teezt

-- BMP Image Viewer for CraftOS-PC with URL support

local function downloadImage(url)
  shell.run("wget", url, "temp.bmp")
  if not fs.exists("temp.bmp") then
    error("Failed to download image")
  end
end

local function readBMP(path)
  local file = fs.open(path, "rb")
  if not file then error("Failed to open file") end

  local header = file.read(54)
  local width = string.unpack("<I4", header:sub(19, 22))
  local height = string.unpack("<I4", header:sub(23, 26))
  local bpp = string.unpack("<I2", header:sub(29, 30))

  if bpp ~= 24 then error("Only 24-bit BMPs supported") end

  local pixels = {}
  local padding = (4 - ((width * 3) % 4)) % 4
  for y = height-1, 0, -1 do
    pixels[y] = {}
    for x = 0, width-1 do
      local b, g, r = file.read(1):byte(), file.read(1):byte(), file.read(1):byte()
      pixels[y][x] = {r, g, b}
    end
    file.read(padding)
  end

  file.close()
  return {width=width, height=height, pixels=pixels}
end

local function displayBMP(bmp)
  term.setGraphicsMode(2) -- Set 256-color mode

  for y = 0, bmp.height-1 do
    for x = 0, bmp.width-1 do
      local r, g, b = table.unpack(bmp.pixels[y][x])
      local color = bit32.bor(bit32.lshift(r, 16), bit32.lshift(g, 8), b)
      term.setPixel(x, y, color)
    end
  end
end

-- Main program
local args = {...}
if #args < 1 then
  print("Usage: bmpviewer <filename or URL>")
  return
end

local path = args[1]
if path:match("^https?://") then
  downloadImage(path)
  path = "temp.bmp"
end

local bmp = readBMP(path)
displayBMP(bmp)

-- Clean up temporary file
if fs.exists("temp.bmp") then
  fs.delete("temp.bmp")
end

-- Wait for key press before exiting
os.pullEvent("key")
term.setGraphicsMode(0) -- Return to text mode