from collections.abc import AsyncIterator

import pytest

from agent_lab.application.contracts import AgentParams, DebugRunRequest, EventAgentParams
from agent_lab.application.runtime import DebugRuntime
from agent_lab.domain.events import ToolCallEvent
from agent_lab.domain.messages import ChatMessage, StreamItem


class FakeChatClient:
    def __init__(self) -> None:
        self.calls = 0

    async def stream_chat(
        self,
        messages: list[ChatMessage],
        tools: list[dict],
        params: AgentParams,
    ) -> AsyncIterator[StreamItem]:
        self.calls += 1
        if self.calls == 1:
            yield StreamItem.event(
                ToolCallEvent(
                    id="call_1",
                    name="handoff_note",
                    arguments={"message": "need event agent"},
                    raw_arguments='{"message":"need event agent"}',
                )
            )
            return

        assert any(message.role == "tool" for message in messages)
        yield StreamItem.message_delta("final answer")


class StrictHistoryChatClient:
    def __init__(self) -> None:
        self.calls = 0
        self.second_call_messages: list[ChatMessage] = []

    async def stream_chat(
        self,
        messages: list[ChatMessage],
        tools: list[dict],
        params: AgentParams,
    ) -> AsyncIterator[StreamItem]:
        self.calls += 1
        if self.calls == 1:
            yield StreamItem.event(
                ToolCallEvent(
                    id="call_1",
                    name="handoff_note",
                    arguments={"message": "need event agent"},
                    raw_arguments='{"message":"need event agent"}',
                )
            )
            return

        self.second_call_messages = list(messages)
        yield StreamItem.message_delta("final answer")


@pytest.mark.asyncio
async def test_runtime_routes_chat_events_through_event_agent_then_continues_chat():
    request = DebugRunRequest(
        user_message="debug this",
        system_prompts=["You are a debugger."],
        pre_messages=[],
        chat_agent=AgentParams(model="fake-model", temperature=0.1, max_tokens=200),
        event_agent=EventAgentParams(enabled_tools=["handoff_note"], max_event_loops=3),
    )
    client = FakeChatClient()
    runtime = DebugRuntime(client)

    outputs = [message async for message in runtime.run(request)]

    assert client.calls == 2
    assert [message["type"] for message in outputs] == [
        "session_started",
        "event",
        "tool_result",
        "message_delta",
        "done",
    ]
    assert outputs[1]["event"]["name"] == "handoff_note"
    assert outputs[3]["content"] == "final answer"


@pytest.mark.asyncio
async def test_runtime_preserves_assistant_tool_calls_before_tool_reply():
    request = DebugRunRequest(
        user_message="debug this",
        system_prompts=["You are a debugger."],
        pre_messages=[],
        chat_agent=AgentParams(model="fake-model", temperature=0.1, max_tokens=200),
        event_agent=EventAgentParams(enabled_tools=["handoff_note"], max_event_loops=2),
    )
    client = StrictHistoryChatClient()
    runtime = DebugRuntime(client)

    outputs = [message async for message in runtime.run(request)]

    assert client.calls == 2
    assert [message.role for message in client.second_call_messages] == [
        "system",
        "user",
        "assistant",
        "tool",
    ]
    assistant_message = client.second_call_messages[2]
    tool_message = client.second_call_messages[3]
    assert assistant_message.content == ""
    assert assistant_message.tool_calls == [
        {
            "id": "call_1",
            "type": "function",
            "function": {
                "name": "handoff_note",
                "arguments": '{"message":"need event agent"}',
            },
        }
    ]
    assert tool_message.tool_call_id == "call_1"
    assert outputs[-1] == {"type": "done"}