<?php

function db_get_results($mysqli, $sql) {
    $result = $mysqli->query($sql);
    if (!$result) return [];
    return $result->fetch_all(MYSQLI_ASSOC);
}

function db_get_row($mysqli, $sql) {
    $result = $mysqli->query($sql);
    if (!$result) return null;
    return $result->fetch_assoc();
}

function db_get_col($mysqli, $sql) {
    $result = $mysqli->query($sql);
    if (!$result) return [];
    $col = [];
    while ($row = $result->fetch_row()) {
        $col[] = $row[0];
    }
    return $col;
}

function db_update($mysqli, $table, $data, $where) {
    $set = [];
    $params = [];
    foreach ($data as $col => $val) {
        $set[] = "`$col` = ?";
        $params[] = $val;
    }

    $cond = [];
    foreach ($where as $col => $val) {
        $cond[] = "`$col` = ?";
        $params[] = $val;
    }

    $sql = "UPDATE `$table` SET ".implode(", ",$set)." WHERE ".implode(" AND ",$cond);
    $stmt = $mysqli->prepare($sql);

    // Bind params dynamically
    $types = str_repeat("s", count($params));
    $stmt->bind_param($types, ...$params);

    $stmt->execute();
    return $stmt->affected_rows;
}

function db_delete($mysqli, $table, $where) {
    $params = [];

    $cond = [];
    foreach ($where as $col => $val) {
        $cond[] = "`$col` = ?";
        $params[] = $val;
    }

    $sql = "DELETE FROM `$table` WHERE ".implode(" AND ",$cond);
    $stmt = $mysqli->prepare($sql);

    // Bind params dynamically
    $types = str_repeat("s", count($params));
    $stmt->bind_param($types, ...$params);

    $stmt->execute();
    return;
}

/**
 * Select rows from a table using mysqli, safely with prepared statements.
 *
 * @param mysqli $mysqli      The active mysqli connection
 * @param string $table       Table name
 * @param array|string $columns  Array of column names OR "*" for all columns
 * @param string|null $where  Optional WHERE clause (without the "WHERE")
 * @param array $params       Parameters for prepared statement (values only)
 * @param string|null $order  Optional ORDER BY (e.g. "id DESC")
 * @param string|null $limit  Optional LIMIT (e.g. "10", "0,20")
 * @return array              Returns array of associative rows
 */
function db_select($mysqli, $table, $columns = "*", $where = null, $params = [], $order = null, $limit = null) {

    // Convert array of columns into SQL string
    if (is_array($columns)) {
        $columns = implode(", ", array_map(fn($c) => "`$c`", $columns));
    }

    $sql = "SELECT $columns FROM `$table`";

    if ($where) {
        $sql .= " WHERE $where";
    }
    if ($order) {
        $sql .= " ORDER BY $order";
    }
    if ($limit) {
        $sql .= " LIMIT $limit";
    }

    $stmt = $mysqli->prepare($sql);

    if (!$stmt) {
        return []; // or throw exception
    }

    // Bind params if there are any
    if (!empty($params)) {
        $types = str_repeat("s", count($params)); // simple: treat everything as string
        $stmt->bind_param($types, ...$params);
    }

    $stmt->execute();
    $result = $stmt->get_result();

    if (!$result) return [];

    return $result->fetch_all(MYSQLI_ASSOC);
}

function db_get_var($mysqli, $sql, $params = []) {
    $stmt = $mysqli->prepare($sql);
    if (!empty($params)) {
        $types = str_repeat('s', count($params)); 
        $stmt->bind_param($types, ...$params);
    }
    $stmt->execute();
    $stmt->bind_result($value);
    $stmt->fetch();
    $stmt->close();
    return $value;
}

function db_get_variable($mysqli, $db_tabelle_var, $params = []) {
    if (count($params) !== 1) return null;
    $stmt = $mysqli->prepare("SELECT `value` FROM $db_tabelle_var WHERE `name` = ?");
    $stmt->bind_param("s", ...$params);
    $stmt->execute();
    $stmt->bind_result($value);
    $stmt->fetch();
    $stmt->close();
    return $value;
}

function db_update_variable($mysqli, $db_tabelle_var, $params = ['name', 'value']) {
    if (count($params) !== 2) return false;
    $stmt = $mysqli->prepare("INSERT INTO $db_tabelle_var (`name`, `value`) VALUES (?, ?) ON DUPLICATE KEY UPDATE `value` = VALUES(`value`)");
    $stmt->bind_param("ss", ...$params);
    $stmt->execute();
    $stmt->close();
    return true;
}

function db_check_var(mysqli $mysqli, string $table, string $where, array $params = []) : bool {

    $table = preg_replace('/[^a-zA-Z0-9_]/', '', $table);
    
    $stmt = $mysqli->prepare("SELECT 1 FROM `" . $table . "` WHERE " . $where);
    if (!$stmt) {
        return false;
    }

    if (!empty($params)) {
        $types = '';
        foreach ($params as $param) {
            if (is_int($param)) {
                $types .= 'i';
            } elseif (is_float($param)) {
                $types .= 'd';
            } else {
                $types .= 's';
            }
        }
        $stmt->bind_param($types, ...$params);
    }

    $stmt->execute();
    
    $stmt->store_result();
    $exists = $stmt->num_rows > 0;
    
    $stmt->close();
    
    return $exists;
}