from datetime import UTC, datetime

import pytest

from tenant_engine.domain import (
    EmptyUpdateError,
    ImmutableFieldError,
    InvalidLifecycleTransitionError,
    Tenant,
    TenantLifecycle,
)

NOW = datetime(2026, 8, 10, 12, 0, tzinfo=UTC)


def _tenant() -> Tenant:
    return Tenant.create(
        tenant_id="t-1", identifier="tenant:friendly:binky", display_name="Binky", created_at=NOW
    )


def test_new_tenant_is_active_at_version_one() -> None:
    tenant = _tenant()
    assert tenant.lifecycle is TenantLifecycle.ACTIVE
    assert tenant.version == 1
    assert tenant.is_active


def test_metadata_update_bumps_version_and_keeps_identity() -> None:
    tenant = _tenant().with_metadata({"display_name": "Binky Ltd"}, at=NOW)

    assert tenant.display_name == "Binky Ltd"
    assert tenant.version == 2
    assert tenant.updated_at == NOW
    assert tenant.tenant_id == "t-1"
    assert tenant.identifier == "tenant:friendly:binky"
    assert tenant.grouping == "friendly"


def test_update_rejects_identifier_mutation() -> None:
    with pytest.raises(ImmutableFieldError):
        _tenant().with_metadata({"identifier": "tenant:large:other"}, at=NOW)


def test_update_rejects_unknown_field() -> None:
    with pytest.raises(ImmutableFieldError):
        _tenant().with_metadata({"nickname": "binks"}, at=NOW)


def test_update_rejects_empty_change_set() -> None:
    with pytest.raises(EmptyUpdateError):
        _tenant().with_metadata({}, at=NOW)


def test_update_rejects_no_op_change() -> None:
    with pytest.raises(EmptyUpdateError):
        _tenant().with_metadata({"display_name": "Binky"}, at=NOW)


def test_retire_is_reversible_and_preserves_identity() -> None:
    retired = _tenant().retire(at=NOW)
    assert retired.lifecycle is TenantLifecycle.RETIRED
    assert retired.retired_at == NOW
    assert retired.version == 2
    assert retired.identifier == "tenant:friendly:binky"

    reactivated = retired.reactivate(at=NOW)
    assert reactivated.lifecycle is TenantLifecycle.ACTIVE
    assert reactivated.reactivated_at == NOW
    assert reactivated.retired_at == NOW  # retirement history is not erased
    assert reactivated.version == 3


def test_double_retirement_is_an_invalid_transition() -> None:
    retired = _tenant().retire(at=NOW)
    with pytest.raises(InvalidLifecycleTransitionError):
        retired.retire(at=NOW)


def test_reactivating_an_active_tenant_is_an_invalid_transition() -> None:
    with pytest.raises(InvalidLifecycleTransitionError):
        _tenant().reactivate(at=NOW)


def test_metadata_update_denied_while_retired() -> None:
    retired = _tenant().retire(at=NOW)
    with pytest.raises(InvalidLifecycleTransitionError):
        retired.with_metadata({"display_name": "Binky Ltd"}, at=NOW)