shh

if not fs.exists(shell.resolve("blittle")) then shell.run("/rom/programs/http/pastebin get ujchRSnU blittle") end
os.loadAPI(shell.resolve("blittle"))

local args = {...}
if #args < 1 then
  printError("Usage: "..shell.getRunningProgram().." <filename>")
  return
end

--[[

{
        ["width"] = (number) image width
        ["height"] = (number) image height

        [1] = {
                [1] = First text row.
                [2] = Second text row.
                -- etc
        },

        [2] = {
                [1] = First textColour row.
                [2] = Second textColour row.
                -- etc
        },

        [3] = {
                [1] = First backgroundColour row.
                [2] = Second backgroundColour row.
                -- etc
        }
}

]]
local lookup = "0123456789abcdef"
local precomp2H = {}
for i=1,#lookup do
  precomp2H[2^(i-1)] = lookup:sub(i,i)
end
local function toHex(dec)
  return precomp2H[dec]
end
local precomp2D = {}
for i=1,#lookup do
  precomp2D[lookup:sub(i,i)] = 2^(i-1)
end
local function toDec(hex)
  return precomp2D[hex]
end

local fn = args[1]
local bimg = {}
if fs.exists(fn) then
  bimg = blittle.load(fn)
else
  bimg = {width=0,height=0,[1]={" "},[2]={"f"},[3]={"f"}}
end

local transpChar = "\127"

local offx,offy = 1,1
local scnw,scnh = term.getSize()

local showToolbar = true
local pallette = {"f","f"}
local dirtyInfo = true
local dirtyLine = -1
local dirtyPallette = true
local blobj = {width=0,height=0,{},{},{}}

local function convertToBLittle()
  local eobj = {}
  for i=1,#bimg[3] do
    eobj[i] = {}
    for n in bimg[3][i]:gmatch(".") do
      table.insert(eobj[i],toDec(n))
    end
  end
  blobj = blittle.shrink(eobj)
end

--sticky is 1 of the following: 0-topLeft 1-topRight 2-bottomLeft 3-bottomRight
local function enlargeCanvas(dx,dy,sticky)
  local newWidth  = bimg.width  + dx
  local newHeight = bimg.height + dy
  local newData = {width=newWidth,height=newHeight,{},{},{}}

  local stickyX = sticky % 2 == 0 and true or false
  local stickyY = sticky < 2      and true or false

  for i=1,newHeight do
    newData[1][i] = (" "):rep(newWidth)
    newData[2][i] = ("0"):rep(newWidth)
    newData[3][i] = ("f"):rep(newWidth)
  end

  --Now copy old data into new canvas
  local counter = 1
  for i = (stickyY and 1 or 1+dy), (stickyY and bimg.height or newHeight) do
    if stickyX then
      newData[3][i] = bimg[3][counter]..("f"):rep(dx) --left aligned
    else
      newData[3][i] = ("f"):rep(dx)..bimg[3][counter] --right aligned
    end
    counter = counter + 1
  end

  offx = offx - (stickyX and 0 or dx)
  offy = offy - (stickyY and 0 or dy)
  dirtyInfo = true

  bimg = newData
end

local drawMode = false --false=normal true=blittle

local function draw()
  if dirtyInfo then
    for i=1,scnh do
      term.setCursorPos(1,i)
      term.setBackgroundColor(colors.black)
      term.setTextColor(colors.gray)
      term.write(transpChar:rep(scnw))
    end
  end
  if drawMode then
    --blittle.draw(table blittle image [, number xPos] [, number yPos] [, table terminal])
    if dirtyInfo then
      blittle.draw(blobj, offx, offy, term.current())
    end
  else
    if dirtyLine < 1 and not dirtyInfo and not dirtyPallette then
      return
    end
    if dirtyInfo then
      for i=1,scnh do
      --for i=offy,math.min(#bimg[1]) do
        if i-offy < bimg.height and i-offy+1 > 0 then
          local py = i-offy+1
          term.setCursorPos(offx,i)
          term.blit(bimg[1][py],bimg[2][py],bimg[3][py])
        end
      end
    elseif dirtyLine > 0 then
      term.setCursorPos(offx,offy+dirtyLine-1)
      term.blit(bimg[1][dirtyLine],bimg[2][dirtyLine],bimg[3][dirtyLine])
    end
    if (dirtyInfo or dirtyPallette) and showToolbar then
      for i=1,16 do
        term.setBackgroundColor(2^(i-1))
        term.setCursorPos(scnw-1,i)
        term.write("  ")
      end
      for i=1,2 do
        term.setBackgroundColor(toDec(pallette[i]))
        term.setTextColor(colors.white)
        term.setCursorPos(scnw-2+i,17)
        term.write("\7\7")
      end
    end
    dirtyInfo = false
  end
end

while true do
  draw()
  local e,p1,p2,p3,p4,p5 = os.pullEvent()
  if e=="key" then
    local k = p1
    local ox,oy = offx, offy
    if k == keys.left or k == keys.a then
      offx = offx - 1
    elseif k == keys.right or k == keys.d then
      offx = offx + 1
    elseif k == keys.up or k == keys.w then
      offy = offy - 1
    elseif k == keys.down or k == keys.d then
      offy = offy + 1
    elseif k == keys.grave then
      drawMode = not drawMode
      if drawMode then
        convertToBLittle()
      end
      dirtyInfo = true
    end
    if ox~=offx or oy~=offy then
      dirtyInfo = true
    end
  elseif e=="mouse_click" or e=="mouse_drag" then
    local b,x,y = p1,p2,p3
    if x>scnw-2 and y<17 then
      --Picking a color
      pallette[b] = toHex(2^(y-1))
      dirtyPallette = true
    elseif x>scnw-2 and y==17 then
      --Copy color
      pallette[b] = pallette[x-(scnw-2)]
      dirtyPallette = true
    end
  end
end