"""U4/G1: Verify 失败回灌 ReAct 测试

characterization-first: 先覆盖现有 verify 行为(max_reinjections=0 等价于不回灌),
再测新回灌行为(reinjection on first fail, break on second fail)。

R1: verify 首次失败 → errors 注入 conversation → LLM 自纠正 → 二次 verify 通过
R2: verify 二次失败 → 中断返回错误附 verify log
R3: max_reinjections 可配置(默认 1),=0 等价于不回灌;回灌受 max_steps 约束
R13: ServerConfig.verification 配置项
R14: max_reinjections 默认值为 1
"""

from __future__ import annotations

from unittest.mock import AsyncMock, MagicMock, patch


from agentkit.core.react import ReActEngine
from agentkit.core.verification_loop import VerificationResult
from agentkit.llm.gateway import LLMGateway
from agentkit.llm.protocol import LLMResponse, TokenUsage


# ── Helpers ──────────────────────────────────────────────


def make_mock_gateway(responses: list[LLMResponse]) -> LLMGateway:
    """创建按顺序返回给定响应的 mock LLMGateway。"""
    gateway = MagicMock(spec=LLMGateway)
    gateway.chat = AsyncMock(side_effect=responses)
    gateway.get_provider_name_for_model = MagicMock(return_value=None)
    return gateway


def make_response(content: str = "") -> LLMResponse:
    return LLMResponse(
        content=content,
        model="test-model",
        usage=TokenUsage(prompt_tokens=10, completion_tokens=20),
        tool_calls=[],
    )


def make_verify_result(passed: bool, errors: list[str] | None = None) -> VerificationResult:
    return VerificationResult(
        passed=passed,
        attempts=1,
        test_output="$ pytest\nFAILED test_x.py" if not passed else "$ pytest\nOK",
        errors=errors or ([] if passed else ["test_x.py::test_failed"]),
    )


def make_mock_vloop(verify_results: list[VerificationResult]) -> MagicMock:
    """创建一个 mock VerificationLoop,verify() 按顺序返回给定结果。"""
    vloop = MagicMock()
    vloop.verify = AsyncMock(side_effect=verify_results)
    return vloop


# ── Characterization: max_reinjections=0 等价于当前行为 ──────────


class TestVerifyCharacterization:
    """现有 verify 行为(max_reinjections=0):失败仅记录 trajectory,不回灌。"""

    async def test_verify_disabled_no_verify_step(self):
        """verification_enabled=False → 不运行 verify,trajectory 无 verification step。"""
        gateway = make_mock_gateway([make_response("final answer")])
        engine = ReActEngine(llm_gateway=gateway, max_steps=3)

        result = await engine.execute(
            messages=[{"role": "user", "content": "do something"}],
        )

        assert result.output == "final answer"
        assert all(s.tool_name != "verification" for s in result.trajectory)

    async def test_verify_pass_no_extra_step(self):
        """verify 通过 → 不追加 verification step。"""
        gateway = make_mock_gateway([make_response("answer")])
        engine = ReActEngine(
            llm_gateway=gateway,
            max_steps=3,
            verification_enabled=True,
            verification_commands=["echo ok"],
            max_reinjections=0,
        )

        with patch(
            "agentkit.core.verification_loop.VerificationLoop",
            return_value=make_mock_vloop([make_verify_result(passed=True)]),
        ):
            result = await engine.execute(
                messages=[{"role": "user", "content": "do something"}],
            )

        assert result.output == "answer"
        assert all(s.tool_name != "verification" for s in result.trajectory)

    async def test_verify_fail_max_zero_no_reinjection(self):
        """max_reinjections=0 + verify 失败 → 仅记录 trajectory,不回灌 LLM。

        这是当前行为的 characterization:gateway.chat 只被调用一次。
        """
        gateway = make_mock_gateway([make_response("bad answer")])
        engine = ReActEngine(
            llm_gateway=gateway,
            max_steps=3,
            verification_enabled=True,
            verification_commands=["false"],
            max_reinjections=0,
        )

        with patch(
            "agentkit.core.verification_loop.VerificationLoop",
            return_value=make_mock_vloop([make_verify_result(passed=False)]),
        ):
            result = await engine.execute(
                messages=[{"role": "user", "content": "do something"}],
            )

