"""Tests for pipeline watchdog (KIN-099, KIN-OBS-015, KIN-OBS-019)."""

import errno
import inspect
import json
import os
import threading
import pytest
from unittest.mock import patch, MagicMock

from core.db import init_db, get_connection
from core import models
from core.watchdog import _check_dead_pipelines, start_watchdog


@pytest.fixture
def conn():
    c = init_db(db_path=":memory:")
    # Seed project + task used by run_pipeline tests
    models.create_project(c, "vdol", "ВДОЛЬ", "~/projects/vdolipoperek",
                          tech_stack=["vue3"])
    models.create_task(c, "VDOL-001", "vdol", "Fix bug",
                       brief={"route_type": "debug"})
    yield c
    c.close()


@pytest.fixture
def project_and_task(conn):
    p = models.create_project(conn, "proj1", "Test Project", "/tmp/test")
    t = models.create_task(conn, "T-001", "proj1", "Test task", priority=3)
    return p, t


def _make_running_pipeline(conn, task_id, project_id, pid=None):
    pipeline = models.create_pipeline(conn, task_id, project_id, "custom", [])
    models.update_pipeline(conn, pipeline["id"], status="running", pid=pid)
    return pipeline


# ---------------------------------------------------------------------------
# get_running_pipelines_with_pid
# ---------------------------------------------------------------------------

def test_get_running_pipelines_returns_only_with_pid(conn, project_and_task):
    _, task = project_and_task
    tid = task["id"]

    _make_running_pipeline(conn, tid, "proj1", pid=12345)
    _make_running_pipeline(conn, tid, "proj1", pid=None)  # no pid — should be excluded

    rows = models.get_running_pipelines_with_pid(conn)
    assert len(rows) == 1
    assert rows[0]["pid"] == 12345


def test_get_running_pipelines_excludes_completed(conn, project_and_task):
    _, task = project_and_task
    tid = task["id"]

    pipeline = models.create_pipeline(conn, tid, "proj1", "custom", [])
    # completed pipeline with pid — should NOT appear
    models.update_pipeline(conn, pipeline["id"], status="completed", pid=99999)

    rows = models.get_running_pipelines_with_pid(conn)
    assert rows == []


# ---------------------------------------------------------------------------
# _check_dead_pipelines (watchdog logic via tmp db file)
# ---------------------------------------------------------------------------

def _db_with_running_pipeline(tmp_path, pid):
    """Create a temp DB file with one running pipeline and return (db_path, task_id)."""
    db_path = tmp_path / "kin.db"
    conn = init_db(db_path=str(db_path))
    models.create_project(conn, "p1", "Proj", "/tmp/p")
    task = models.create_task(conn, "T-W01", "p1", "watchdog task", priority=1)
    tid = task["id"]
    pipeline = models.create_pipeline(conn, tid, "p1", "custom", [])
    models.update_pipeline(conn, pipeline["id"], status="running", pid=pid)
    conn.close()
    return db_path, tid, pipeline["id"]


def test_watchdog_alive_pid_no_change(tmp_path):
    """Живой PID не должен менять статус задачи."""
    live_pid = os.getpid()  # Our own PID — definitely alive
    db_path, task_id, pipeline_id = _db_with_running_pipeline(tmp_path, live_pid)

    _check_dead_pipelines(db_path)

    conn = init_db(db_path=str(db_path))
    task = models.get_task(conn, task_id)
    pipeline_row = conn.execute("SELECT status FROM pipelines WHERE id=?", (pipeline_id,)).fetchone()
    conn.close()

    assert task["status"] != "blocked"
    assert pipeline_row["status"] == "running"


def test_watchdog_dead_pid_blocks_task(tmp_path):
    """Мёртвый PID → pipeline=failed, task=blocked с blocked_reason."""
    dead_pid = 2**31 - 1  # Guaranteed non-existent PID
    db_path, task_id, pipeline_id = _db_with_running_pipeline(tmp_path, dead_pid)

