export.lua

-- Get current sprite
local sourceSprite = app.activeSprite

-- Exit if we're not currently looking at a sprite
if not sourceSprite then
  return app.alert("There is no active sprite")
end

-- Initiate the important variables
local executionDialog = Dialog("AwesomeExport is creating your sprite...   ")
local layerCount = 0
local outputHeight = 0
local outputSprite = Sprite(sourceSprite.width, sourceSprite.height, sourceSprite.colorMode)
local outputWidth = 0
local originalLayerStates = {}
local tagCount = 0

-- Cache original layer visibility states, then hide all layers
-- Also count how many top level layers there are
for i, layer in ipairs(sourceSprite.layers) do
  originalLayerStates[i] = layer.isVisible
  layer.isVisible = false

  layerCount = layerCount + 1
end

-- Open the execution dialog to indicate that we're busy
executionDialog:show{ wait=false }

-- Set the output width to the width of the source * the length of the longest tag
-- Also count how many tags there are
for i, tag in ipairs(sourceSprite.tags) do
  local newWidth = tag.frames * sourceSprite.width

  if newWidth < outputSprite.width then
    newWidth = outputSprite.width
  end

  outputWidth = newWidth
  tagCount = tagCount + 1
end

-- Update the output height based on the number of layers and tags
outputHeight = sourceSprite.height * (layerCount * tagCount)

-- Resize the output
outputSprite:resize(outputWidth, outputHeight)

-- Loop over every frame once for every layer, copying the content of that frame into the output
for i, layer in ipairs(sourceSprite.layers) do
  layer.isVisible = true

  for j, frame in ipairs(sourceSprite.frames) do
    local x = sourceSprite.width * (j - 1)
    local y = sourceSprite.height * (i - 1)

    local cel = outputSprite:newCel(outputSprite.layers[1], 1)

    cel.image:drawSprite(sourceSprite, frame)
  end

  layer.isVisible = false
end

-- Reset the layers in the source sprite to their original states
for i, layer in ipairs(sourceSprite.layers) do
  layer.isVisible = originalLayerStates[i]
end

-- TODO: Create flipped copies of layers
-- TODO: Render to export file

-- outputSprite:close()
executionDialog:close()