import { err, ok } from "@tailor-platform/erp-kit/core";
import { Decimal } from "decimal.js";
import type { Transaction } from "../generated/kysely-tailordb";
import { IncomingPaymentTargetIneligibleError } from "../lib/errors.generated";

export type IncomingPaymentSettlementTargetInput = {
  accountReceivableDueScheduleLineId: string;
};

export type IncomingPaymentIdentity = {
  companyId: string;
  customerAccountId: string;
  currencyId: string;
};

export type IncomingPaymentSettlementTargetDocument = IncomingPaymentIdentity & {
  documentType: string;
  status: string;
};

export type IncomingPaymentSettlementDocumentType = "INVOICE" | "CREDIT_MEMO";

export function isIncomingPaymentSettlementTargetEligible(
  document: IncomingPaymentSettlementTargetDocument,
  payment: IncomingPaymentIdentity,
) {
  return (
    (document.documentType === "INVOICE" || document.documentType === "CREDIT_MEMO") &&
    document.status === "POSTED" &&
    document.companyId === payment.companyId &&
    document.customerAccountId === payment.customerAccountId &&
    document.currencyId === payment.currencyId
  );
}

export function toSignedSettlementAmount(
  documentType: IncomingPaymentSettlementDocumentType,
  settledAmount: string,
) {
  const amount = new Decimal(settledAmount);
  return documentType === "CREDIT_MEMO" ? amount.negated() : amount;
}

export async function validateIncomingPaymentSettlementTargets(
  db: Transaction,
  payment: IncomingPaymentIdentity,
  settlements: IncomingPaymentSettlementTargetInput[],
) {
  if (settlements.length === 0) return ok({});

  const dueScheduleLineIds = settlements.map(
    (settlement) => settlement.accountReceivableDueScheduleLineId,
  );
  const targets = await db
    .selectFrom("AccountReceivableDueScheduleLine as dueSchedule")
    .innerJoin(
      "AccountReceivableDocument as document",
      "document.id",
      "dueSchedule.accountReceivableDocumentId",
    )
    .select([
      "dueSchedule.id as dueScheduleLineId",
      "document.id as accountReceivableDocumentId",
      "document.documentType as documentType",
      "document.status as status",
      "document.companyId as companyId",
      "document.customerAccountId as customerAccountId",
      "document.currencyId as currencyId",
    ])
    .where("dueSchedule.id", "in", dueScheduleLineIds)
    .execute();

  const targetByDueScheduleLineId = new Map(
    targets.map((target) => [target.dueScheduleLineId, target]),
  );
  for (const dueScheduleLineId of dueScheduleLineIds) {
    const target = targetByDueScheduleLineId.get(dueScheduleLineId);
    if (!target || !isIncomingPaymentSettlementTargetEligible(target, payment)) {
      return err(new IncomingPaymentTargetIneligibleError(dueScheduleLineId));
    }
  }

  return ok({});
}