Reconciliation Engine

charges.forEach(charge => {
  const ex = charge.ex_tax;
  const rate = charge.gst_rate_hint || weightedAvgItemGstRate;
  const gst = ex * (rate / 100);
  const inc = ex + gst;
  
  if (charge.taxable) {
    chargesEx += ex;
    // Add to GST bucket for proper subtotal computation
    bucketEx[String(rate)] = (bucketEx[String(rate)] || 0) + ex;
  } else {
    // Non-taxable charge (e.g., late fee)
    nonTaxableChargesEx += ex;
  }
});

const candidates = [
  { name: "as_is", doc: recomputeDoc(input) },
  { name: "as_is_items_only_when_no_hsn", doc: recomputeDoc(input, { preferItemsOnlyWhenNoHSN: true }) },
  { name: "from_printed_with_tax", doc: rerateFromPrinted(input, "WITH_TAX") },
  { name: "from_printed_without_tax", doc: rerateFromPrinted(input, "WITHOUT_TAX") }
];

const score = error_absolute + max(0, Math.abs(implied_round_off) - 1);

const doc = reconcileV4(input);

if (doc.reconciliation.error_absolute <= 0.05) {
  // Perfect or near-perfect match
  return { status: 'valid', confidence: 'high' };
} else if (doc.reconciliation.error_absolute <= 1.00) {
  // Acceptable, likely rounding differences
  return { status: 'valid', confidence: 'medium', warning: 'Minor discrepancy' };
} else {
  // Requires review
  return { status: 'review_required', confidence: 'low', error: doc.reconciliation.error_absolute };
}

console.log(doc.reconciliation.alternates_considered);
// [
//   "as_is:err=0.00,implied_round=0.00,score=0.00",
//   "as_is_items_only_when_no_hsn:err=125.50,implied_round=0.00,score=125.50",
//   "from_printed_with_tax:err=2500.00,implied_round=2500.00,score=5000.00",
//   "from_printed_without_tax:err=0.50,implied_round=0.50,score=1.00"
// ]

// The first one (score=0.00) was chosen

if (doc.reconciliation.warnings.length > 0) {
  doc.reconciliation.warnings.forEach(w => {
    if (w.includes('Excluded non-taxable charges')) {
      // Non-taxable charges were not included in totals
      // Verify this matches invoice layout
    }
  });
}

const response = await fetch('/api/ocr-structured-v4', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    pdfBase64: pdfData,
    filename: 'invoice.pdf'
  })
});

const doc: V4Doc = await response.json();

function validateInvoice(doc: V4Doc): ValidationResult {
  const { error_absolute, warnings } = doc.reconciliation;
  
  if (error_absolute <= 0.05) {
    return {
      status: 'approved',
      confidence: 'high',
      message: 'All numbers match'
    };
  }
  
  if (error_absolute <= 1.00) {
    return {
      status: 'approved',
      confidence: 'medium',
      message: 'Minor rounding difference',
      warning: `Error: ₹${error_absolute.toFixed(2)}`
    };
  }
  
  return {
    status: 'review_required',
    confidence: 'low',
    message: 'Significant discrepancy detected',
    error: `₹${error_absolute.toFixed(2)}`,
    details: warnings
  };
}

// Check for non-taxable charge exclusions
if (doc.reconciliation.warnings.some(w => w.includes('non-taxable charges'))) {
  // Verify against invoice layout
  const layoutHasChargesInTotal = checkInvoiceLayout(doc);
  if (!layoutHasChargesInTotal) {
    // Expected behavior, no action needed
  } else {
    // Flag for manual review
    flagForReview(doc, 'Charges exclusion mismatch');
  }
}

// Check alternate hypotheses
const alternates = doc.reconciliation.alternates_considered;
const scores = alternates.map(a => {
  const match = a.match(/score=([\d.]+)/);
  return match ? parseFloat(match[1]) : Infinity;
});

if (Math.min(...scores) > 50) {
  // All hypotheses had high errors
  flagForReview(doc, 'No good hypothesis found');
}