"""Tests for streaming error handling in providers/nvidia_nim/client.py."""

import json
from types import SimpleNamespace
from unittest.mock import AsyncMock, MagicMock, patch

import httpx
import openai
import pytest

from config.nim import NimSettings
from core.anthropic.stream_contracts import (
    assert_anthropic_stream_contract,
    parse_sse_text,
)
from providers.base import ProviderConfig
from providers.nvidia_nim import NvidiaNimProvider
from tests.provider_request_mocks import make_openai_compat_stream_request


class AsyncStreamMock:
    """Async iterable mock that yields chunks then optionally raises."""

    def __init__(self, chunks, error=None):
        self._chunks = chunks
        self._error = error

    def __aiter__(self):
        return self._aiter()

    async def _aiter(self):
        for chunk in self._chunks:
            yield chunk
        if self._error:
            raise self._error


def _make_provider():
    """Create a provider instance for testing."""
    config = ProviderConfig(
        api_key="test_key",
        base_url="https://test.api.nvidia.com/v1",
        rate_limit=10,
        rate_window=60,
    )
    return NvidiaNimProvider(config, nim_settings=NimSettings())


def _make_provider_with_thinking_enabled(enabled: bool):
    """Create a provider instance with thinking explicitly enabled or disabled."""
    config = ProviderConfig(
        api_key="test_key",
        base_url="https://test.api.nvidia.com/v1",
        rate_limit=10,
        rate_window=60,
        enable_thinking=enabled,
    )
    return NvidiaNimProvider(config, nim_settings=NimSettings())


def _make_request(model="test-model", stream=True):
    """Create a mock request with all fields build_request_body needs."""
    return make_openai_compat_stream_request(model=model, stream=stream)


def _make_chunk(
    content=None, finish_reason=None, tool_calls=None, reasoning_content=None
):
    """Create a mock streaming chunk."""
    delta = MagicMock()
    delta.content = content
    delta.tool_calls = tool_calls
    delta.reasoning_content = reasoning_content if reasoning_content else None

    choice = MagicMock()
    choice.delta = delta
    choice.finish_reason = finish_reason

    chunk = MagicMock()
    chunk.choices = [choice]
    chunk.usage = None
    return chunk


def _make_tool_calls_chunk(*, name: str, arguments: str, tool_id: str, index: int = 0):
    """Single OpenAI-style tool_calls delta (starts a native streamed tool block)."""
    tc = MagicMock()
    tc.index = index
    tc.id = tool_id
    fn = MagicMock()
    fn.name = name
    fn.arguments = arguments
    tc.function = fn
    return _make_chunk(tool_calls=[tc])


async def _collect_stream(provider, request):
    """Collect all SSE events from a stream."""
    return [e async for e in provider.stream_response(request)]


def _assert_no_content_deltas_after_error_text(
    events: list[str], error_substr: str
) -> None:
    """After the error text delta, only block close + message tail events may follow."""
    parsed = parse_sse_text("".join(events))
    first_error_idx = None
    for i, ev in enumerate(parsed):
        if ev.event != "content_block_delta":
            continue
        delta = ev.data.get("delta", {})
        if delta.get("type") == "text_delta" and error_substr in str(
            delta.get("text", "")
        ):
            first_error_idx = i
            break
    assert first_error_idx is not None, (error_substr, "".join(events))
    for ev in parsed[first_error_idx + 1 :]:
        assert ev.event in ("content_block_stop", "message_delta", "message_stop"), (
            ev.event,
            ev.data,
        )


def _assert_error_not_in_text_deltas_after_tool(
    events: list[str], error_substr: str
) -> None:
    """Transport errors after a native tool call must not use assistant text_delta (issue #206)."""
    blob = "".join(events)
    for ev in parse_sse_text(blob):
        if ev.event != "content_block_delta":
            continue
        delta = ev.data.get("delta", {})
        if delta.get("type") == "text_delta" and error_substr in str(
            delta.get("text", "")
        ):
            raise AssertionError(
                f"error leaked as text_delta after tool_use: {ev.data!r} full={blob!r}"
            )


class TestStreamingExceptionHandling:
    """Tests for error paths during stream_response."""

