import json
from unittest.mock import patch

import pytest

from mlflow.entities.trace_data import TraceData
from mlflow.entities.trace_info import TraceInfo
from mlflow.entities.trace_location import TraceLocation
from mlflow.entities.trace_state import TraceState
from mlflow.tracing.utils.truncation import _get_truncated_preview, set_request_response_preview


@pytest.fixture(autouse=True)
def patch_max_length():
    # Patch max length to 50 to make tests faster
    with patch("mlflow.tracing.utils.truncation._get_max_length", return_value=50):
        yield


@pytest.mark.parametrize(
    ("input_str", "expected"),
    [
        ("short string", "short string"),
        ("{'a': 'b'}", "{'a': 'b'}"),
        ("start" + "a" * 50, "start" + "a" * 42 + "..."),
        (None, None),
    ],
    ids=["short string", "short json", "long string", "none"],
)
def test_truncate_simple_string(input_str, expected):
    assert _get_truncated_preview(input_str, role="user") == expected


def test_truncate_long_non_message_json():
    input_str = json.dumps({
        "a": "b" + "a" * 30,
        "b": "c" + "a" * 30,
    })
    result = _get_truncated_preview(input_str, role="user")
    assert len(result) == 50
    assert result.startswith('{"a": "b')


_TEST_MESSAGE_HISTORY = [
    {"role": "user", "content": "First"},
    {"role": "assistant", "content": "Second"},
    {"role": "user", "content": "Third" + "a" * 50},
    {"role": "assistant", "content": "Fourth"},
]


@pytest.mark.parametrize(
    "input",
    [
        # ChatCompletion API
        {"messages": _TEST_MESSAGE_HISTORY},
        # Responses API
        {"input": _TEST_MESSAGE_HISTORY},
        # Responses Agent
        {"request": {"input": _TEST_MESSAGE_HISTORY}},
    ],
    ids=["chat_completion", "responses", "responses_agent"],
)
def test_truncate_request_messages(input):
    input_str = json.dumps(input)
    assert _get_truncated_preview(input_str, role="assistant") == "Fourth"
    # Long content should be truncated
    assert _get_truncated_preview(input_str, role="user") == "Third" + "a" * 42 + "..."
    # If non-existing role is provided, return the last message
    assert _get_truncated_preview(input_str, role="system") == "Fourth"


def test_truncate_request_choices():
    input_str = json.dumps({
        "choices": [
            {
                "index": 1,
                "message": {"role": "assistant", "content": "First" + "a" * 50},
                "finish_reason": "stop",
            },
        ],
        "object": "chat.completions",
    })
    assert _get_truncated_preview(input_str, role="assistant").startswith("First")


def test_truncate_multi_content_messages():
    # If text content exists, use it
    assert (
        _get_truncated_preview(
            json.dumps({
                "messages": [{"role": "user", "content": [{"type": "text", "text": "a" * 60}]}]
            }),
            role="user",
        )
        == "a" * 47 + "..."
    )

    # Ignore non text content
    assert (
        _get_truncated_preview(
            json.dumps({
                "messages": [
                    {
                        "role": "user",
                        "content": [
                            {"type": "text", "text": "a" * 60},
                            {"type": "image", "image_url": "http://example.com/image.jpg"},
                        ],
                    },
                ]
            }),
            role="user",
        )
        == "a" * 47 + "..."
    )

    # If non-text content exists, truncate the full json as-is
    assert _get_truncated_preview(
        json.dumps({
            "messages": [
                {
                    "role": "user",
                    "content": [
                        {
                            "type": "image",
                            "image_url": "http://example.com/image.jpg" + "a" * 50,
                        }
                    ],
                },
            ]
        }),
        role="user",
    ).startswith('{"messages":')


def test_truncate_responses_api_output():
    input_str = json.dumps({
        "output": [
            {
                "type": "message",
                "id": "test",
                "role": "assistant",
                "content": [{"type": "output_text", "text": "a" * 60}],
            }
        ],
    })

    assert _get_truncated_preview(input_str, role="assistant") == "a" * 47 + "..."


@pytest.mark.parametrize(
    "input_data",
    [
        {"messages": 123, "long_data": "a" * 50},
        {"messages": []},
        {"input": "string"},
        {"output": 123},
        {"choices": {"0": "value"}},
        {"request": "string"},
        {"choices": [{"message": "not a dict"}]},
        {"choices": [{"message": {"role": "user"}}]},
    ],
)
def test_truncate_invalid_messages(input_data):
    input_str = json.dumps(input_data)
    result = _get_truncated_preview(input_str, role="user")
    if "long_data" in input_data:
        assert len(result) == 50
        assert result.startswith(input_str[:20])
    else:
        assert result == input_str


@pytest.mark.parametrize(
    ("request_data", "expected_content", "should_not_contain"),
    [
        (
            {"request": {"input": [{"role": "user", "content": "Hello"}]}},
            "Hello",
            "request",
        ),
        (
            {"request": {"tool_choice": None, "input": [{"role": "user", "content": "Weather?"}]}},
            "Weather?",
            '"tool_choice"',
        ),
        (
            {"request": {"input": [{"role": "user", "content": "Hi"}]}},
            "Hi",
            '"request"',
        ),
    ],
    ids=["short_structured_json", "agent_format_with_null_fields", "responses_agent_short"],
)
def test_truncate_structured_json_extracts_content(
    request_data, expected_content, should_not_contain
):
    input_str = json.dumps(request_data)
    result = _get_truncated_preview(input_str, role="user")
    assert result == expected_content
    assert should_not_contain not in result


@pytest.mark.parametrize(
    ("content_value", "expected_in_result"),
    [
        (None, '"content": null'),
        ("", '"content": ""'),
        (123, '"content": 123'),
    ],
    ids=["null_content", "empty_string_content", "numeric_content"],
)
def test_truncate_invalid_content_falls_back_to_json(content_value, expected_in_result):
    request_data = {"input": [{"role": "user", "content": content_value}]}
    input_str = json.dumps(request_data)
    result = _get_truncated_preview(input_str, role="user")
    assert expected_in_result in result or result.endswith("...")


def test_set_request_response_preview_skips_none_data():
    trace_info = TraceInfo(
        trace_id="tr-test",
        trace_location=TraceLocation.from_experiment_id("0"),
        request_time=1000,
        state=TraceState.OK,
    )
    trace_data = TraceData(spans=[], request=None, response=None)
    set_request_response_preview(trace_info, trace_data)

    assert trace_info.request_preview is None
    assert trace_info.response_preview is None