<?php
header('Content-Type: application/json');
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

require_once(__DIR__ . '/class/db-functions.php');

$db = DBHandlerSelect::getInstance();
$pdo = $db->getConnection();

$data = json_decode(file_get_contents("php://input"), true);

if (!isset($data['template_id'], $data['excel_column'], $data['mysql_column'], $data['tablename'])) {
    echo json_encode(["success" => false, "message" => "Missing required fields"]);
    exit;
}

// Rimuove l'associazione
$stmtDelete = $pdo->prepare("
    DELETE FROM excel_column_mappings 
    WHERE template_id = ? AND excel_column = ? AND mysql_column = ? AND tablename = ?
");
$result = $stmtDelete->execute([
    $data['template_id'],
    $data['excel_column'],
    $data['mysql_column'],
    $data['tablename']
]);

if (!$result) {
    echo json_encode(["success" => false, "message" => "Failed to delete mapping"]);
    exit;
}

// Dopo la rimozione, aggiorna la lista delle colonne disponibili
$stmtColumns = $pdo->prepare("SHOW COLUMNS FROM " . $data['tablename']);
$stmtColumns->execute();
$all_mysql_columns = array_column($stmtColumns->fetchAll(PDO::FETCH_ASSOC), 'Field');

$stmtHeader = $pdo->prepare("SELECT headerexcel FROM excel_column_mappings WHERE template_id = ? LIMIT 1");
$stmtHeader->execute([$data['template_id']]);
$headerRow = $stmtHeader->fetch(PDO::FETCH_ASSOC);
$xls_headers = isset($headerRow['headerexcel']) ? explode(",", $headerRow['headerexcel']) : [];

// Ricalcola le colonne non associate
$stmtMappings = $pdo->prepare("SELECT excel_column, mysql_column FROM excel_column_mappings WHERE template_id = ?");
$stmtMappings->execute([$data['template_id']]);
$existingMappings = $stmtMappings->fetchAll(PDO::FETCH_ASSOC);

$mapped_xls_columns = array_column($existingMappings, 'excel_column');
$mapped_mysql_columns = array_column($existingMappings, 'mysql_column');

$remaining_xls_columns = array_diff($xls_headers, $mapped_xls_columns);
$remaining_mysql_columns = array_diff($all_mysql_columns, $mapped_mysql_columns);

echo json_encode([
    "success" => true,
    "remaining_xls_columns" => array_values($remaining_xls_columns),
    "remaining_mysql_columns" => array_values($remaining_mysql_columns)
]);
exit;