    @pytest.mark.asyncio
    async def test_api_error_emits_sse_error_event(self):
        """When API raises during streaming, SSE error event is emitted."""
        provider = _make_provider()
        request = _make_request()

        mock_stream = AsyncMock()
        mock_stream.__aiter__ = MagicMock(side_effect=RuntimeError("API failed"))

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                side_effect=RuntimeError("API failed"),
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)

        # Should have message_start, error text block, close blocks, message_delta, message_stop
        event_text = "".join(events)
        assert "message_start" in event_text
        assert "API failed" in event_text
        assert "message_stop" in event_text
        _assert_no_content_deltas_after_error_text(events, "API failed")

    @pytest.mark.asyncio
    async def test_read_timeout_with_empty_message_emits_fallback(self):
        """ReadTimeout(TimeoutError()) should emit a visible, non-empty timeout message."""
        provider = _make_provider()
        request = _make_request()

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                side_effect=httpx.ReadTimeout(""),
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = [
                e
                async for e in provider.stream_response(
                    request,
                    request_id="req_timeout123",
                )
            ]

        event_text = "".join(events)
        assert "timed out after" in event_text
        assert "Request ID: req_timeout123" in event_text
        assert "message_stop" in event_text
        _assert_no_content_deltas_after_error_text(events, "timed out after")

    @pytest.mark.asyncio
    async def test_error_after_partial_content(self):
        """Error after partial content: blocks closed, error emitted."""
        provider = _make_provider()
        request = _make_request()

        chunk1 = _make_chunk(content="Hello ")
        stream_mock = AsyncStreamMock([chunk1], error=RuntimeError("Connection lost"))

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)

        event_text = "".join(events)
        assert "Hello" in event_text
        assert "Connection lost" in event_text
        assert "message_stop" in event_text
        _assert_no_content_deltas_after_error_text(events, "Connection lost")

    @pytest.mark.asyncio
    async def test_error_after_native_tool_call_uses_top_level_error_event(self):
        """After a streamed tool_call, do not append error text as a new assistant text block."""
        provider = _make_provider()
        request = _make_request()
        tool_chunk = _make_tool_calls_chunk(
            name="echo_smoke", arguments="{}", tool_id="call_206", index=0
        )
        stream_mock = AsyncStreamMock(
            [tool_chunk], error=RuntimeError("Connection lost after tool")
        )
        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)
        event_text = "".join(events)
        assert "tool_use" in event_text
        assert "Connection lost after tool" in event_text
        assert "event: error\n" in event_text
        assert "message_stop" in event_text
        _assert_error_not_in_text_deltas_after_tool(
            events, "Connection lost after tool"
        )

    @pytest.mark.asyncio
    async def test_empty_response_gets_space(self):
        """Empty response with no text/tools gets a single space text block."""
        provider = _make_provider()
        request = _make_request()

        empty_chunk = _make_chunk(finish_reason="stop")
        stream_mock = AsyncStreamMock([empty_chunk])

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)

        event_text = "".join(events)
        assert '"text_delta"' in event_text
        assert "message_stop" in event_text

    @pytest.mark.asyncio
    async def test_upstream_completion_tokens_null_emits_int_usage(self):
        """NIM/GLM may send usage.completion_tokens=null; final SSE must not use JSON null."""
        provider = _make_provider()
        request = _make_request()

        delta = SimpleNamespace(
            content="hello",
            tool_calls=None,
            reasoning_content=None,
        )
        choice = SimpleNamespace(delta=delta, finish_reason="stop")
        usage = SimpleNamespace(completion_tokens=None, prompt_tokens=None)
        chunk = SimpleNamespace(choices=[choice], usage=usage)
        stream_mock = AsyncStreamMock([chunk])

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)

        parsed = parse_sse_text("".join(events))
        delta_events = [e for e in parsed if e.event == "message_delta"]
        assert len(delta_events) == 1
        usage_out = delta_events[0].data.get("usage", {})
        assert isinstance(usage_out.get("output_tokens"), int)
        assert usage_out["output_tokens"] is not None
        assert '"output_tokens": null' not in "".join(events)

    @pytest.mark.asyncio
    async def test_reasoning_only_stream_emits_placeholder_text(self):
        """When the model streams only ``reasoning_content`` (no ``content``), add text block.

