from datetime import datetime, timezone

from fastapi import HTTPException, status
from sqlalchemy.orm import Session

from api.v1.modules.crm.accounts.models import Account
from api.v1.modules.crm.quotes.models import Quote
from api.v1.modules.crm.service_requests.models import ServiceRequest
from api.v1.modules.crm.suppliers.models import Supplier

from .dto import (
    ShipmentCreate,
    ShipmentDocumentCreate,
    ShipmentDocumentUpdate,
    ShipmentEventCreate,
    ShipmentEventUpdate,
    ShipmentUpdate,
)
from .models import Shipment, ShipmentDocument, ShipmentEvent

# Hitos por defecto según el tipo de operación (Diagramas 2 y 3)
_DEFAULT_MILESTONES = {
    "exportacion": [
        ("recoleccion", "Recolección de mercancía"),
        ("despacho_exportacion", "Despacho de exportación"),
        ("embarque", "Embarque"),
        ("zarpe", "Zarpe / Salida del transporte"),
        ("arribo", "Arribo a destino"),
        ("entrega", "Entrega al consignatario"),
    ],
    "importacion": [
        ("aviso_llegada", "Aviso de llegada"),
        ("recepcion_docs", "Recepción de documentos (MBL/MAWB)"),
        ("despacho_importacion", "Despacho de importación"),
        ("liberacion", "Liberación de mercancía"),
        ("retiro", "Retiro en puerto / aeropuerto"),
        ("traslado", "Traslado a bodega del importador"),
        ("entrega", "Entrega final al cliente"),
    ],
}


def _exists(db: Session, model, _id: int | None, tenant_id: int, company_id: int) -> bool:
    if _id is None:
        return True
    return (
        db.query(model.id)
        .filter(
            model.id == _id,
            model.tenant_id == tenant_id,
            model.company_id == company_id,
            model.deleted_at.is_(None),
        )
        .first()
        is not None
    )


def _validate_refs(db: Session, data: dict, tenant_id: int, company_id: int) -> None:
    checks = [
        ("account_id", Account, "El cliente asociado no existe"),
        ("quote_id", Quote, "La cotización asociada no existe"),
        ("service_request_id", ServiceRequest, "La solicitud asociada no existe"),
        ("carrier_supplier_id", Supplier, "El transportista/naviera no existe"),
        ("customs_agent_id", Supplier, "El agente aduanal no existe"),
        ("destination_agent_id", Supplier, "El agente en destino no existe"),
    ]
    for field, model, msg in checks:
        if field in data and not _exists(db, model, data.get(field), tenant_id, company_id):
            raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail=msg)


def get_shipments(
    db: Session,
    tenant_id: int,
    company_id: int,
    search: str | None = None,
    shipment_status: str | None = None,
    account_id: int | None = None,
) -> list[Shipment]:
    query = db.query(Shipment).filter(
        Shipment.tenant_id == tenant_id,
        Shipment.company_id == company_id,
        Shipment.deleted_at.is_(None),
    )
    if shipment_status:
        query = query.filter(Shipment.status == shipment_status)
    if account_id is not None:
        query = query.filter(Shipment.account_id == account_id)
    if search:
        pattern = f"%{search}%"
        query = query.filter(
            Shipment.reference.ilike(pattern)
            | Shipment.booking_number.ilike(pattern)
            | Shipment.origin.ilike(pattern)
            | Shipment.destination.ilike(pattern)
        )
    return query.order_by(Shipment.created_at.desc()).all()


def get_shipment(db: Session, shipment_id: int, tenant_id: int, company_id: int) -> Shipment:
    obj = (
        db.query(Shipment)
        .filter(
            Shipment.id == shipment_id,
            Shipment.tenant_id == tenant_id,
            Shipment.company_id == company_id,
            Shipment.deleted_at.is_(None),
        )
        .first()
    )
    if not obj:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Embarque no encontrado")
    return obj


