<?php

require_once __DIR__ . '/db.php';

function recalculate_account_balance(int $accountId): void
{
    $pdo = db();

    $stmt = $pdo->prepare("SELECT id, account_type, opening_balance FROM accounts WHERE id = ?");
    $stmt->execute([$accountId]);
    $account = $stmt->fetch();

    if (!$account) {
        return;
    }

    $opening = (float)$account['opening_balance'];
    $type = $account['account_type'];
    $balance = $opening;

    if ($type === 'bank' || $type === 'cash' || $type === 'other') {
        $stmt = $pdo->prepare("
            SELECT
                COALESCE(SUM(CASE
                    WHEN transaction_type = 'income' AND account_id = :id THEN amount
                    ELSE 0 END), 0) AS income_sum,

                COALESCE(SUM(CASE
                    WHEN transaction_type = 'expense' AND account_id = :id THEN amount
                    ELSE 0 END), 0) AS expense_sum,

                COALESCE(SUM(CASE
                    WHEN transaction_type = 'transfer' AND account_id = :id THEN amount
                    ELSE 0 END), 0) AS transfer_out_sum,

                COALESCE(SUM(CASE
                    WHEN transaction_type = 'transfer' AND related_account_id = :id THEN amount
                    ELSE 0 END), 0) AS transfer_in_sum,

                COALESCE(SUM(CASE
                    WHEN transaction_type = 'card_payment' AND account_id = :id THEN amount
                    ELSE 0 END), 0) AS card_payment_sum
            FROM transactions
            WHERE account_id = :id OR related_account_id = :id
        ");
        $stmt->execute(['id' => $accountId]);
        $row = $stmt->fetch();

        $balance += (float)$row['income_sum'];
        $balance -= (float)$row['expense_sum'];
        $balance -= (float)$row['transfer_out_sum'];
        $balance += (float)$row['transfer_in_sum'];
        $balance -= (float)$row['card_payment_sum'];
    } elseif ($type === 'card') {
        $stmt = $pdo->prepare("
            SELECT
                COALESCE(SUM(CASE
                    WHEN transaction_type = 'expense' AND account_id = :id THEN amount
                    ELSE 0 END), 0) AS card_use_sum,

                COALESCE(SUM(CASE
                    WHEN transaction_type = 'card_payment' AND related_account_id = :id THEN amount
                    ELSE 0 END), 0) AS paid_sum
            FROM transactions
            WHERE account_id = :id OR related_account_id = :id
        ");
        $stmt->execute(['id' => $accountId]);
        $row = $stmt->fetch();

        $balance += (float)$row['card_use_sum'];
        $balance -= (float)$row['paid_sum'];
    }

    $stmt = $pdo->prepare("UPDATE accounts SET current_balance = ? WHERE id = ?");
    $stmt->execute([$balance, $accountId]);
}