"""Tests de recuperación ante overflow de ventana de contexto.

Cubre: detección del error de context-length del proveedor, y el envoltorio del
adapter que lo traduce a `ContextOverflowError` (dominio) tanto si salta al
iniciar el stream como durante la iteración.
"""

from __future__ import annotations

import asyncio
import enum
import sys
import types

import pytest

if not hasattr(enum, "StrEnum"):
    class _CompatStrEnum(str, enum.Enum):
        pass

    enum.StrEnum = _CompatStrEnum

if "anthropic" not in sys.modules:
    anthropic_stub = types.ModuleType("anthropic")
    anthropic_stub.AsyncAnthropic = type("_AsyncAnthropic", (), {})
    sys.modules["anthropic"] = anthropic_stub

if "openai" not in sys.modules:
    openai_stub = types.ModuleType("openai")
    openai_stub.AsyncOpenAI = type("_AsyncOpenAI", (), {})
    sys.modules["openai"] = openai_stub

from src.adapters.base import ContextOverflowError
from src.adapters.openai_adapter import OpenAIAdapter, _is_context_overflow


class TestOverflowDetection:
    def test_detects_by_message(self):
        assert _is_context_overflow(
            Exception("This model's maximum context length is 8192 tokens, however you requested 9000")
        )
        assert _is_context_overflow(Exception("context_length_exceeded"))
        assert _is_context_overflow(Exception("Please reduce the length of the messages"))

    def test_does_not_flag_unrelated_errors(self):
        assert not _is_context_overflow(Exception("rate limit exceeded"))
        assert not _is_context_overflow(Exception("invalid api key"))

    def test_detects_by_type_name(self):
        class ContextWindowExceededError(Exception):
            pass

        assert _is_context_overflow(ContextWindowExceededError("boom"))


class TestStreamWrapperMapsOverflow:
    def _make_adapter(self):
        # Saltamos __init__ (no necesitamos el cliente AsyncOpenAI: parcheamos
        # _stream_impl). Así el test no depende del stub de openai.
        return OpenAIAdapter.__new__(OpenAIAdapter)

    def test_overflow_at_stream_init_becomes_domain_error(self, monkeypatch):
        adapter = self._make_adapter()

        async def _impl(messages, tools=None, config=None):
            raise RuntimeError("maximum context length is 32768 tokens")
            yield  # noqa: hace de esto un async generator

        monkeypatch.setattr(adapter, "_stream_impl", _impl)

        async def _run():
            async for _ in adapter.stream([{"role": "user", "content": "hola"}]):
                pass

        with pytest.raises(ContextOverflowError):
            asyncio.run(_run())

    def test_non_overflow_error_propagates_unchanged(self, monkeypatch):
        adapter = self._make_adapter()

        async def _impl(messages, tools=None, config=None):
            raise RuntimeError("connection reset by peer")
            yield

        monkeypatch.setattr(adapter, "_stream_impl", _impl)

        async def _run():
            async for _ in adapter.stream([{"role": "user", "content": "hola"}]):
                pass

        with pytest.raises(RuntimeError) as exc:
            asyncio.run(_run())
        assert not isinstance(exc.value, ContextOverflowError)