--[[
   Parse CUE files

 Copyright (C) 2009 Laurent Aimar

 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.
--]]

-- Probe function.
function probe()
    if( not string.match( vlc.path, "%.[cC][uU][eE]$" ) ) then
        return false
    end
    header = vlc.peek( 2048 )
    return string.match( header, "FILE.*WAVE%s*[\r\n]+" ) or
           string.match( header, "FILE.*AIFF%s*[\r\n]+" ) or
           string.match( header, "FILE.*MP3%s*[\r\n]+" )
end

-- Helpers
function is_utf8( src )
    return vlc.strings.from_charset( "UTF-8", src ) == src
end

function cue_string( src )
    if not is_utf8( src ) then
        -- Convert to UTF-8 since it's probably Latin1
        src = vlc.strings.from_charset( "ISO_8859-1", src )
    end
    local sub = string.match( src, "^\"(.*)\".*$" );
    if( sub ) then
        return sub
    end
    return string.match( src, "^(%S+).*$" )
end

function cue_path( src )
    if( string.match( src, "^/" ) or
        string.match( src, "^\\" ) or
        string.match( src, "^[%l%u]:\\" ) ) then
        return vlc.strings.make_uri(src)
    end

    local slash = string.find( string.reverse( vlc.path ), '/' )
        local prefix = vlc.access .. "://" .. string.sub( vlc.path, 1, -slash )
        -- FIXME: postfix may not be encoded correctly (esp. slashes)
        local postfix = vlc.strings.encode_uri_component(src)
    return prefix .. postfix
end

function cue_track( global, track )
    if( track.index01 == nil ) then
        return nil
    end

    t = {}
    t.path = cue_path( track.file or global.file )
    t.title = track.title
    t.album = global.title
    t.artist = track.performer or global.performer
    t.genre = track.genre or global.genre
    t.date = track.date or global.date
    t.description = global.comment
    t.tracknum = track.num
    t.options = { ":start-time=" .. track.index01}

    return t
end

function cue_append( tracks, global, track )
    local t = cue_track( global, track )
    if( t ~= nil ) then
        if( #tracks > 0 ) then
            local prev = tracks[#tracks]
            table.insert( prev.options, ":stop-time=" .. track.index01)
        end
        table.insert( tracks, t )
    end
end

-- Parse function.
function parse()
    p = {}
    global_data = nil
    data = {}
    file = nil

    while true
    do 
        line = vlc.readline()
        if not line then break end

        cmd, arg = string.match( line, "^%s*(%S+)%s*(.*)$" )

        if(  cmd == "REM" and arg ) then
            subcmd, value = string.match( arg, "^(%S+)%s*(.*)$" )
            if( subcmd == "GENRE" and value ) then
                data.genre = cue_string( value )
            elseif( subcmd == "DATE" and value ) then
                data.date = cue_string( value )
            elseif( subcmd == "COMMENT" and value ) then
                data.comment = cue_string( value )
            end
        elseif( cmd == "PERFORMER" and arg ) then
            data.performer = cue_string( arg )
        elseif( cmd == "TITLE" and arg ) then
            data.title = cue_string( arg )
        elseif( cmd == "FILE" ) then
            file = cue_string( arg )
        elseif( cmd == "TRACK" ) then
            if( not global_data ) then
                global_data = data
            else
                cue_append( p, global_data, data )
            end
            data =  { file = file, num = string.match( arg, "^(%d+)" ) }
        elseif( cmd == "INDEX" ) then
            local idx, m, s, f = string.match( arg, "(%d+)%s+(%d+):(%d+):(%d+)" )
            if( idx == "01" and m ~= nil and s ~= nil and f ~= nil ) then
                data.index01 = m * 60 + s + f / 75
            end
        end
    end

    cue_append( p, global_data, data )

    return p
end