        # LLM 只被调用一次(无回灌)
        assert gateway.chat.await_count == 1
        # 输出仍保留
        assert result.output == "bad answer"
        # trajectory 包含 verification step
        verify_steps = [s for s in result.trajectory if s.tool_name == "verification"]
        assert len(verify_steps) == 1
        assert verify_steps[0].result["passed"] is False


# ── R1: 回灌后 LLM 自纠正 → 二次 verify 通过 ──────────


class TestVerifyReinjection:
    """verify 失败回灌 conversation,LLM 自纠正后二次 verify 通过。"""

    async def test_first_fail_reinject_second_pass(self):
        """R1: verify 首次失败 → errors 注入 conversation → LLM 修正 → 二次 verify 通过。"""
        gateway = make_mock_gateway(
            [
                make_response("bad code"),  # 第一次:错误答案
                make_response("fixed code"),  # 第二次:修正后答案
            ]
        )
        engine = ReActEngine(
            llm_gateway=gateway,
            max_steps=5,
            verification_enabled=True,
            verification_commands=["pytest"],
            max_reinjections=1,  # 默认值,允许 1 次回灌
        )

        with patch(
            "agentkit.core.verification_loop.VerificationLoop",
            return_value=make_mock_vloop(
                [
                    make_verify_result(passed=False),  # 第一次 verify 失败
                    make_verify_result(passed=True),  # 第二次 verify 通过
                ]
            ),
        ):
            result = await engine.execute(
                messages=[{"role": "user", "content": "write code"}],
            )

        # LLM 被调用两次
        assert gateway.chat.await_count == 2
        # 最终输出是修正后的答案
        assert result.output == "fixed code"
        # 二次 verify 通过,不追加 verification step
        verify_steps = [s for s in result.trajectory if s.tool_name == "verification"]
        assert len(verify_steps) == 0

    async def test_reinjected_user_message_appears_in_conversation(self):
        """R1 集成:回灌的 user 消息出现在 conversation,含 errors 文本。"""
        gateway = make_mock_gateway(
            [
                make_response("bad"),
                make_response("good"),
            ]
        )
        engine = ReActEngine(
            llm_gateway=gateway,
            max_steps=5,
            verification_enabled=True,
            verification_commands=["pytest"],
            max_reinjections=1,
        )

        with patch(
            "agentkit.core.verification_loop.VerificationLoop",
            return_value=make_mock_vloop(
                [
                    make_verify_result(passed=False, errors=["AssertionError: x != y"]),
                    make_verify_result(passed=True),
                ]
            ),
        ):
            await engine.execute(
                messages=[{"role": "user", "content": "write code"}],
            )

        # 第二次 LLM 调用时,conversation 应包含回灌的 user 消息
        second_call = gateway.chat.await_args_list[1]
        msgs_sent = second_call.kwargs.get("messages") or second_call[1].get("messages")
        reinjected = [
            m for m in msgs_sent if m.get("role") == "user" and "验证失败" in m.get("content", "")
        ]
        assert len(reinjected) >= 1
        assert "AssertionError: x != y" in reinjected[-1]["content"]


# ── R2: 二次 verify 失败 → 中断返回错误 ──────────


class TestVerifyDoubleFailure:
    """verify 二次失败 → 中断,返回错误附 verify log。"""

    async def test_second_fail_breaks_with_verify_log(self):
        """R2: 二次 verify 失败 → 中断,trajectory 含 verify log + errors。"""
        gateway = make_mock_gateway(
            [
                make_response("bad v1"),
                make_response("bad v2"),
            ]
        )
        engine = ReActEngine(
            llm_gateway=gateway,
            max_steps=5,
            verification_enabled=True,
            verification_commands=["pytest"],
            max_reinjections=1,
        )

        with patch(
            "agentkit.core.verification_loop.VerificationLoop",
            return_value=make_mock_vloop(
                [
                    make_verify_result(passed=False, errors=["err1"]),
                    make_verify_result(passed=False, errors=["err2"]),
                ]
            ),
        ):
            result = await engine.execute(
                messages=[{"role": "user", "content": "write code"}],
            )

        # LLM 被调用两次(initial + 1 reinjection)
        assert gateway.chat.await_count == 2
        # 状态标记 verify 失败
        assert result.status == "verify_failed"
        # 输出保留(LLM 最后的答案)
        assert result.output == "bad v2"
        # trajectory 含 verification step with errors
        verify_steps = [s for s in result.trajectory if s.tool_name == "verification"]
        assert len(verify_steps) == 1
        assert verify_steps[0].result["passed"] is False
        assert "err2" in verify_steps[0].result["errors"]


