import { UpdateUsage, Usage } from '../interfaces/Usage';
import { Invoice, InvoiceUsage } from '../services/InvoiceService';

export type InvoiceCheck = {
  hasCredits: boolean;
  hasDocuments: boolean;
  hasSyncs: boolean;
}

const checkInvoice = (invoice: Invoice | null): InvoiceCheck => {
  return {
    hasCredits: (invoice?.usage?.credits ?? 0) <= (invoice?.usageLimits?.credits ?? 0),
    hasDocuments: (invoice?.usage?.documents ?? 0) <= (invoice?.usageLimits?.documents ?? 0),
    hasSyncs: (invoice?.usage?.syncs ?? 0) <= (invoice?.usageLimits?.syncs ?? 0),
  };
};

const changeReport = (
  invoice: Invoice | null,
  usageDiff: UpdateUsage,

): InvoiceCheck => {
  if (!invoice) return checkInvoice(null);

  const newUsage = Object.keys(invoice.usage).reduce((cur, nextKey: string) => {
    const value = usageDiff?.[nextKey as keyof InvoiceUsage] ?? 0;
    cur[nextKey as keyof Usage] += value;
    return cur;
  }, { ...invoice.usage });

  return checkInvoice({
    ...invoice,
    usage: newUsage,
  });
};

const addUsage = (current: Usage, addend: UpdateUsage): Usage => {
  return Object.keys(addend).reduce((cur, nextKey: string) => {
    const value = addend?.[nextKey as keyof Usage] ?? 0;
    cur[nextKey as keyof Usage] += value;
    return cur;
  }, { ...current });
};

const usagePercentage = (invoice: Invoice | null): Usage | null => {
  if (!invoice) return null;
  const current = invoice.usage;
  const limits = invoice.usageLimits;

  return {
    credits: Math.round((current.credits / limits.credits) * 100),
    documents: Math.round((current.documents / limits.documents) * 100),
    syncs: Math.round((current.syncs / limits.syncs) * 100),
  };
};

const InvoiceUtil = {
  checkInvoice,
  changeReport,
  addUsage,
  usagePercentage,
};

export default InvoiceUtil;