var base_num_copies = 2;
var extra_copy_price = 25;
var mirrored_copy_price = 75;

function mirror_click(plan_id, elem) {
  plan.opts.mirrored = elem.checked;
  update_page(plan_id);
}
function copies_click(plan_id, elem) {
  plan.opts.extra_copies = elem.value;
  update_page(plan_id);
}

function update_page(plan_id) {
  var f = document.getElementById(plan_id+'_buyform');
  f.item_name.value = plan.basename + ' (includes ' + (base_num_copies + 1*plan.opts.extra_copies) + ' printed plan sets + CD-ROM) ' + (plan.opts.mirrored?' + mirrored layout':'');
  f.amount.value =
      1*plan.baseprice
    + (1*extra_copy_price * 1*plan.opts.extra_copies)
    + (plan.opts.mirrored?mirrored_copy_price:0)
    ;
  document.getElementById(plan_id+'_price').innerHTML = f.amount.value;
  document.getElementById(plan_id+'_numcopies').innerHTML = base_num_copies + 1*plan.opts.extra_copies;
  document.getElementById(plan_id+'_mirrored').style.display = (plan.opts.mirrored?'block':'none');
}

function init_buyform(plan_id) {
  var f = document.getElementById(plan_id+'_buyform');
  if (f) {
    f.item_number.value = plan.id;
    f.item_name.value = plan.basename + " (includes 2 printed plan sets + CD-ROM) ";
    f.amount.value = plan.baseprice
  }
}