from datetime import datetime, timedelta
from typing import Optional, Union

from fastapi import HTTPException, status
from sqlalchemy import Delete, Select, and_, desc, func, not_, or_
from sqlalchemy.dialects.postgresql import insert
from sqlalchemy.orm import selectinload

from src.auth.service import CurrentUser
from src.database.core import DbSession, CollectorDbSession
from src.utils import update_model
from src.database.service import CommonParameters, search_filter_sort_paginate
from src.overhaul_scope.model import OverhaulScope
from src.standard_scope.enum import ScopeEquipmentType
from src.standard_scope.model import EquipmentOHHistory
from src.workorder.model import MasterWorkOrder
from src.equipment_workscope_group.model import EquipmentWorkscopeGroup
from src.workscope_group.model import MasterActivity
from src.workscope_group_maintenance_type.model import WorkscopeOHType
from src.overhaul_scope.model import MaintenanceType
from src.overhaul_scope.service import get as get_overhaul
from src.maximo.service import get_history_oh_wo    
from .model import MasterEquipment, MasterEquipmentTree, StandardScope
from .schema import ScopeEquipmentCreate, ScopeEquipmentUpdate
from uuid import UUID

async def get_by_location_tag(*, db_session: DbSession, location_tag: str):
    query = (
        Select(StandardScope)
        .filter(StandardScope.location_tag == location_tag)
        .options(selectinload(StandardScope.master_equipment))
    )

    result = await db_session.execute(query)
    return result.unique().scalars().one_or_none()


async def get_all(*, common, oh_scope: Optional[str] = None):
    """Returns all documents."""
    query = Select(StandardScope).options(
        selectinload(StandardScope.master_equipment)
    )

    query = query.order_by(desc(StandardScope.created_at)).options(selectinload(StandardScope.master_equipment))

    if oh_scope:
        query = (
            query
            .outerjoin(StandardScope.oh_history)  # Use outerjoin to handle None values
            .join(StandardScope.workscope_groups)
            .join(EquipmentWorkscopeGroup.workscope_group)
            .join(MasterActivity.oh_types)
            .join(WorkscopeOHType.oh_type)
            .join(StandardScope.master_equipment)
            .filter(MasterEquipment.location_tag.is_not(None))
            .filter(MaintenanceType.name == oh_scope)

            # .filter(
            #     (StandardScope.is_alternating_oh == False) |
            #     (StandardScope.oh_history == None) |
            #     (StandardScope.oh_history.has(EquipmentOHHistory.last_oh_type != selected_overhaul.maintenance_type.name))
            # ).distinct()
        )

    results = await common['db_session'].execute(query)
    
    items = results.scalars().all()
    
    
    return {
        "items": items,
        "total": len(items)
    }


async def get_by_oh_session_id(*, db_session: DbSession, oh_session_id: UUID):
    overhaul = await get_overhaul(db_session=db_session, overhaul_session_id=oh_session_id)

    query = (
            Select(StandardScope)
            .outerjoin(StandardScope.oh_history)  # Use outerjoin to handle None values
            .join(StandardScope.workscope_groups)
            .join(EquipmentWorkscopeGroup.workscope_group)
            .join(MasterActivity.oh_types)
            .join(WorkscopeOHType.oh_type)
            .join(MasterEquipment, StandardScope.location_tag == MasterEquipment.location_tag)
            .filter(MaintenanceType.name == overhaul.maintenance_type.name).filter(
                (StandardScope.is_alternating_oh == False) |
                (StandardScope.oh_history == None) |
                (StandardScope.oh_history.has(EquipmentOHHistory.last_oh_type != overhaul.maintenance_type.name))
            ).distinct()
    )

    result = await db_session.execute(query)
    return result.scalars().all(), overhaul

async def create(*, db_session: DbSession, scope_equipment_in: ScopeEquipmentCreate):
    """Creates a new document."""
    # scope_equipment = StandardScope(**scope_equipment_in.model_dump())
    assetnums = scope_equipment_in.assetnums
    results = []
    removal_date = scope_equipment_in.removal_date

    if scope_equipment_in.type == ScopeEquipmentType.TEMP:
        # Search for the next or ongoing overhaul session for the given scope
        stmt = (
            Select(OverhaulScope.end_date)
            .where(
                OverhaulScope.type == scope_equipment_in.scope_name,
                (OverhaulScope.start_date <= datetime.now())
                & (OverhaulScope.end_date >= datetime.now())  # Ongoing
                | (OverhaulScope.start_date > datetime.now()),  # Upcoming
            )
            .order_by(OverhaulScope.start_date.asc())
            .limit(1)
        )

        result = await db_session.execute(stmt)
        removal_date = result.scalar_one_or_none()

