import "CoreLibs/graphics"
import "CoreLibs/object"

local gfx <const> = playdate.graphics

class("PipMeter").extends(gfx.sprite)

function PipMeter:init(initialValue, numPips, baseSize, sizeIncrement, spacing, circle)
   PipMeter.super.init(self)

   self.numPips = numPips
   self.baseSize = baseSize
   self.sizeIncrement = sizeIncrement or 1
   self.spacing = spacing or 1
   self:setZIndex(999)
   
   -- using arithmetic progression: sum = (n * (firstValue + lastValue)) / 2
   -- (plus spacing)
   local padBaseSize = baseSize + spacing
   local lastSize = padBaseSize + (numPips - 1) * sizeIncrement
   local width = (numPips * (padBaseSize + lastSize)) / 2 - spacing
   self:setSize(width, lastSize)

   if circle then
      self.drawFunc = gfx.drawCircleInRect
      self.fillFunc = gfx.fillCircleInRect
   else
      self.drawFunc = gfx.drawRect
      self.fillFunc = gfx.fillRect
   end

   self:setValue(initialValue)
end

function PipMeter:setValue(value)
   local img = gfx.image.new(self:getSize())
   gfx.pushContext(img)
      local offset = 0
      for i=1, self.numPips, 1 do
         local size = self.baseSize+(self.sizeIncrement*(i-1))

         if value >= i then
            self.fillFunc(offset, self.height - size, size, size)
         else
            self.drawFunc(offset, self.height - size, size, size)
            gfx.setColor(gfx.kColorWhite)
            self.fillFunc(offset+1, self.height - size +1, size-2, size-2)
            gfx.setColor(gfx.kColorBlack)
         end

         offset += size + self.spacing
      end
   gfx.popContext()
   self:setImage(img)
end