local self = {}

local quality = 256
local graph = {}

self.touchtimer = 0

local timer = 0

function self.update(dt)
  for i = 1, quality do
    local a = (i - 1) / (quality - 1)
    if not graph[i] then
      graph[i] = ease.ease(a)
    end
  end
  for i,v in ipairs(graph) do
    local a = (i - 1) / (quality - 1)
    local b = ease.ease(a)
    if minEase then
      b = b / 2 + 0.5
    end
    graph[i] = mix(v, b, math.min(dt * 18, 1))
    if graph[i] ~= graph[i] then -- is nan
      graph[i] = b
    end
  end
  self.touchtimer = mix(self.touchtimer, 0, dt * 2)

  -- lots of math just for the timer
  -- may need to abstract this out, somehow
  -- todo
  local sw, sh = love.graphics.getDimensions()
  local csize = 10 -- preview point size
  local size = math.min((sw - outerpadding) - ((dropdown.kget('ease2') or dropdown.kget('ease1')).x + dropdownWidth + padding), sh - outerpadding * 2 - padding * 3 - csize)
  local x, y, w, h = sw - outerpadding - size, outerpadding, size, size
  local mx, my = love.mouse.getPosition()

  if not (love.mouse.isDown(1) and mx > x and mx < x + w and my > y and my < y + h) then
    timer = (timer + dt * (slider.kvalue('bpm')/120)) % 2
  else
    timer = mix(timer, (mx - x) / w, dt * 14)
  end
end

function self.render()
  local sw, sh = love.graphics.getDimensions()

  if mode == 1 or mode == 2 then
    local csize = 10 -- preview point size
    local size = math.min((sw - outerpadding) - ((dropdown.kget('ease2') or dropdown.kget('ease1')).x + dropdownWidth + padding), sh - outerpadding * 2 - padding * 3 - csize)

    local x, y, w, h = sw - outerpadding - size, outerpadding, size, size
    love.graphics.setColor(1, 1, 1, 1)
    love.graphics.rectangle('line', x, y, w, h)

    -- grid
    love.graphics.setColor(0.2, 0.2, 0.4, 0.2)
    local gridsize = 64
    for gx = 1, gridsize - 2 do
      love.graphics.line(x + margin + gx * w/gridsize, y + margin, x + margin + gx * w/gridsize, y + h - margin)
    end
    for gy = 1, gridsize - 2 do
      love.graphics.line(x + margin, y + margin + gy * h/gridsize, x + w - margin, y + margin + gy * h/gridsize)
    end

    -- mixease point
    if mode == 2 and slider.kget('mix') then
      love.graphics.setColor(1, 1, 1, 0.2 + self.touchtimer * 0.6)
      love.graphics.line(x + margin + slider.kvalue('mix') * w, y, x + margin + slider.kvalue('mix') * w, y + h)
    end

    -- preview point
    local t = timer % 1
    love.graphics.setColor(0.4, 0.4, 1, 0.4)
    love.graphics.line(x + margin + t * w, y, x + margin + t * w, y + h)

    -- y = 0 point
    -- todo: this will break with eases that dont have the first point at y0
    local py = graph[1]
    love.graphics.setColor(0.7, 0.7, 0.7, 0.4 * (1 - math.abs(py - 0.5) / 0.5))
    love.graphics.line(x, y + h - py * h, x + w, y + py * h)

    -- polygone
    -- this isnt done with a polygon because else itd waste a Bunch of ram and i kinda, dont want to do that?
    love.graphics.setColor(1, 1, 1, 1)
    local last = graph[1] or 0
    for gx = 1, quality - 1 do
      local a = gx/quality
      local b = graph[gx + 1] or 0
      local px, py = x + margin + gx * ((w - margin)/quality), y + h - margin - b * (h - margin * 2)
      local ox, oy = x + margin + (gx - 1) * ((w - margin)/quality), y + h - margin - last * (h - margin * 2)
      if math.abs(b - last) < 1 then
        love.graphics.line(ox, oy, px, py)
      end
      last = b
    end

    -- preview
    love.graphics.setColor(1, 1, 1, 0.2)
    love.graphics.line(x + margin, y + h + padding * 2 + csize/2, x + w - margin, y + h + padding * 2 + csize/2)

    love.graphics.setColor(0.4, 0.4, 1, 1)
    local a1 = ease.ease(t)
    local a2 = ease.ease(math.max(math.min(t - 0.1, 1), 0))
    local da = a1
    if timer % 2 > 1 and math.floor(ease.ease(0) + 0.5) ~= math.floor(ease.ease(1) + 0.5) then
      da = 1 - da
    end
    if minEase then
      da = da / 2 + 0.5
    end

    love.graphics.ellipse('fill', x + margin + (w - margin * 2) * da, y + h + padding * 2 + csize/2, csize * (1 + math.min(math.abs(a1 - a2), 3) * 1.2), csize)
  end
end

return self