#!/usr/bin/env luajit
local chapters = 27
local start = {
  "Introduction",
}
local finish = {

}

local list = {}
for _, section_name in ipairs(start) do
  list[#list + 1] = "file '" .. section_name .. ".m4a'"
end
for i = 1, chapters do
  list[#list + 1] = "file 'Chapter " .. i .. ".m4a'"
end
for _, section_name in ipairs(finish) do
  list[#list + 1] = "file '" .. section_name .. ".m4a'"
end

local file = io.open("list.txt", "w")
file:write(table.concat(list, "\n"))
file:write("\n")
file:close()

os.execute("ffmpeg -safe 0 -f concat -i list.txt -c copy audiobook.m4a")
os.execute("mv audiobook.m4a audiobook.m4b")
os.execute("rm list.txt")