--[[
 Youtube playlist importer for VLC media player 1.1 and 2.0
 Copyright 2012 Guillaume Le Maout

 Authors:  Guillaume Le Maout
 Contact: http://addons.videolan.org/messages/?action=newmessage&username=exebetche

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
--]]

-- Helper function to get a parameter's value in a URL
function get_url_param( url, name )
    local _, _, res = string.find( url, "[&?]"..name.."=([^&]*)" )
    return res
end

-- Probe function.
function probe()
    if vlc.access ~= "http" and vlc.access ~= "https" then
        return false
    end
    
    return string.match(vlc.path:match("([^/]+)"),"%w+.youtube.com") and 
		(string.match(vlc.path, "list=") 
		or string.match(vlc.path, "/watch%?") 
		or string.match(vlc.path, "/watch%?") 
		or string.match(vlc.path, "/player2.swf"))
end

-- Parse function.
function parse()
	if string.match( vlc.path, "list=" ) then
		local p = {}
		local playlistID = get_url_param( vlc.path, "list" )
		local videoID = get_url_param( vlc.path, "v" )
		local playlistURL = "http://www.youtube.com/list_ajax?action_get_list=1&style=xml&list="..playlistID
		local s = vlc.stream(playlistURL)
		local playlistData = ""
		local line = ""
		while line do 
			playlistData = playlistData..line
			line = s:readline()
		end

		local playlist_parsed = parse_xml(playlistData).root.video
		
		for i, video in ipairs(playlist_parsed) do
			local item = {}
			item.path = "http://www.youtube.com/watch?v="..video.encrypted_id.CDATA
			item.title = video.title.CDATA
			item.artist = video.author.CDATA
			item.arturl = video.thumbnail.CDATA
			--~ item.description = video.description
			--~ item.rating = video.rating
			table.insert (p, item)
		end
		return p
	elseif string.match( vlc.path, "/watch%?" )
    then 
        while true do
            line = vlc.readline()
            if not line then break end
            path = string.match( line, 'yt%.preload%.start%("([^"]+generate_204[^"]+)"%);' ) 
            
            if path then break end
        end
        
        if not path then
            vlc.msg.err( "Couldn't extract youtube video URL, please check for updates to this script/report this bug here:\nhttp://addons.videolan.org/content/show.php?content=149909" )
            return { }
        end

        path = path:gsub("generate_204", "videoplayback")
		path = path:gsub("\\/", "/")
		path = path:gsub("\\u0026", "&")
        
        local video_id = get_url_param( vlc.path, "v" )
        local video_info_url = "http://gdata.youtube.com/feeds/api/videos/"..video_id
		local s = vlc.stream(video_info_url)
		
		
		local video_data = ""
		local line = ""
		
		while line do 
			video_data = video_data..line
			line = s:readline()
		end
		
		local video_info_parsed = parse_xml(video_data)
		local arturl = video_info_parsed.entry['media:group']['media:thumbnail'][1].ATTR.url
		local title = video_info_parsed.entry['media:group']['media:title'].CDATA
		local description = video_info_parsed.entry['media:group']['media:description'].CDATA
		
        return { { path = path; title = title; description = description; arturl = arturl } }
    elseif string.match( vlc.path, "/v/" )
    then -- This is the flash player's URL
        video_id = get_url_param( vlc.path, "video_id" )
        if not video_id then
            _,_,video_id = string.find( vlc.path, "/v/([^?]*)" )
        end
        if not video_id then
            vlc.msg.err( "Couldn't extract youtube video URL" )
            return { }
        end
        fmt = get_url_param( vlc.path, "fmt" )
        if fmt then
            format = "&fmt=" .. fmt
        else
            format = ""
        end
        return { { path = "http://www.youtube.com/watch?v="..video_id..format } }
    end
end


function parse_xml(data)
	local tree = {}
	local stack = {}
	local tmp = {}
	local tmpTag = ""
	local level = 0
	
	table.insert(stack, tree)
	
	for op, tag, attr, empty, val in string.gmatch(data, "<(%p?)([^%s>/]+)([^>]-)(%/?)>[%s\r\n\t]*([^<]*)[%s\r\n\t]*") do
		if op=="?" then
			--~ DOCTYPE
		elseif op=="/" then
			if level>0 then
				level = level - 1
				table.remove(stack)
			end
		else
			level = level + 1
			
			if op=="!" then
				stack[level]['CDATA'] = vlc.strings.resolve_xml_special_chars(string.gsub(tag..attr, "%[CDATA%[(.+)%]%]", "%1"))
				attr = ""
				level = level - 1
			elseif type(stack[level][tag]) == "nil" then
				stack[level][tag] = {}
				table.insert(stack, stack[level][tag])
			else
				if type(stack[level][tag][1]) == "nil" then
					tmp = nil
					tmp = stack[level][tag]
					stack[level][tag] = nil
					stack[level][tag] = {}
					table.insert(stack[level][tag], tmp)
				end
				tmp = nil
				tmp = {}
				table.insert(stack[level][tag], tmp)
				table.insert(stack, tmp)
			end
			
			if val~="" then
				stack[level][tag]['CDATA'] = {}
				stack[level][tag]['CDATA'] = vlc.strings.resolve_xml_special_chars(val)
			end
			
			if attr ~= "" then
				stack[level][tag]['ATTR'] = {}
				string.gsub(attr, "(%w+)=[\"'](.-)[\"']", function (name, value)
					stack[level][tag]['ATTR'][name] = value
				end)
			end
			
			if empty ~= "" then
				level = level - 1
				table.remove(stack)
			end
		end
	end
	return tree
end