var ajax_counter = 0;

function is_http_success(status) {
   return ((status >= 200)&&(status < 300))
}

//Eseguo un metodo remoto via xmlhttp
function Request(url, query, http_method) {

    var xmlhttp=GetXmlHttpObject();
    var amiasynchronous = true;
    if (!http_method) http_method="POST"
    xmlhttp.open(http_method, url, amiasynchronous);
    xmlhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded")
    xmlhttp.send(query);
}

//Eseguo un metodo remoto via xmlhttp
function SyncRequest(url, query, http_method) {

    var xmlhttp=GetXmlHttpObject();
    var amiasynchronous = false;
    if (!http_method) http_method="POST"
    xmlhttp.open(http_method, url, amiasynchronous);
    xmlhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded")
    xmlhttp.send(query);
    return eval("("+xmlhttp.responseText+")");
}

//Rimpiazzo il contenuto di un elemento via xmlhttp
function SetInnerHTMLbyUrl(el, url, query, http_method, final_handler) {

    var xmlhttp=GetXmlHttpObject();
    var amiasynchronous = true;
    if (!http_method) http_method="POST"
    xmlhttp.open(http_method, url, amiasynchronous);
    xmlhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded")
    xmlhttp.send(query);
    ajax_counter += 1;
    var ajax_is_loading = GetElementById('ajax_is_loading')
    xmlhttp.onreadystatechange=function() {

       if (xmlhttp.readyState==4) {          
          if (is_http_success(xmlhttp.status)) {
             SetInnerHTML(el, xmlhttp.responseText);

             if (final_handler) {
                final_handler(el);
             }
          }
          else
             dispatch_xmlhttp_error(xmlhttp);

          ajax_counter -= 1;
          if (!ajax_counter) 
             ajax_is_loading.style.visibility='hidden';

       }
    }

    if (xmlhttp.readyState != 4)
          ajax_is_loading.style.visibility='visible';
}

function AddInnerHTMLbyUrl(el, url, query, http_method, final_handler) {

    var xmlhttp=GetXmlHttpObject();
    var amiasynchronous = true;
    if (!http_method) http_method="POST"
    xmlhttp.open(http_method, url, amiasynchronous);
    xmlhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded")
    xmlhttp.send(query);
    ajax_counter += 1;
    var ajax_is_loading = GetElementById('ajax_is_loading')
    xmlhttp.onreadystatechange=function() {

       if (xmlhttp.readyState==4) {
          if (is_http_success(xmlhttp.status)) {
             AddInnerHTML(el, xmlhttp.responseText);
             if (final_handler) {
                final_handler(el);
             }
          }
          else
             dispatch_xmlhttp_error(xmlhttp);

          ajax_counter -= 1;
          if (!ajax_counter) 
             ajax_is_loading.style.visibility='hidden';

       }
    }

    if (xmlhttp.readyState != 4)
       ajax_is_loading.style.visibility='visible';

}

function AddHTMLRowbyUrl(el, url, query, http_method, final_handler) {

    var xmlhttp=GetXmlHttpObject();
    var amiasynchronous = true;
    if (!http_method) http_method="POST"
    xmlhttp.open(http_method, url, amiasynchronous);
    xmlhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded")
    xmlhttp.send(query);
    ajax_counter += 1;
    var ajax_is_loading = GetElementById('ajax_is_loading')
    xmlhttp.onreadystatechange=function() {

       if (xmlhttp.readyState==4) {
          if (is_http_success(xmlhttp.status)) {
             AddHTMLRow(el, xmlhttp.responseText);
             if (final_handler) {
                final_handler(el);
             }
          }
          else
             dispatch_xmlhttp_error(xmlhttp);

          ajax_counter -= 1;
          if (!ajax_counter) 
             ajax_is_loading.style.visibility='hidden';

       }
    }

    if (xmlhttp.readyState != 4)
       ajax_is_loading.style.visibility='visible';

}

//Apro un link via xmlrpc in modo sincrono (per inizializzazione albero)
function SetSyncInnerHTMLbyUrl(el, url, query) {
    var xmlhttp=GetXmlHttpObject();
    var amiasynchronous = false;

    ajax_counter += 1;
    var ajax_is_loading = GetElementById('ajax_is_loading')
    ajax_is_loading.style.visibility='visible';

    xmlhttp.open("POST", url, amiasynchronous);
    xmlhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded")
    xmlhttp.send(query);
    if (is_http_success(xmlhttp.status)) {
       SetInnerHTML(el, xmlhttp.responseText);
    }
    else
       dispatch_xmlhttp_error(xmlhttp);

    ajax_counter -= 1;
    if (!ajax_counter) 
       ajax_is_loading.style.visibility='hidden';

