import { createClient } from '@/lib/supabase/server'

export interface ReconciliationResult {
  supplier_ledger_total: number
  account_2440_balance: number
  difference: number
  is_reconciled: boolean
}

/**
 * Compare sum of open supplier invoices against account 2440 balance
 */
export async function generateReconciliation(
  userId: string,
  periodId: string
): Promise<ReconciliationResult> {
  const supabase = await createClient()

  // Get total outstanding from supplier invoices
  const { data: invoices } = await supabase
    .from('supplier_invoices')
    .select('remaining_amount')
    .eq('user_id', userId)
    .in('status', ['registered', 'approved', 'partially_paid', 'overdue'])

  const supplierLedgerTotal = (invoices || [])
    .reduce((sum, inv) => sum + (inv.remaining_amount || 0), 0)

  // Get account 2440 balance from journal entry lines
  const { data: journalLines } = await supabase
    .from('journal_entry_lines')
    .select('debit_amount, credit_amount, journal_entry_id')
    .eq('account_number', '2440')

  // Filter to posted entries in the period
  let account2440Balance = 0
  if (journalLines) {
    // Account 2440 is a liability: credit normal balance
    // Balance = credits - debits
    for (const line of journalLines) {
      account2440Balance += (line.credit_amount || 0) - (line.debit_amount || 0)
    }
  }

  const difference = Math.round((supplierLedgerTotal - account2440Balance) * 100) / 100

  return {
    supplier_ledger_total: Math.round(supplierLedgerTotal * 100) / 100,
    account_2440_balance: Math.round(account2440Balance * 100) / 100,
    difference,
    is_reconciled: Math.abs(difference) < 0.01,
  }
}