#!%%LOCALBASE%%/bin/lua
-- $OpenBSD: yt.lua,v 1.5 2007/08/26 21:47:46 jasper Exp $
-- Fetch videos from YouTube.com and convert them to MPEG.
-- Written by Pedro Martelletto in August 2006. Public domain.
-- Example: lua yt.lua http://www.youtube.com/watch?v=c5uoo1Kl_uA

http = require("socket.http")

-- Make sure a URL was given.
url = assert(arg[1], "Wrong usage, no URL given")

-- Set this to a command capable of talking HTTP and following 3XX requests.
fetch = "ftp -o <file> <url>"

-- Set this to a command capable of converting from FLV to MPEG.
convert = "ffmpeg -y -i <flv> -b 1000k -vcodec mpeg4 -acodec copy <avi> 1>/dev/null 2>&1"

-- Set this to the base location where to fetch YouTube videos from.
base_url = "http://www.youtube.com/get_video?video_id="

-- Fetch the page holding the embedded video.
print(string.format("Getting %s ...", url))
body = assert(http.request(url))

-- Look for the video title.
pattern = "<meta name=\"title\" content=\"(.-)\""
title = assert(string.match(body, pattern))

-- Build a name for the files the video will be stored in.
file = string.gsub(title, " ", "_")
file = string.gsub(title, "[^%w-]", "_")
file = "youtube-" .. string.lower(file)
flv = file .. ".flv"
avi = file .. ".avi"

-- Escape the file names.
e_flv = string.format("%q", flv)
e_avi = string.format("%q", avi)

-- Look for the video ID.
pattern = "/watch_fullscreen.*video_id=(.-)&fs="
id = assert(string.match(body, pattern))

-- Fetch the video.
url = string.format("%q", base_url .. id)
cmd = string.gsub(fetch, "<(%w+)>", { url = url, file = e_flv })
assert(os.execute(cmd) == 0, "Failed")

-- Convert it to MPEG.
cmd = string.gsub(convert, "<(%w+)>", { flv = e_flv, avi = e_avi })
print("Converting ...")
assert(os.execute(cmd) == 0, "Failed")

os.remove(flv)
print("Done. Video saved in " .. avi .. ".")