from datetime import date, datetime, timezone
from decimal import Decimal

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

from ..accounts.models import Account
from ..catalogs.models import CatalogItem
from ..common.folios import next_folio
from ..service_requests.models import RateRequest, ServiceRequest
from ..suppliers.models import Supplier
from .dto import QuoteCreate, QuoteItemCreate, QuoteItemUpdate, QuoteUpdate
from .models import Quote, QuoteItem


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:
    if not _exists(db, Account, data.get("account_id"), tenant_id, company_id):
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="El cliente asociado no existe")
    if not _exists(db, ServiceRequest, data.get("service_request_id"), tenant_id, company_id):
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="La solicitud asociada no existe")


def _recompute_totals(db: Session, quote: Quote) -> None:
    """Recalcula total_cost/total_sale a partir de los conceptos vigentes."""
    cost, sale = (
        db.query(
            func.coalesce(func.sum(QuoteItem.quantity * QuoteItem.unit_cost), 0),
            func.coalesce(func.sum(QuoteItem.quantity * QuoteItem.unit_sale), 0),
        )
        .filter(QuoteItem.quote_id == quote.id, QuoteItem.deleted_at.is_(None))
        .one()
    )
    quote.total_cost = Decimal(cost or 0)
    quote.total_sale = Decimal(sale or 0)


# ----- Quotes -----

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


def get_quote(db: Session, quote_id: int, tenant_id: int, company_id: int) -> Quote:
    obj = (
        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 obj:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Cotización no encontrada")
    return obj


def _sr_direction(db: Session, service_request_id: int | None) -> str | None:
    """Dirección impo/expo heredada de la solicitud asociada (para el folio)."""
    if not service_request_id:
        return None
    sr = db.query(ServiceRequest).filter(ServiceRequest.id == service_request_id).first()
    return sr.operation_type if sr else None


def create_quote(
    db: Session, payload: QuoteCreate, tenant_id: int, company_id: int, user_id: str | None = None
) -> Quote:
    data = payload.model_dump()
    _validate_refs(db, data, tenant_id, company_id)
    obj = Quote(**data, tenant_id=tenant_id, company_id=company_id, created_by=user_id, updated_by=user_id)
    # Fecha de la cotización: por defecto hoy si no se capturó
    if obj.issue_date is None:
        obj.issue_date = date.today()
    # Folio C... auto-generado (mensual), con la dirección heredada de la solicitud
    if not obj.reference:
        obj.reference = next_folio(db, tenant_id, company_id, "C", _sr_direction(db, obj.service_request_id))
    db.add(obj)
    db.commit()
    db.refresh(obj)
    return obj


def create_quotes_from_service_request(
    db: Session, service_request_id: int, tenant_id: int, company_id: int, user_id: str | None = None
) -> list[Quote]:
    """Genera cotización(es) a partir de una solicitud de servicio.

    Si la solicitud es "Ambas" (FCL y LCL), genera **dos** cotizaciones (una por
    variante) para comparar. Cada cotización toma su propio folio C... y hereda la
    dirección impo/expo de la solicitud. Los conceptos se siembran desde las
    solicitudes de tarifa (RateRequest) capturadas en la solicitud.
    """
    sr = (
        db.query(ServiceRequest)
        .filter(
            ServiceRequest.id == service_request_id,
            ServiceRequest.tenant_id == tenant_id,
            ServiceRequest.company_id == company_id,
            ServiceRequest.deleted_at.is_(None),
        )
        .first()
    )
    if not sr:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Solicitud no encontrada")

    variants = ["FCL", "LCL"] if (sr.load_type or "").upper() == "AMBAS" else [sr.load_type or None]
    rate_requests = (
        db.query(RateRequest)
        .filter(
            RateRequest.service_request_id == sr.id,
            RateRequest.tenant_id == tenant_id,
            RateRequest.company_id == company_id,
            RateRequest.deleted_at.is_(None),
        )
        .all()
    )
    # Etiquetas legibles de los servicios adicionales (global + tenant) para los conceptos
    service_labels = {
        code: label
        for code, label in db.query(CatalogItem.code, CatalogItem.label).filter(
            CatalogItem.catalog == "servicio_adicional"
        )
    }
    service_costs = sr.additional_service_costs or {}