        NIM / some templates may emit no main ``content``; a minimal text block matches
        the empty-body placeholder and helps clients that expect a text segment.
        """
        provider = _make_provider_with_thinking_enabled(True)
        request = _make_request()
        chunk1 = _make_chunk(reasoning_content="reasoning only from provider")
        chunk2 = _make_chunk(finish_reason="stop")
        stream_mock = AsyncStreamMock([chunk1, chunk2])
        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)
        event_text = "".join(events)
        assert "thinking_delta" in event_text
        assert '"text_delta"' in event_text
        assert "message_stop" in event_text

    @pytest.mark.asyncio
    async def test_stream_with_thinking_content(self):
        """Thinking content via think tags is emitted as thinking blocks."""
        provider = _make_provider()
        request = _make_request()

        chunk1 = _make_chunk(content="<think>reasoning</think>answer")
        chunk2 = _make_chunk(finish_reason="stop")
        stream_mock = AsyncStreamMock([chunk1, chunk2])

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)

        event_text = "".join(events)
        assert "thinking" in event_text
        assert "reasoning" in event_text
        assert "answer" in event_text

    @pytest.mark.asyncio
    async def test_stream_with_reasoning_content_field(self):
        """reasoning_content delta field is emitted as thinking block."""
        provider = _make_provider()
        request = _make_request()

        chunk1 = _make_chunk(reasoning_content="I think...")
        chunk2 = _make_chunk(content="The answer")
        chunk3 = _make_chunk(finish_reason="stop")
        stream_mock = AsyncStreamMock([chunk1, chunk2, chunk3])

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)

        event_text = "".join(events)
        assert "thinking_delta" in event_text
        assert "I think..." in event_text
        assert "The answer" in event_text

    @pytest.mark.asyncio
    async def test_stream_with_reasoning_content_suppressed_when_disabled(self):
        """reasoning deltas are stripped while normal text still streams."""
        provider = _make_provider_with_thinking_enabled(False)
        request = _make_request()

        chunk1 = _make_chunk(reasoning_content="I think...")
        chunk2 = _make_chunk(content="<think>secret</think>The answer")
        chunk3 = _make_chunk(finish_reason="stop")
        stream_mock = AsyncStreamMock([chunk1, chunk2, chunk3])

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)

        event_text = "".join(events)
        assert "thinking_delta" not in event_text
        assert "I think..." not in event_text
        assert "secret" not in event_text
        assert "The answer" in event_text

    @pytest.mark.asyncio
    async def test_stream_with_upstream_405_mentions_provider_name(self):
        """HTTP 405s are surfaced as upstream method/endpoint rejections."""
        provider = _make_provider()
        request = _make_request()

        response = httpx.Response(
            status_code=405,
            request=httpx.Request("POST", "https://example.com/v1/chat/completions"),
        )
        error = httpx.HTTPStatusError(
            "Method Not Allowed",
            request=response.request,
            response=response,
        )

        with patch.object(
            provider._client.chat.completions,
            "create",
            new_callable=AsyncMock,
            side_effect=error,
        ):
            events = [
                e
                async for e in provider.stream_response(
                    request,
                    request_id="REQ405",
                )
            ]

        event_text = "".join(events)
        assert (
            "Upstream provider NIM rejected the request method or endpoint (HTTP 405)."
            in event_text
        )
        assert "Request ID: REQ405" in event_text
        _assert_no_content_deltas_after_error_text(
            events,
            "Upstream provider NIM rejected the request method or endpoint (HTTP 405).",
        )

    @pytest.mark.asyncio
    async def test_stream_with_openai_bad_request_surfaces_upstream_body(self):
        """OpenAI SDK bodies should be emitted so users can copy exact provider errors."""
        provider = _make_provider()
        request = _make_request()
        response = httpx.Response(
            status_code=400,
            request=httpx.Request("POST", "https://example.com/v1/chat/completions"),
        )
        body = {
            "error": {
                "type": "BadRequest",
                "message": "Thinking mode does not support this tool_choice",
            }
        }
        error = openai.BadRequestError("Bad Request", response=response, body=body)

        with patch.object(
            provider._client.chat.completions,
            "create",
            new_callable=AsyncMock,
            side_effect=error,
        ):
            events = [
                e
                async for e in provider.stream_response(
                    request,
                    request_id="REQ_BODY",
                )
            ]

        event_text = "".join(events)
        message_text = "".join(
            str(ev.data.get("delta", {}).get("text", ""))
            for ev in parse_sse_text(event_text)
            if ev.event == "content_block_delta"
            and ev.data.get("delta", {}).get("type") == "text_delta"
        )
        assert "Upstream provider NIM returned HTTP 400." in event_text
        assert "Category: BadRequest" in event_text
        assert "Thinking mode does not support this tool_choice" in event_text
        assert (
            '{"error":{"type":"BadRequest","message":"Thinking mode does not support this tool_choice"}}'
            in message_text
        )
        assert "Request ID: REQ_BODY" in event_text
        _assert_no_content_deltas_after_error_text(
            events,
            "Upstream provider NIM returned HTTP 400.",
        )