# ── R3: 配置 + 边界 ──────────


class TestVerifyReinjectionConfig:
    """max_reinjections 配置测试。"""

    def test_default_max_reinjections_is_one(self):
        """R14 self-check: max_reinjections 默认值为 1。"""
        gateway = make_mock_gateway([])
        engine = ReActEngine(llm_gateway=gateway)
        assert engine._max_reinjections == 1

    async def test_max_reinjections_zero_skips_reinjection(self):
        """R3: max_reinjections=0 → 等价于不回灌(当前行为)。"""
        gateway = make_mock_gateway([make_response("only answer")])
        engine = ReActEngine(
            llm_gateway=gateway,
            max_steps=5,
            verification_enabled=True,
            verification_commands=["false"],
            max_reinjections=0,
        )

        with patch(
            "agentkit.core.verification_loop.VerificationLoop",
            return_value=make_mock_vloop([make_verify_result(passed=False)]),
        ):
            result = await engine.execute(
                messages=[{"role": "user", "content": "do something"}],
            )

        assert gateway.chat.await_count == 1  # 无回灌
        assert result.output == "only answer"

    async def test_reinjection_hits_max_steps_interrupts(self):
        """R3 edge: 回灌期间达到 max_steps → 中断(不无限循环)。"""
        # max_steps=2, max_reinjections=5(max_steps 先到)
        # LLM 调用 1:final answer → verify 失败 → reinject
        # LLM 调用 2:final answer → verify 失败 → step=2=max_steps → 中断
        gateway = make_mock_gateway(
            [
                make_response("ans1"),
                make_response("ans2"),
            ]
        )
        engine = ReActEngine(
            llm_gateway=gateway,
            max_steps=2,
            verification_enabled=True,
            verification_commands=["false"],
            max_reinjections=5,  # 远大于 max_steps,验证 max_steps 优先
        )

        with patch(
            "agentkit.core.verification_loop.VerificationLoop",
            return_value=make_mock_vloop(
                [
                    make_verify_result(passed=False),
                    make_verify_result(passed=False),
                ]
            ),
        ):
            result = await engine.execute(
                messages=[{"role": "user", "content": "do something"}],
            )

        # LLM 被调用 2 次(受 max_steps=2 限制)
        assert gateway.chat.await_count == 2
        # 第二次 verify 失败,因 max_reinjections=5 未到但 max_steps 到了
        # → 应中断(verify_failed 或 partial)
        assert result.status in ("verify_failed", "partial")


# ── execute_stream 回灌 ──────────


class TestVerifyReinjectionStream:
    """execute_stream 模式下的回灌行为。"""

    async def test_stream_reinjection_first_fail_second_pass(self):
        """R1 stream: verify 首次失败 → 回灌 → 二次通过。"""
        from agentkit.llm.protocol import StreamChunk

        def make_stream_chunks(content: str):
            """返回一个返回 chunk 列表的 async generator factory。"""

            async def _stream(**kwargs):
                # Simulate streaming: yield content in 2 chunks
                mid = len(content) // 2
                yield StreamChunk(content=content[:mid], model="test-model")
                yield StreamChunk(content=content[mid:], model="test-model")

            return _stream

        gateway = MagicMock(spec=LLMGateway)
        gateway.chat_stream = MagicMock(
            side_effect=[
                make_stream_chunks("bad code")(),
                make_stream_chunks("fixed code")(),
            ]
        )
        gateway.get_provider_name_for_model = MagicMock(return_value=None)

        engine = ReActEngine(
            llm_gateway=gateway,
            max_steps=5,
            verification_enabled=True,
            verification_commands=["pytest"],
            max_reinjections=1,
        )

        with patch(
            "agentkit.core.verification_loop.VerificationLoop",
            return_value=make_mock_vloop(
                [
                    make_verify_result(passed=False),
                    make_verify_result(passed=True),
                ]
            ),
        ):
            events = []
            async for event in engine.execute_stream(
                messages=[{"role": "user", "content": "write code"}],
            ):
                events.append(event)

        # chat_stream 被调用两次
        assert gateway.chat_stream.call_count == 2
        # 有 final_answer 事件
        final_events = [e for e in events if e.event_type == "final_answer"]
        assert len(final_events) >= 1
        # 最终输出是修正后的答案
        assert "fixed code" in final_events[-1].data.get("output", "")