import { monthlyPayroll } from '~/types/members'

/**
 * Computes months of runway from cash, reserves, and burn rate
 * Formula: (cash + savings) ÷ average monthly burn in scenario
 */
export const useRunway = () => {
  const membersStore = useMembersStore()
  const policiesStore = usePoliciesStore()
  const budgetStore = useBudgetStore()
  
  const calculateRunway = (cash: number, savings: number, monthlyBurn: number): number => {
    if (monthlyBurn <= 0) return Infinity
    return (cash + savings) / monthlyBurn
  }
  
  // Calculate monthly burn based on operating mode
  const getMonthlyBurn = (mode?: 'minimum' | 'target') => {
    const operatingMode = mode || policiesStore.operatingMode || 'minimum'
    
    // Get payroll costs based on mode
    const payrollCost = monthlyPayroll(membersStore.members, operatingMode)
    
    // Add oncosts
    const oncostPct = policiesStore.payrollOncostPct || 0
    const totalPayroll = payrollCost * (1 + oncostPct / 100)
    
    // Add overhead costs
    const overheadCost = budgetStore.overheadCosts.reduce((sum, cost) => sum + (cost.amount || 0), 0)
    
    return totalPayroll + overheadCost
  }
  
  // Calculate runway for both modes
  const getDualModeRunway = (cash: number, savings: number) => {
    const minBurn = getMonthlyBurn('minimum')
    const targetBurn = getMonthlyBurn('target')
    
    return {
      minimum: calculateRunway(cash, savings, minBurn),
      target: calculateRunway(cash, savings, targetBurn),
      minBurn,
      targetBurn
    }
  }
  
  const getRunwayStatus = (months: number): 'green' | 'yellow' | 'red' => {
    if (months >= 3) return 'green'
    if (months >= 2) return 'yellow'
    return 'red'
  }
  
  const formatRunway = (months: number): string => {
    if (months === Infinity) return '∞ months'
    return `${months.toFixed(1)} months`
  }
  
  return {
    calculateRunway,
    getRunwayStatus,
    formatRunway,
    getMonthlyBurn,
    getDualModeRunway
  }
}