"""Regression tests for empty-response recovery transcript persistence."""

from run_agent import AIAgent


def _agent_with_stubbed_persistence():
    agent = AIAgent.__new__(AIAgent)
    agent._persist_user_message_idx = None
    agent._persist_user_message_override = None
    agent._session_db = None
    agent._session_messages = []
    agent.flushed_session_db_messages = []
    agent._flush_messages_to_session_db = lambda messages, conversation_history=None: (
        agent.flushed_session_db_messages.append([m.copy() for m in messages])
    )
    return agent


def test_persist_session_strips_trailing_empty_recovery_scaffolding():
    """After stripping scaffolding, also rewind past orphan trailing tool-result
    messages that the failed iteration left behind. Otherwise the next user
    message lands after a bare ``tool`` and produces a protocol-invalid
    sequence that most providers silently fail on, retriggering the empty-
    retry loop indefinitely.
    """
    agent = _agent_with_stubbed_persistence()
    messages = [
        {"role": "user", "content": "run the task"},
        {
            "role": "assistant",
            "content": "",
            "tool_calls": [{"id": "call_1", "type": "function",
                            "function": {"name": "x", "arguments": "{}"}}],
        },
        {"role": "tool", "content": "{}", "tool_call_id": "call_1"},
        {
            "role": "assistant",
            "content": "(empty)",
            "_empty_recovery_synthetic": True,
        },
        {
            "role": "user",
            "content": (
                "You just executed tool calls but returned an empty response. "
                "Please process the tool results above and continue with the task."
            ),
            "_empty_recovery_synthetic": True,
        },
    ]

    AIAgent._persist_session(agent, messages, conversation_history=[])

    # After strip + rewind, only the original user message remains. The
    # assistant(tool_calls) + tool pair is dropped because its iteration
    # never produced a real response.
    assert messages == [
        {"role": "user", "content": "run the task"},
    ]
    assert agent.flushed_session_db_messages[-1] == messages
    assert all(not msg.get("_empty_recovery_synthetic") for msg in messages)


def test_persist_session_keeps_unmarked_terminal_empty_response():
    agent = _agent_with_stubbed_persistence()
    messages = [
        {"role": "user", "content": "run the task"},
        {"role": "assistant", "content": "(empty)"},
    ]

    AIAgent._persist_session(agent, messages, conversation_history=[])

    assert messages == [
        {"role": "user", "content": "run the task"},
        {"role": "assistant", "content": "(empty)"},
    ]
    assert agent.flushed_session_db_messages[-1] == messages


def test_persist_session_strips_marked_terminal_empty_sentinel():
    agent = _agent_with_stubbed_persistence()
    messages = [
        {"role": "user", "content": "continue"},
        {
            "role": "assistant",
            "content": "(empty)",
            "_empty_terminal_sentinel": True,
        },
    ]

    AIAgent._persist_session(agent, messages, conversation_history=[])

    assert messages == [{"role": "user", "content": "continue"}]
    assert agent.flushed_session_db_messages[-1] == messages
    assert all(not msg.get("_empty_terminal_sentinel") for msg in messages)
