import type { Filing } from '@/lib/types';
import type { TaxonomyFact } from '@/lib/server/taxonomy/types';

const METRIC_LOCAL_NAME_PRIORITY = {
  revenue: [
    'Revenues',
    'SalesRevenueNet',
    'RevenueFromContractWithCustomerExcludingAssessedTax',
    'TotalRevenuesAndOtherIncome'
  ],
  netIncome: ['NetIncomeLoss', 'ProfitLoss'],
  totalAssets: ['Assets'],
  cash: [
    'CashAndCashEquivalentsAtCarryingValue',
    'CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents'
  ],
  debtDirect: [
    'DebtAndFinanceLeaseLiabilities',
    'Debt',
    'LongTermDebtAndCapitalLeaseObligations'
  ],
  debtCurrent: [
    'DebtCurrent',
    'ShortTermBorrowings',
    'LongTermDebtCurrent'
  ],
  debtNonCurrent: [
    'LongTermDebtNoncurrent',
    'LongTermDebt',
    'DebtNoncurrent'
  ]
} as const;

function normalizeDateToEpoch(value: string | null) {
  if (!value) {
    return Number.NaN;
  }

  return Date.parse(value);
}

function sameLocalName(left: string, right: string) {
  return left.toLowerCase() === right.toLowerCase();
}

function pickPreferredFact(facts: TaxonomyFact[]) {
  const ordered = [...facts].sort((left, right) => {
    const leftDimensionScore = left.isDimensionless ? 1 : 0;
    const rightDimensionScore = right.isDimensionless ? 1 : 0;
    if (leftDimensionScore !== rightDimensionScore) {
      return rightDimensionScore - leftDimensionScore;
    }

    const leftDate = normalizeDateToEpoch(left.periodEnd ?? left.periodInstant);
    const rightDate = normalizeDateToEpoch(right.periodEnd ?? right.periodInstant);
    if (Number.isFinite(leftDate) && Number.isFinite(rightDate) && leftDate !== rightDate) {
      return rightDate - leftDate;
    }

    return Math.abs(right.value) - Math.abs(left.value);
  });

  return ordered[0] ?? null;
}

function pickBestFact(facts: TaxonomyFact[], localNames: readonly string[]) {
  for (const localName of localNames) {
    const matches = facts.filter((fact) => sameLocalName(fact.localName, localName));
    if (matches.length === 0) {
      continue;
    }

    return pickPreferredFact(matches);
  }

  return null;
}

function sumIfBoth(left: number | null, right: number | null) {
  if (left === null || right === null) {
    return null;
  }

  return left + right;
}

export function deriveTaxonomyMetrics(facts: TaxonomyFact[]): NonNullable<Filing['metrics']> {
  const revenue = pickBestFact(facts, METRIC_LOCAL_NAME_PRIORITY.revenue)?.value ?? null;
  const netIncome = pickBestFact(facts, METRIC_LOCAL_NAME_PRIORITY.netIncome)?.value ?? null;
  const totalAssets = pickBestFact(facts, METRIC_LOCAL_NAME_PRIORITY.totalAssets)?.value ?? null;
  const cash = pickBestFact(facts, METRIC_LOCAL_NAME_PRIORITY.cash)?.value ?? null;

  const directDebt = pickBestFact(facts, METRIC_LOCAL_NAME_PRIORITY.debtDirect)?.value ?? null;
  const debt = directDebt ?? sumIfBoth(
    pickBestFact(facts, METRIC_LOCAL_NAME_PRIORITY.debtCurrent)?.value ?? null,
    pickBestFact(facts, METRIC_LOCAL_NAME_PRIORITY.debtNonCurrent)?.value ?? null
  );

  return {
    revenue,
    netIncome,
    totalAssets,
    cash,
    debt
  };
}