let rangeValues = {};
let xhrUpd = new XMLHttpRequest();

xhrUpd.onreadystatechange = function(){
  if(xhrUpd.readyState == 4) {
    if (xhrUpd.status == 200){
      console.log(xhrUpd.responseText);
    }
    else {
      console.log("status:", xhrUpd.status);
    }
  }
}

function reloadRangeValues() {
  let url = "/update";
  // if there are scheduled updates, send them
  if(Object.keys(rangeValues).length > 0) {
    let params = [];
    for(let p in rangeValues)
      params.push(encodeURIComponent(p) + "=" + encodeURIComponent(rangeValues[p]));
    params = params.join("&");

    xhrUpd.open("POST", url, true);
    xhrUpd.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
    xhrUpd.send(params);

    rangeValues = {};
  }

  setTimeout(reloadRangeValues, 1000);
};
reloadRangeValues();

function sendRangeValue(range, val) {
  rangeValues[range] = val;
  console.log(rangeValues);
};

// connect actions to range inputs
function rangeToOutput(range, output) {
  document.getElementById(range).oninput = function() {
    document.getElementById(output).innerHTML = this.value;
    sendRangeValue(this.id, this.value);
  }
}

rangeToOutput("range_act_pwm", "out_act_pwm");
rangeToOutput("range_idl_pwm", "out_idl_pwm");
rangeToOutput("range_tim_sta", "out_tim_sta");
rangeToOutput("range_tim_ldr", "out_tim_ldr");
rangeToOutput("range_ldr_shw", "out_ldr_shw");

let xhr = new XMLHttpRequest();
              
xhr.onreadystatechange = function(){
  if(xhr.readyState == 4) {
    if (xhr.status == 200){
      console.log(xhr.responseText);
      terminal = document.getElementById("term");
      autoscroll = document.getElementById("scroll");
      terminal.innerHTML += xhr.responseText;
      if(autoscroll.checked)
        terminal.scrollTop = terminal.scrollHeight;
    }
    else {
      console.log("status:", xhr.status);
    }
  }
}
function reloadTerminal() {
  xhr.open("POST", "/terminal", true);
  xhr.send();
  setTimeout(reloadTerminal, 1000);
};
reloadTerminal();
function clearTerminal() {
  document.getElementById("term").innerHTML = '';
}