from datetime import datetime, timezone

import pytest

from app_new import db
from app_new.core.models.college import Building, HousingUnit, Room, Zone
from app_new.core.models.equipment import Equipment, EquipmentCategory
from app_new.core.models.planning import Meter, MeterReading, MeterReadingCorrection
from app_new.core.services.meter_service import (
    MeterDomainError, correct_meter_reading, create_meter, record_meter_reading,
    replace_meter,
)


def _equipment():
    category = EquipmentCategory(name="TEST_UI_C1_CATEGORY")
    building = Building(name="TEST_UI_C1_BUILDING")
    room = Room(name="TEST_UI_C1_ROOM", code="TEST_UI_C1_ROOM", building=building)
    equipment = Equipment(name="TEST_UI_C1_EQUIPMENT", category=category, room=room)
    db.session.add_all([category, building, room, equipment])
    db.session.flush()
    return equipment, building, room


def test_meter_supports_all_patrimony_scopes_and_multiple_roots(app):
    with app.app_context():
        equipment, building, room = _equipment()
        zone = Zone(name="TEST_UI_C1_ZONE", building=building)
        housing = HousingUnit(name="TEST_UI_C1_HOUSING", building=building)
        db.session.add_all([zone, housing])
        db.session.flush()
        meters = [
            create_meter(name="Equipment", equipment_id=equipment.id, commit=False),
            create_meter(name="Building", building_id=building.id, commit=False),
            create_meter(name="Zone", zone_id=zone.id, commit=False),
            create_meter(name="Room", room_id=room.id, commit=False),
            create_meter(name="Housing", housing_unit_id=housing.id, commit=False),
            create_meter(name="Other root", building_id=building.id, commit=False),
        ]
        db.session.commit()
        assert {meter.building_id or meter.zone_id or meter.room_id or meter.housing_unit_id or meter.equipment_id for meter in meters}
        assert all(Meter.query.get(meter.id) is not None for meter in meters)


def test_meter_hierarchy_rejects_self_and_deep_cycles(app):
    with app.app_context():
        _, building, _ = _equipment()
        root = create_meter(name="Root", building_id=building.id)
        child = create_meter(name="Child", building_id=building.id, parent=root)
        grandchild = create_meter(name="Grandchild", building_id=building.id, parent=child)
        with pytest.raises(MeterDomainError):
            root.parent = grandchild
            from app_new.core.services.meter_service import validate_meter_scope
            validate_meter_scope(root)
        with pytest.raises(MeterDomainError):
            root.parent = root
            from app_new.core.services.meter_service import validate_meter_scope
            validate_meter_scope(root)
        root.parent = None


def test_reading_reset_correction_and_current_value_are_consistent(app, admin_user):
    with app.app_context():
        _, building, _ = _equipment()
        meter = create_meter(name="Water", meter_type="eau", unit="m³", building_id=building.id)
        first = record_meter_reading(meter=meter, value=100, user_id=admin_user["id"], reading_date=datetime(2026, 1, 1, tzinfo=timezone.utc))
        with pytest.raises(MeterDomainError):
            record_meter_reading(meter=meter, value=90, user_id=admin_user["id"])
        reset = record_meter_reading(meter=meter, value=10, user_id=admin_user["id"], is_reset=True, reset_reason="TEST_UI_C1 remise à zéro")
        correction = correct_meter_reading(reading=first, new_value=101, user_id=admin_user["id"], reason="TEST_UI_C1 correction")
        assert reset.is_reset is True
        assert correction.value == 101
        assert meter.current_value == 10
        assert MeterReadingCorrection.query.filter_by(reading_id=first.id).one().old_value == 100


def test_replacement_keeps_old_history_and_links_new_meter(app, admin_user):
    with app.app_context():
        _, building, _ = _equipment()
        old = create_meter(name="Old", building_id=building.id)
        record_meter_reading(meter=old, value=12, user_id=admin_user["id"])
        new = replace_meter(old_meter=old, name="New", user_id=admin_user["id"])
        assert old.status == "replaced"
        assert old.is_active is False
        assert new.replaces_meter_id == old.id
        assert MeterReading.query.filter_by(meter_id=old.id).count() == 1