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from __future__ import annotations

from unittest.mock import MagicMock, patch

import pytest

from airflow.providers.common.ai.decorators.llm import _LLMDecoratedOperator


def _make_mock_run_result(output):
    """Create a mock AgentRunResult compatible with log_run_summary."""
    mock_result = MagicMock()
    mock_result.output = output
    mock_result.usage.return_value = MagicMock(
        requests=1, tool_calls=0, input_tokens=0, output_tokens=0, total_tokens=0
    )
    mock_result.response = MagicMock(model_name="test-model")
    mock_result.all_messages.return_value = []
    return mock_result


class TestLLMDecoratedOperator:
    def test_custom_operator_name(self):
        assert _LLMDecoratedOperator.custom_operator_name == "@task.llm"

    @patch("airflow.providers.common.ai.operators.llm.PydanticAIHook", autospec=True)
    def test_execute_calls_callable_and_returns_output(self, mock_hook_cls):
        """The callable's return value becomes the LLM prompt."""
        mock_agent = MagicMock(spec=["run_sync"])
        mock_agent.run_sync.return_value = _make_mock_run_result("This is a summary.")
        mock_hook_cls.get_hook.return_value.create_agent.return_value = mock_agent

        def my_prompt():
            return "Summarize this text"

        op = _LLMDecoratedOperator(task_id="test", python_callable=my_prompt, llm_conn_id="my_llm")
        result = op.execute(context={})

        assert result == "This is a summary."
        assert op.prompt == "Summarize this text"
        mock_agent.run_sync.assert_called_once_with("Summarize this text", usage_limits=None)

    @pytest.mark.parametrize(
        "return_value",
        [42, "", "   ", None],
        ids=["non-string", "empty", "whitespace", "none"],
    )
    def test_execute_raises_on_invalid_prompt(self, return_value):
        """TypeError when the callable returns a non-string or blank string."""
        op = _LLMDecoratedOperator(
            task_id="test",
            python_callable=lambda: return_value,
            llm_conn_id="my_llm",
        )
        with pytest.raises(TypeError, match="non-empty string"):
            op.execute(context={})

    @patch("airflow.providers.common.ai.operators.llm.PydanticAIHook", autospec=True)
    def test_execute_merges_op_kwargs_into_callable(self, mock_hook_cls):
        """op_kwargs are resolved by the callable to build the prompt."""
        mock_agent = MagicMock(spec=["run_sync"])
        mock_agent.run_sync.return_value = _make_mock_run_result("done")
        mock_hook_cls.get_hook.return_value.create_agent.return_value = mock_agent

        def my_prompt(topic):
            return f"Summarize {topic}"

        op = _LLMDecoratedOperator(
            task_id="test",
            python_callable=my_prompt,
            llm_conn_id="my_llm",
            op_kwargs={"topic": "quantum computing"},
        )
        op.execute(context={"task_instance": MagicMock()})

        assert op.prompt == "Summarize quantum computing"
        mock_agent.run_sync.assert_called_once_with("Summarize quantum computing", usage_limits=None)
