function build_image_preview () {
    var url = window.location.href 
    var cur = url.split('/')[6];
    if (cur) {
        var container = document.createElement("div");
        container.className = "form-row field-image";
        var wrapper = document.createElement("div");
        var label = document.createElement("label");
        label.textContent = "Image:";
        var pwrap = document.createElement("p");
        var img = document.createElement("img");

        var request = new XMLHttpRequest();
        request.open('GET', '/photos/data/admin/preview/'+cur+'/', true);
        request.onload = function() {
            if (request.status >= 200 && request.status < 400) {
                var data = JSON.parse(request.responseText);
                //console.log(data);
                img.src = data['url'];
            } else {
                console.log("server error");
            }
        };
        request.onerror = function() {
            console.log("error on request");
        };
        request.send();
        pwrap.appendChild(img);
        wrapper.appendChild(label);
        wrapper.appendChild(pwrap);
        container.appendChild(wrapper);
        parent = document.getElementById("luximage_form");
        node = parent.children[1].children[0];
        node.parentNode.insertBefore(container, node.previousSibling);
    } else {
        return;
    }
}

document.addEventListener("DOMContentLoaded", function(event) { 
    build_image_preview();
});