    created: list[Quote] = []
    for variant in variants:
        quote = Quote(
            account_id=sr.account_id,
            service_request_id=sr.id,
            currency=sr.currency or "USD",
            load_type=variant,
            status="borrador",
            issue_date=date.today(),
            notes=sr.client_notes or sr.notes,
            owner_user_id=sr.owner_user_id,
            reference=next_folio(db, tenant_id, company_id, "C", sr.operation_type),
            tenant_id=tenant_id,
            company_id=company_id,
            created_by=user_id,
            updated_by=user_id,
        )
        db.add(quote)
        db.flush()
        for rr in rate_requests:
            amount = rr.rate_amount if rr.rate_amount is not None else Decimal(0)
            db.add(QuoteItem(
                quote_id=quote.id, concept=rr.concept, description=rr.description,
                supplier_id=rr.supplier_id, quantity=Decimal(1),
                unit_cost=amount, unit_sale=amount, currency=rr.currency,
                tenant_id=tenant_id, company_id=company_id,
            ))
        # Servicios adicionales marcados en la solicitud → conceptos con su costo estimado
        for code in (sr.additional_services or []):
            amount = Decimal(str(service_costs.get(code) or 0))
            db.add(QuoteItem(
                quote_id=quote.id, concept=code[:60],
                description=service_labels.get(code, "Servicio adicional"),
                quantity=Decimal(1), unit_cost=amount, unit_sale=amount,
                currency=sr.currency, tenant_id=tenant_id, company_id=company_id,
            ))
        db.flush()
        _recompute_totals(db, quote)
        created.append(quote)

    db.commit()
    for quote in created:
        db.refresh(quote)
    return created


def update_quote(
    db: Session, quote_id: int, payload: QuoteUpdate, tenant_id: int, company_id: int, user_id: str | None = None
) -> Quote:
    obj = get_quote(db, quote_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_quote(db: Session, quote_id: int, tenant_id: int, company_id: int) -> None:
    obj = get_quote(db, quote_id, tenant_id, company_id)
    obj.deleted_at = datetime.now(timezone.utc)
    db.commit()


def _set_service_request_status(db: Session, quote: Quote, new_status: str) -> None:
    if quote.service_request_id:
        sr = db.query(ServiceRequest).filter(ServiceRequest.id == quote.service_request_id).first()
        if sr:
            sr.status = new_status


def send_quote(db: Session, quote_id: int, tenant_id: int, company_id: int) -> Quote:
    quote = get_quote(db, quote_id, tenant_id, company_id)
    quote.status = "enviada"
    quote.sent_at = datetime.now(timezone.utc)
    _set_service_request_status(db, quote, "cotizada")
    db.commit()
    db.refresh(quote)
    return quote


def accept_quote(db: Session, quote_id: int, tenant_id: int, company_id: int) -> Quote:
    quote = get_quote(db, quote_id, tenant_id, company_id)
    quote.status = "aceptada"
    quote.accepted_at = datetime.now(timezone.utc)
    _set_service_request_status(db, quote, "aceptada")
    db.commit()
    db.refresh(quote)
    return quote


def reject_quote(db: Session, quote_id: int, tenant_id: int, company_id: int) -> Quote:
    quote = get_quote(db, quote_id, tenant_id, company_id)
    quote.status = "rechazada"
    quote.rejected_at = datetime.now(timezone.utc)
    _set_service_request_status(db, quote, "rechazada")
    db.commit()
    db.refresh(quote)
    return quote


def clone_quote(
    db: Session, quote_id: int, tenant_id: int, company_id: int, user_id: str | None = None
) -> Quote:
    """Clona una cotización (y sus conceptos) como borrador para re-cotizar (R-C-12).