    # Ensure the PID is actually dead
    with pytest.raises((ProcessLookupError, OSError)):
        os.kill(dead_pid, 0)

    _check_dead_pipelines(db_path)

    conn = init_db(db_path=str(db_path))
    task = models.get_task(conn, task_id)
    pipeline_row = conn.execute("SELECT status FROM pipelines WHERE id=?", (pipeline_id,)).fetchone()
    conn.close()

    assert task["status"] == "blocked"
    assert str(dead_pid) in (task.get("blocked_reason") or "")
    assert pipeline_row["status"] == "failed"


def test_watchdog_pipeline_without_pid_skipped(tmp_path):
    """Pipeline без pid не трогается watchdog'ом."""
    db_path = tmp_path / "kin.db"
    conn = init_db(db_path=str(db_path))
    models.create_project(conn, "p2", "Proj2", "/tmp/p2")
    task = models.create_task(conn, "T-W02", "p2", "no-pid task", priority=1)
    tid = task["id"]
    pipeline = models.create_pipeline(conn, tid, "p2", "custom", [])
    models.update_pipeline(conn, pipeline["id"], status="running")  # pid=None
    conn.close()

    _check_dead_pipelines(db_path)

    conn = init_db(db_path=str(db_path))
    task = models.get_task(conn, tid)
    conn.close()

    assert task["status"] != "blocked"


# ---------------------------------------------------------------------------
# DB migration (KIN-099): pid column exists and is nullable
# ---------------------------------------------------------------------------

def test_db_migration_pid_column_exists(conn):
    """После init_db поле pid должно присутствовать в таблице pipelines."""
    cols = {row[1] for row in conn.execute("PRAGMA table_info(pipelines)").fetchall()}
    assert "pid" in cols


def test_db_migration_pid_column_nullable(conn, project_and_task):
    """pid nullable: INSERT pipeline без pid должен работать."""
    _, task = project_and_task
    # create_pipeline не передаёт pid — должно вставиться без ошибок
    pipeline = models.create_pipeline(conn, task["id"], "proj1", "custom", [])
    row = conn.execute("SELECT pid FROM pipelines WHERE id=?", (pipeline["id"],)).fetchone()
    assert row["pid"] is None


# ---------------------------------------------------------------------------
# PID saved after run_pipeline()
# ---------------------------------------------------------------------------

def _make_mock_claude_success():
    mock = MagicMock()
    mock.stdout = json.dumps({
        "result": "done",
        "usage": {"total_tokens": 100},
        "cost_usd": 0.001,
    })
    mock.stderr = ""
    mock.returncode = 0
    return mock


def test_run_pipeline_saves_pid(conn):
    """run_pipeline() сохраняет os.getpid() в поле pid таблицы pipelines."""
    from agents.runner import run_pipeline

    steps = [{"role": "tester", "model": "haiku", "brief": "test brief"}]

    with patch("agents.runner.subprocess.run") as mock_run, \
         patch("agents.runner.check_claude_auth"):
        mock_run.return_value = _make_mock_claude_success()
        run_pipeline(conn, "VDOL-001", steps)

    # Проверяем, что хоть один pipeline записан с pid = os.getpid()
    row = conn.execute(
        "SELECT pid FROM pipelines WHERE task_id='VDOL-001' ORDER BY id DESC LIMIT 1"
    ).fetchone()
    assert row is not None
    assert row["pid"] == os.getpid()


# ---------------------------------------------------------------------------
# Parent process check per pipeline step
# ---------------------------------------------------------------------------

def test_run_pipeline_aborts_when_parent_dies(conn):
    """Если parent process мёртв — pipeline завершается с failed, task blocked."""
    import errno as _errno
    from agents.runner import run_pipeline

    steps = [{"role": "tester", "model": "haiku", "brief": "test brief"}]

    dead_ppid = 2**31 - 1  # guaranteed non-existent

    def _fake_kill(pid, sig):
        if pid == dead_ppid and sig == 0:
            # Must carry errno=ESRCH so _check_parent_alive recognises it
            raise OSError(_errno.ESRCH, os.strerror(_errno.ESRCH))
        # Other PIDs (e.g. our own) — allow silently
        return None

    with patch("agents.runner.os.getppid", return_value=dead_ppid), \
         patch("agents.runner.os.kill", side_effect=_fake_kill), \
         patch("agents.runner.check_claude_auth"), \
         patch("agents.runner.subprocess.run") as mock_run:
        mock_run.return_value = _make_mock_claude_success()
        result = run_pipeline(conn, "VDOL-001", steps)

    assert result["success"] is False
    assert result.get("error") == "parent_process_died"

    # task должна быть blocked с упоминанием dead_ppid
    task = models.get_task(conn, "VDOL-001")
    assert task["status"] == "blocked"
    assert str(dead_ppid) in (task.get("blocked_reason") or "")

