"""Tests for AioSandbox concurrent command serialization (#1433)."""

import threading
from types import SimpleNamespace
from unittest.mock import MagicMock, patch

import pytest


@pytest.fixture()
def sandbox():
    """Create an AioSandbox with a mocked client."""
    with patch("deerflow.community.aio_sandbox.aio_sandbox.AioSandboxClient"):
        from deerflow.community.aio_sandbox.aio_sandbox import AioSandbox

        sb = AioSandbox(id="test-sandbox", base_url="http://localhost:8080")
        return sb


class TestExecuteCommandSerialization:
    """Verify that concurrent exec_command calls are serialized."""

    def test_lock_prevents_concurrent_execution(self, sandbox):
        """Concurrent threads should not overlap inside execute_command."""
        call_log = []
        barrier = threading.Barrier(3)

        def slow_exec(command, **kwargs):
            call_log.append(("enter", command))
            import time

            time.sleep(0.05)
            call_log.append(("exit", command))
            return SimpleNamespace(data=SimpleNamespace(output=f"ok: {command}"))

        sandbox._client.shell.exec_command = slow_exec

        def worker(cmd):
            barrier.wait()  # ensure all threads contend for the lock simultaneously
            sandbox.execute_command(cmd)

        threads = []
        for i in range(3):
            t = threading.Thread(target=worker, args=(f"cmd-{i}",))
            threads.append(t)

        for t in threads:
            t.start()
        for t in threads:
            t.join()

        # Verify serialization: each "enter" should be followed by its own
        # "exit" before the next "enter" (no interleaving).
        enters = [i for i, (action, _) in enumerate(call_log) if action == "enter"]
        exits = [i for i, (action, _) in enumerate(call_log) if action == "exit"]
        assert len(enters) == 3
        assert len(exits) == 3
        for e_idx, x_idx in zip(enters, exits):
            assert x_idx == e_idx + 1, f"Interleaved execution detected: {call_log}"


class TestErrorObservationRetry:
    """Verify ErrorObservation detection and fresh-session retry."""

    def test_retry_on_error_observation(self, sandbox):
        """When output contains ErrorObservation, retry with a fresh session."""
        call_count = 0

        def mock_exec(command, **kwargs):
            nonlocal call_count
            call_count += 1
            if call_count == 1:
                return SimpleNamespace(data=SimpleNamespace(output="'ErrorObservation' object has no attribute 'exit_code'"))
            return SimpleNamespace(data=SimpleNamespace(output="success"))

        sandbox._client.shell.exec_command = mock_exec

        result = sandbox.execute_command("echo hello")
        assert result == "success"
        assert call_count == 2

    def test_retry_passes_fresh_session_id(self, sandbox):
        """The retry call should include a new session id kwarg."""
        calls = []

        def mock_exec(command, **kwargs):
            calls.append(kwargs)
            if len(calls) == 1:
                return SimpleNamespace(data=SimpleNamespace(output="'ErrorObservation' object has no attribute 'exit_code'"))
            return SimpleNamespace(data=SimpleNamespace(output="ok"))

        sandbox._client.shell.exec_command = mock_exec

        sandbox.execute_command("test")
        assert len(calls) == 2
        assert "id" not in calls[0]
        assert "id" in calls[1]
        assert len(calls[1]["id"]) == 36  # UUID format

    def test_no_retry_on_clean_output(self, sandbox):
        """Normal output should not trigger a retry."""
        call_count = 0

        def mock_exec(command, **kwargs):
            nonlocal call_count
            call_count += 1
            return SimpleNamespace(data=SimpleNamespace(output="all good"))

        sandbox._client.shell.exec_command = mock_exec

        result = sandbox.execute_command("echo hello")
        assert result == "all good"
        assert call_count == 1


class TestListDirSerialization:
    """Verify that list_dir also acquires the lock."""

    def test_list_dir_uses_lock(self, sandbox):
        """list_dir should hold the lock during execution."""
        lock_was_held = []

        original_exec = MagicMock(return_value=SimpleNamespace(data=SimpleNamespace(output="/a\n/b")))

        def tracking_exec(command, **kwargs):
            lock_was_held.append(sandbox._lock.locked())
            return original_exec(command, **kwargs)

        sandbox._client.shell.exec_command = tracking_exec

        result = sandbox.list_dir("/test")
        assert result == ["/a", "/b"]
        assert lock_was_held == [True], "list_dir must hold the lock during exec_command"


class TestConcurrentFileWrites:
    """Verify file write paths do not lose concurrent updates."""

    def test_append_should_preserve_both_parallel_writes(self, sandbox):
        storage = {"content": "seed\n"}
        active_reads = 0
        state_lock = threading.Lock()
        overlap_detected = threading.Event()

        def overlapping_read_file(path):
            nonlocal active_reads
            with state_lock:
                active_reads += 1
                snapshot = storage["content"]
                if active_reads == 2:
                    overlap_detected.set()

            overlap_detected.wait(0.05)

            with state_lock:
                active_reads -= 1

            return snapshot

        def write_back(*, file, content, **kwargs):
            storage["content"] = content
            return SimpleNamespace(data=SimpleNamespace())

        sandbox.read_file = overlapping_read_file
        sandbox._client.file.write_file = write_back

        barrier = threading.Barrier(2)

        def writer(payload: str):
            barrier.wait()
            sandbox.write_file("/tmp/shared.log", payload, append=True)

        threads = [
            threading.Thread(target=writer, args=("A\n",)),
            threading.Thread(target=writer, args=("B\n",)),
        ]

        for thread in threads:
            thread.start()
        for thread in threads:
            thread.join()

        assert storage["content"] in {"seed\nA\nB\n", "seed\nB\nA\n"}