local Animation = {}
Animation.__index = Animation

function Animation.new(imageOrPath, width, height, duration)
  local self = setmetatable({}, Animation)
  
  if type(imageOrPath) == "string" then
    self.spriteSheet = love.graphics.newImage(imageOrPath)
  else
    self.spriteSheet = imageOrPath
  end
  
  self.frameWidth = width
  self.frameHeight = height
  self.quads = {}
  
  local imgW, imgH = self.spriteSheet:getDimensions()
  for y = 0, imgH - height, height do
    for x = 0, imgW - width, width do
      table.insert(self.quads, love.graphics.newQuad(x, y, width, height, imgW, imgH))
    end
  end
  
  self.duration = duration or 1
  self.currentTime = 0
  
  return self
end

function Animation:update(dt)
  self.currentTime = self.currentTime + dt
  if self.looping == false then
    if self.currentTime > self.duration then
      self.currentTime = self.duration
    end
  else
    if self.currentTime >= self.duration then
      self.currentTime = self.currentTime % self.duration
    end
  end
end

function Animation:reset()
  self.currentTime = 0
end

-- Returns true only for non-looping animations that have played through once.
function Animation:isFinished()
  return self.looping == false and self.currentTime >= self.duration
end

function Animation:draw(x, y, flipHorizontal)
  if #self.quads == 0 then return end
  
  local t = self.currentTime / self.duration
  local index = math.floor(t * #self.quads) + 1
  if index > #self.quads then index = #self.quads end
  
  local quad = self.quads[index]
  local sx = (flipHorizontal and -1) or 1
  local sy = 1
  local ox = flipHorizontal and self.frameWidth or 0
  local oy = 0
  
  love.graphics.draw(self.spriteSheet, quad, x, y, 0, sx, sy, ox, oy)
end

return Animation