    # pipeline должен быть failed
    row = conn.execute(
        "SELECT status FROM pipelines WHERE task_id='VDOL-001' ORDER BY id DESC LIMIT 1"
    ).fetchone()
    assert row["status"] == "failed"


# ---------------------------------------------------------------------------
# KIN-OBS-015: start_watchdog() double-start guard
# ---------------------------------------------------------------------------

def test_start_watchdog_sets_started_flag(tmp_path):
    """start_watchdog() устанавливает _watchdog_started = True."""
    import core.watchdog as wd
    wd._watchdog_started = False

    db_path = tmp_path / "kin_flag.db"
    init_db(db_path=str(db_path))

    with patch("core.watchdog.threading.Thread") as mock_thread_cls:
        mock_thread = MagicMock()
        mock_thread_cls.return_value = mock_thread

        start_watchdog(db_path, interval=9999)

        assert wd._watchdog_started is True

    wd._watchdog_started = False  # restore


def test_start_watchdog_double_call_no_second_thread(tmp_path):
    """Повторный вызов start_watchdog() не создаёт второй поток."""
    import core.watchdog as wd
    wd._watchdog_started = False

    db_path = tmp_path / "kin_double.db"
    init_db(db_path=str(db_path))

    with patch("core.watchdog.threading.Thread") as mock_thread_cls:
        mock_thread = MagicMock()
        mock_thread_cls.return_value = mock_thread

        start_watchdog(db_path, interval=9999)  # first call
        start_watchdog(db_path, interval=9999)  # second call — guard должен заблокировать

        # Thread создан и запущен ровно один раз
        assert mock_thread_cls.call_count == 1
        assert mock_thread.start.call_count == 1

    wd._watchdog_started = False  # restore


# ---------------------------------------------------------------------------
# KIN-OBS-015: _check_dead_pipelines использует get_connection()
# ---------------------------------------------------------------------------

def test_check_dead_pipelines_calls_get_connection(tmp_path):
    """_check_dead_pipelines вызывает get_connection() — WAL и foreign_keys PRAGMA применяются."""
    db_path = tmp_path / "kin_gc.db"
    real_conn = init_db(db_path=str(db_path))
    real_conn.close()

    with patch("core.watchdog.get_connection", wraps=get_connection) as mock_gc:
        _check_dead_pipelines(db_path)
        mock_gc.assert_called_once_with(db_path)


def test_get_connection_applies_wal_and_foreign_keys(tmp_path):
    """get_connection() применяет PRAGMA journal_mode=WAL и foreign_keys=ON."""
    db_path = tmp_path / "kin_pragma.db"
    conn = get_connection(db_path)

    jm = conn.execute("PRAGMA journal_mode").fetchone()[0]
    fk = conn.execute("PRAGMA foreign_keys").fetchone()[0]
    conn.close()

    assert jm == "wal"
    assert fk == 1


# ---------------------------------------------------------------------------
# KIN-OBS-015: OSError+errno.ESRCH и другие errno — mock-based
# ---------------------------------------------------------------------------

def test_check_dead_pipelines_esrch_via_mock(tmp_path):
    """OSError с errno=ESRCH перехватывается как мёртвый процесс и блокирует задачу."""
    fake_pid = 54321
    db_path, task_id, pipeline_id = _db_with_running_pipeline(tmp_path, fake_pid)

    def _fake_kill(pid, sig):
        if pid == fake_pid and sig == 0:
            raise OSError(errno.ESRCH, "No such process")

    with patch("core.watchdog.os.kill", side_effect=_fake_kill):
        _check_dead_pipelines(db_path)

    conn = init_db(db_path=str(db_path))
    task = models.get_task(conn, task_id)
    pipeline_row = conn.execute(
        "SELECT status FROM pipelines WHERE id=?", (pipeline_id,)
    ).fetchone()
    conn.close()

    assert task["status"] == "blocked"
    assert str(fake_pid) in (task.get("blocked_reason") or "")
    assert pipeline_row["status"] == "failed"


def test_check_dead_pipelines_permission_error_ignored(tmp_path):
    """OSError с errno=EACCES (процесс жив, нет прав) — статус задачи не меняется."""
    fake_pid = 54322
    db_path, task_id, pipeline_id = _db_with_running_pipeline(tmp_path, fake_pid)

    def _fake_kill(pid, sig):
        if pid == fake_pid and sig == 0:
            raise OSError(errno.EACCES, "Operation not permitted")

    with patch("core.watchdog.os.kill", side_effect=_fake_kill):
        _check_dead_pipelines(db_path)

    conn = init_db(db_path=str(db_path))
    task = models.get_task(conn, task_id)
    pipeline_row = conn.execute(
        "SELECT status FROM pipelines WHERE id=?", (pipeline_id,)
    ).fetchone()
    conn.close()

    assert task["status"] != "blocked"
    assert pipeline_row["status"] == "running"


