local data = require("druid.data")
local formats = require("druid.helper.formats")
local helper = require("druid.helper.ui_helper")

local M = {}

M.interest = {
  data.LAYOUT_CHANGED,
  data.ON_UPDATE
}

local empty = function() end

function M.init(instance, seconds_from, seconds_to, callback)
  seconds_from = math.max(seconds_from, 0)
  seconds_to = math.max(seconds_to or 0, 0)
  callback = callback or empty

  instance:set_to(seconds_from)
  instance:set_interval(seconds_from, seconds_to)
  instance.callback = callback

  if seconds_to - seconds_from == 0 then
    instance:set_state(false)
    instance.callback(instance.parent.parent, instance)
  end
  return instance
end


--- Set text to text field
-- @param set_to - set value in seconds
function M.set_to(instance, set_to)
  instance.last_value = set_to
  gui.set_text(instance.node, formats.second_string_min(set_to))
end


--- Called when layout updated (rotate for example)
function M.on_layout_updated(instance)
  M.set_to(instance, instance.last_value)
end


--- Called when update
-- @param is_on - boolean is timer on
function M.set_state(instance, is_on)
  instance.is_on = is_on
end


--- Set time interval
-- @param from - "from" time in seconds
-- @param to - "to" time in seconds
function M.set_interval(instance, from, to)
  instance.from = from
  instance.value = from
  instance.temp = 0
  instance.target = to
  M.set_state(instance, true)
  M.set_to(instance, from)
end


--- Called when update
-- @param dt - delta time
function M.update(instance, dt)
  if instance.is_on then
    instance.temp = instance.temp + dt
    local dist = math.min(1, math.abs(instance.value - instance.target))

    if instance.temp > dist then
      instance.temp = instance.temp - dist
      instance.value = helper.step(instance.value, instance.target, 1)
      M.set_to(instance, instance.value)
      if instance.value == instance.target then
        instance:set_state(false)
        instance.callback(instance.parent.parent, instance)
      end
    end
  end
end

return M