    @pytest.mark.asyncio
    async def test_error_after_native_tool_call_top_level_error_includes_body(self):
        """After a tool_use block, detailed provider errors remain top-level SSE errors."""
        provider = _make_provider()
        request = _make_request()
        tool_chunk = _make_tool_calls_chunk(
            name="echo_smoke", arguments="{}", tool_id="call_body", index=0
        )
        response = httpx.Response(
            status_code=400,
            request=httpx.Request("POST", "https://example.com/v1/chat/completions"),
        )
        body = {"error": {"message": "bad after tool"}}
        error = openai.BadRequestError("Bad Request", response=response, body=body)
        stream_mock = AsyncStreamMock([tool_chunk], error=error)

        with patch.object(
            provider._client.chat.completions,
            "create",
            new_callable=AsyncMock,
            return_value=stream_mock,
        ):
            events = [
                e
                async for e in provider.stream_response(
                    request,
                    request_id="REQ_TOOL_BODY",
                )
            ]

        event_text = "".join(events)
        assert "tool_use" in event_text
        assert "event: error\n" in event_text
        assert "bad after tool" in event_text
        assert "Request ID: REQ_TOOL_BODY" in event_text
        _assert_error_not_in_text_deltas_after_tool(events, "bad after tool")

    @pytest.mark.asyncio
    async def test_clean_eof_after_complete_tool_call_salvages_tool_use(self):
        """A complete tool JSON payload missing finish_reason is committed as tool_use."""
        provider = _make_provider()
        request = _make_request()
        tool_chunk = _make_tool_calls_chunk(
            name="echo_smoke", arguments='{"message":"ok"}', tool_id="call_eof"
        )
        stream_mock = AsyncStreamMock([tool_chunk])

        with patch.object(
            provider._client.chat.completions,
            "create",
            new_callable=AsyncMock,
            return_value=stream_mock,
        ):
            events = await _collect_stream(provider, request)

        parsed = parse_sse_text("".join(events))
        assert parsed[-1].event == "message_stop"
        assert any(
            event.event == "message_delta"
            and event.data.get("delta", {}).get("stop_reason") == "tool_use"
            for event in parsed
        )
        assert not any(event.event == "error" for event in parsed)

    @pytest.mark.asyncio
    async def test_precommit_openai_holdback_retries_without_leaking_partial(self):
        """A retryable early cutoff before holdback commit is retried invisibly."""
        provider = _make_provider()
        request = _make_request()
        first_stream = AsyncStreamMock(
            [_make_chunk(content="hidden")],
            error=httpx.ReadError("early cutoff"),
        )
        second_stream = AsyncStreamMock(
            [
                _make_chunk(content="visible"),
                _make_chunk(finish_reason="stop"),
            ]
        )

        with patch.object(
            provider._client.chat.completions,
            "create",
            new_callable=AsyncMock,
            side_effect=[first_stream, second_stream],
        ) as mock_create:
            events = await _collect_stream(provider, request)

        event_text = "".join(events)
        assert mock_create.await_count == 2
        assert "hidden" not in event_text
        assert "visible" in event_text
        assert parse_sse_text(event_text)[-1].event == "message_stop"

    @pytest.mark.asyncio
    async def test_clean_eof_after_text_continues_with_overlap_trim(self):
        """A truncated text stream is continued and duplicate overlap is trimmed."""
        provider = _make_provider()
        request = _make_request()
        stream_mock = AsyncStreamMock([_make_chunk(content="hello wor")])

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider,
                "_collect_recovery_text",
                new_callable=AsyncMock,
                return_value=("world", ""),
            ),
        ):
            events = await _collect_stream(provider, request)

        parsed = parse_sse_text("".join(events))
        text = "".join(
            event.data.get("delta", {}).get("text", "")
            for event in parsed
            if event.event == "content_block_delta"
        )
        assert text == "hello world"
        assert any(
            event.event == "message_delta"
            and event.data.get("delta", {}).get("stop_reason") == "end_turn"
            for event in parsed
        )
        assert not any(event.event == "error" for event in parsed)

