I am encountering challenges in implementing necessary automations.

Seems like you are missing some code based on what you outlined. See if adding the following helps:

// Add function to set the cycle start date
function set_cycle_start_date($user_id) {
    update_user_meta($user_id, 'cycle_start_date', current_time('Y-m-d'));
}

// Add function to get the cycle start date
function get_cycle_start_date($user_id) {
    return get_user_meta($user_id, 'cycle_start_date', true);
}

// Modify the restart_interest_calculation function
function restart_interest_calculation($order_id) {
    $order = wc_get_order($order_id);
    if (!$order) return;

    $user_id = $order->get_user_id();
    $cycle_start_date = get_cycle_start_date($user_id);
    $cycle_day = (current_time('timestamp') - strtotime($cycle_start_date)) / DAY_IN_SECONDS;

    if ($cycle_day <= 15) {
        if ($order->get_status() === 'completed') {
            refund_old_order($order_id);
            start_interest_calculation($order_id);
        }
    } else {
        set_cycle_start_date($user_id); // Reset the cycle
    }
}

// Modify the handle_15th_day_special_case function
function handle_15th_day_special_case($order_id) {
    $user_id = get_post_meta($order_id, '_customer_user', true);
    if (!$user_id) return;

    $cycle_start_date = get_cycle_start_date($user_id);
    $cycle_day = (current_time('timestamp') - strtotime($cycle_start_date)) / DAY_IN_SECONDS;

    if ($cycle_day == 15) {
        return; // Do not calculate interest or refund on the 15th cycle day
    }

    start_interest_calculation($order_id);
}

This the updated version of the code not tried about to

<?php

// Hook to initiate interest calculation after order completion
add_action('woocommerce_order_status_completed', 'start_interest_calculation');

function start_interest_calculation($order_id) {
    $completed_time = get_post_meta($order_id, '_completed_date', true);
    $current_time = current_time('timestamp');
    $elapsed_time = $current_time - strtotime($completed_time);

    if ($elapsed_time < 86400) { // 86400 seconds = 24 hours
        $order_amount = get_post_meta($order_id, '_order_total', true);
        $interest = $order_amount * 0.25;

        // Code to add interest amount to user's WooCommerce wallet
        update_user_wallet($order_id, $interest);

        // Schedule event to stop interest calculation after 24 hours
        wp_schedule_single_event(current_time('timestamp') + 86400, 'stop_interest_calculation', array($order_id));
    }
}

// Hook to stop interest calculation after 24 hours
add_action('stop_interest_calculation', 'stop_interest_calculation');

function stop_interest_calculation($order_id) {
    // Code to stop interest calculation for the given order
    update_order_interest_status($order_id);
}

// Hook to restart interest calculation and refund old order on new order placement
add_action('woocommerce_new_order', 'restart_interest_calculation');

function restart_interest_calculation($order_id) {
    $order = wc_get_order($order_id);
    if (!$order) return;

    $user_id = $order->get_user_id();
    $cycle_start_date = get_cycle_start_date($user_id);
    $cycle_day = (current_time('timestamp') - strtotime($cycle_start_date)) / DAY_IN_SECONDS;

    if ($cycle_day < 15 && $order->get_status() === 'completed') {
        refund_old_order($order_id);
        start_interest_calculation($order_id);
    } else {
        set_cycle_start_date($user_id); // Reset the cycle
    }
}

// Hook to handle the 15th day special case
add_action('woocommerce_new_order', 'handle_15th_day_special_case');

function handle_15th_day_special_case($order_id) {
    $user_id = get_post_meta($order_id, '_customer_user', true);
    if (!$user_id) return;

    $cycle_start_date = get_cycle_start_date($user_id);
    $cycle_day = (current_time('timestamp') - strtotime($cycle_start_date)) / DAY_IN_SECONDS;

    if ($cycle_day == 15) {
        return; // Do not calculate interest or refund on the 15th cycle day
    }

    start_interest_calculation($order_id);
}

// Functions - Implement these based on your requirements

/**
 * Function to update user's WooCommerce wallet with interest amount.
 *
 * @param int $order_id Order ID.
 * @param float $interest Interest amount to be added to the wallet.
 */
function update_user_wallet($order_id, $interest) {
    // Get the user ID associated with the order
    $user_id = get_post_meta($order_id, '_customer_user', true);

    // Check if a user ID is available
    if ($user_id) {
        // Get the current wallet balance from user meta
        $current_wallet_balance = get_user_meta($user_id, 'wallet_balance', true);

        // If the user meta doesn't exist, initialize the wallet balance
        if (!$current_wallet_balance) {
            $current_wallet_balance = 0.0;
        }

        // Calculate the new wallet balance after adding interest
        $new_wallet_balance = $current_wallet_balance + $interest;

        // Update user meta with the new wallet balance
        update_user_meta($user_id, 'wallet_balance', $new_wallet_balance);
    }
}

/**
 * Function to update order interest status.
 *
 * @param int $order_id Order ID.
 */
function update_order_interest_status($order_id) {
    // Implement code to update order interest status
    // Example: update_post_meta($order_id, '_interest_calculated', true);

    // Adding custom meta field '_interest_calculated' to mark interest as calculated
    update_post_meta($order_id, '_interest_calculated', true);
}

/**
 * Function to refund old order amount along with interest to user's WooCommerce wallet.
 *
 * @param int $order_id Order ID.
 */
function refund_old_order($order_id) {
    // Get the order object
    $order = wc_get_order($order_id);

    // Ensure the order exists
    if ($order) {
        // Calculate the refund amount (order total + interest)
        $refund_amount = $order->get_total() + get_post_meta($order_id, '_order_interest', true);

        // Create a refund for the entire order amount
        $refund = wc_create_refund(array(
            'order_id'     => $order_id,
            'amount'       => $refund_amount,
            'reason'       => 'Interest Refund',
            'refund_id'    => uniqid('refund_'), // Generate a unique refund ID
        ));

        if (is_wp_error($refund)) {
            // Handle error
            error_log('Error creating refund: ' . $refund->get_error_message());
        } else {
            // Update order meta to track that a refund has been processed
            update_post_meta($order_id, '_refund_processed', true);

            // Optionally update other order-related information
            // ...

            // Log refund information
            error_log('Refund created successfully for order ID: ' . $order_id);
        }
    }
}

// Add function to set the cycle start date
function set_cycle_start_date($user_id) {
    update_user_meta($user_id, 'cycle_start_date', current_time('Y-m-d'));
}

// Add function to get the cycle start date
function get_cycle_start_date($user_id) {
    return get_user_meta($user_id, 'cycle_start_date', true);
}

?>

Hi mamagee,

The process description isn’t clear.

• How many products do you sell? Are they all included in this process?
• What if the user never purchases additional products, after the first purchase?
• What if the user purchases multiple products in a single order?
  Interest is calculated in compounding periods. The current code gives the purchaser a one-time, 25% interest payment on any new order. Is this what you want?
• Its not clear whether “15” means the 15th day of the month or a 15 day sliding window from the date a product is purchased?