"""Contract tests for get_critical_path 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 TestGetCriticalPathContract:
    """Contract tests verifying get_critical_path tool interface."""

    async def test_get_critical_path_returns_critical_activities(
        self, sample_xer_single_project: Path
    ) -> None:
        """get_critical_path returns activities with driving_path_flag set."""
        from xer_mcp.tools.get_critical_path import get_critical_path
        from xer_mcp.tools.load_xer import load_xer

        await load_xer(file_path=str(sample_xer_single_project))

        result = await get_critical_path()

        assert "critical_activities" in result
        assert len(result["critical_activities"]) == 4

    async def test_get_critical_path_includes_expected_fields(
        self, sample_xer_single_project: Path
    ) -> None:
        """get_critical_path returns activities with required fields."""
        from xer_mcp.tools.get_critical_path import get_critical_path
        from xer_mcp.tools.load_xer import load_xer

        await load_xer(file_path=str(sample_xer_single_project))

        result = await get_critical_path()

        activity = result["critical_activities"][0]
        assert "task_id" in activity
        assert "task_code" in activity
        assert "task_name" in activity
        assert "target_start_date" in activity
        assert "target_end_date" in activity
        assert "total_float_hr_cnt" in activity

    async def test_get_critical_path_ordered_by_date(self, sample_xer_single_project: Path) -> None:
        """get_critical_path returns activities ordered by start date."""
        from xer_mcp.tools.get_critical_path import get_critical_path
        from xer_mcp.tools.load_xer import load_xer

        await load_xer(file_path=str(sample_xer_single_project))

        result = await get_critical_path()

        activities = result["critical_activities"]
        for i in range(len(activities) - 1):
            assert activities[i]["target_start_date"] <= activities[i + 1]["target_start_date"]

    async def test_get_critical_path_excludes_non_critical(
        self, sample_xer_single_project: Path
    ) -> None:
        """get_critical_path excludes activities not on critical path."""
        from xer_mcp.tools.get_critical_path import get_critical_path
        from xer_mcp.tools.load_xer import load_xer

        await load_xer(file_path=str(sample_xer_single_project))

        result = await get_critical_path()

        # A1020 "Foundation Work" has driving_path_flag = N
        activity_names = [a["task_name"] for a in result["critical_activities"]]
        assert "Foundation Work" not in activity_names

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

        set_file_loaded(False)
        result = await get_critical_path()

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