local Logger = {
  fn = function() end,
  filteredEvents = { },
}

function Logger.setLogger(fn)
  Logger.fn = fn
end

function Logger.disable()
  Logger.setLogger(function() end)
end

function Logger.setDaemonLogging()
  Logger.setLogger(function (text)
    os.queueEvent('log', { text = text })
  end)
end

function Logger.setMonitorLogging()
  local debugMon = device.monitor

  if not debugMon then
    debugMon.setTextScale(.5)
    debugMon.clear()
    debugMon.setCursorPos(1, 1)
    Logger.setLogger(function(text)
      debugMon.write(text)
      debugMon.scroll(-1)
      debugMon.setCursorPos(1, 1)
    end)
  end
end

function Logger.setScreenLogging()
  Logger.setLogger(function(text)
    local x, y = term.getCursorPos()
    if x ~= 1 then
      local sx, sy = term.getSize()
      term.setCursorPos(1, sy)
      --term.scroll(1)
    end
    print(text)
  end)
end

function Logger.setWirelessLogging()
  if device.wireless_modem then
    Logger.filter('modem_message')
    Logger.filter('modem_receive')
    Logger.filter('rednet_message')
    Logger.setLogger(function(text)
      device.wireless_modem.transmit(59998, os.getComputerID(), {
        type = 'log', contents = text
      })
    end)
    Logger.debug('Logging enabled')
    return true
  end
end

function Logger.setFileLogging(fileName)
  fs.delete(fileName)
  Logger.setLogger(function (text)
    local logFile

    local mode = 'w'
    if fs.exists(fileName) then
      mode = 'a'
    end
    local file = io.open(fileName, mode)
    if file then
      file:write(text)
      file:write('\n')
      file:close()
    end
  end)
end

function Logger.log(category, value, ...)
  if Logger.filteredEvents[category] then
    return
  end

  if type(value) == 'table' then
    local str
    for k,v in pairs(value) do
      if not str then
        str = '{ '
      else
        str = str .. ', '
      end
      str = str .. k .. '=' .. tostring(v)
    end
    if str then
      value = str .. ' }'
    else
      value = '{ }'
    end
  elseif type(value) == 'string' then
    local args = { ... }
    if #args > 0 then
      value = string.format(value, unpack(args))
    end
  else
    value = tostring(value)
  end
  Logger.fn(category .. ': ' .. value)
end

function Logger.debug(value, ...)
  Logger.log('debug', value, ...)
end

function Logger.logNestedTable(t, indent)
  for _,v in ipairs(t) do
    if type(v) == 'table' then
      log('table')
      logNestedTable(v) --, indent+1)
    else
      log(v)
    end
  end
end

function Logger.filter( ...)
  local events = { ... }
  for _,event in pairs(events) do
    Logger.filteredEvents[event] = true
  end
end

return Logger