        # If no overhaul found, set a default removal date or handle the error
        if removal_date is None:
            # Handle if no overhaul session is found, set default or raise an error
            removal_date = datetime.now() + timedelta(
                days=30
            )  # Example: 30 days from now

    for assetnum in assetnums:
        stmt = insert(StandardScope).values(
            assetnum=assetnum,
            scope_overhaul=scope_equipment_in.scope_name,
            type=scope_equipment_in.type,
            removal_date=removal_date,
        )

        stmt = stmt.on_conflict_do_nothing(
            index_elements=["assetnum", "scope_overhaul"]
        )

        await db_session.execute(stmt)
        results.append(assetnum)

    # await db_session.commit()
    return results


async def update(
    *,
    db_session: DbSession,
    scope_equipment: StandardScope,
    scope_equipment_in: ScopeEquipmentUpdate
):
    """Updates a document."""
    data = scope_equipment_in.model_dump()

    # update_data = scope_equipment_in.model_dump(exclude_defaults=True)

    # update_model(scope_equipment, update_data)

    # await db_session.commit()

    return scope_equipment


async def delete(*, db_session: DbSession, assetnum: str):
    """Deletes a document."""
    # query = Delete(StandardScope).where(StandardScope.assetnum == assetnum)
    # await db_session.execute(query)
    # await db_session.commit()

    return assetnum

async def get_by_oh_scope(
    *, db_session: DbSession, oh_scope: str
):
    pass

    query = (Select(StandardScope)
            .outerjoin(StandardScope.oh_history)  # Use outerjoin to handle None values
            .join(StandardScope.workscope_groups)
            .join(EquipmentWorkscopeGroup.workscope_group)
            .join(MasterActivity.oh_types)
            .join(WorkscopeOHType.oh_type)
            .filter(MaintenanceType.name == oh_scope)
            # .filter(
            #     (StandardScope.is_alternating_oh == False) |
            #     (StandardScope.oh_history == None) |
            #     (StandardScope.oh_history.has(EquipmentOHHistory.last_oh_type != selected_overhaul.maintenance_type.name))
            # ).distinct()
    )

    results = await db_session.execute(query)
    return results.scalars().all()


async def get_all_master_equipment(*, common: CommonParameters, scope_name):
    equipments_scope = [
        equip.location_tag
        for equip in await get_by_oh_scope(
            db_session=common.get("db_session"), oh_scope=scope_name
        )
    ]

    query = Select(MasterEquipment).filter(MasterEquipment.location_tag.is_not(None))

    # Only add not_in filter if there are items in equipments_scope
    if equipments_scope:
        query = query.filter(MasterEquipment.location_tag.not_in(equipments_scope))

    results = await search_filter_sort_paginate(model=query, **common)
    return results


async def get_equipment_level_by_no(*, db_session: DbSession, level: int):
    query = (
        Select(MasterEquipment)
        .join(MasterEquipment.equipment_tree)
        .where(MasterEquipmentTree.level_no == level)
    )

    result = await db_session.execute(query)
    return result.scalars().all()


async def get_history_standard_scope_wo_service(*, db_session: DbSession, collector_db_session:CollectorDbSession, oh_session_id:UUID):
    planning_oh_data = await get_by_oh_session_id(db_session=db_session, oh_session_id=oh_session_id)
    
    planning_scopes = planning_oh_data[0]
    overhaul = planning_oh_data[1]
    
    results = await get_history_oh_wo(
        db_session=db_session, 
        collector_db_session=collector_db_session, 
        oh_session_id=oh_session_id,
        parent_wo_num=overhaul.wo_parent
    ) 

    scope_cost_map = {scope.location_tag: scope.service_cost for scope in planning_scopes}

    for result in results:
        result["planning_service_cost"] = scope_cost_map.get(result["location_tag"], 0)

    return results