}

//Recupero del menu contestuale via XMLHttpRequest
function show_context_menu(e, type, id) {

    var xmlhttp=GetXmlHttpObject();
    var amiasynchronous = true
    var url = "https://almaview.unibo.it//kform/avng/utils/context_menu/get_html_context_menu?type=" + type + "&id=" + id
    xmlhttp.open("GET", url, amiasynchronous);
    xmlhttp.send(null)

    leftedge = GetClientXPosition(e) + GetScrollXPosition();
    topedge = GetClientYPosition(e) + GetScrollYPosition();
    ajax_counter += 1;
    var ajax_is_loading = GetElementById('ajax_is_loading')
    xmlhttp.onreadystatechange=function() {
       if (xmlhttp.readyState==4) {
          if (is_http_success(xmlhttp.status)) {
                SetInnerHTML(GetElementById('context_menu'), xmlhttp.responseText);
                showmenu(leftedge, topedge);
          }
          else
             dispatch_xmlhttp_error(xmlhttp);

          ajax_counter -= 1;
          if (!ajax_counter) 
             ajax_is_loading.style.visibility='hidden';

       }
    }

    if (xmlhttp.readyState != 4)
       ajax_is_loading.style.visibility='visible';

}

//Dato il nome di un'opzione, il valore, l'identificativo di una select da rimpiazzare, e l'url da invocare
//lo script recupera le opzioni correlate al valore scelto
function set_related_select(opt_name, opt_value, select_id, geturl, auto_enable, new_value, xattrs) {

    var selectEl = GetElementById(select_id);

    var option = document.createElement("option")
    option.value = -1;
    option.text = "Attendere prego...";

    SetInnerHTMLFrag(selectEl, option)

    var amiasynchronous = true
    var url = geturl + "?"+ opt_name + "=" + opt_value
    var xmlhttp=GetXmlHttpObject();
    xmlhttp.open("GET", url, amiasynchronous);
    xmlhttp.send(null)
    ajax_counter += 1;
    var ajax_is_loading = GetElementById('ajax_is_loading')

    xmlhttp.onreadystatechange=function() {

       if (xmlhttp.readyState==4) {

          if (is_http_success(xmlhttp.status)) {
             var opts = eval(xmlhttp.responseText);
             DelInnerHTML(selectEl);
             
             if (!opts) {
                opts = [["Opzioni non disponibili",-1]]
             }

             for (var i=0;i<opts.length;i++) {
                option = document.createElement("option")
                var parts = opts[i];
		option.text = parts[0];
		option.value = parts[1];
                if (xattrs) { //set extra attributes
                   for (var n=0;n<xattrs.length;n++) {                   
                       option.setAttribute(xattrs[n], parts[n+2])
                   }
                }
                AddInnerHTMLFrag(selectEl, option);
             }

             if (opts&&auto_enable) selectEl.disabled = false;
             if (new_value) selectEl.value = new_value;
          }
          else
             dispatch_xmlhttp_error(xmlhttp);

          ajax_counter -= 1;
          if (!ajax_counter) 
             ajax_is_loading.style.visibility='hidden';

       }
    }

    if (xmlhttp.readyState != 4)
             ajax_is_loading.style.visibility='visible';

}

//Dato il nome di un'opzione, il valore, l'identificativo di una select da rimpiazzare, l'url da invocare e il valore da impostare
//lo script recupera le opzioni correlate al valore scelto in modo sincrono e setta il nuovo valore
function set_sync_related_select(opt_name, opt_value, select_id, geturl, auto_enable, new_value, xattrs) {

    var selectEl = GetElementById(select_id);

    var option = document.createElement("option")
    option.value = -1;
    option.text = "Attendere prego...";

    SetInnerHTMLFrag(selectEl, option)

    ajax_counter += 1;
    var ajax_is_loading = GetElementById('ajax_is_loading')
    ajax_is_loading.style.visibility='visible';

    var amiasynchronous = false
    var url = geturl + "?"+ opt_name + "=" + opt_value
    var xmlhttp=GetXmlHttpObject();
    xmlhttp.open("GET", url, amiasynchronous);
    xmlhttp.send(null)

    if (xmlhttp.readyState==4) {

          if (is_http_success(xmlhttp.status)) {
             var opts = eval(xmlhttp.responseText);
             DelInnerHTML(selectEl);
             if (!opts) {
                opts = [["Opzioni non disponibili",-1]]
             }

             for (var i=0;i<opts.length;i++) {
                option = document.createElement("option")
                var parts = opts[i];
                option.text = parts[0];
                option.value = parts[1];
                if (xattrs) { //set extra attributes
                   for (var n=0;n<xattrs.length;n++) {                   
                       option.setAttribute(xattrs[n], parts[n+2])
                   }
                }
                AddInnerHTMLFrag(selectEl, option);
             }

             if (opts&&auto_enable) selectEl.disabled = false;
             if (new_value) selectEl.value = new_value;
          }
          else
             dispatch_xmlhttp_error(xmlhttp);

          ajax_counter -= 1;
          if (!ajax_counter) 
             ajax_is_loading.style.visibility='hidden';
    }
}