from typing import Optional
from sqlalchemy import Select
from sqlalchemy.orm import selectinload
from src.database.core import DbSession
from src.database.service import search_filter_sort_paginate
from src.overhaul_activity.model import OverhaulActivity
from src.utils import time_now, update_model
from src.standard_scope.model import MasterEquipment, StandardScope, EquipmentOHHistory
from src.workscope_group.model import MasterActivity
from src.workscope_group_maintenance_type.model import WorkscopeOHType
from src.equipment_workscope_group.model import EquipmentWorkscopeGroup
from .model import OverhaulScope, MaintenanceType
from .schema import ScopeCreate, ScopeUpdate
from .utils import get_material_cost, get_service_cost
from datetime import datetime
from uuid import UUID
from src.soft_delete import apply_not_deleted_filter, soft_delete_record

async def get(*, db_session: DbSession, overhaul_session_id: UUID) -> Optional[OverhaulScope]:
    query = Select(OverhaulScope).filter(OverhaulScope.id == overhaul_session_id).options(selectinload(OverhaulScope.maintenance_type))
    query = apply_not_deleted_filter(query, OverhaulScope)
    result = await db_session.execute(query)
    return result.scalars().one_or_none()

async def get_prev_oh(*, db_session: DbSession, overhaul_session: OverhaulScope) -> Optional[OverhaulScope]:
    result = Select(OverhaulScope).where(OverhaulScope.end_date < overhaul_session.end_date).order_by(OverhaulScope.end_date.desc()).limit(1)
    result = apply_not_deleted_filter(result, OverhaulScope)
    result = await db_session.execute(result)
    return result.scalars().one_or_none()

async def get_all(*, common, scope_name: Optional[str]=None):
    query = Select(OverhaulScope)
    query = apply_not_deleted_filter(query, OverhaulScope)
    if scope_name:
        query = query.filter(OverhaulScope.maintenance_type.name == scope_name)
    results = await search_filter_sort_paginate(model=query, **common)
    return results

async def create(*, db_session: DbSession, scope_in: ScopeCreate):
    if isinstance(scope_in.start_date, str):
        try:
            start_date = datetime.fromisoformat(scope_in.start_date.replace('Z', '+00:00'))
        except ValueError:
            start_date = datetime.strptime(scope_in.start_date, '%Y-%m-%d %H:%M:%S')
    else:
        start_date = scope_in.start_date
    end_date = None
    if scope_in.end_date:
        if isinstance(scope_in.end_date, str):
            try:
                end_date = datetime.fromisoformat(scope_in.end_date.replace('Z', '+00:00'))
            except ValueError:
                end_date = datetime.strptime(scope_in.end_date, '%Y-%m-%d %H:%M:%S')
        else:
            end_date = scope_in.end_date
    duration_days = None
    if start_date and end_date:
        duration_days = (end_date - start_date).days
    maintenance_type = Select(MaintenanceType).where(MaintenanceType.name == scope_in.type).with_for_update()
    maintenance_type_exec = await db_session.execute(maintenance_type)
    maintenance_type = maintenance_type_exec.scalars().one_or_none()
    if maintenance_type is None:
        try:
            async with db_session.begin_nested():
                maintenance_type = MaintenanceType(name=scope_in.type)
                db_session.add(maintenance_type)
                await db_session.flush()
        except BaseException:
            maintenance_type_exec = await db_session.execute(Select(MaintenanceType).where(MaintenanceType.name == scope_in.type).with_for_update())
            maintenance_type = maintenance_type_exec.scalars().one_or_none()
    overhaul_session = OverhaulScope(start_date=scope_in.start_date, end_date=scope_in.end_date, maintenance_type=maintenance_type, duration_oh=duration_days, crew_number=scope_in.crew_number, status=scope_in.status)
    db_session.add(overhaul_session)
    await db_session.flush()
    scope_name = scope_in.type
    equipments = await get_by_scope_name(db_session=db_session, scope_name=scope_name)
    material_cost = get_material_cost(scope=overhaul_session.type, total_equipment=len(equipments))
    service_cost = get_service_cost(scope=overhaul_session.type, total_equipment=len(equipments))
    scope_equipments = [OverhaulActivity(assetnum=equipment.assetnum, overhaul_scope_id=overhaul_session.id, material_cost=material_cost, service_cost=service_cost) for equipment in equipments]
    if scope_equipments:
        db_session.add_all(scope_equipments)
    await db_session.commit()
    return overhaul_session