    Si la cotización origen fue rechazada, reabre su solicitud a 'en_analisis' para
    cerrar el ciclo de reintento del Diagrama 1.
    """
    src = get_quote(db, quote_id, tenant_id, company_id)
    new_quote = Quote(
        reference=(f"{src.reference}-R" if src.reference else None),
        service_request_id=src.service_request_id,
        account_id=src.account_id,
        currency=src.currency,
        status="borrador",
        valid_until=src.valid_until,
        notes=src.notes,
        terms=src.terms,
        owner_user_id=src.owner_user_id,
        tenant_id=tenant_id,
        company_id=company_id,
        created_by=user_id,
        updated_by=user_id,
    )
    db.add(new_quote)
    db.flush()
    src_items = (
        db.query(QuoteItem)
        .filter(QuoteItem.quote_id == src.id, QuoteItem.deleted_at.is_(None))
        .all()
    )
    for it in src_items:
        db.add(QuoteItem(
            quote_id=new_quote.id, concept=it.concept, description=it.description,
            supplier_id=it.supplier_id, quantity=it.quantity, unit_cost=it.unit_cost,
            unit_sale=it.unit_sale, currency=it.currency,
            tenant_id=tenant_id, company_id=company_id,
        ))
    db.flush()
    _recompute_totals(db, new_quote)
    # Reabre la solicitud origen para el ciclo de re-cotización
    if src.service_request_id:
        sr = db.query(ServiceRequest).filter(ServiceRequest.id == src.service_request_id).first()
        if sr and sr.status in ("rechazada", "cotizada"):
            sr.status = "en_analisis"
    db.commit()
    db.refresh(new_quote)
    return new_quote


# ----- Quote items -----

def get_quote_items(db: Session, quote_id: int, tenant_id: int, company_id: int) -> list[QuoteItem]:
    get_quote(db, quote_id, tenant_id, company_id)  # valida scope
    return (
        db.query(QuoteItem)
        .filter(
            QuoteItem.quote_id == quote_id,
            QuoteItem.tenant_id == tenant_id,
            QuoteItem.company_id == company_id,
            QuoteItem.deleted_at.is_(None),
        )
        .order_by(QuoteItem.id.asc())
        .all()
    )


def _get_item(db: Session, item_id: int, tenant_id: int, company_id: int) -> QuoteItem:
    item = (
        db.query(QuoteItem)
        .filter(
            QuoteItem.id == item_id,
            QuoteItem.tenant_id == tenant_id,
            QuoteItem.company_id == company_id,
            QuoteItem.deleted_at.is_(None),
        )
        .first()
    )
    if not item:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Concepto no encontrado")
    return item


def create_quote_item(db: Session, payload: QuoteItemCreate, tenant_id: int, company_id: int) -> QuoteItem:
    quote = get_quote(db, payload.quote_id, tenant_id, company_id)
    if not _exists(db, Supplier, payload.supplier_id, tenant_id, company_id):
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="El proveedor no existe")
    item = QuoteItem(**payload.model_dump(), tenant_id=tenant_id, company_id=company_id)
    db.add(item)
    db.flush()
    _recompute_totals(db, quote)
    db.commit()
    db.refresh(item)
    return item


def update_quote_item(
    db: Session, item_id: int, payload: QuoteItemUpdate, tenant_id: int, company_id: int
) -> QuoteItem:
    item = _get_item(db, item_id, tenant_id, company_id)
    data = payload.model_dump(exclude_unset=True)
    if "supplier_id" in data and not _exists(db, Supplier, data["supplier_id"], tenant_id, company_id):
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="El proveedor no existe")
    for field, value in data.items():
        setattr(item, field, value)
    db.flush()
    quote = get_quote(db, item.quote_id, tenant_id, company_id)
    _recompute_totals(db, quote)
    db.commit()
    db.refresh(item)
    return item


def delete_quote_item(db: Session, item_id: int, tenant_id: int, company_id: int) -> None:
    item = _get_item(db, item_id, tenant_id, company_id)
    quote_id = item.quote_id
    item.deleted_at = datetime.now(timezone.utc)
    db.flush()
    quote = get_quote(db, quote_id, tenant_id, company_id)
    _recompute_totals(db, quote)
    db.commit()