wp-postcode-plugin/session_dialog.php

<?php

session_start();
function if_needed_place_postcode_form($uri)
{
    if (
        strpos($uri, "/shop") !== false ||
        strpos($uri, "/winkel") !== false ||
        strpos($uri, "/product") !== false
    ) {
        render_dialog_html();
        add_action("wp_enqueue_scripts", "modal_styles");
        add_action("wp_footer", "send_postcode_data");
        if (!has_postcode()) {
            add_action("wp_footer", "show_modal");
        }
    }
}

function modal_styles()
{
    wp_enqueue_style(
        "prijs-per-postcode",
        plugins_url("/assets/postcode_modal.css", __FILE__),
    );
}

function show_modal()
{
    ?>
        <script>
          const postcodeModal = document.querySelector("#postcode_modal");
          postcodeModal.showModal();
        </script>
    <?php
}

function send_postcode_data()
{
    ?>
    <script type="module">
        const postcodeModal = document.querySelector("#postcode_modal");
        const submitBtn = document.querySelector("#postcode_modal_form");

        submitBtn.addEventListener('submit', async (e) => {
            e.preventDefault();
            const formData = new FormData(e.target);
            const data = Object.fromEntries(formData.entries());
            const json = JSON.stringify(data);

            try {
              const resp = await fetch('<? echo get_rest_url(null, "postcode-modal/v1/submit"); ?>', {
                method: 'POST',
                headers: {
                  'Content-Type': 'application/json',
                  'X-WP-Nonce': '<? echo wp_create_nonce("wp_rest"); ?>'
                },
                body: json
              });

              if(!resp.ok){
                throw new Error(`HTTP Error! status: ${resp.status}` );
              }
              const data = await resp.json();
              console.log("Data returnd", data);

              if (data.status === "error"){

              }

              if (data.status === "success"){
                //postcodeModal.close();
                location.reload();
              }
            }catch(err){
              console.error("Fetch Failed:", err);
              throw err;
            }
        });
    </script>
    <?php
}

function render_dialog_html()
{
    ?>
    <dialog id="postcode_modal" class="postcode_modal" closedby="none">
        <h2>Vul je postcode en huisnummer in.</h2>
        <form id="postcode_modal_form" method="post" action="">
            <div class="form_fields">
                <div>
                    <input type="text" name="postcode"
                        title="Voer een geldige Nederlandse postcode in (bijv. 1234AB of 1234 AB)."
                        pattern="[1-9][0-9]{3} ?(?!sa|sd|ss)[a-zA-Z]{2}"
                        placeholder= "1010 AA"
                        size="10"
                        required
                    />

                    <input type="text" name="huisnummer"
                        pattern="\d+([-\s]?[a-zA-Z]+)?"
                        title="Voer een geldig huisnummer in (bijv. 1, 1A, 1-A, 1a)."
                        placeholder= "12a"
                        size="5"
                        required
                    />
                </div>
                <button id="postcode_modal_submit" type="submit">verzend</button>
            </div>
        <form>
        <div class="error_message" id="error_message"></div>
    </dialog>
    <?php
}

function has_postcode()
{
    if (isset($_SESSION["postcode"])) {
        return true;
    }
    return false;
}

function handle_postcode_modal($data)
{
    $params = $data->get_params();
    $nonce = $data->get_header("X-WP-Nonce");

    if (wp_verify_nonce($nonce, "wp_rest")) {
        if (!verify_postcode($params["postcode"])) {
            $resp = [
                "status" => "error",
                "message" => "postcode",
            ];
            echo json_encode($resp);
            exit();
        }

        if (!verify_huisnummer($params["huisnummer"])) {
            $resp = [
                "status" => "error",
                "message" => "huisnummer",
            ];
            echo json_encode($resp);
            exit();
        }

        $result = getStraatnaam($params["postcode"], $params["huisnummer"]);
        if (isset($result["error"])) {
            $resp = [
                "status" => "error",
                "message" => $result["error"],
                "apirequest" => "openpostcode.nl",
            ];
            echo json_encode($resp);
            exit();
        }

        $_SESSION["postcode"] = $params["postcode"];
        $_SESSION["huisnummer"] = $params["huisnummer"];
        $_SESSION["straatnaam"] = $result["straatnaam"];
        $_SESSION["woonplaats"] = $result["woonplaats"];

        $_SESSION["lokaal_tarief"] = postcode_in_range(
            $params["postcode"],
            5000,
            5800,
        );

        $resp = [
            "status" => "success",
            "message" => "all good",
            "straatnaam" => $result["straatnaam"],
            "lokaal_trarief" => postcode_in_range(
                $params["postcode"],
                5000,
                5800,
            ),
        ];
    } else {
        $resp = [
            "status" => "error",
            "message" => "nononce",
        ];
    }
    echo json_encode($resp);
    exit();
}

function register_modal_api()
{
    register_rest_route("postcode-modal/v1", "submit", [
        "methods" => "POST",
        "callback" => "handle_postcode_modal",
    ]);
}

function verify_postcode($postcode)
{
    if (!preg_match('/^[0-9]{4}\s?[A-Za-z]{2}$/', $postcode) === 1) {
        return false;
    }
    return true;
}

function verify_huisnummer($huisnummer)
{
    if (!preg_match('/^[0-9]{4}\s?[A-Za-z]{2}$/', $huisnummer) === 1) {
        return false;
    }
    return true;
}

function getStraatnaam($postcode, $huisnummer)
{
    $url =
        "https://openpostcode.nl/api/v2/address?postcode=" .
        urlencode($postcode) .
        "&huisnummer=" .
        urlencode($huisnummer);

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_TIMEOUT, 10);
    curl_setopt($ch, CURLOPT_USERAGENT, "PHP/OpenPostcodeClient");

    $response = curl_exec($ch);

    if (curl_error($ch)) {
        curl_close($ch);
        return ["error" => "cURL error: " . curl_error($ch)];
    }

    curl_close($ch);

    $data = json_decode($response, true);

    if (isset($data["error"])) {
        return [
            "error" => $data["error"]["message"],
            "code" => $data["error"]["code"],
        ];
    }

    return [
        "straatnaam" => $data["results"][0]["straat"],
        "woonplaats" => $data["results"][0]["woonplaats"],
    ];
}

function postcode_in_range($postcode, $start, $end)
{
    $cleanPostcode = strtoupper(preg_replace("/\s+/", "", $postcode));

    if (!preg_match('/^\d{4}[A-Z]{2}$/', $cleanPostcode)) {
        return false;
    }

    $numberPart = (int) substr($cleanPostcode, 0, 4);

    return $numberPart >= $start && $numberPart <= $end;
}