async def update(*, db_session: DbSession, scope_id: str, scope_in: ScopeUpdate):
    query = Select(OverhaulScope).filter(OverhaulScope.id == scope_id).options(selectinload(OverhaulScope.maintenance_type)).with_for_update()
    query = apply_not_deleted_filter(query, OverhaulScope)
    result = await db_session.execute(query)
    scope = result.scalars().one_or_none()
    if not scope:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail='A data with this id does not exist.')
    await db_session.refresh(scope)
    update_data = scope_in.model_dump(exclude_defaults=True)
    update_model(scope, update_data)
    await db_session.commit()
    return scope

async def delete(*, db_session: DbSession, scope_id: str):
    await soft_delete_record(db_session=db_session, model=OverhaulScope, record_id=scope_id)

async def get_overview_overhaul(*, db_session: DbSession):
    current_date = time_now().date()
    ongoing_query = Select(OverhaulScope).where(OverhaulScope.start_date <= current_date, OverhaulScope.end_date >= current_date)
    ongoing_query = apply_not_deleted_filter(ongoing_query, OverhaulScope)
    ongoing_result = await db_session.execute(ongoing_query.options(selectinload(OverhaulScope.maintenance_type)))
    ongoing_overhaul = ongoing_result.scalar_one_or_none()
    if ongoing_overhaul is None:
        next_overhaul_query = Select(OverhaulScope).where(OverhaulScope.start_date > current_date).order_by(OverhaulScope.start_date.asc()).limit(1)
        next_overhaul_query = apply_not_deleted_filter(next_overhaul_query, OverhaulScope)
        next_result = await db_session.execute(next_overhaul_query.options(selectinload(OverhaulScope.maintenance_type)))
        next_overhaul = next_result.scalar_one_or_none()
        if next_overhaul:
            print(f'Next scheduled overhaul starts on: {next_overhaul.start_date}')
            selected_overhaul = next_overhaul
        else:
            print('No upcoming overhauls scheduled')
            selected_overhaul = None
    else:
        print(f'Ongoing overhaul found: {ongoing_overhaul.start_date} to {ongoing_overhaul.end_date}')
        selected_overhaul = ongoing_overhaul
    equipments = Select(StandardScope).outerjoin(StandardScope.oh_history).join(StandardScope.workscope_groups).join(EquipmentWorkscopeGroup.workscope_group).join(MasterActivity.oh_types).join(MasterEquipment, StandardScope.location_tag == MasterEquipment.location_tag).filter(WorkscopeOHType.maintenance_type_id == selected_overhaul.maintenance_type_id).filter((StandardScope.is_alternating_oh == False) | (StandardScope.oh_history == None) | StandardScope.oh_history.has(EquipmentOHHistory.last_oh_type != selected_overhaul.maintenance_type.name)).distinct()
    equipments = apply_not_deleted_filter(equipments, StandardScope)
    results = await db_session.execute(equipments)
    remaining_days = (selected_overhaul.start_date - current_date).days if selected_overhaul.status == 'Upcoming' else (selected_overhaul.end_date - current_date).days
    return {'status': selected_overhaul.status, 'overhaul': {'id': selected_overhaul.id, 'type': selected_overhaul.maintenance_type.name, 'start_date': selected_overhaul.start_date, 'end_date': selected_overhaul.end_date, 'duration_oh': selected_overhaul.duration_oh, 'crew_number': selected_overhaul.crew_number, 'remaining_days': remaining_days, 'equipment_count': len(results.scalars().all())}}

async def get_all_oh_with_history_service(*, db_session: DbSession):
    query = Select(OverhaulScope).options(selectinload(OverhaulScope.maintenance_type)).where(OverhaulScope.wo_parent.isnot(None))
    query = apply_not_deleted_filter(query, OverhaulScope)
    results = await db_session.execute(query)
    return results.scalars().all()