Introduction
============

Cantata is a GUI front-end for MPD. The code is forked from QtMPC. However,
both the code itself, and the GUI are now *very* different to QtMPC.


Dependencies
============

Cantata requires/uses the following libraries:

1. Qt4
2. KDElibs4 - if Cantata is not built with KDE4 support, then device support
   will not be available.
3. QtWebKit - required for the artist/album information page. If QtWebKit is
   not found, the page will not be built.
4. TagLib - required to for the tag edit dialog, and for UMS device support.
5. LibMTP - required to support MTP devices.
6. FFMPEG (libavcodec) - used for ReplayGain detection.
7. SpeexDSP - used by ReplayGain detection code.
8. MPG123 - used for ReplayGain detection (optional).


Translations
============

Cantata is mainly a KDE-based application, but it can be compiled as Qt only.
Because of its KDE base, the translation files are based upon KDE's i18n
framework - these are located with the 'po' folder.

Translations for the Qt-only builds are created from the KDE translations using
'lconvert'. To work-around issues with plural translations, Qt builds will have
contain extra strings to handle plural forms.

e.g.

    KDE will have:
        msgid "1 Track"
        msgid_plural "%1 Tracks"
        msgstr[0] ""
        msgstr[1] ""

    Qt will have:
        msgid "1 Track"
        msgstr ""
        msgid "%1 Tracks"
        msgstr ""

In the code, cantata will use "%1 Tracks" for any count other than 1. If the
language you are translating into has more plural forms (i.e. the above two
strings are not sufficient), then please translate both into the form
"Tracks: N" - e.g.

    Qt will now have:
        msgid "1 Track"
        msgstr "Tracks: 1"
        msgid "%1 Tracks"
        msgstr "Tracks: %1"


Covers
======

When displaying covers, Cantata will load album covers in the following order:

...if MPD folder exists, is not specified as a http URL, and is readable, then
   cantata will look for the following within the folder containing the song:

 1. cover.jpg
 2. cover.png
 3. AlbumArt.jpg
 4. AlbumArt.png
 5. folder.jpg
 6. folder.png
 7. ${file}.jpg
 8. ${file}.png
 9. ${albumArtist} - ${album}.jpg
10. ${albumArtist} - ${album}.png
11. ${album}.jpg
12. ${album}.jpg
13. Image embedded within current songs tags.
14. ANY other jpg, or png

...then Cantata will check its cache folder (~/.cache/cantata/covers), for :

15. ${albumArtist}/${album}.jpg
16. ${albumArtist}/${album}.png

...if compiled for Linux

17. Matching Amarok cover
18. Matching Clementine cover

...if the MPD folder was specified as a http URL

19. ${url}/${dirFromFile}/cover.jpg
20. ${url}/${dirFromFile}/cover.png

...lastly

21. Query last.fm using ${albumArtist} and ${album}. Cantata will attempt to
    download the image specified with the "extralarge" size.

Downloaded images will be saved as cover.jpg/png within the song folder if
possible. If not, then they will be saved in Cantata's cache folder.


For artist images:

...if MPD folder exists, is not specified as a http URL, and is readable, then
   cantata will look for the following within the folder containing the song:

1. ${albumArtist}.jpg
2. ${albumArtist}.png
3. artist.jpg
4. artist.png

... the above will be repeated for each parent folder (until we reach the MPD
    root folder)

...then Cantata will check its cache folder (~/.cache/cantata/covers), for :

5. ${albumArtist}.jpg
6. ${albumArtist}.png

...lastly

7. Query last.fm using ${albumArtist}. Cantata will attempt to download the
   image specified with the "extralarge" size.

Downloaded artist images are saved to Cantata's cache folder.


Single/Double Click Activation
==============================

As of 0.8.3 Cantata forces single-click activation of items in the left hand
pages (e.g. Library view). To revert to having this controlled via the style,
you need to edit the Cantata config file. For a KDE build this will usually be
~/.kde/share/config/cantatarc, for a Qt-only build on Linux this will usually
be ~/.config/cantata/cantata.conf. For a windows build, you will need to use
regedit and navigate to HKEY_CURRENT_USER/Software/cantata/cantata. The config
item to be changed is forceSingleClick in the General section. e.g.

