-- Prepare ImageGen gait poses; align bodies and retain coherent run anatomy.
local src=app.open(app.params.source)
local img=Image(src.cels[1].image)
local cells=dofile(app.params.boxes)
local target_h=tonumber(app.params.height)
local head_cut=tonumber(app.params.head_cut)
local is_fiddler=app.params.character=='fiddler'
local source_native=app.params.source_native=='true' or is_fiddler
local old=app.open(app.params.template)
local old_img=Image(old.cels[1].image)
for pixel in img:pixels() do
  local c=pixel()
  if app.pixelColor.rgbaA(c)>=192 then
    pixel(app.pixelColor.rgba(app.pixelColor.rgbaR(c),app.pixelColor.rgbaG(c),app.pixelColor.rgbaB(c),255))
  else pixel(0) end
end
local maxw,maxh=0,0
for _,box in ipairs(cells) do maxw,maxh=math.max(maxw,box.w),math.max(maxh,box.h) end
local factor=math.min(40/maxw,target_h/maxh)
local atlas=Image(192,256,ColorMode.RGB)
local idle_atlas=Image(48,256,ColorMode.RGB)
local frames={}
local function patch(dst,ref,x,y,w,h)
  for yy=y,y+h-1 do for xx=x,x+w-1 do dst:putPixel(xx,yy,ref:getPixel(xx,yy)) end end
end
local references={}
if not source_native then
  for row=0,3 do
    local ref=Image(48,64,ColorMode.RGB)
    ref:drawImage(old_img,Point(-48,-row*64))
    references[row+1]=ref
    local idle=Image(48,64,ColorMode.RGB)
    idle:drawImage(old_img,Point(-48,-row*64))
    idle_atlas:drawImage(idle,Point(0,row*64))
  end
end
for index,box in ipairs(cells) do
  local crop=Image(box.w,box.h,ColorMode.RGB)
  crop:drawImage(img,Point(-box.x,-box.y))
  local tmp=Sprite(box.w,box.h,ColorMode.RGB)
  tmp.cels[1].image=crop
  local w,h=math.max(1,math.floor(box.w*factor+0.5)),math.max(1,math.floor(box.h*factor+0.5))
  app.command.SpriteSize{ui=false,width=w,height=h,method='nearest-neighbor'}
  local frame=Image(48,64,ColorMode.RGB)
  local dx=math.floor(24-box.head_x*factor+0.5)
  dx=math.max(1,math.min(47-w,dx))
  local row=math.floor((index-1)/4)
  frame:drawImage(tmp.cels[1].image,Point(dx,61-h))
  -- Running has a forward-leaning head and neck. Pasting an upright idle head
  -- over it leaves the generated jaw below the seam (a second chin).
  -- Keep the complete generated run figure, including its own head and arms.
  if app.params.mode~='run' and not source_native then
    patch(frame,references[row+1],0,0,48,head_cut)
  end
  if app.params.mode~='run' and not source_native then
    -- A small torso core stays fixed; swinging sleeves/hands stay outside it.
    patch(frame,references[row+1],20,head_cut,9,math.max(0,43-head_cut))
  end
  if app.params.mode=='run' and index%2==0 then
    local airborne=Image(48,64,ColorMode.RGB)
    airborne:drawImage(frame,Point(0,-2));frame=airborne
  end
  frames[index]=frame
  atlas:drawImage(frame,Point(((index-1)%4)*48,row*64))
  tmp:close()
end
-- AI contact poses sometimes repeat the same leading leg. Correct only the
-- central leg pixels; never mirror the asymmetric instrument or scabbard.
if app.params.character=='commander' or is_fiddler then
  for _,row in ipairs({0,3}) do
    local start_y=app.params.character=='commander' and 46 or (row==3 and 52 or 49)
    for _,pair in ipairs({{3,1},{4,2}}) do
      local dst,ref=frames[row*4+pair[1]],frames[row*4+pair[2]]
      for y=start_y,63 do for x=14,33 do dst:putPixel(x,y,ref:getPixel(47-x,y)) end end
    end
  end
  atlas=Image(192,256,ColorMode.RGB)
  for index,frame in ipairs(frames) do atlas:drawImage(frame,Point(((index-1)%4)*48,math.floor((index-1)/4)*64)) end
end
if source_native then
  -- A revised full figure supplies its own idle; do not paste a superseded
  -- head or torso back onto the corrected character proportions.
  local cuts={}
  for cut in string.gmatch(app.params.source_head_cuts or '', '%d+') do
    table.insert(cuts,tonumber(cut))
  end
  for row=0,3 do
    if cuts[row+1] then
      -- Per-view bounds include the complete jaw/neck but stop above the
      -- moving forearms. Use this source's own passing pose, never old art.
      local ref=Image(frames[row*4+2])
      for col=0,3 do patch(frames[row*4+col+1],ref,0,0,48,cuts[row+1]) end
    end
  end
  atlas=Image(192,256,ColorMode.RGB)
  for index,frame in ipairs(frames) do
    atlas:drawImage(frame,Point(((index-1)%4)*48,math.floor((index-1)/4)*64))
  end
  idle_atlas=Image(48,256,ColorMode.RGB)
  for row=0,3 do idle_atlas:drawImage(frames[row*4+2],Point(0,row*64)) end
end
old:close();src:close()
local out=Sprite(192,256,ColorMode.RGB)
out.cels[1].image=atlas;out:saveAs(app.params.output)
app.command.SpriteSize{ui=false,width=576,height=768,method='nearest-neighbor'}
out:saveAs(app.params.preview_prefix..'_sheet_3x.png');out:close()
if app.params.idle then
  local idle=Sprite(48,256,ColorMode.RGB)
  idle.cels[1].image=idle_atlas;idle:saveAs(app.params.idle);idle:close()
end
local names={'south','west','east','north'}
for row=0,3 do
  local gif=Sprite(48,64,ColorMode.RGB)
  for col=0,3 do
    if col>0 then gif:newFrame() end
    gif.cels[col+1].image=Image(frames[row*4+col+1])
    gif.frames[col+1].duration=app.params.mode=='run' and 0.083333 or 0.125
  end
  app.command.SpriteSize{ui=false,width=144,height=192,method='nearest-neighbor'}
  gif:saveAs(app.params.preview_prefix..'_'..names[row+1]..'.gif');gif:close()
end
print('Prepared16 gait frames; coherent run anatomy; head-based x alignment; factor '..factor)