local self = {}

local icon = {
  inease = love.graphics.newImage('inease-icon.png'),
  outease = love.graphics.newImage('outease-icon.png'),
  inoutease = love.graphics.newImage('inoutease-icon.png'),
  transientease = love.graphics.newImage('transientease-icon.png'),
  unknownease = love.graphics.newImage('unknownease-icon.png'),
  linearease = love.graphics.newImage('linearease-icon.png'),
  instantease = love.graphics.newImage('instantease-icon.png'),
  pulseease = love.graphics.newImage('pulseease-icon.png'),
}

local dropdowns = {}

local dropdownValueCache = {}
local dropdownScrollCache = {}

local maxDropdown = 16

self.openDropdown = 0
local dropdownScroll = 0
local dropdownScrollE = 0

local function skeys(t)
  local k = {}
  for n,v in pairs(t) do table.insert(k, {n, v}) end
  table.sort(k, function(a, b) return a[2].i < b[2].i end)
  local k2 = {}
  for _,v in ipairs(k) do table.insert(k2, v[1]) end
  return k2
end

local function icons(keys)
  local e = {}
  for i,v in ipairs(keys) do
    table.insert(e, (ease.eases[v].type or 'unknown') .. 'ease')
  end
  return e
end

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

function self.selected(index)
  return dropdowns[index].options[dropdowns[index].selected]
end

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

function self.kselected(key)
  for _, v in ipairs(dropdowns) do
    if v.name == key then
      return v.options[v.selected]
    end
  end
end

local dropdownId
local function insertDropdown(tab, f)
  dropdownId = dropdownId + 1
  f.selected = (self.kget(f.name) or dropdownValueCache[f.name] or {selected = 1}).selected
  f.selected = (f.selected - 1) % #f.options + 1
  f.open = (self.kget(f.name) or {open = 0}).open
  return table.insert(tab, f)
end
function self.createDropdowns()
  local d = {}
  dropdownId = 0
  insertDropdown(d, {
    x = outerpadding,
    y = outerpadding,
    width = dropdownWidth,
    options = {
      'Preview Ease',
      'Mix Eases',
      'Create Ease'
    },
    name = 'mode'
  })

  local param1 = {}
  local param2 = {}

  local eases = skeys(ease.eases)

  if d[dropdownId].selected == 1 then -- preview ease
    insertDropdown(d, {
      x = outerpadding + dropdownWidth + padding,
      y = outerpadding,
      width = dropdownWidth,
      options = eases,
      name = 'ease1',
      icons = icons(eases)
    })
    local _e = ease.eases[d[dropdownId].options[d[dropdownId].selected]]
    param1[1] = slider.kvalue(_e.name .. 'param11') or (_e.params[1] and _e.params[1].default) or 1
    param1[2] = slider.kvalue(_e.name .. 'param12') or (_e.params[2] and _e.params[2].default) or 1
    ease.ease = function(x)
      return _e.f(x, param1[1], param1[2])
    end
  elseif d[dropdownId].selected == 2 then -- mix eases
    insertDropdown(d, {
      x = outerpadding + dropdownWidth + padding,
      y = outerpadding,
      width = dropdownWidth,
      options = eases,
      name = 'ease1',
      icons = icons(eases)
    })
    insertDropdown(d, {
      x = outerpadding + dropdownWidth + padding + dropdownWidth + padding,
      y = outerpadding,
      width = dropdownWidth,
      options = eases,
      name = 'ease2',
      icons = icons(eases)
    })

    local _e1 = ease.eases[d[dropdownId - 1].options[d[dropdownId - 1].selected]]
    local _e2 = ease.eases[d[dropdownId].options[d[dropdownId].selected]]
    param1[1] = slider.kvalue(_e1.name .. 'param11') or (_e1.params[1] and _e1.params[1].default) or 1
    param1[2] = slider.kvalue(_e1.name .. 'param12') or (_e1.params[2] and _e1.params[2].default) or 1
    param2[1] = slider.kvalue(_e2.name .. 'param21') or (_e2.params[1] and _e2.params[1].default) or 1
    param2[2] = slider.kvalue(_e2.name .. 'param22') or (_e2.params[2] and _e2.params[2].default) or 1
    ease.ease = ease.mixEase(_e1.f, _e2.f, slider.kvalue('mix'), param1, param2)
  elseif d[dropdownId].selected == 3 then -- create eases
    insertDropdown(d, {
      x = outerpadding + dropdownWidth + padding,
      y = outerpadding,
      width = dropdownWidth,
      options = eases,
      name = 'ease1',
      icons = icons(eases)
    })
  end

  dropdowns = d
  minEase = (self.kselected('ease1') and ease.eases[self.kselected('ease1')].min == -1) or (self.kselected('ease2') and ease.eases[self.kselected('ease2')].min == -1)
  mode = dropdown.kget('mode').selected
end

function self.update(dt)
  if self.openDropdown ~= 0 then
    dropdownScroll = math.max(dropdownScroll, -(#self.get(self.openDropdown).options - maxDropdown + 1))
    dropdownScroll = math.min(dropdownScroll, 0)
    dropdownScrollE = mix(dropdownScrollE, dropdownScroll, dt * 10)
  end

  for i, v in ipairs(dropdowns) do
    if i == self.openDropdown then
      v.open = mix(v.open, 1, dt * 14)
    else
      v.open = mix(v.open, 0, dt * 20)
    end
  end
end

function self.render()
  local mx, my = love.mouse.getPosition()
  for i,v in ipairs(dropdowns) do
    local x, y, w, h = v.x, v.y, v.width, fontHeight + margin