    [General]
    albumFirst=false
    ...
    forceSingleClick=true
    groupMultiple=true
    ...


Amarok Radio Streams
====================

The script amarok2cantata.sh may be used to covert Amarok Radio plugins
into an XML file suitable to be imported into Cantata. The script is
rather basic and requires the Amarok plugin to list its streams in 'main.js'
with the following syntax:

    Station( "NAME", "URL")

Each station *must* be on its own line, and must be all in *one* line.

'script.spec' is used to ascertain the Amarok plugin name, for this the
script will look for the line starting with "Name="


Dynamic Helper Script
=====================

When a dynamic playlist is loaded in Cantata, the cantata-dynamic helper script
is executed in the background to do the actual song selection. In this way the
dynamic playlist can still function even when cantata is terminated. It is
possible for this script to be controlled on the command line (although it was
never written with this in mind).

The list of dynamic playlists may be obtained by looking in
~/.config/cantata/dynamic

To 'load' a dynamic play list, all you need to do is symlink the desired one in
~/.config/cantata/dynamic to ~/.cache/cantata/dynamic/rules. Then you can start
the helper by calling '/usr/bin/cantata-dynamic start'  (or first call
'/usr/bin/cantata-dynamic stop' to stop any current play list).

To pass connection details, cantata-dynamic reads the same environment variables
as mpc - namely MPD_HOST and MPD_PORT

e.g. the following bash script (not tested!) will stop any current dynamic
playlist, load the 'MyPlaylist' playlist, and start this on the mpd at
'hostname:1234' with password 'pass'

    # Stop current dynamic playlist
    /usr/bin/cantata-dynamic stop
    # Clear the playqueue (this requires mpc)
    MPD_HOST=pass@hostname MPD_PORT=1234 mpc clear
    # 'Load' new playlist
    if [ -f "$HOME/.cache/cantata/dynamic/rules" ] ; then
        rm "$HOME/.cache/cantata/dynamic/rules"
    fi
    ln -s "$HOME/.config/cantata/dynamic/MyPlaylist.rules" "$HOME/.cache/cantata/dynamic/rules"
    # Restart dynamic script
    MPD_HOST=pass@hostname MPD_PORT=1234 /usr/bin/cantata-dynamic start


Dynamic Helper - Server Mode
============================

In addition to the above, the helper script may be installed on the system
containg MPD, and run in 'server' mode. When run in this mode, it is intended
that the script be run system-wide and started when the system (or MPD) is
started. e.g. The script should be started as:

    <install dir>/cantata-dynamic server <location of config file>

    e.g.:  /usr/bin/cantata-dynamic server /etc/cantata-dynamic.conf

When run as described above, the script will automatically daemonize itself.

Cantata's 'Connection' settings page contains entries to configure the host and
port of where the dynamic script is running. If Cantata is configured in this
manner, then it will attempt to talk to the helper via its HTTP API, and will
not start/stop a per-user instance of the script. If the config is left blank,
then cantata will assume the script is to be run in local mode.


Configuration
-------------

The server mode has a simple ini-style configuration file, that has the
following paramters (shown here with the defaulr values):

    pidFile=/var/run/cantata-dynamic/pid
    filesDir=/var/lib/mpd/dynamic
    activeFile=/var/run/cantata-dynamic/rules
    mpdHost=localhost
    mpdPort=6600
    mpdPassword=
    httpPort=6601
    httpControlPage=0
    useFirstImage=1
    mpdDir=/var/lib/mpd/music

'filesDir' This controls where the dyamic rules are stored. The user the script
is run as should have read/write permissions to this folder.

'activeFile' When a set of rule is made 'active', all cantata does is create a
symbolic link from the rules file to the file specified in 'activeFile'

'mpdHost', 'mpdPort', and 'mpdPassword' are the connection details of the MPD
server.

'httpPort' is the port to be opened by the script to allow it to be controlled.

'httpControlPage' If set to '1' then if you point a browser to
'http://<host>:<httpPort>' then the script will return a simple web-page
containing a list of the dyamic rules (which if clicked will become 'active'),
and a butotn to stop dynamic mode. Set to '0' to disable this page.

