs and map a timed-out ProcResult to their existing
    contract (``(False, "re-test timeout after <T>s")`` / ``None``).
No network, no Plane/Gitea, no Claude CLI.
"""
import os
import tempfile
import time

os.environ.setdefault("ORCH_DB_PATH", os.path.join(tempfile.gettempdir(), "test_orch110_lifecycle.db"))
os.environ.setdefault("ORCH_REPOS_DIR", tempfile.gettempdir())
os.environ.setdefault("ORCH_GITEA_TOKEN", "test-token")
os.environ.setdefault("ORCH_PLANE_API_TOKEN", "test-token")

import sys  # noqa: E402

import pytest  # noqa: E402

from src import coverage_gate as cg  # noqa: E402
from src import merge_gate  # noqa: E402
from src import proc_group  # noqa: E402
from src.proc_group import ProcResult, run_in_process_group  # noqa: E402

_POSIX = hasattr(os, "killpg") and hasattr(os, "setsid")


def _alive(pid: int) -> bool:
    """True iff ``pid`` is a live (non-reaped) process."""
    try:
        os.kill(pid, 0)
        return True
    except ProcessLookupError:
        return False
    except PermissionError:
        return True


# ---------------------------------------------------------------------------
# TC-01: real grandchild is tree-killed on timeout (the FR-2 / AC-4 proof).
# ---------------------------------------------------------------------------
@pytest.mark.skipif(not _POSIX, reason="process-group tree-kill is POSIX-only")
def test_tc01_grandchild_orphan_is_tree_killed_on_timeout(tmp_path):
    pidfile = tmp_path / "grandchild.pid"
    script = tmp_path / "spawner.py"
    # The leader spawns a long-sleeping grandchild, records its pid, then sleeps far
    # past the timeout. A naive subprocess.run(timeout=) would kill ONLY the leader
    # and leak the grandchild (the ORCH-109 bug). The process-group tree-kill must
    # reap the grandchild too.
    script.write_text(
        "import subprocess, sys, time\n"
        "gc = subprocess.Popen([sys.executable, '-c', 'import time; time.sleep(120)'])\n"
        "open(sys.argv[1], 'w').write(str(gc.pid))\n"
        "time.sleep(120)\n",
        encoding="utf-8",
    )

    res = run_in_process_group(
        [sys.executable, str(script), str(pidfile)],
        cwd=str(tmp_path), timeout=2, grace_s=1, tree_kill=True,
    )
    assert res.timed_out is True

    # Wait for the leader to actually have written the grandchild pid.
    deadline = time.time() + 5
    while time.time() < deadline and not pidfile.exists():
        time.sleep(0.05)
    assert pidfile.exists(), "spawner never recorded the grandchild pid"
    gc_pid = int(pidfile.read_text().strip())

    # The grandchild must die (be reaped) within a short window after the tree-kill.
    deadline = time.time() + 8
    while time.time() < deadline and _alive(gc_pid):
        time.sleep(0.1)
    assert not _alive(gc_pid), "grandchild orphan survived the timeout tree-kill (FR-2/AC-4)"


@pytest.mark.skipif(not _POSIX, reason="process-group runner is POSIX-only")
def test_tc01_green_and_red_returncodes_passthrough(tmp_path):
    """The runner returns the real exit code on a normal (non-timeout) completion."""
    ok = run_in_process_group(
        [sys.executable, "-c", "import sys; sys.exit(0)"],
        cwd=str(tmp_path), timeout=30, tree_kill=True,
    )
    assert ok.timed_out is False and ok.returncode == 0
    red = run_in_process_group(
        [sys.executable, "-c", "import sys; sys.exit(3)"],
        cwd=str(tmp_path), timeout=30, tree_kill=True,
    )
    assert red.timed_out is False and red.returncode == 3


def test_tc01_fallback_when_tree_kill_disabled(tmp_path, monkeypatch):
    """tree_kill=False -> degrades to subprocess.run (never-break); still times out."""
    res = run_in_process_group(
        [sys.executable, "-c", "import time; time.sleep(30)"],
        cwd=str(tmp_path), timeout=1, tree_kill=False,
    )
    assert res.timed_out is True


def test_tc01_fallback_on_non_posix(tmp_path, monkeypatch):
    """No os.killpg/setsid (non-POSIX) -> the plain subprocess.run fallback runs."""
    monkeypatch.setattr(proc_group, "_tree_kill_supported", lambda: False)
    res = run_in_process_group(
        [sys.executable, "-c", "import sys; sys.exit(0)"],
        cwd=str(tmp_path), timeout=30,
    )
    assert res.timed_out is False and res.returncode == 0