    @pytest.mark.asyncio
    async def test_incomplete_tool_call_repair_appends_schema_valid_suffix(self):
        """A truncated tool JSON prefix is repaired append-only before tool_use tail."""
        provider = _make_provider()
        request = _make_request()
        request.tools = [
            SimpleNamespace(
                name="echo_smoke",
                description="Echo",
                input_schema={
                    "type": "object",
                    "properties": {"message": {"type": "string"}},
                    "required": ["message"],
                    "additionalProperties": False,
                },
            )
        ]
        tool_chunk = _make_tool_calls_chunk(
            name="echo_smoke", arguments='{"message":', tool_id="call_repair"
        )
        stream_mock = AsyncStreamMock([tool_chunk])

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider,
                "_collect_recovery_text",
                new_callable=AsyncMock,
                return_value=('"ok"}', ""),
            ),
        ):
            events = await _collect_stream(provider, request)

        event_text = "".join(events)
        parsed = parse_sse_text(event_text)
        assert '"partial_json": "\\"ok\\"}"' in event_text
        assert any(
            event.event == "message_delta"
            and event.data.get("delta", {}).get("stop_reason") == "tool_use"
            for event in parsed
        )
        assert not any(event.event == "error" for event in parsed)

    @pytest.mark.asyncio
    async def test_stream_rate_limited_retries_via_execute_with_retry(self):
        """When rate limited, execute_with_retry handles retries transparently."""
        provider = _make_provider()
        request = _make_request()

        chunk1 = _make_chunk(content="Response")
        chunk2 = _make_chunk(finish_reason="stop")
        stream_mock = AsyncStreamMock([chunk1, chunk2])

        with patch.object(
            provider._client.chat.completions,
            "create",
            new_callable=AsyncMock,
            return_value=stream_mock,
        ):
            # Mock execute_with_retry to pass through to the actual function
            async def _passthrough(fn, *args, **kwargs):
                return await fn(*args, **kwargs)

            with patch.object(
                provider._global_rate_limiter,
                "execute_with_retry",
                new_callable=AsyncMock,
                side_effect=_passthrough,
            ):
                events = await _collect_stream(provider, request)

        event_text = "".join(events)
        assert "Response" in event_text


class TestProcessToolCall:
    """Tests for _process_tool_call method."""

    def test_tool_call_with_id(self):
        """Tool call with id starts a tool block."""
        provider = _make_provider()
        from core.anthropic import SSEBuilder

        sse = SSEBuilder("msg_test", "test-model")
        tc = {
            "index": 0,
            "id": "call_123",
            "function": {"name": "search", "arguments": '{"q": "test"}'},
        }
        events = list(provider._process_tool_call(tc, sse))
        event_text = "".join(events)
        assert "tool_use" in event_text
        assert "search" in event_text
        assert "call_123" in event_text

    def test_tool_call_id_arrives_before_name_still_emits_id_and_name(self):
        """Split-stream tool: id (no name) then name then args; id preserved on start."""
        provider = _make_provider()
        from core.anthropic import SSEBuilder

        sse = SSEBuilder("msg_test", "test-model")
        t1 = {
            "index": 0,
            "id": "call_split",
            "function": {"name": None, "arguments": ""},
        }
        t2 = {
            "index": 0,
            "id": "call_split",
            "function": {"name": "Grep", "arguments": ""},
        }
        t3 = {
            "index": 0,
            "id": "call_split",
            "function": {"name": None, "arguments": "{}"},
        }
        b1 = "".join(provider._process_tool_call(t1, sse))
        b2 = "".join(provider._process_tool_call(t2, sse))
        b3 = "".join(provider._process_tool_call(t3, sse))
        combined = b1 + b2 + b3
        assert "call_split" in combined
        assert "Grep" in combined
        assert b1 == ""

    def test_tool_call_arguments_buffered_until_name(self):
        """Argument deltas before tool name are emitted after the block starts."""
        provider = _make_provider()
        from core.anthropic import SSEBuilder