'useFirstImage' and 'mpdDir' As the dyanmic script contains a HTTP server, it
can also be used to server cover images to Cantata. If 'useFirstImage' is set
to '1', and Cantata requests 'cover.jpg' but neither 'cover.jpg' nor
'cover.png' exist, then the script will return the first '.jpg' file found in
the supplied folder. 'mpdDir' is used to specify the root MPD music folder to
append to any supplied URLs. e.g.

    http://127.0.0.1:6601/Artist/Album/cover.jpg will be looked for as
    /var/lib/mpd/music/Artist/Album/cover.jpg


Installation
-------------

Within the dynamic/init are example configuration and init files. Copy one of
the example init scripts (or create a new one) to /etc/init.d/cantata.dynamic -
and create the appropriate links in /etc/rc?.d

Copy dynamic/init/cantata-dynamic.conf to /etc, and edit as appropriate.


API
---

This is a brief (and probably incomplete) explanation of the HTTP API.
Currently it is only used by Cantata.

GetStatus
    Mode:   HTTP GET
    URL:    http://host:port/status
    Params: statusTime=${clientStatusTime}
    Return: String containing
            STATE:<current status>
            RULES:<name of currently active rule>
            TIME:<epoch time since started, or last rule modification>

    <current status> may be:
        IDLE       - dynamic mode is not running
        NO_SONGS   - no songs matched current rules
        HAVE_SONGS - dynamic mode running, and songs found
        STARTING   - dynamic mode is starting

    The client should store the TIME value, and use it to determine whether
    any rules have been changed since it last retrieved the list.

ListPlaylists:
    Mode:   HTTP GET
    URL:    http://host:port/list
    Params: statusTime=${clientStatusTime}
    Return: String containd list of current rules. if 'withDetails' is set to
            '1' then the contents of the rules are also returned.

    Example return:
        FILENAME: Wibble.rules
        Rule
        Artist: Wibble
        FILENAME: Heavy Metal.rules
        Rule
        Genre: Heavy Metal

GetPlaylist:
    Mode:   HTTP GET
    URL:    http://host:port/${playlist}
    Params: statusTime=${clientStatusTime}
    Return: Returns the contents of the specified 'playlist'. Or, a string
            starting with 'ERROR:' in the case of failure.

DeletePlaylist:
    Mode:   HTTP DELETE
    URL:    http://host:port/${playlist}
    Return:

SavePlaylist:
    Mode:   HTTP POST
    URL:    http://host:port/save
    Params: name=${playlist}  [Required]
    BODY:   Playlist content
    Return:

SetActive:
    Mode:   HTTP POST
    URL:    http://host:port/setActive
    Params: name=${playlist}  [Required]
            start={1/0}       If set to '1' dynamic mode is also started.

ControlDynamizer:
    Mode:   HTTP POST
    URL:    http://host:port/control
    Params: state={start/stop} [Required]

GetCover:
    Mode: HTTP GETT
    URL:  http://host:port/${path}/cover.jpg
          http://host:port/${path}/cover.png


In order to detect whether the set of stored rules has changed, a client should
supp,y the 'statusTime' parameter with the value set to the last 'TIME' value
returned by a 'status' call. (If the client has no current value, use '1') The
script will then return the current statusTime, as well as the string
UPDATE_REQUIRED if the client should update its list of playlists (by calling
the 'ListPlaylists' API)


Credits
=======

Cantata contains code/icons from:
    Amarok         - amarok.kde.org
    Clementine     - www.clementine-player.org
    libmaia        - https://github.com/wiedi/libmaia
    libebur128     - https://github.com/jiixyj/libebur128
    wikipedia icon - Social Media Mini by Paul Robert Lloyd License: Commons licence: Attribution-Share Alike 2.0 UK: England & Wales


Windows
=======

To compile for windows:

1. Install Qt, MinGW, cmake, TagLib. TagLib will probably need compiling.
2. Call cmake:
     cmake ../cantata -G "MinGW Makefiles" -DTAGLIB_INCLUDES="C:\taglib\include" -DTAGLIB_LIBRARIES="C:\tagglib\bin\libtag.dll"
3. make! :-)

This build is as per Qt-only, but does not have support for dbus, dockmanager,
or dynamic playlists.

To run you will also need Oxygen icons.