<?php

namespace App\Database\Migrations;

use CodeIgniter\Database\Migration;

class Migration_RefundTracking extends Migration
{
    /**
     * Perform a migration step.
     */
    public function up(): void
    {
        helper(['migration', 'locale']);
        execute_script(APPPATH . 'Database/Migrations/sqlscripts/3.3.0_refundtracking.sql');

        // Add missing cash_refund amounts to payments table
        $decimals = totals_decimals();

        $trans_amount = 'ROUND(SUM(CASE WHEN sales_items.discount_type = ' . PERCENT
            . ' THEN sales_items.item_unit_price * sales_items.quantity_purchased * (1 - sales_items.discount / 100) '
            . 'ELSE sales_items.item_unit_price * sales_items.quantity_purchased - sales_items.discount END), ' . $decimals . ') AS trans_amount';

        $cash_payment = lang('Sales.cash');

        $this->db->query(
            'CREATE TEMPORARY TABLE IF NOT EXISTS ' . $this->db->prefixTable('migrate_taxes') .
                ' (INDEX(sale_id)) ENGINE=MEMORY
            (
                SELECT sales.sale_id, SUM(sales_taxes.sale_tax_amount) AS total_taxes
                FROM ' . $this->db->prefixTable('sales') . ' AS sales
                LEFT OUTER JOIN ' . $this->db->prefixTable('sales_taxes') . ' AS sales_taxes
                    ON sales.sale_id = sales_taxes.sale_id
                WHERE sales.sale_status = \'' . COMPLETED . '\' AND sales_taxes.tax_type = \'1\'
                GROUP BY sale_id
            )'
        );

        $this->db->query(
            'CREATE TEMPORARY TABLE IF NOT EXISTS ' . $this->db->prefixTable('migrate_sales') .
                ' (INDEX(sale_id)) ENGINE=MEMORY
            (
                SELECT sales.sale_id, ' . $trans_amount . ', sales.employee_id, sales.sale_time'
                . ' FROM ' . $this->db->prefixTable('sales') . ' AS sales '
                . 'LEFT OUTER JOIN ' . $this->db->prefixTable('sales_items') . ' AS sales_items '
                . 'ON sales.sale_id = sales_items.sale_id '
                . 'LEFT OUTER JOIN ' . $this->db->prefixTable('migrate_taxes') . ' AS sumpay_taxes '
                . 'ON sales.sale_id = sumpay_taxes.sale_id '
                . 'WHERE sales.sale_status = \'' . COMPLETED . '\' GROUP BY sale_id
            )'
        );

        $this->db->query('UPDATE ' . $this->db->prefixTable('migrate_sales') . ' AS sumpay_items '
            . 'SET trans_amount = trans_amount + IFNULL((SELECT total_taxes FROM ' . $this->db->prefixTable('migrate_taxes')
            . ' AS sumpay_taxes WHERE sumpay_items.sale_id = sumpay_taxes.sale_id),0)');

        $this->db->query(
            'CREATE TEMPORARY TABLE IF NOT EXISTS ' . $this->db->prefixTable('migrate_payments') .
                ' (INDEX(sale_id)) ENGINE=MEMORY
            (
                SELECT sales.sale_id, COUNT(sales.sale_id) AS number_payments,
                    SUM(sales_payments.payment_amount - sales_payments.cash_refund) AS total_payments
                FROM ' . $this->db->prefixTable('sales') . ' AS sales
                LEFT OUTER JOIN ' . $this->db->prefixTable('sales_payments') . ' AS sales_payments
                    ON sales.sale_id = sales_payments.sale_id
                WHERE sales.sale_status = \'' . COMPLETED . '\' GROUP BY sale_id
            )'
        );

        // You may be asking yourself why the following is not creating a temporary table.
        // It should be, it originallly was, but there is a bug in MySQL where temporary tables where some SQL statements fail.
        //  The update statement that follows this CREATE TABLE is one of those statements.
        $this->db->query(
            'CREATE TABLE IF NOT EXISTS ' . $this->db->prefixTable('migrate_refund') .
                ' (INDEX(sale_id)) ENGINE=MEMORY
            (
                SELECT a.sale_id, total_payments - trans_amount AS refund_amount
                FROM ' . $this->db->prefixTable('migrate_sales') . ' AS a
                JOIN ' . $this->db->prefixTable('migrate_payments') . ' AS b ON a.sale_id = b.sale_id
                WHERE total_payments > trans_amount AND number_payments = 1
            )'
        );

        // Update existing cash transactions with refund amount
        $this->db->query(
            'UPDATE ' . $this->db->prefixTable('sales_payments') . ' AS a
            SET a.cash_refund =
            (SELECT b.refund_amount
                FROM ' . $this->db->prefixTable('migrate_refund') . ' AS b
                WHERE a.sale_id = b.sale_id AND a.payment_type = \'' . $cash_payment . '\')
            WHERE EXISTS
                (SELECT b.refund_amount
                    FROM ' . $this->db->prefixTable('migrate_refund') . ' AS b
                    WHERE a.sale_id = b.sale_id AND a.payment_type = \'' . $cash_payment . ' \')'
        );

        // Insert new cash refund transactions for non-cash payments
        $this->db->query(
            'INSERT INTO ' . $this->db->prefixTable('sales_payments') .
                ' (sale_id, payment_type, employee_id, payment_time, payment_amount, cash_refund)
            SELECT r.sale_id, \'' . $cash_payment . '\', s.employee_id, sale_time, 0, r.refund_amount
            FROM ' . $this->db->prefixTable('migrate_refund') . ' AS r
            JOIN ' . $this->db->prefixTable('sales_payments') . ' AS p ON r.sale_id = p.sale_id
            JOIN ' . $this->db->prefixTable('migrate_sales') . ' AS s ON r.sale_id = s.sale_id
            WHERE p.payment_type != \'' . $cash_payment . '\''
        );

        // Post migration cleanup
        $this->db->query('DROP TABLE IF EXISTS ' . $this->db->prefixTable('migrate_refund'));
    }

    /**
     * Revert a migration step.
     */
    public function down(): void {}
}