<?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 (!$data || !isset($data['id'], $data['field'])) {
    echo json_encode(["success" => false, "message" => "Invalid or missing parameters"]);
    exit;
}

$mappingId = (int)$data['id'];
$field = $data['field'];
$value = isset($data['value']) && $data['value'] ? 1 : 0;

// Whitelist rigorosa dei campi aggiornabili: evita SQL injection sul nome colonna
$allowedFields = ['main_field', 'is_visible_import', 'is_visible_parts'];

if (!in_array($field, $allowedFields, true)) {
    echo json_encode(["success" => false, "message" => "Invalid field"]);
    exit;
}

try {
    // Recupero il template_id della riga per poter applicare i vincoli a livello di template
    $stmt = $pdo->prepare("SELECT template_id FROM template_mapping WHERE id = ?");
    $stmt->execute([$mappingId]);
    $row = $stmt->fetch(PDO::FETCH_ASSOC);

    if (!$row) {
        echo json_encode(["success" => false, "message" => "Mapping not found"]);
        exit;
    }

    $templateId = (int)$row['template_id'];

    // Vincolo: max 2 righe con main_field = 1 per template
    if ($field === 'main_field' && $value === 1) {
        $stmt = $pdo->prepare("
            SELECT COUNT(*) 
            FROM template_mapping 
            WHERE template_id = ? AND main_field = '1' AND id != ?
        ");
        $stmt->execute([$templateId, $mappingId]);
        $count = (int)$stmt->fetchColumn();

        if ($count >= 2) {
            echo json_encode([
                "success" => false,
                "limit_reached" => true,
                "message" => "Massimo 2 campi Main consentiti per questo template"
            ]);
            exit;
        }
    }

    $pdo->beginTransaction();

    $uncheckedOthers = false;

    // Vincolo: solo 1 riga con is_visible_parts = 1 per template (comportamento radio)
    if ($field === 'is_visible_parts' && $value === 1) {
        $stmt = $pdo->prepare("
            UPDATE template_mapping 
            SET is_visible_parts = 0 
            WHERE template_id = ? AND id != ? AND is_visible_parts = 1
        ");
        $stmt->execute([$templateId, $mappingId]);
        $uncheckedOthers = $stmt->rowCount() > 0;
    }

    $bindValue = ($field === 'main_field') ? (string)$value : $value;
    $stmt = $pdo->prepare("UPDATE template_mapping SET {$field} = ? WHERE id = ?");
    $result = $stmt->execute([$bindValue, $mappingId]);

    if (!$result) {
        $pdo->rollBack();
        echo json_encode(["success" => false, "message" => "Database update failed"]);
        exit;
    }

    $pdo->commit();

    echo json_encode([
        "success" => true,
        "message" => "Flag updated successfully",
        "unchecked_others" => $uncheckedOthers,
        "saved" => [
            "id" => $mappingId,
            "field" => $field,
            "value" => $value
        ]
    ]);
} catch (Throwable $e) {
    if ($pdo->inTransaction()) {
        $pdo->rollBack();
    }
    echo json_encode(["success" => false, "message" => "Error: " . $e->getMessage()]);
}

exit;