def create_shipment(
    db: Session, payload: ShipmentCreate, tenant_id: int, company_id: int, user_id: str | None = None
) -> Shipment:
    data = payload.model_dump()
    _validate_refs(db, data, tenant_id, company_id)
    obj = Shipment(**data, tenant_id=tenant_id, company_id=company_id, created_by=user_id, updated_by=user_id)
    db.add(obj)
    db.commit()
    db.refresh(obj)
    return obj


def update_shipment(
    db: Session, shipment_id: int, payload: ShipmentUpdate, tenant_id: int, company_id: int, user_id: str | None = None
) -> Shipment:
    obj = get_shipment(db, shipment_id, tenant_id, company_id)
    data = payload.model_dump(exclude_unset=True)
    _validate_refs(db, data, tenant_id, company_id)
    for field, value in data.items():
        setattr(obj, field, value)
    obj.updated_by = user_id
    db.commit()
    db.refresh(obj)
    return obj


def delete_shipment(db: Session, shipment_id: int, tenant_id: int, company_id: int) -> None:
    obj = get_shipment(db, shipment_id, tenant_id, company_id)
    obj.deleted_at = datetime.now(timezone.utc)
    db.commit()


def create_shipment_from_quote(
    db: Session, quote_id: int, tenant_id: int, company_id: int, user_id: str | None = None
) -> Shipment:
    """Liberar a Operaciones: crea el embarque a partir de una cotización aceptada."""
    quote = (
        db.query(Quote)
        .filter(
            Quote.id == quote_id,
            Quote.tenant_id == tenant_id,
            Quote.company_id == company_id,
            Quote.deleted_at.is_(None),
        )
        .first()
    )
    if not quote:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Cotización no encontrada")
    if quote.status != "aceptada":
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="La cotización debe estar aceptada para liberarse a Operaciones",
        )

    sr = None
    if quote.service_request_id:
        sr = db.query(ServiceRequest).filter(ServiceRequest.id == quote.service_request_id).first()

    shipment = Shipment(
        reference=quote.reference,
        quote_id=quote.id,
        service_request_id=quote.service_request_id,
        account_id=quote.account_id,
        operation_type=sr.operation_type if sr else None,
        transport_mode=sr.transport_mode if sr else None,
        service_type=sr.service_type if sr else None,
        incoterm=sr.incoterm if sr else None,
        origin=sr.origin if sr else None,
        destination=sr.destination if sr else None,
        destination_agent_id=sr.destination_agent_id if sr else None,
        status="abierta",
        owner_user_id=quote.owner_user_id,
        tenant_id=tenant_id,
        company_id=company_id,
        created_by=user_id,
        updated_by=user_id,
    )
    db.add(shipment)
    if sr:
        sr.status = "liberada"
    db.commit()
    db.refresh(shipment)
    return shipment


# ----- Documentos del embarque -----

def get_shipment_documents(
    db: Session, tenant_id: int, company_id: int, shipment_id: int | None = None
) -> list[ShipmentDocument]:
    query = db.query(ShipmentDocument).filter(
        ShipmentDocument.tenant_id == tenant_id,
        ShipmentDocument.company_id == company_id,
        ShipmentDocument.deleted_at.is_(None),
    )
    if shipment_id is not None:
        query = query.filter(ShipmentDocument.shipment_id == shipment_id)
    return query.order_by(ShipmentDocument.id.asc()).all()


def _get_document(db: Session, doc_id: int, tenant_id: int, company_id: int) -> ShipmentDocument:
    obj = (
        db.query(ShipmentDocument)
        .filter(
            ShipmentDocument.id == doc_id,
            ShipmentDocument.tenant_id == tenant_id,
            ShipmentDocument.company_id == company_id,
            ShipmentDocument.deleted_at.is_(None),
        )
        .first()
    )
    if not obj:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Documento no encontrado")
    return obj


def create_shipment_document(
    db: Session, payload: ShipmentDocumentCreate, tenant_id: int, company_id: int
) -> ShipmentDocument:
    get_shipment(db, payload.shipment_id, tenant_id, company_id)  # valida scope
    obj = ShipmentDocument(**payload.model_dump(), tenant_id=tenant_id, company_id=company_id)
    db.add(obj)
    db.commit()
    db.refresh(obj)
    return obj