# ---------------------------------------------------------------------------
# TC-01b: retest_branch delegates to the process-group runner with the right
# kwargs and maps a timeout to its existing contract.
# ---------------------------------------------------------------------------
def test_tc01b_retest_branch_uses_process_group_and_maps_timeout(tmp_path, monkeypatch):
    wt = tmp_path / "wt"
    wt.mkdir()
    monkeypatch.setattr(merge_gate, "get_worktree_path", lambda repo, branch: str(wt))
    monkeypatch.setattr(merge_gate.settings, "merge_retest_timeout_s", 900, raising=False)
    monkeypatch.setattr(merge_gate.settings, "subprocess_tree_kill_enabled", True, raising=False)
    monkeypatch.setattr(merge_gate.settings, "agent_kill_grace_seconds", 7, raising=False)

    captured = {}

    def _fake(cmd, *, cwd, timeout, env=None, grace_s=5.0, tree_kill=True):
        captured.update(cmd=cmd, cwd=cwd, timeout=timeout, grace_s=grace_s, tree_kill=tree_kill)
        return ProcResult(returncode=None, stdout="", stderr="", timed_out=True)

    monkeypatch.setattr(merge_gate, "run_in_process_group", _fake)
    ok, reason = merge_gate.retest_branch("orchestrator", "feature/x")
    assert ok is False
    assert reason == "re-test timeout after 900s"
    # FR-2: spawned via the process-group runner with tree-kill + the agent grace.
    assert captured["tree_kill"] is True
    assert captured["grace_s"] == 7
    assert captured["cmd"][:3] == ["python", "-m", "pytest"]


# ---------------------------------------------------------------------------
# TC-02: coverage_gate.measure_coverage — sibling orphan source (BR-3). Timeout
# tree-kills + returns None; uses the same runner with tree-kill from settings.
# ---------------------------------------------------------------------------
def test_tc02_measure_coverage_timeout_tree_kill_returns_none(tmp_path, monkeypatch):
    monkeypatch.setattr(cg, "ensure_worktree", lambda r, b: str(tmp_path))
    monkeypatch.setattr(cg.settings, "subprocess_tree_kill_enabled", True, raising=False)
    monkeypatch.setattr(cg.settings, "agent_kill_grace_seconds", 5, raising=False)
    monkeypatch.setattr(cg.settings, "coverage_run_timeout_s", 900, raising=False)

    captured = {}

    def _fake(cmd, *, cwd, timeout, env=None, grace_s=5.0, tree_kill=True):
        captured.update(tree_kill=tree_kill, grace_s=grace_s, timeout=timeout)
        return ProcResult(returncode=None, stdout="", stderr="", timed_out=True)

    monkeypatch.setattr(cg, "run_in_process_group", _fake)
    assert cg.measure_coverage("orchestrator", "feature/x") is None
    assert captured["tree_kill"] is True
    assert captured["grace_s"] == 5
    assert captured["timeout"] == 900


def test_tc02_measure_coverage_respects_tree_kill_killswitch(tmp_path, monkeypatch):
    """With the tree-kill kill-switch off, the runner is asked for the fallback path."""
    monkeypatch.setattr(cg, "ensure_worktree", lambda r, b: str(tmp_path))
    monkeypatch.setattr(cg.settings, "subprocess_tree_kill_enabled", False, raising=False)
    captured = {}

    def _fake(cmd, *, cwd, timeout, env=None, grace_s=5.0, tree_kill=True):
        captured.update(tree_kill=tree_kill)
        return ProcResult(returncode=None, stdout="", stderr="", timed_out=True)

    monkeypatch.setattr(cg, "run_in_process_group", _fake)
    assert cg.measure_coverage("orchestrator", "feature/x") is None
    assert captured["tree_kill"] is False