interface MRRComponents {
  new_mrr: number;       // Revenue from new customers
  expansion_mrr: number; // Upsells and upgrades
  contraction_mrr: number; // Downgrades
  churned_mrr: number;   // Cancellations
}

function calculateNetNewMRR(mrr: MRRComponents): number {
  return mrr.new_mrr + mrr.expansion_mrr - mrr.contraction_mrr - mrr.churned_mrr;
}

function calculateARR(mrr: number): number {
  return mrr * 12;
}

interface UnitEconomics {
  arpu: number;          // Average Revenue Per User
  grossMargin: number;   // 0-1
  monthlyChurn: number;  // 0-1
  salesMarketingCost: number;
  newCustomers: number;
}

function calculateCAC(data: UnitEconomics): number {
  return data.salesMarketingCost / data.newCustomers;
}

function calculateLTV(data: UnitEconomics): number {
  const avgLifespan = 1 / data.monthlyChurn;
  return data.arpu * data.grossMargin * avgLifespan;
}

function calculateLTVCACRatio(ltv: number, cac: number): number {
  return ltv / cac;
}

function calculateCACPayback(cac: number, arpu: number, margin: number): number {
  return cac / (arpu * margin); // months
}

interface FinancialHealth {
  cashBalance: number;
  monthlyExpenses: number;
  monthlyRevenue: number;
}

function calculateGrossBurn(data: FinancialHealth): number {
  return data.monthlyExpenses;
}

function calculateNetBurn(data: FinancialHealth): number {
  return data.monthlyExpenses - data.monthlyRevenue;
}

function calculateRunway(data: FinancialHealth): number {
  const netBurn = calculateNetBurn(data);
  return netBurn > 0 ? data.cashBalance / netBurn : Infinity;
}

function calculateNRR(
  startMRR: number,
  churnedMRR: number,
  expansionMRR: number
): number {
  return ((startMRR - churnedMRR + expansionMRR) / startMRR) * 100;
}

function calculateQuickRatio(
  newMRR: number,
  expansionMRR: number,
  churnedMRR: number,
  contractionMRR: number
): number {
  return (newMRR + expansionMRR) / (churnedMRR + contractionMRR);
}

function calculateRuleOf40(growthRate: number, profitMargin: number): number {
  return growthRate + profitMargin;
}

function calculateCMGR(lastMonth: number, firstMonth: number, months: number): number {
  return Math.pow(lastMonth / firstMonth, 1 / months) - 1;
}

// Actions
- 'calculate_unit_economics': Compute CAC, LTV, payback
- 'assess_health': Quick Ratio, Rule of 40 analysis
- 'stage_metrics': Recommend metrics for current stage
- 'benchmark_compare': Compare against industry benchmarks
- 'forecast_runway': Project runway based on growth