        sse = SSEBuilder("msg_test", "test-model")
        t1 = {
            "index": 0,
            "id": "call_buf",
            "function": {"name": None, "arguments": '{"x":'},
        }
        t2 = {
            "index": 0,
            "id": "call_buf",
            "function": {"name": "Read", "arguments": "1}"},
        }
        b1 = "".join(provider._process_tool_call(t1, sse))
        b2 = "".join(provider._process_tool_call(t2, sse))
        assert b1 == ""
        combined = b2
        assert "Read" in combined
        assert "call_buf" in combined
        assert '{"x":' in combined or "partial_json" in combined

    def test_tool_call_without_id_generates_uuid(self):
        """Tool call without id generates a uuid-based id."""
        provider = _make_provider()
        from core.anthropic import SSEBuilder

        sse = SSEBuilder("msg_test", "test-model")
        tc = {
            "index": 0,
            "id": None,
            "function": {"name": "test", "arguments": "{}"},
        }
        events = list(provider._process_tool_call(tc, sse))
        event_text = "".join(events)
        assert "tool_" in event_text

    def test_task_tool_forces_background_false(self):
        """Task tool with run_in_background=true is forced to false."""
        provider = _make_provider()
        from core.anthropic import SSEBuilder

        sse = SSEBuilder("msg_test", "test-model")
        args = json.dumps({"run_in_background": True, "prompt": "test"})
        tc = {
            "index": 0,
            "id": "call_task",
            "function": {"name": "Task", "arguments": args},
        }
        events = list(provider._process_tool_call(tc, sse))
        event_text = "".join(events)
        # The intercepted args should have run_in_background=false
        assert "false" in event_text.lower()

    def test_task_tool_chunked_args_forces_background_false(self):
        """Chunked Task args are buffered until valid JSON, then forced to false."""
        provider = _make_provider()
        from core.anthropic import SSEBuilder

        sse = SSEBuilder("msg_test", "test-model")
        tc1 = {
            "index": 0,
            "id": "call_task_chunked",
            "function": {"name": "Task", "arguments": '{"run_in_background": true,'},
        }
        tc2 = {
            "index": 0,
            "id": "call_task_chunked",
            "function": {"name": None, "arguments": ' "prompt": "test"}'},
        }

        events1 = list(provider._process_tool_call(tc1, sse))
        assert len(events1) > 0
        assert "false" not in "".join(events1).lower()

        events2 = list(provider._process_tool_call(tc2, sse))
        event_text = "".join(events1 + events2)
        assert "false" in event_text.lower()

    def test_task_tool_invalid_json_logs_warning_on_flush(self, caplog):
        """Invalid JSON args for Task tool emits {} on flush and logs a warning."""
        provider = _make_provider()
        from core.anthropic import SSEBuilder

        sse = SSEBuilder("msg_test", "test-model")
        tc = {
            "index": 0,
            "id": "call_task2",
            "function": {"name": "Task", "arguments": "not json"},
        }
        events = list(provider._process_tool_call(tc, sse))
        assert len(events) > 0

        with caplog.at_level("WARNING"):
            flushed = list(provider._flush_task_arg_buffers(sse))
        assert len(flushed) > 0
        assert "{}" in "".join(flushed)
        assert any("Task args invalid JSON" in r.message for r in caplog.records)

    def test_negative_tool_index_fallback(self):
        """tc_index < 0 uses len(tool_indices) as fallback."""
        provider = _make_provider()
        from core.anthropic import SSEBuilder

        sse = SSEBuilder("msg_test", "test-model")
        tc = {
            "index": -1,
            "id": "call_neg",
            "function": {"name": "test", "arguments": "{}"},
        }
        events = list(provider._process_tool_call(tc, sse))
        # Should not crash, should still emit events
        assert len(events) > 0

    def test_none_tool_index_defaults_to_zero(self):
        """Gemini may stream tool_call deltas with a null index."""
        provider = _make_provider()
        from core.anthropic import SSEBuilder

        sse = SSEBuilder("msg_test", "test-model")
        tc = {
            "index": None,
            "id": "call_none",
            "function": {"name": "test", "arguments": "{}"},
        }
        events = list(provider._process_tool_call(tc, sse))
        event_text = "".join(events)

        assert "tool_use" in event_text
        assert "call_none" in event_text

    def test_tool_args_emitted_as_delta(self):
        """Arguments are emitted as input_json_delta events."""
        provider = _make_provider()
        from core.anthropic import SSEBuilder

        sse = SSEBuilder("msg_test", "test-model")
        tc = {
            "index": 0,
            "id": "call_args",
            "function": {"name": "grep", "arguments": '{"pattern": "test"}'},
        }
        events = list(provider._process_tool_call(tc, sse))
        event_text = "".join(events)
        assert "input_json_delta" in event_text


class TestStreamChunkEdgeCases:
    """Tests for edge cases in stream chunk handling."""

