from __future__ import annotations

from dataclasses import dataclass, field
from datetime import datetime, timezone
from typing import Any, List
from uuid import uuid4

import pytest

from backend.app.models import CombinedTrackModel
from backend.app.repositories.combined_tracks import CombinedTrackRepository
from backend.app.repositories.tracks import TrackRepository
from backend.app.services.combined_tracks import create_combined_track


@dataclass
class DummySession:
    added: List[Any] = field(default_factory=list)
    scalars_result: List[Any] = field(default_factory=list)
    scalar_result: Any = None
    statements: List[Any] = field(default_factory=list)
    committed: bool = False
    rolled_back: bool = False
    closed: bool = False

    def add(self, instance: Any) -> None:
        self.added.append(instance)

    def add_all(self, instances: list[Any]) -> None:
        self.added.extend(instances)

    def scalars(self, statement: Any) -> list[Any]:
        self.statements.append(statement)
        return list(self.scalars_result)

    def scalar(self, statement: Any) -> Any:
        self.statements.append(statement)
        return self.scalar_result

    def flush(
        self, _objects: list[Any] | None = None
    ) -> None:  # pragma: no cover - optional
        return None

    def commit(self) -> None:  # pragma: no cover - optional
        self.committed = True

    def rollback(self) -> None:  # pragma: no cover - optional
        self.rolled_back = True

    def close(self) -> None:  # pragma: no cover - optional
        self.closed = True


def _now() -> datetime:
    return datetime.now(timezone.utc)


def test_combined_track_model_round_trip() -> None:
    timestamp = _now()
    combined_track = CombinedTrackModel(
        id="combined-track-1",
        start_station_id="station-1",
        end_station_id="station-2",
        length_meters=3000.0,
        max_speed_kph=100,
        status="operational",
        is_bidirectional=True,
        coordinates=[(52.52, 13.405), (52.6, 13.5), (52.7, 13.6)],
        constituent_track_ids=["track-1", "track-2"],
        created_at=timestamp,
        updated_at=timestamp,
    )
    assert combined_track.length_meters == 3000.0
    assert combined_track.start_station_id != combined_track.end_station_id
    assert len(combined_track.coordinates) == 3
    assert len(combined_track.constituent_track_ids) == 2


def test_combined_track_repository_create() -> None:
    """Test creating a combined track through the repository."""
    session = DummySession()
    repo = CombinedTrackRepository(session)  # type: ignore[arg-type]

    # Create test data
    from backend.app.models import CombinedTrackCreate

    create_data = CombinedTrackCreate(
        start_station_id="550e8400-e29b-41d4-a716-446655440000",
        end_station_id="550e8400-e29b-41d4-a716-446655440001",
        coordinates=[(52.52, 13.405), (52.6, 13.5)],
        constituent_track_ids=["track-1"],
        length_meters=1500.0,
        max_speed_kph=120,
        status="operational",
    )

    combined_track = repo.create(create_data)

    assert combined_track.start_station_id is not None
    assert combined_track.end_station_id is not None
    assert combined_track.length_meters == 1500.0
    assert combined_track.max_speed_kph == 120
    assert combined_track.status == "operational"
    assert session.added and session.added[0] is combined_track


def test_combined_track_repository_exists_between_stations() -> None:
    """Test checking if combined track exists between stations."""
    session = DummySession()
    repo = CombinedTrackRepository(session)  # type: ignore[arg-type]

    # Initially should not exist (scalar_result is None by default)
    assert not repo.exists_between_stations(
        "550e8400-e29b-41d4-a716-446655440000",
        "550e8400-e29b-41d4-a716-446655440001"
    )

    # Simulate existing combined track
    session.scalar_result = True
    assert repo.exists_between_stations(
        "550e8400-e29b-41d4-a716-446655440000",
        "550e8400-e29b-41d4-a716-446655440001"
    )


def test_combined_track_service_create_no_path() -> None:
    """Test creating combined track when no path exists."""
    # Mock session and repositories
    session = DummySession()

    # Mock TrackRepository to return no path
    class MockTrackRepository:
        def __init__(self, session):
            pass

        def find_path_between_stations(self, start_id, end_id):
            return None

    # Mock CombinedTrackRepository
    class MockCombinedTrackRepository:
        def __init__(self, session):
            pass

        def exists_between_stations(self, start_id, end_id):
            return False

    # Patch the service to use mock repositories
    import backend.app.services.combined_tracks as service_module
    original_track_repo = service_module.TrackRepository
    original_combined_repo = service_module.CombinedTrackRepository

    service_module.TrackRepository = MockTrackRepository
    service_module.CombinedTrackRepository = MockCombinedTrackRepository

    try:
        result = create_combined_track(
            session,  # type: ignore[arg-type]
            "550e8400-e29b-41d4-a716-446655440000",
            "550e8400-e29b-41d4-a716-446655440001"
        )
        assert result is None
    finally:
        # Restore original classes
        service_module.TrackRepository = original_track_repo
        service_module.CombinedTrackRepository = original_combined_repo