

<?php

// Create the datbase file using SQL
/*
CREATE TABLE MYLIB.CUST (
    ID BIGINT NOT NULL,
    ADDR VARCHAR(255) CCSID 1208 NOT NULL,
    PRIMARY KEY (ID)
);*/



// 1. Initialize session storage to remember driver preferences
if (session_status() === PHP_SESSION_NONE) {
    session_start();
}
// Force diagnostic errors onto the screen for debugging
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);
// Ensure the IBMi CLI driver layer handles character translations in UTF-8
putenv("DB2CODEPAGE=1208"); 
// Determine active driver (Defaults to PDO_ODBC)
if (isset($_POST['toggle_driver'])) {
    $_SESSION['active_driver'] = $_POST['toggle_driver'];
}
$driver_type = isset($_SESSION['active_driver']) ? $_SESSION['active_driver'] : "PDO_ODBC";
$database = "*LOCAL"; 
$user     = "MYUSER";
$password = "mypass";
$message = "";
$message_type = "success";
$records = [];
try {
    $driver_chosen = strtoupper($driver_type);
    // 2. Dynamic Driver Connection Initialization
    if ($driver_chosen === 'PDO_ODBC') {
        $dsn = "odbc:DSN=" . $database . ";";
        $options = [
            PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        ];
        $conn = new PDO($dsn, strtoupper($user), $password, $options);
    } elseif ($driver_chosen === 'IBM_DB2') {
        // Dynamic function check prevents compilation crashes if extension isn't loaded
        if (!function_exists('db2_connect')) {
            throw new Exception("The native 'ibm_db2' PHP extension is not enabled in your current environment.");
        }
        $i5_naming = defined('DB2_I5_NAMING_OFF') ? constant('DB2_I5_NAMING_OFF') : 0;
        $case_mode = defined('DB2_CASE_UPPER') ? constant('DB2_CASE_UPPER') : 1;
        $options = [
            'i5_naming' => $i5_naming,
            'DB2_ATTR_CASE' => $case_mode
        ];
        $conn = call_user_func('db2_connect', $database, strtoupper($user), $password, $options);
        if (!$conn) {
            $err_func = 'db2_conn_errormsg';
            throw new Exception("ibm_db2 Connection Failed: " . $err_func());
        }
    } else {
        throw new Exception("Unknown driver type requested.");
    }
    // 3. Process Inbound Form Actions using Secure Prepared Statements
    if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['action'])) {
        $action = $_POST['action'];
        $id = isset($_POST['id']) ? trim($_POST['id']) : '';
        $addr = isset($_POST['addr']) ? trim($_POST['addr']) : '';
        $sql = "";
        $params = [];
        if ($action === 'create' && !empty($id) && !empty($addr)) {
            $sql = "INSERT INTO MYLIB.CUST (ID, ADDR) VALUES (?, ?)";
            $params = [$id, $addr];
            $message = "Record ID $id added successfully using $driver_type!";
        } elseif ($action === 'update' && !empty($id) && !empty($addr)) {
            $sql = "UPDATE MYLIB.CUST SET ADDR = ? WHERE ID = ?";
            $params = [$addr, $id];
            $message = "Record ID $id updated successfully using $driver_type!";
        } elseif ($action === 'delete' && !empty($id)) {
            $sql = "DELETE FROM MYLIB.CUST WHERE ID = ?";
            $params = [$id];
            $message = "Record ID $id dropped successfully using $driver_type!";
        }
        if (!empty($sql)) {
            if ($driver_chosen === 'PDO_ODBC') {
                $stmt = $conn->prepare($sql);
                $stmt->execute($params);
            } else {
                $stmt = call_user_func('db2_prepare', $conn, $sql);
                if (!$stmt) { $err = 'db2_stmt_errormsg'; throw new Exception($err()); }
                $res = call_user_func('db2_execute', $stmt, $params);
                if (!$res) { $err = 'db2_stmt_errormsg'; throw new Exception($err()); }
            }
        }
    }
    // 4. Unified Record Dataset Fetching
    $select_sql = "SELECT ID, ADDR FROM MYLIB.CUST ORDER BY ID ASC";
    if ($driver_chosen === 'PDO_ODBC') {
        $stmt = $conn->query($select_sql);
        $records = $stmt->fetchAll();
    } else {
        $stmt = call_user_func('db2_prepare', $conn, $select_sql);
        call_user_func('db2_execute', $stmt);
        while ($row = call_user_func('db2_fetch_assoc', $stmt)) {
            // Normalizes array casing variations between extensions
            $records[] = array_change_key_case($row, CASE_UPPER);
        }
    }
} catch (Exception $e) {
    $message = "Driver Layer Alert: " . $e->getMessage();
    $message_type = "error";
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>IBMi Record Manager</title>
    <style>
        body { font-family: Arial, sans-serif; background: #f9f9f9; padding: 20px; }
        .container { max-width: 900px; margin: 0 auto; background: white; padding: 20px; border-radius: 5px; box-shadow: 0 0 10px rgba(0,0,0,0.1); }
        .alert { padding: 12px; margin-bottom: 20px; border-radius: 4px; font-weight: bold; }
