Unblock FG Stock -> UnblockQTY_Validation

fetblk = FG_Block_Stock1[ID == input.FG_Block_Stock_ID];
if(fetblk.Status != "Partially UnBlocked")
{
	input.Balance_Blocked_Qty = ifnull(fetblk.Block_Qty,0) - ifnull(input.Unblock_Qty,0);
}
if(fetblk.Status == "Partially UnBlocked")
{
	input.Balance_Blocked_Qty = ifnull(fetblk.Quantity_Blocked_So_far,0) - ifnull(input.Unblock_Qty,0);
}
if(input.Balance_Blocked_Qty < 0)
{
	input.Balance_Blocked_Qty = 0;
}
if(input.Unblock_Qty <= 0)
{
	alert "Unblock qty not should be zero or less than zero";
	input.Unblock_Qty = null;
	input.Balance_Blocked_Qty = 0;
	input.Balance_Blocked_Qty = 0;
}
else if(input.Unblock_Qty > Blocked_Qty)
{
	alert "Unblock qty not more than blocked qty";
	input.Unblock_Qty = null;
}
if(fetblk.Status == "Partially UnBlocked" && input.Unblock_Qty > fetblk.Balance_Blocked_Qty)
{
	alert "Unblock Qty shouldn't be greater than Balance Blocked Qty";
	input.Unblock_Qty = fetblk.Balance_Blocked_Qty;
}