# ---------------------------------------------------------------------------
# _check_parent_alive: EACCES и ProcessLookupError (KIN-099, решения #341/#358)
# ---------------------------------------------------------------------------

def test_check_parent_alive_eacces_does_not_abort(conn):
    """EACCES при os.kill(ppid, 0) — процесс жив (нет прав) → pipeline продолжается (решение #358)."""
    import errno as _errno
    from agents.runner import _check_parent_alive

    pipeline = models.create_pipeline(conn, "VDOL-001", "vdol", "custom", [])
    eacces_ppid = 99990

    with patch("agents.runner.os.getppid", return_value=eacces_ppid), \
         patch("agents.runner.os.kill", side_effect=OSError(_errno.EACCES, "Operation not permitted")):
        result = _check_parent_alive(conn, pipeline, "VDOL-001", "vdol")

    assert result is False

    task = models.get_task(conn, "VDOL-001")
    assert task["status"] != "blocked"


def test_check_parent_alive_process_lookup_error_aborts(conn):
    """ProcessLookupError (errno=ESRCH) при os.kill → pipeline прерывается (решение #341)."""
    import errno as _errno
    from agents.runner import _check_parent_alive

    pipeline = models.create_pipeline(conn, "VDOL-001", "vdol", "custom", [])
    dead_ppid = 99991

    with patch("agents.runner.os.getppid", return_value=dead_ppid), \
         patch("agents.runner.os.kill", side_effect=ProcessLookupError(_errno.ESRCH, "No such process")):
        result = _check_parent_alive(conn, pipeline, "VDOL-001", "vdol")

    assert result is True

    task = models.get_task(conn, "VDOL-001")
    assert task["status"] == "blocked"
    assert str(dead_ppid) in (task.get("blocked_reason") or "")


# ---------------------------------------------------------------------------
# KIN-OBS-019: регрессионные тесты через inspect.getsource() — decision #367
# ---------------------------------------------------------------------------

def test_watchdog_source_has_no_sqlite3_connect():
    """Регрессия: watchdog не должен содержать прямой вызов sqlite3.connect() (decision #367)."""
    import core.watchdog as wd
    source = inspect.getsource(wd)
    assert "sqlite3.connect" not in source, (
        "REGRESSION: core/watchdog.py содержит sqlite3.connect() — "
        "должен использовать get_connection() из core.db"
    )


def test_watchdog_source_has_no_explicit_process_lookup_error():
    """Регрессия: watchdog не должен перехватывать ProcessLookupError явно (decision #357).

    Обработка мёртвых процессов унифицирована через OSError + errno.ESRCH.
    Проверяем через AST: в except-обработчиках не должно быть ProcessLookupError.
    """
    import ast
    import core.watchdog as wd
    source = inspect.getsource(wd)
    tree = ast.parse(source)

    process_lookup_in_except = False
    for node in ast.walk(tree):
        if isinstance(node, ast.ExceptHandler) and node.type is not None:
            for name_node in ast.walk(node.type):
                if isinstance(name_node, ast.Name) and name_node.id == "ProcessLookupError":
                    process_lookup_in_except = True
                    break

    assert not process_lookup_in_except, (
        "REGRESSION: core/watchdog.py перехватывает ProcessLookupError явно — "
        "должен использовать OSError + errno.ESRCH"
    )


def test_check_dead_pipelines_kill_succeeds_no_change(tmp_path):
    """os.kill успешно (нет исключения) → процесс жив, статус задачи не меняется."""
    fake_pid = 54323
    db_path, task_id, pipeline_id = _db_with_running_pipeline(tmp_path, fake_pid)

    # os.kill returns None (no exception) — process is alive
    with patch("core.watchdog.os.kill", return_value=None):
        _check_dead_pipelines(db_path)

    conn = init_db(db_path=str(db_path))
    task = models.get_task(conn, task_id)
    pipeline_row = conn.execute(
        "SELECT status FROM pipelines WHERE id=?", (pipeline_id,)
    ).fetchone()
    conn.close()

    assert task["status"] != "blocked"
    assert pipeline_row["status"] == "running"