def update_shipment_document(
    db: Session, doc_id: int, payload: ShipmentDocumentUpdate, tenant_id: int, company_id: int
) -> ShipmentDocument:
    obj = _get_document(db, doc_id, tenant_id, company_id)
    for field, value in payload.model_dump(exclude_unset=True).items():
        setattr(obj, field, value)
    db.commit()
    db.refresh(obj)
    return obj


def delete_shipment_document(db: Session, doc_id: int, tenant_id: int, company_id: int) -> None:
    obj = _get_document(db, doc_id, tenant_id, company_id)
    obj.deleted_at = datetime.now(timezone.utc)
    db.commit()


# ----- Bitácora / hitos del embarque -----

def get_shipment_events(db: Session, tenant_id: int, company_id: int, shipment_id: int | None = None) -> list[ShipmentEvent]:
    query = db.query(ShipmentEvent).filter(
        ShipmentEvent.tenant_id == tenant_id,
        ShipmentEvent.company_id == company_id,
        ShipmentEvent.deleted_at.is_(None),
    )
    if shipment_id is not None:
        query = query.filter(ShipmentEvent.shipment_id == shipment_id)
    return query.order_by(ShipmentEvent.position.asc(), ShipmentEvent.id.asc()).all()


def _get_event(db: Session, event_id: int, tenant_id: int, company_id: int) -> ShipmentEvent:
    obj = (
        db.query(ShipmentEvent)
        .filter(
            ShipmentEvent.id == event_id,
            ShipmentEvent.tenant_id == tenant_id,
            ShipmentEvent.company_id == company_id,
            ShipmentEvent.deleted_at.is_(None),
        )
        .first()
    )
    if not obj:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Hito no encontrado")
    return obj


def create_shipment_event(db: Session, payload: ShipmentEventCreate, tenant_id: int, company_id: int) -> ShipmentEvent:
    get_shipment(db, payload.shipment_id, tenant_id, company_id)
    obj = ShipmentEvent(**payload.model_dump(), tenant_id=tenant_id, company_id=company_id)
    db.add(obj)
    db.commit()
    db.refresh(obj)
    return obj


def update_shipment_event(db: Session, event_id: int, payload: ShipmentEventUpdate, tenant_id: int, company_id: int) -> ShipmentEvent:
    obj = _get_event(db, event_id, tenant_id, company_id)
    for field, value in payload.model_dump(exclude_unset=True).items():
        setattr(obj, field, value)
    db.commit()
    db.refresh(obj)
    return obj


def complete_shipment_event(db: Session, event_id: int, tenant_id: int, company_id: int) -> ShipmentEvent:
    obj = _get_event(db, event_id, tenant_id, company_id)
    obj.status = "completado"
    obj.actual_date = datetime.now(timezone.utc)
    db.commit()
    db.refresh(obj)
    return obj


def delete_shipment_event(db: Session, event_id: int, tenant_id: int, company_id: int) -> None:
    obj = _get_event(db, event_id, tenant_id, company_id)
    obj.deleted_at = datetime.now(timezone.utc)
    db.commit()


def seed_default_milestones(db: Session, shipment_id: int, tenant_id: int, company_id: int) -> list[ShipmentEvent]:
    """Crea los hitos por defecto del embarque según su tipo de operación (import/export)."""
    shipment = get_shipment(db, shipment_id, tenant_id, company_id)
    existing = get_shipment_events(db, tenant_id, company_id, shipment_id)
    if existing:
        return existing
    milestones = _DEFAULT_MILESTONES.get(shipment.operation_type or "", [])
    if not milestones:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="Define el tipo de operación (importación/exportación) para generar los hitos",
        )
    created = []
    for position, (event_type, title) in enumerate(milestones):
        ev = ShipmentEvent(
            shipment_id=shipment_id, event_type=event_type, title=title, status="pendiente",
            position=position, tenant_id=tenant_id, company_id=company_id,
        )
        db.add(ev)
        created.append(ev)
    db.commit()
    for ev in created:
        db.refresh(ev)
    return created