from datetime import UTC, datetime
from pathlib import Path

import pytest

from app.health import dependency_status, effective_status, validate_dependencies
from app.incidents import incident_overview
from app.models import HealthStatus, ProbeResult, ServiceCreate, ServiceKind, ServiceUpdate
from app.store import Store


def _probe(service_id: str, status: HealthStatus) -> ProbeResult:
    return ProbeResult(
        id=f"probe-{service_id}-{status.value}",
        service_id=service_id,
        status=status,
        latency_ms=1.0,
        detail=status.value,
        checked_at=datetime.now(UTC),
    )


def test_down_dependency_degrades_healthy_service(tmp_path: Path) -> None:
    store = Store(str(tmp_path / "servicemap.db"))
    database = store.create_service(
        ServiceCreate(name="Database", kind=ServiceKind.TCP, host="127.0.0.1", port=5432)
    )
    api = store.create_service(
        ServiceCreate(
            name="API",
            kind=ServiceKind.HTTP,
            url="https://example.test",
            depends_on=[database.id],
        )
    )
    store.save_probe(_probe(database.id, HealthStatus.DOWN))
    store.save_probe(_probe(api.id, HealthStatus.HEALTHY))

    assert dependency_status(api, store) == HealthStatus.DOWN
    assert effective_status(api, store) == HealthStatus.DEGRADED


def test_service_without_dependencies_has_healthy_dependency_state(tmp_path: Path) -> None:
    store = Store(str(tmp_path / "servicemap.db"))
    service = store.create_service(
        ServiceCreate(name="Standalone", kind=ServiceKind.HTTP, url="https://example.test")
    )

    assert dependency_status(service, store) == HealthStatus.HEALTHY
    assert effective_status(service, store) == HealthStatus.UNKNOWN


def test_cycle_validation_rejects_recursive_dependencies(tmp_path: Path) -> None:
    store = Store(str(tmp_path / "servicemap.db"))
    database = store.create_service(
        ServiceCreate(name="Database", kind=ServiceKind.TCP, host="127.0.0.1", port=5432)
    )
    api = store.create_service(
        ServiceCreate(name="API", kind=ServiceKind.HTTP, url="https://example.test", depends_on=[database.id])
    )

    with pytest.raises(ValueError, match="cycle"):
        validate_dependencies([api.id], store, service_id=database.id)

    validate_dependencies([database.id], store, service_id=api.id)
    updated = store.update_service(
        api.id,
        ServiceUpdate(name="API", kind=ServiceKind.HTTP, url="https://example.test", depends_on=[database.id]),
    )
    assert updated is not None


def test_incident_overview_finds_root_cause_and_multihop_impact(tmp_path: Path) -> None:
    store = Store(str(tmp_path / "servicemap.db"))
    database = store.create_service(
        ServiceCreate(name="Database", kind=ServiceKind.TCP, host="127.0.0.1", port=5432)
    )
    api = store.create_service(
        ServiceCreate(name="API", kind=ServiceKind.HTTP, url="https://example.test", depends_on=[database.id])
    )
    web = store.create_service(
        ServiceCreate(name="Web", kind=ServiceKind.HTTP, url="https://web.test", depends_on=[api.id])
    )
    store.save_probe(_probe(database.id, HealthStatus.DOWN))
    store.save_probe(_probe(api.id, HealthStatus.HEALTHY))
    store.save_probe(_probe(web.id, HealthStatus.HEALTHY))

    assert effective_status(api, store) == HealthStatus.DEGRADED
    assert dependency_status(web, store) == HealthStatus.DEGRADED
    assert effective_status(web, store) == HealthStatus.DEGRADED

    overview = incident_overview(store)

    assert overview.active is True
    assert overview.down_service_ids == [database.id]
    assert set(overview.degraded_service_ids) == {api.id, web.id}
    assert overview.candidates[0].service_id == database.id
    assert api.id in overview.candidates[0].affected_service_ids
    assert web.id in overview.candidates[0].affected_service_ids