        .alert-success { background-color: #d4edda; color: #155724; border: 1px solid #c3e6cb; }
        .alert-error { background-color: #f8d7da; color: #721c24; border: 1px solid #f5c6cb; }
        .control-header { display: flex; justify-content: space-between; align-items: center; border-bottom: 2px solid #ddd; padding-bottom: 10px; margin-bottom: 20px; }
        .form-section { background: #f1f1f1; padding: 15px; margin-bottom: 25px; border-radius: 4px; border: 1px solid #ddd; }
        table { width: 100%; border-collapse: collapse; margin-top: 15px; }
        th, td { border: 1px solid #ddd; padding: 10px; text-align: left; }
        th { background: #0056b3; color: white; }
        tr:nth-child(even) { background-color: #f2f2f2; }
        .btn { padding: 6px 12px; border: none; border-radius: 4px; cursor: pointer; font-weight: bold; color: white; }
        .btn-add { background: #28a745; }
        .btn-update { background: #ffc107; color: #212529; }
        .btn-delete { background: #dc3545; }
        .input-field { padding: 6px; border: 1px solid #ccc; border-radius: 4px; }
        select.input-field { font-weight: bold; background: #23272b; color: white; padding: 8px; cursor: pointer; }
    </style>
</head>
<body>
<div class="container">
    <div class="control-header">
        <h2 style="margin:0;">MYLIB.CUST Management Matrix</h2>
        <form method="POST" id="driver-toggle-form" style="margin:0;">
            <label for="toggle_driver" style="font-weight:bold; margin-right:5px; color:#444;">Active Extension:</label>
            <select name="toggle_driver" id="toggle_driver" class="input-field" onchange="document.getElementById('driver-toggle-form').submit();">
                <option value="PDO_ODBC" <?php echo ($driver_type === 'PDO_ODBC') ? 'selected' : ''; ?>>PDO_ODBC</option>
                <option value="IBM_DB2" <?php echo ($driver_type === 'IBM_DB2') ? 'selected' : ''; ?>>IBM_DB2 (Native)</option>
            </select>
        </form>
    </div>
    <?php if (!empty($message)): ?>
        <div class="alert alert-<?php echo $message_type; ?>"><?php echo htmlspecialchars($message); ?></div>
    <?php endif; ?>
    <?php if ($message_type !== 'error'): ?>
        <div class="form-section">
            <h3>➕ Add Record</h3>
            <form method="POST">
                <input type="hidden" name="action" value="create">
                <input type="number" name="id" class="input-field" placeholder="ID" required min="1">
                <input type="text" name="addr" class="input-field" placeholder="Address" required style="width: 50%;">
                <button type="submit" class="btn btn-add">Save Entry</button>
            </form>
        </div>
    <?php endif; ?>
    <h3>📋 Current Table Records</h3>
    <table>
        <thead>
            <tr>
                <th style="width: 15%;">ID</th>
                <th style="width: 55%;">ADDRESS</th>
                <th style="width: 30%;">ACTIONS</th>
            </tr>
        </thead>
        <tbody>
            <?php if (count($records) > 0): ?>
                <?php foreach ($records as $row): ?>
                    <tr>
                        <td><?php echo htmlspecialchars($row['ID']); ?></td>
                        <td>
                            <form id="row-edit-<?php echo $row['ID']; ?>" method="POST" style="margin: 0; display: inline;">
                                <input type="hidden" name="id" value="<?php echo htmlspecialchars($row['ID']); ?>">
                                <input type="text" name="addr" class="input-field" value="<?php echo htmlspecialchars($row['ADDR']); ?>" style="width: 90%;">
                            </form>
                        </td>
                        <td>
                            <button type="submit" form="row-edit-<?php echo $row['ID']; ?>" name="action" value="update" class="btn btn-update">Update</button>
                            <form method="POST" style="display: inline;" onsubmit="return confirm('Permanently delete row ID <?php echo $row['ID']; ?>?');">
                                <input type="hidden" name="action" value="delete">
                                <input type="hidden" name="id" value="<?php echo htmlspecialchars($row['ID']); ?>">
                                <button type="submit" class="btn btn-delete">Delete</button>
                            </form>
                        </td>
                    </tr>
                <?php endforeach; ?>
            <?php else: ?>
                <tr>
                    <td colspan="3" style="text-align: center; color: #888;">
                        <?php echo ($message_type === 'error') ? 'Resolve the connection constraint noted above.' : 'No rows found inside database.'; ?>
                    </td>
                </tr>
            <?php endif; ?>
        </tbody>
    </table>
</div>
</body>
</html>