nb_config_set("custom.var0=");
nb_config_set("custom.var1=");

ID = 1;
if (is_void(page = nb_page_register(ID, "User Profile", "Change Password"))) exit(1);

template entry {
   name; configvar; value; text;

   int entry(string n, c, t) {
      this.name = n;
      this.configvar = c;
      this.value = nb_config_get(c);
      this.text = t;
      return 0;
   }
};

string summary_get(string summary, string key)
{
   pat = strcat(key, "=");

   s = strstr(summary, pat);
   if (is_void(s)) return "";

   // Trim after “key=”
   s = substr(s, strlen(pat));

   // Trim to the end of the line
   nl = strstr(s, "\n");
   if (is_void(nl)) return s;

   // Länge vor '\n' = strlen(s) - strlen(nl)
   return substr(s, 0, strlen(s) - strlen(nl));
}

fields = mkarray();
fields[i=0]  = new entry("user",     "custom.var0", "User");          // stores indices 0 through 19
fields[++i]  = new entry("password", "custom.var1", "New password");
fields[++i]  = new entry("confirm",  "custom.var2", "Confirm new password"); // is NOT saved

for (;;) {
   if (request = nb_page_request(page)) {

      // Get GET (POST is empty for you)
      params = struct_get(request, "GET");
      if (is_void(params)) params = struct_get(request, "get");
      if (is_void(params)) params = mkarray();

      // Check doSave (Position 1)
      doSave = 0;
      if (length(params) >= 2 && params[1].value == "1")
         doSave = 1;

      msg = "";
      msgColor = "black";

      if (doSave) {
         offset = length(params) - length(fields);
         if (offset < 0) offset = 0;

         // Transfer values from `params` to `fields` (in order)
         for (i = 0; i < length(fields); i++) {
            k = i + offset;
            if (k >= length(params)) break;
            fields[i].value = params[k].value;
         }

         // User Index Default if empty (also validated below)
         if (fields[0].value == "") fields[0].value = "0";

         // Password Rules
         pw  = fields[1].value;
         cpw = fields[2].value;

         if (strlen(pw) < 10) {
            msg = "Error: Password must be at least 10 characters.";
            msgColor = "red";

         } else if (pw != cpw) {
            msg = "Error: Password and Confirm do not match.";
            msgColor = "red";

         } else {
            // Save: username + password (DO NOT save confirmation)
            for (i = 0; i < length(fields); i++) {
               if (fields[i].name == "confirm") continue;

               cfg = strcat(fields[i].configvar, "=");
               cfg = strcat(cfg, fields[i].value);
               rc = nb_config_set(cfg);
            }

            msg = "Saved.";
            msgColor = "green";
         }
      }

      // ----- HTML -----
      nb_page_respond(page, "<form action='sdkPage.php' method='get'>");
      nb_page_respond(page, "<input type='hidden' name='id' value='%08X'>", ID);
      nb_page_respond(page, "<input type='hidden' name='doSave' value='1'>");

      if (msg != "") {
         nb_page_respond(page,
            "<div style='color:%s; font-weight:bold; margin-bottom:10px;'>%s</div>",
            msgColor, msg
         );
      }

      // ---------------------------
      // USER Pull-Down (DYNAMIC)
      // ---------------------------
      summary = nb_config_summary();

      users   = mkarray();   // Display name: user/test/...
      userIdx = mkarray();   // Index as a string: “0” through “19”
      j = 0;

      for (u = 0; u < 20; u++) {
         key = strcat("user.", u);
         key = strcat(key, ".name");

         uname =  nb_config_get(key);

         // Show only registered users
         if (uname != "") {
            users[j]   = uname;
            userIdx[j] = strcat("", u);   // Index als String
            j++;
         }
      }

      // Default/Validation: If empty or no longer available -> select the first available option
      if (length(users) > 0) {
         valid = 0;
         for (k = 0; k < length(userIdx); k++) {
            if (fields[0].value == userIdx[k]) { valid = 1; break; }
         }
         if (fields[0].value == "" || !valid)
            fields[0].value = userIdx[0];
      }
      nb_page_respond(page, "%s<br>", fields[0].text);
      nb_page_respond(page, "<select name='%s' style='width: 400px;'>", fields[0].name);

      if (length(users) == 0) {
         nb_page_respond(page, "<option value='' selected>(no users configured)</option>");
      } else {
         for (k = 0; k < length(users); k++) {
            if (fields[0].value == userIdx[k])
               nb_page_respond(page, "<option value='%s' selected>%s</option>", userIdx[k], users[k]);
            else
               nb_page_respond(page, "<option value='%s'>%s</option>", userIdx[k], users[k]);
         }
      }
      nb_page_respond(page, "</select><br><br>");

      // Do not pre-fill PASSWORD/CONFIRM
      nb_page_respond(page,
         "%s<br><input type='password' value='' name='%s' size='80'><br><br>",
         fields[1].text, fields[1].name
      );
      nb_page_respond(page,
         "%s<br><input type='password' value='' name='%s' size='80'><br><br>",
         fields[2].text, fields[2].name
      );
      nb_page_respond(page, "<input type='submit' value='Submit'></form>");
      nb_page_finish(page);
   }
}