"""host-state 并发保存回归测试（2026-10-29 断点丢失实弹）。

旧写法两处同时失效：tmp 文件名只含 pid（容器内 host.py 全是
pid 1，并发保存写同一个 tmp 交错出坏 JSON）；flock 在 runsc
容器间不互斥（实测双双 0 秒拿到排他锁）。坏 JSON 又被
_read_state_file 静默当成空 state，下一次保存合法地重写，
全部任务条目一起丢、版本从 390 跌回个位数。

本文件锁死三条修法：tmp 名每个写者唯一、mkdir 原子锁跨进程
互斥、磁盘已损坏时保存直接拒绝覆盖。
"""

import glob
import json
import multiprocessing
import os
import tempfile
import time
import unittest
import host


def _save_one(args):
    path, name = args
    state = {"tasks": {name: {"status": "running"}}, "automations": []}
    host.save_state(path, state)
    return name


def _tmp_name(_ignored):
    return host._state_tmp_path("/tmp/x/host-state.json")


class StateTmpNameTest(unittest.TestCase):
    def test_tmp_names_unique_in_process(self):
        names = {host._state_tmp_path("/tmp/x/host-state.json")
                 for _ in range(100)}
        self.assertEqual(len(names), 100)

    def test_tmp_names_unique_across_processes(self):
        ctx = multiprocessing.get_context("fork")
        with ctx.Pool(8) as pool:
            names = pool.map(_tmp_name, range(8))
        self.assertEqual(len(set(names)), 8)


class StateMkdirLockTest(unittest.TestCase):
    def test_concurrent_saves_all_tasks_survive(self):
        with tempfile.TemporaryDirectory() as tmp:
            path = os.path.join(tmp, "host-state.json")
            ctx = multiprocessing.get_context("fork")
            names = [f"task-{i}" for i in range(8)]
            with ctx.Pool(8) as pool:
                pool.map(_save_one, [(path, n) for n in names])
            with open(path, encoding="utf-8") as f:
                data = json.load(f)
            self.assertEqual(set(data["tasks"]), set(names))
            self.assertEqual(data["version"], 8)
            self.assertFalse(glob.glob(path + ".tmp.*"))
            self.assertFalse(os.path.exists(path + ".lockdir"))

    def test_stale_lock_is_recovered(self):
        with tempfile.TemporaryDirectory() as tmp:
            path = os.path.join(tmp, "host-state.json")
            lock_dir = path + ".lockdir"
            os.mkdir(lock_dir)
            old = time.time() - 1000
            os.utime(lock_dir, (old, old))
            host.save_state(path, {"tasks": {"a": {}}, "automations": []})
            self.assertFalse(os.path.exists(lock_dir))
            with open(path, encoding="utf-8") as f:
                self.assertIn("a", json.load(f)["tasks"])

    def test_fresh_lock_timeout_raises_instead_of_writing_unlocked(self):
        with tempfile.TemporaryDirectory() as tmp:
            path = os.path.join(tmp, "host-state.json")
            os.mkdir(path + ".lockdir")
            old_timeout = host._STATE_LOCK_TIMEOUT
            host._STATE_LOCK_TIMEOUT = 0.3
            try:
                with self.assertRaises(RuntimeError):
                    host.save_state(path, {"tasks": {"a": {}},
                                           "automations": []})
            finally:
                host._STATE_LOCK_TIMEOUT = old_timeout
            self.assertFalse(os.path.exists(path))


class StateCorruptRefusalTest(unittest.TestCase):
    def test_corrupt_disk_refuses_to_overwrite(self):
        with tempfile.TemporaryDirectory() as tmp:
            path = os.path.join(tmp, "host-state.json")
            garbage = b"{not json, torn write"
            with open(path, "wb") as f:
                f.write(garbage)
            with self.assertRaises(RuntimeError):
                host.save_state(path, {"tasks": {"a": {}},
                                       "automations": []})
            with open(path, "rb") as f:
                self.assertEqual(f.read(), garbage)
            self.assertFalse(os.path.exists(path + ".bak"))
            self.assertFalse(os.path.exists(path + ".lockdir"))

    def test_wrong_shaped_disk_refuses_to_overwrite(self):
        with tempfile.TemporaryDirectory() as tmp:
            path = os.path.join(tmp, "host-state.json")
            with open(path, "w", encoding="utf-8") as f:
                json.dump({"tasks": ["not", "an", "object"],
                           "automations": []}, f)
            with self.assertRaises(RuntimeError):
                host.save_state(path, {"tasks": {"a": {}},
                                       "automations": []})


if __name__ == "__main__":
    unittest.main()