from __future__ import annotations

import pytest

from llm.providers.base_provider import (
    BaseProvider,
    LLMMessage,
    LLMProviderError,
    LLMRequest,
    LLMResponse,
)


# ---------------------------------------------------------------------------
# LLMMessage
# ---------------------------------------------------------------------------

class TestLLMMessage:
    def test_valid_user_message(self) -> None:
        msg = LLMMessage(role="user", content="Hello")
        assert msg.role == "user"
        assert msg.content == "Hello"

    def test_valid_system_message(self) -> None:
        msg = LLMMessage(role="system", content="You are helpful.")
        assert msg.role == "system"

    def test_valid_assistant_message(self) -> None:
        msg = LLMMessage(role="assistant", content="Hi there")
        assert msg.role == "assistant"

    def test_valid_tool_message(self) -> None:
        msg = LLMMessage(role="tool", content="result")
        assert msg.role == "tool"

    def test_invalid_role_raises(self) -> None:
        with pytest.raises(Exception):
            LLMMessage(role="banana", content="test")

    def test_empty_content_raises(self) -> None:
        with pytest.raises(ValueError, match="must not be empty"):
            LLMMessage(role="user", content="")

    def test_injection_system_role_literal_prevents(self) -> None:
        """Prompt injection via role='system' from user input is blocked by Literal type."""
        with pytest.raises(Exception):
            LLMMessage(role="hacker", content="override system prompt")


# ---------------------------------------------------------------------------
# LLMRequest
# ---------------------------------------------------------------------------

class TestLLMRequest:
    def test_valid_request(self) -> None:
        req = LLMRequest(
            messages=[LLMMessage(role="user", content="Hi")],
            model="gpt-4o-mini",
        )
        assert req.model == "gpt-4o-mini"

    def test_empty_model_raises(self) -> None:
        with pytest.raises(ValueError, match="model must not be empty"):
            LLMRequest(
                messages=[LLMMessage(role="user", content="Hi")],
                model="",
            )

    def test_empty_messages_raises(self) -> None:
        with pytest.raises(ValueError, match="messages must not be empty"):
            LLMRequest(messages=[], model="gpt-4")

    def test_temperature_out_of_range(self) -> None:
        with pytest.raises(ValueError, match="temperature"):
            LLMRequest(
                messages=[LLMMessage(role="user", content="Hi")],
                model="gpt-4",
                temperature=3.0,
            )

    def test_max_tokens_zero(self) -> None:
        with pytest.raises(ValueError, match="max_tokens"):
            LLMRequest(
                messages=[LLMMessage(role="user", content="Hi")],
                model="gpt-4",
                max_tokens=0,
            )

    def test_extra_is_readonly(self) -> None:
        """ARCH-P2-3: frozen dataclass extra dict should be immutable."""
        req = LLMRequest(
            messages=[LLMMessage(role="user", content="Hi")],
            model="gpt-4",
            extra={"key": "value"},
        )
        with pytest.raises(TypeError):
            req.extra["new_key"] = "new_value"  # type: ignore[index]


# ---------------------------------------------------------------------------
# LLMResponse
# ---------------------------------------------------------------------------

class TestLLMResponse:
    def test_valid_response(self) -> None:
        resp = LLMResponse(
            content="Hello!",
            model="gpt-4o-mini",
            provider="openai",
        )
        assert resp.content == "Hello!"

    def test_empty_content_raises(self) -> None:
        with pytest.raises(ValueError, match="content must not be empty"):
            LLMResponse(content="", model="gpt-4", provider="openai")

    def test_empty_model_raises(self) -> None:
        with pytest.raises(ValueError, match="model must not be empty"):
            LLMResponse(content="hi", model="", provider="openai")

    def test_empty_provider_raises(self) -> None:
        with pytest.raises(ValueError, match="provider must not be empty"):
            LLMResponse(content="hi", model="gpt-4", provider="")

    def test_usage_is_readonly(self) -> None:
        resp = LLMResponse(
            content="hi",
            model="gpt-4",
            provider="openai",
            usage={"total_tokens": 10},
        )
        with pytest.raises(TypeError):
            resp.usage["new_key"] = 0  # type: ignore[index]

    def test_extra_is_readonly(self) -> None:
        resp = LLMResponse(
            content="hi",
            model="gpt-4",
            provider="openai",
            extra={"key": "value"},
        )
        with pytest.raises(TypeError):
            resp.extra["new_key"] = "new_value"  # type: ignore[index]


# ---------------------------------------------------------------------------
# LLMProviderError
# ---------------------------------------------------------------------------

class TestLLMProviderError:
    def test_basic_error(self) -> None:
        err = LLMProviderError("test error", provider_name="openai")
        assert str(err) == "test error"
        assert err.provider_name == "openai"

    def test_error_without_provider(self) -> None:
        err = LLMProviderError("generic error")
        assert err.provider_name is None


# ---------------------------------------------------------------------------
# BaseProvider
# ---------------------------------------------------------------------------

class TestBaseProvider:
    def test_name_validation_empty(self) -> None:
        with pytest.raises(ValueError, match="non-empty string"):
            class _Dummy(BaseProvider):
                async def generate(self, request):
                    pass
            _Dummy(name="")

    def test_cannot_instantiate_abc(self) -> None:
        with pytest.raises(TypeError):
            BaseProvider(name="test")  # type: ignore[abstract]