local self = {}

local sliders = {}

function self.get(index)
  return sliders[index]
end

function self.value(index)
  return sliders[index].value
end

function self.kget(key)
  for _, v in ipairs(sliders) do
    if v.name == key then
      return v
    end
  end
end

function self.kvalue(key)
  return self.kget(key).oldvalue
end

local sliderId
local function insertSlider(tab, f)
  sliderId = sliderId + 1
  f.value = (self.kget(f.name) or {value = f.default}).value
  f.oldvalue = (self.kget(f.name) or {oldvalue = f.value}).oldvalue
  f.spintimer = (self.kget(f.name) or {spintimer = 0}).spintimer
  f.spin = (self.kget(f.name) or {spin = 0}).spin
  return table.insert(tab, f)
end
function self.createSliders()
  local s = {}
  sliderId = 0

  if mode == 2 then -- mix eases
    insertSlider(s, {
      x = outerpadding,
      y = outerpadding + fontHeight + padding,
      width = dropdownWidth,
      min = 0,
      max = 1,
      default = 0.5,
      name = 'mix',
      displayname = 'Mix'
    })
  end

  sliders = s
end

function self.update(dt)
  for i, v in ipairs(sliders) do
    v.spintimer = mix(v.spintimer + math.abs(v.value - v.oldvalue), 0, math.min(dt * 8))
    v.oldvalue = mix(v.oldvalue, v.value, math.min(dt * 20, 1))

    if v.spintimer > 2 then
      v.spintimer = v.spintimer - 2
      v.spin = v.spin + 4
    end

    v.spin = mix(v.spin, 0, dt * 3)
  end
end

function self.render()
  local mx, my = love.mouse.getPosition()

  for i, v in ipairs(sliders) do
    local x, y, w, h = v.x, v.y, v.width, 32

    love.graphics.setColor(0.7, 0.7, 0.7, 0.4)
    love.graphics.line(x, y + h/2, x + w, y + h/2)

    local sx, sy = x + w * v.oldvalue, y + h/2
    local ssize = h * 0.5

    love.graphics.push()

    love.graphics.translate(sx, sy)
    love.graphics.rotate((v.value - v.oldvalue) * 4 + v.spin * math.pi * 2)

    local hovering = mx > sx - ssize/2 and mx < sx + ssize/2 and my > sy - ssize/2 and my < sy + ssize/2 and dropdown.openDropdown == 0
    local dragging = mx > x and mx < x + w and my > y and my < y + h and love.mouse.isDown(1) and dropdown.openDropdown == 0

    love.graphics.setColor(0, 0, 0, 1)
    if hovering or dragging then
      love.graphics.setColor(0.2, 0.2, 0.3, 1)
    end
    love.graphics.rectangle('fill', -ssize/2, -ssize/2, ssize, ssize)
    love.graphics.setColor(1, 1, 1, 1)
    love.graphics.rectangle('line', -ssize/2, -ssize/2, ssize, ssize)

    love.graphics.rotate((v.value - v.oldvalue) * -2)

    love.graphics.setColor(1, 1, 1, 1)
    love.graphics.printf(math.floor(v.value * 100)/100, -ssize * 6, ssize - 2, ssize * 12, 'center')

    love.graphics.pop()

    love.graphics.printf(v.displayname, v.x + margin * 2 - ssize * 6, v.y - 5, ssize * 12, 'center')

    if dragging then
      v.value = (mx - x) / w
      graph.touchtimer = 1
      createUI()
    end
  end
end

return self