<?php
require_once __DIR__ . '/db/config.php';

function syncRepayments() {
    $db = db();
    $now = date('Y-m-d');
    
    // Find all active investments where a payment is due
    $stmt = $db->prepare("
        SELECT i.*, s.founder_id 
        FROM investments i
        JOIN startups s ON i.startup_id = s.id
        WHERE i.status = 'approved' AND i.next_payment_date <= ? AND i.next_payment_date IS NOT NULL
    ");
    $stmt->execute([$now]);
    $dueInvestments = $stmt->fetchAll();
    
    foreach ($dueInvestments as $inv) {
        $db->beginTransaction();
        try {
            $amountToPay = $inv['monthly_dividend'];
            
            // Ensure we don't overpay
            if ($inv['paid_amount'] + $amountToPay > $inv['total_return']) {
                $amountToPay = $inv['total_return'] - $inv['paid_amount'];
            }
            
            if ($amountToPay > 0) {
                // 1. Deduct from founder
                $stmt = $db->prepare("UPDATE users SET balance = balance - ? WHERE id = ?");
                $stmt->execute([$amountToPay, $inv['founder_id']]);
                
                // 2. Add to investor
                $stmt = $db->prepare("UPDATE users SET balance = balance + ? WHERE id = ?");
                $stmt->execute([$amountToPay, $inv['investor_id']]);
                
                // 3. Update investment record
                $newPaidAmount = $inv['paid_amount'] + $amountToPay;
                $newStatus = ($newPaidAmount >= $inv['total_return']) ? 'completed' : 'approved';
                $nextPayment = date('Y-m-d', strtotime($inv['next_payment_date'] . ' +1 month'));
                
                // If completed, clear next payment date
                if ($newStatus === 'completed') {
                    $nextPayment = null;
                }
                
                $stmt = $db->prepare("UPDATE investments SET paid_amount = ?, status = ?, next_payment_date = ? WHERE id = ?");
                $stmt->execute([$newPaidAmount, $newStatus, $nextPayment, $inv['id']]);
                
                // 4. Create a notification for both parties (Optional but good)
                $stmt = $db->prepare("INSERT INTO notifications (user_id, content) VALUES (?, ?)");
                $stmt->execute([$inv['investor_id'], "You received a dividend payment of £" . number_format($amountToPay, 2) . " from " . $inv['id']]);
                $stmt->execute([$inv['founder_id'], "A dividend payment of £" . number_format($amountToPay, 2) . " was paid to an investor."]);
            }
            
            $db->commit();
        } catch (Exception $e) {
            $db->rollBack();
            // Log error or ignore for now
        }
    }
}