    @pytest.mark.asyncio
    async def test_stream_chunk_with_empty_choices_skipped(self):
        """Chunk with choices=[] is skipped without crashing."""
        provider = _make_provider()
        request = _make_request()

        empty_choices_chunk = MagicMock()
        empty_choices_chunk.choices = []
        empty_choices_chunk.usage = None

        finish_chunk = _make_chunk(finish_reason="stop")
        stream_mock = AsyncStreamMock([empty_choices_chunk, finish_chunk])

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)

        event_text = "".join(events)
        assert "message_start" in event_text
        assert "message_stop" in event_text

    @pytest.mark.asyncio
    async def test_stream_chunk_with_none_delta_handled(self):
        """Chunk with choice.delta=None is handled defensively."""
        provider = _make_provider()
        request = _make_request()

        none_delta_chunk = MagicMock()
        none_delta_chunk.usage = None
        choice = MagicMock()
        choice.delta = None
        choice.finish_reason = None
        none_delta_chunk.choices = [choice]

        finish_chunk = _make_chunk(finish_reason="stop")
        stream_mock = AsyncStreamMock([none_delta_chunk, finish_chunk])

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)

        event_text = "".join(events)
        assert "message_start" in event_text
        assert "message_stop" in event_text

    @pytest.mark.asyncio
    async def test_stream_generator_cleanup_on_exception(self):
        """When stream raises mid-iteration, message_stop still emitted."""
        provider = _make_provider()
        request = _make_request()

        chunk1 = _make_chunk(content="Partial")
        stream_mock = AsyncStreamMock(
            [chunk1], error=ConnectionResetError("Connection reset")
        )

        with (
            patch.object(
                provider._client.chat.completions,
                "create",
                new_callable=AsyncMock,
                return_value=stream_mock,
            ),
            patch.object(
                provider._global_rate_limiter,
                "wait_if_blocked",
                new_callable=AsyncMock,
                return_value=False,
            ),
        ):
            events = await _collect_stream(provider, request)

        event_text = "".join(events)
        assert "Partial" in event_text
        assert "Connection reset" in event_text
        assert "message_stop" in event_text
        _assert_no_content_deltas_after_error_text(events, "Connection reset")

    def test_stream_malformed_tool_args_chunked(self):
        """Chunked tool args that never form valid JSON are flushed with {}."""
        provider = _make_provider()
        from core.anthropic import SSEBuilder

        sse = SSEBuilder("msg_test", "test-model")
        tc1 = {
            "index": 0,
            "id": "call_malformed",
            "function": {"name": "Task", "arguments": '{"broken":'},
        }
        tc2 = {
            "index": 0,
            "id": "call_malformed",
            "function": {"name": None, "arguments": " never valid }"},
        }

        events1 = list(provider._process_tool_call(tc1, sse))
        events2 = list(provider._process_tool_call(tc2, sse))
        flushed = list(provider._flush_task_arg_buffers(sse))

        event_text = "".join(events1 + events2 + flushed)
        assert "tool_use" in event_text
        assert "{}" in event_text


@pytest.mark.asyncio
async def test_openai_compat_stream_ends_with_contract_when_tool_name_never_arrives() -> (
    None
):
    """Nameless / incomplete tool-call buffer must not break Anthropic stream contract."""
    provider = _make_provider()
    request = _make_request()
    tc0 = SimpleNamespace(
        index=0,
        id="call_inc",
        function=SimpleNamespace(name=None, arguments="{}"),
    )
    stream_mock = AsyncStreamMock([_make_chunk(tool_calls=[tc0])])
    with (
        patch.object(
            provider._client.chat.completions,
            "create",
            new_callable=AsyncMock,
            return_value=stream_mock,
        ),
        patch.object(
            provider._global_rate_limiter,
            "wait_if_blocked",
            new_callable=AsyncMock,
            return_value=False,
        ),
    ):
        events = await _collect_stream(provider, request)
    text = "".join(events)
    assert_anthropic_stream_contract(parse_sse_text(text))
    assert "text_delta" in text