"""Contract tests for list_relationships MCP tool."""

from pathlib import Path

import pytest

from xer_mcp.db import db


@pytest.fixture(autouse=True)
def setup_db():
    """Initialize and clear database for each test."""
    db.initialize()
    yield
    db.clear()


class TestListRelationshipsContract:
    """Contract tests verifying list_relationships tool interface."""

    async def test_list_relationships_returns_paginated_results(
        self, sample_xer_single_project: Path
    ) -> None:
        """list_relationships returns relationships with pagination metadata."""
        from xer_mcp.tools.list_relationships import list_relationships
        from xer_mcp.tools.load_xer import load_xer

        await load_xer(file_path=str(sample_xer_single_project))

        result = await list_relationships()

        assert "relationships" in result
        assert "pagination" in result
        assert len(result["relationships"]) == 5
        assert result["pagination"]["total_count"] == 5

    async def test_list_relationships_with_pagination(
        self, sample_xer_single_project: Path
    ) -> None:
        """list_relationships respects limit and offset parameters."""
        from xer_mcp.tools.list_relationships import list_relationships
        from xer_mcp.tools.load_xer import load_xer

        await load_xer(file_path=str(sample_xer_single_project))

        result = await list_relationships(limit=2, offset=0)

        assert len(result["relationships"]) == 2
        assert result["pagination"]["has_more"] is True

    async def test_list_relationships_includes_expected_fields(
        self, sample_xer_single_project: Path
    ) -> None:
        """list_relationships returns relationships with all expected fields."""
        from xer_mcp.tools.list_relationships import list_relationships
        from xer_mcp.tools.load_xer import load_xer

        await load_xer(file_path=str(sample_xer_single_project))

        result = await list_relationships()

        rel = result["relationships"][0]
        assert "task_pred_id" in rel
        assert "task_id" in rel
        assert "pred_task_id" in rel
        assert "pred_type" in rel
        assert "lag_hr_cnt" in rel

    async def test_list_relationships_no_file_loaded_returns_error(self) -> None:
        """list_relationships without loaded file returns NO_FILE_LOADED error."""
        from xer_mcp.server import set_file_loaded
        from xer_mcp.tools.list_relationships import list_relationships

        set_file_loaded(False)
        result = await list_relationships()

        assert "error" in result
        assert result["error"]["code"] == "NO_FILE_LOADED"