"""Tests for the ZeroGPU integration helper."""

from __future__ import annotations

import unittest
from unittest.mock import MagicMock, patch

from zsgdp.gpu import zero_gpu


class IsZeroGPUAvailableTests(unittest.TestCase):
    def test_returns_false_when_spaces_module_missing(self):
        # Default state on a local dev box: spaces is not installed.
        with patch.object(zero_gpu, "_SPACES_AVAILABLE", False):
            self.assertFalse(zero_gpu.is_zero_gpu_available())

    def test_returns_true_when_spaces_module_present(self):
        with patch.object(zero_gpu, "_SPACES_AVAILABLE", True):
            self.assertTrue(zero_gpu.is_zero_gpu_available())


class GpuDecoratorTests(unittest.TestCase):
    def test_passthrough_when_off_space(self):
        with patch.object(zero_gpu, "_SPACES_AVAILABLE", False):
            decorator = zero_gpu.gpu(duration=42)

            def my_function(x: int) -> int:
                return x * 2

            wrapped = decorator(my_function)
            # Off-Space: the decorator is a no-op, the function is unchanged.
            self.assertIs(wrapped, my_function)
            self.assertEqual(wrapped(7), 14)

    def test_delegates_to_spaces_gpu_when_available(self):
        # Build a fake `spaces` module whose GPU(duration=...) returns a
        # specific decorator we can recognise.
        fake_spaces = MagicMock()
        marker = lambda fn: fn  # noqa: E731 — sentinel decorator
        fake_spaces.GPU.return_value = marker

        with patch.object(zero_gpu, "_SPACES_AVAILABLE", True), patch.object(
            zero_gpu, "_spaces", fake_spaces
        ):
            decorator = zero_gpu.gpu(duration=180)

        fake_spaces.GPU.assert_called_once_with(duration=180)
        self.assertIs(decorator, marker)

    def test_decorator_passes_duration_through(self):
        fake_spaces = MagicMock()
        fake_spaces.GPU.return_value = lambda fn: fn

        with patch.object(zero_gpu, "_SPACES_AVAILABLE", True), patch.object(
            zero_gpu, "_spaces", fake_spaces
        ):
            zero_gpu.gpu(duration=60)
            zero_gpu.gpu(duration=300)

        calls = [call.kwargs for call in fake_spaces.GPU.call_args_list]
        self.assertEqual(calls, [{"duration": 60}, {"duration": 300}])


class RuntimeStatusSurfacesZeroGPUTests(unittest.TestCase):
    def test_zero_gpu_available_field_in_runtime_status(self):
        from zsgdp.config import load_config
        from zsgdp.gpu.runtime import collect_gpu_runtime_status

        config = load_config()

        with patch.object(zero_gpu, "_SPACES_AVAILABLE", False):
            status = collect_gpu_runtime_status(config).to_dict()
        self.assertFalse(status["zero_gpu_available"])

        with patch.object(zero_gpu, "_SPACES_AVAILABLE", True):
            status = collect_gpu_runtime_status(config).to_dict()
        self.assertTrue(status["zero_gpu_available"])
        self.assertTrue(
            any("ZeroGPU SDK detected" in note for note in status["notes"]),
            msg=f"notes={status['notes']}",
        )


class DecoratedClientsStillWorkOffSpaceTests(unittest.TestCase):
    """End-to-end check: decorating EmbeddingRetriever / TransformersClient
    must not break their off-Space behaviour."""

    def test_embedding_retriever_index_and_query_unchanged_off_space(self):
        from zsgdp.benchmarks.embedding_retriever import EmbeddingRetriever
        from zsgdp.schema import Chunk

        # Tiny deterministic embedder.
        def embedder(texts):
            return [[float(len(t)), 1.0] for t in texts]

        retriever = EmbeddingRetriever(embedder=embedder)
        chunks = [
            Chunk(
                chunk_id=f"c{i}",
                doc_id="d",
                page_start=1,
                page_end=1,
                section_path=[],
                content_type="prose",
                text=text,
                token_count=len(text.split()),
            )
            for i, text in enumerate(["short text", "this is a much longer sentence"])
        ]

        with patch.object(zero_gpu, "_SPACES_AVAILABLE", False):
            retriever.index(chunks)
            ranking = retriever.query("a much longer sentence", top_k=2)

        self.assertEqual(set(ranking), {"c0", "c1"})

    def test_transformers_client_returns_unavailable_off_space(self):
        # Without a model_id the client refuses to invoke; the @zero_gpu_slot
        # decorator must not change that contract.
        from zsgdp.gpu.transformers_client import TransformersClient

        client = TransformersClient(model_id=None)
        with patch.object(zero_gpu, "_SPACES_AVAILABLE", False):
            result = client.execute_task({"task_id": "t1"})
        self.assertEqual(result["status"], "backend_unavailable")


if __name__ == "__main__":
    unittest.main()