"""U2 / G2 Prompt Cache 双块结构测试。

覆盖 R4-R7, R13:
- R4 stable/volatile 双块结构
- R5 记忆注入从 system_prompt 末尾移到 volatile 层
- R6 跨 provider 统一 cache 策略(Anthropic blocks / OpenAI 字符串)
- R7 多轮 stable 不变(由构造保证)
- R13 配置化(prompt_cache_enable=False 退化)
"""

from __future__ import annotations

from typing import Any


from agentkit.core.react import ReActEngine


class _StubGateway:
    """模拟 LLMGateway,记录最后一次 chat_stream 调用的 messages。"""

    def __init__(self, provider_name: str | None = "anthropic"):
        self._provider_name = provider_name
        self.captured_messages: list[dict[str, Any]] | None = None

    def get_provider_name_for_model(self, model: str) -> str | None:
        return self._provider_name

    async def chat_stream(self, **kwargs):
        self.captured_messages = list(kwargs.get("messages", []))
        return
        yield  # makes this an async generator


def _make_engine(provider_name: str | None = "anthropic", *, cache_enable: bool = True) -> tuple[ReActEngine, _StubGateway]:
    gw = _StubGateway(provider_name=provider_name)
    engine = ReActEngine.__new__(ReActEngine)
    engine._llm_gateway = gw
    engine._prompt_cache_enable = cache_enable
    return engine, gw


# ---- R4/R6 Anthropic: stable + volatile → content blocks ----


def test_anthropic_provider_returns_content_blocks_with_cache_control():
    engine, _ = _make_engine("anthropic")
    result = engine._build_system_message(
        stable="You are a helpful assistant.",
        volatile="Memory: foo",
        model="claude-sonnet-4",
    )
    assert isinstance(result, list)
    assert result[0] == {
        "type": "text",
        "text": "You are a helpful assistant.",
        "cache_control": {"type": "ephemeral"},
    }
    assert result[1] == {"type": "text", "text": "## 参考信息\nMemory: foo"}


# ---- R5 Anthropic: empty volatile → only stable block ----


def test_anthropic_empty_volatile_returns_only_stable_block():
    engine, _ = _make_engine("anthropic")
    result = engine._build_system_message(
        stable="base prompt",
        volatile="",
        model="claude",
    )
    assert isinstance(result, list)
    assert len(result) == 1
    assert result[0]["text"] == "base prompt"
    assert "cache_control" in result[0]


# ---- R6 Non-Anthropic: returns string concat ----


def test_non_anthropic_returns_string_concat():
    engine, _ = _make_engine("openai")
    result = engine._build_system_message(
        stable="base",
        volatile="ctx",
        model="gpt-4",
    )
    assert isinstance(result, str)
    assert result == "base\n\n## 参考信息\nctx"


def test_unknown_provider_returns_string_concat():
    """provider_name 无法确定时(gateway 返回 None),回退字符串拼接不报错。"""
    engine, _ = _make_engine(None)
    result = engine._build_system_message(
        stable="base",
        volatile="ctx",
        model="default",
    )
    assert isinstance(result, str)
    assert "## 参考信息" in result


# ---- R13 Config: prompt_cache_enable=False → 退化字符串 ----


def test_prompt_cache_disabled_falls_back_to_string():
    engine, _ = _make_engine("anthropic", cache_enable=False)
    result = engine._build_system_message(
        stable="base",
        volatile="ctx",
        model="claude",
    )
    # 即便是 Anthropic,enable=False 时也返回字符串(行为同改动前)
    assert isinstance(result, str)
    assert "cache_control" not in result


# ---- R4 Edge: no stable + no volatile → None ----


def test_empty_stable_and_volatile_returns_none():
    engine, _ = _make_engine("anthropic")
    result = engine._build_system_message(stable="", volatile="", model="claude")
    assert result is None


# ---- R5 Edge: empty stable + volatile → only volatile block (Anthropic) ----


def test_anthropic_empty_stable_returns_only_volatile_block():
    engine, _ = _make_engine("anthropic")
    result = engine._build_system_message(
        stable="",
        volatile="only memory",
        model="claude",
    )
    assert isinstance(result, list)
    assert len(result) == 1
    assert result[0]["text"] == "## 参考信息\nonly memory"
    assert "cache_control" not in result[0]  # volatile 块无 cache_control


# ---- Integration: execute_stream uses _build_system_message end-to-end ----


async def test_execute_stream_with_anthropic_uses_content_blocks():
    """execute_stream 把双块 system content 透传给 gateway。"""
    from agentkit.tools.base import Tool

    class _NoopTool(Tool):
        def __init__(self):
            super().__init__(name="noop", description="noop")

        async def execute(self, **kwargs):
            return {}

    class _MockGateway:
        def __init__(self):
            self.captured_messages = None

        def get_provider_name_for_model(self, model: str) -> str | None:
            return "anthropic"

        async def chat_stream(self, **kwargs):
            self.captured_messages = list(kwargs.get("messages", []))
            # yield one chunk then end
            from agentkit.llm.protocol import StreamChunk
            yield StreamChunk(content="done", model="claude")

    class _MemRetriever:
        async def get_context_string(self, **kw):
            return "retrieved context"

    gw = _MockGateway()
    engine = ReActEngine(llm_gateway=gw, prompt_cache_enable=True)
    events = []
    async for ev in engine.execute_stream(
        messages=[{"role": "user", "content": "hi"}],
        tools=[],
        model="claude",
        system_prompt="base",
        memory_retriever=_MemRetriever(),
    ):
        events.append(ev)

    assert gw.captured_messages is not None
    sys_msg = gw.captured_messages[0]
    assert sys_msg["role"] == "system"
    assert isinstance(sys_msg["content"], list)
    assert sys_msg["content"][0]["text"] == "base"
    assert "cache_control" in sys_msg["content"][0]
    assert sys_msg["content"][1]["text"] == "## 参考信息\nretrieved context"


# ---- Anthropic provider _convert_messages passes through list-type system ----


def test_anthropic_convert_messages_passes_through_list_system_content():
    """AnthropicProvider._convert_messages 应直接透传 list-type system content。"""
    from agentkit.llm.providers.anthropic import AnthropicProvider

    provider = AnthropicProvider.__new__(AnthropicProvider)
    blocks = [
        {"type": "text", "text": "stable", "cache_control": {"type": "ephemeral"}},
        {"type": "text", "text": "volatile"},
    ]
    messages = [{"role": "system", "content": blocks}]
    system_prompt, anthropic_messages = provider._convert_messages(messages)
    assert system_prompt is blocks  # same object, transparent passthrough
    assert anthropic_messages == []


def test_anthropic_convert_messages_string_system_still_works():
    """传统 string system content 仍能透传(向后兼容)。"""
    from agentkit.llm.providers.anthropic import AnthropicProvider

    provider = AnthropicProvider.__new__(AnthropicProvider)
    messages = [{"role": "system", "content": "old style"}]
    system_prompt, _ = provider._convert_messages(messages)
    assert system_prompt == "old style"