Cursed term.blit formatting thing

--- Combine values into valid blit strings, in the format of
--- `a1 .. a2 .. a3, b1 .. b2 .. b3, c1 .. c2 .. c3`.
--- The input values are expected to be in the format of
--- `a1, b1, c1, a2, b2, c2, a3, b3, c3`.
---@vararg string|table The values to combine. Tables will be pulled apart to allow for multiple values if calling functions.
---@return string text The combined text values.
---@return string text_color The combined text color values.
---@return string bg_color The combined background color values.
local function combine_blit(...)
  local text = ""
  local text_color = ""
  local bg_color = ""

  local args = table.pack(...)

  local fixed_args = {}

  -- Rip subtables out and insert them as if they were arguments.
  for i = 1, args.n do
    local arg = args[i]
    if type(arg) == "table" then
      for j = 1, #arg do
        table.insert(fixed_args, arg[j])
      end
    else
      table.insert(fixed_args, arg)
    end
  end

  for i = 1, #fixed_args, 3 do
    local s1, s2, s3 = fixed_args[i], fixed_args[i + 1], fixed_args[i + 2]
    expect(i, s1, "string")
    expect(i + 1, s2, "string")
    expect(i + 2, s3, "string")

    if #s1 ~= #s2 or #s1 ~= #s3 then
      error(("Bad arguments %d, %d, %d: Must be same length (got %d, %d, %d)"):format(i, i + 1, i + 2, #s1, #s2, #s3), 2)
    end

    text = text .. s1
    text_color = text_color .. s2
    bg_color = bg_color .. s3
  end

  return text, text_color, bg_color
end