    love.graphics.setColor(0.06, 0.06, 0.12, 0.6)
    if love.mouse.getX() > x and love.mouse.getX() < x + w and love.mouse.getY() > y and love.mouse.getY() < y + h then
      love.graphics.setColor(0.8, 0.8, 1, love.mouse.isDown(1) and 0.4 or 0.3)
    end
    love.graphics.rectangle('fill', x, y, w, h)

    love.graphics.setColor(1, 1, 1, 1)

    love.graphics.rectangle('line', x, y, w, h)
    love.graphics.print(self.selected(i), x + margin/2, y + margin/2)
    -- love.graphics.rectangle('line', x + w - h, y, h, h)
    love.graphics.setLineWidth(1)
    love.graphics.polygon('line', x + w - h/2 + 0.3 * h, y + h/2 - 0.3 * h, x + w - h/2 - 0.3 * h, y + h/2 - 0.3 * h, x + w - h/2, y + h/2 + 0.3 * h)

    if self.openDropdown == i or v.open > 0.01 then
      for i,o in ipairs(v.options) do
        local x, y, w, h = x, y + ((i - 1) * v.open + 1) * h, w, h * v.open

        y = y + dropdownScrollE * h * v.open
        local gi = y / h
        if gi > (maxDropdown + 1) or gi < 1 then
          goto continue
        end

        -- help
        local a = (1 - math.min(math.max((1 - (maxDropdown - gi)) * (1 - (math.abs(dropdownScrollE) / (#v.options - maxDropdown + 1))), 0), 1)) * math.max(math.min(gi - 1, 1), 0) * v.open

        love.graphics.setColor(0.06, 0.06, 0.12, 0.6 * a)
        if mx > x and mx < x + w and my > y and my < y + h then
          love.graphics.setColor(0.4, 0.4, 1, (love.mouse.isDown(1) and 0.8 or 0.7) * a)
        end
        love.graphics.rectangle('fill', x, y, w, h)

        love.graphics.setColor(1, 1, 1, 0.75 * a)
        love.graphics.rectangle('line', x, y, w, h)

        love.graphics.setColor(1, 1, 1, 1 * a)
        if i == v.selected then
          love.graphics.setColor(0.5, 0.5, 1, 1 * a)
        end

        if v.icons and v.icons[i] then
          local sprite = icon[v.icons[i]]
          love.graphics.draw(sprite, x + 2, y + 2, 0, fontHeight / sprite:getWidth(), fontHeight / sprite:getHeight())
          love.graphics.print(v.options[i], x + 2 + fontHeight, y + 2)
        else
          love.graphics.print(v.options[i], x + 2, y + 2)
        end

        ::continue::
      end

      -- scrollwheel

      if #v.options > maxDropdown then
        local displayed = maxDropdown / (#v.options)
        local scroll = math.abs(dropdownScrollE) / (#v.options - maxDropdown + 1)
        local size = margin

        love.graphics.setColor(1, 1, 1, 0.9 * v.open)
        love.graphics.rectangle('fill', x + w - size, y + h + scroll * (1 - displayed) * (maxDropdown - 1) * h * v.open, size, displayed * (maxDropdown - 1) * h * v.open)
      end
    end
    love.graphics.setLineWidth(lineWidth)
  end
end

function self.mousepressed(x, y, m)
  local clickedDropdown = false
  for i,v in ipairs(dropdowns) do
    local h = fontHeight + margin
    if self.openDropdown == 0 then
      if x > v.x and x < v.x + v.width and y > v.y and y < v.y + h + margin then
        if m == 1 then
          self.openDropdown = i
          clickedDropdown = true
          dropdownScroll = dropdownScrollCache[i] or 0
          dropdownScrollE = dropdownScrollCache[i] or 0
        elseif m == 3 then
          dropdowns[i].selected = math.random(1, #dropdowns[i].options)
          createUI()
        end
      end
    elseif self.openDropdown == i then
      if x > v.x and x < v.x + v.width and y > v.y + h and y < v.y + h * (math.min(#v.options, maxDropdown) + 1) and m == 1 then
        clickedDropdown = true
      end
    end
  end

  if not clickedDropdown and m == 1 then
    dropdownScrollCache[self.openDropdown] = dropdownScroll
    self.openDropdown = 0
    return true
  end
end

function self.mousereleased(x, y, m)
  for i,v in ipairs(dropdowns) do
    local h = fontHeight + margin
    if self.openDropdown == i then
      if x > v.x and x < v.x + v.width and y > v.y + h and y < v.y + h * (math.min(#v.options, maxDropdown) + 1) and m == 1 then
        v.selected = math.floor((y - v.y) / h - dropdownScrollE)
        self.openDropdown = 0
        dropdownValueCache[v.name] = {selected = v.selected}
        dropdownScrollCache[i] = dropdownScroll
        createUI()
      end
    end
  end
end

function self.wheelmoved(x, y)
  if self.openDropdown ~= 0 then
    dropdownScroll = dropdownScroll + y
  else
    local mx, my = love.mouse.getPosition()
    for i,v in ipairs(dropdowns) do
      local h = fontHeight + margin
      if mx > v.x and mx < v.x + v.width and my > v.y and my < v.y + h + margin then
        dropdowns[i].selected = dropdowns[i].selected - math.floor(y)
        dropdowns[i].selected = (dropdowns[i].selected - 1) % #dropdowns[i].options + 1
        createUI()
      end
    end
  end
end

return self