video.vala

using Soup;
using Json;
using Xml;
using Gee;

namespace Media
{
    // struct for keep video url(s).

    public struct Item
    {
        public string url;
        public string quality;
        public string type;
    }

    public class Video
    {
        protected string data;

        /*
        A Gee ArrayList<Item> , which contain video links retrieved.
         */

        public ArrayList<Item?> urls{get; protected set;}
        public string title {get; protected set;}

        public Video()
        {
            urls = new ArrayList<Item?>();
        }

        public Video.from_url(string url)
        {
            urls = new ArrayList<Item?>();
            data = IO.download_string(url);
        }
    }

    public errordomain VideoError
    {
        Null,
        Forbidden
    }

    public class Youtube : Video
    {
        public Youtube(string url) throws VideoError
        {
            string[] prms = url.split_set("?&");
            foreach(string p in prms){
                string[] i = p.split("=");
                if(i[0]=="v"){this.id(i[1]);break;}
            }
        }

        public Youtube.id(string id) throws VideoError
        {
            base();
            IO.download_file("http://www.youtube.com/watch?v="+id,"temp.html");

            /// html parsing section, with libxml-2.0 ///
            Html.ParserCtxt ctx = new Html.ParserCtxt();
            ctx.use_options(Html.ParserOption.NOERROR | Html.ParserOption.NOBLANKS | Html.ParserOption.NOWARNING | Html.ParserOption.NONET);
            Html.Doc *doc = ctx.read_file("temp.html");
            XPath.Context c = new XPath.Context(doc);
            XPath.Object *o = c.eval("//script");
            XPath.NodeSet *nodeset = o->nodesetval;
            string script = nodeset->item(4)->get_content();
            /// end of section ///
            /// json parsing ///
            int i = script.index_of("ytplayer.config = ");
            string json = script.substring(i+"ytplayer.config = ".length).replace("};","}");
            Json.Parser p = new Json.Parser();
            p.load_from_data(json);
            Json.Object obj = p.get_root().get_object().get_object_member("args");
            title = obj.get_string_member("title");
            string[] map = obj.get_string_member("url_encoded_fmt_stream_map").split(",");
            /// end of json ///
            foreach(string s in map){
                /* personal unescape, Youtube slipped vicious characters (like , instead of &)
                 * also, random distribution of the parameters
                 */
                string st = Uri.unescape_string(s).replace("\"","%22").replace("sig=","signature=");
                ArrayList<string> list = new ArrayList<string>();
                string[] t = st.split("&");
                string itag = "";
                string quality = "";
                string type = "";
                foreach(string str in t){
                    if(str.index_of("quality=")==0)quality = str.split("=")[1];
                    if(str.index_of("type=")==0)type = str.split("=")[1].split(";")[0];
                    if(str.index_of("itag=")==0){itag = str;continue;} // Finally, the dual presence of itag parameter
                    list.add(str);
                }
                while(true){
                    /// shift the list to the beginning of url
                    if(list[0].index_of("url=")==0)break;
                    string stri = list.remove_at(0);
                    list.add(stri);
                }
                st = "";
                foreach(string str in list)
                    st += str+"&";
                st += itag;
                urls.add({st.substring(4),quality,type});
            }
        }
    }

    public class Dailymotion : Video
    {
        public Dailymotion(string url)
        {
            base.from_url(url);
            FileUtils.set_data("temp",data.data);
            title = GLib.Uri.unescape_string(data.split("<title>")[1].split("</title>")[0]);
            Json.Parser parser = new Json.Parser();
            FileStream fs = FileStream.open("temp","r");
            string str;
            // reads a line as long as the parameter is not reached
            while((str = fs.read_line())!=null){
                if(str.contains("var flashvars")){
                    string[] tab = str.split(" = ",10);
                    tab[1] = tab[1].replace(";","");
                    parser.load_from_data(tab[1]);
                    break;
                }
            }
            var o = parser.get_root().get_object();
            str = Uri.unescape_string(o.get_string_member("sequence"));
            parser.load_from_data(str);
            o = parser.get_root().get_object();
            //parsing json to the list of video urls
            o = o.get_array_member("sequence")
            .get_object_element(0).get_array_member("layerList")
            .get_object_element(0).get_array_member("sequenceList")
            .get_object_element(2).get_array_member("layerList")
            .get_object_element(2).get_object_member("param");
            urls.add({o.get_string_member("ldURL"),"ld","mp4"});
            urls.add({o.get_string_member("sdURL"),"sd","mp4"});
            urls.add({o.get_string_member("hqURL"),"hq","mp4"});
        }
    }

    public class IGN : Video
    {
        public IGN(string url){
            base.from_url(url);
            FileUtils.set_data("temp",data.data);
            title = GLib.Uri.unescape_string(data.split("<title>")[1].split("</title>")[0]).replace("&#039;","&");
            FileStream fs = FileStream.open("temp","r");
            string str = "";
            string[] t = new string[]{""};
            while((str = fs.read_line())!=null){
                if(str.contains("iPadVideoSource_0")){
                    stdout.printf(str+"\n");
                    t = str.split("\"");
                    urls.add({t[3],"hq","mp4"});
                }
                if(str.contains("videoSource_0")){
                    t = str.split("\"");
                    urls.add({t[3],"sd","mp4"});
                }
                if(str.contains("mVideoSource_0")){
                    t = str.split("\"");
                    urls.add({t[3],"ld","mp4"});
                }
            }
        }
    }
}


/*
    static methods for convenience
*/

namespace IO
{
    public errordomain Error
    {
        Null
    }

    public static void download_file(string uri, string dest_file) throws IO.Error
    {
        if(dest_file == null)throw new IO.Error.Null("name of destination cannot be null");
        uint8[] data = download_data(uri);
        if(data.length < 1)throw new IO.Error.Null("data length is too short or null");
        FileUtils.set_data(dest_file,data);
    }

    public static uint8[] download_data(string uri){
        var session = new SessionSync();
        var message = new Message("GET",uri);
        session.send_message(message);
        return message.response_body.data;
    }

    public static string download_string(string uri){
        return (string)download_data(uri);
    }
}