Calculation of the newest library entries

[klassikmann]

EDIT Nov 21: Some typos
Some investigations (#1971 (reply in thread)) identified that the LATEST count and the LATEST albums are wrong in rAudio if one or more albums contain tracks with different tag values of "DATE", let's say (n) different "dates", than they are (n) equal entries in albumbyartist-year.

The tag value "DATE" is commonly used by the record company to store the release date of an album. But I think this a not the intended purpose of "DATE". For example, the FLAC specification explicitly defines the tag DATE as the date the track was recorded. That's the way I'm using the DATE tag.

@Sagnasty
Therefore let me present a different algorithm using linux shell commands (e.g. outside of the rAudio GUI) to sort the albums from newest to oldest ones together with their respective age.
I'm using a step-by-step approach for better understanding. (I'm not an experienced shell programmer at all.)

Step 1: Specify leaves in the directory tree, e.g. directories whithout subdirectories
Assumption: All audio files are contained in a leave directory .
You have to consider whether the music library is presented by a) a linux filesystem (e.g. ext4 filesystem connected via USB) or a NFS share (not tested) or b) a general algorithm which works on e.g. a NTFS formatted disk (USB) or a CIFS share.

First go to the root of your music library (all commands executed on rAudio):
cd /mnt/MPD/NAS # or cd /mnt/MPD/SD or cd /mnt/MPD/USB

Case a) using the so-called link-count is particularly elegant and fast, but works only on a linux filesystem.
find . -type d -links 2 > ~/leaves.txt

Case b) on the other side runs on any filesystem type:
find . -type d \( -exec sh -c 'find "$1" -mindepth 1 -maxdepth 1 -type d -print0 | grep -cz "^" >/dev/null 2>&1' _ {} \; -o -print \) > ~/leaves.txt
Comment: This command is a "hack" calling for improvement regarding readability.

Step 2: Compute an unsorted list of the age in days of the leaf directories
while IFS= read -r line; do sh -c "echo -n $(((($(date +%s) - $(date -r "$line" +%s)))/86400))"; echo " " $line; done <~/leaves.txt >~/unsorted.txt
Comments:

• Compute the difference of actual number of seconds since "The Epoch" (01.01.1970) of system time to actual number of seconds since "The Epoch" of leaf-directory
• 86400: number of seconds of a day

Step 3: Sort the list

cd
sort -g <unsorted.txt >sorted.txt

These are the first lines of my sorted.list

4  ./Musik/Alte Musik/Vivaldi, Antonio/Vivaldi Edition Naïve/Vol. 74 - Gloria e Imeneo/01 Concerto per archi RV138 in fa maggiore
4  ./Musik/Alte Musik/Vivaldi, Antonio/Vivaldi Edition Naïve/Vol. 74 - Gloria e Imeneo/02 Serenata 'La Gloria e Imeneo' RV687
7  ./Musik/Alte Musik/The Harp Consort/Missa Mexicana
16  ./Musik/Klassik+Romantik/Haydn, Joseph/Die Jahreszeiten/Jordi Savall + La Capella Nacional de Catalunya + Le Concert des Nations/Teil 1 - Der Frühling
16  ./Musik/Klassik+Romantik/Haydn, Joseph/Die Jahreszeiten/Jordi Savall + La Capella Nacional de Catalunya + Le Concert des Nations/Teil 2 - Der Sommer
16  ./Musik/Klassik+Romantik/Haydn, Joseph/Die Jahreszeiten/Jordi Savall + La Capella Nacional de Catalunya + Le Concert des Nations/Teil 3 - Der Herbst
16  ./Musik/Klassik+Romantik/Haydn, Joseph/Die Jahreszeiten/Jordi Savall + La Capella Nacional de Catalunya + Le Concert des Nations/Teil 4 - Der Winter
.......

Vivaldi is 4 days old, Harp Consort 7 days, Haydn 16 days.

Any comment is highly appreciated, be it questions, criticism, improvements, suggestions for integration in rAudio, ...

[Sagnasty]

@klassikmann

I am curious to know if a root cause was ever found on why the Latest feature was working fine in earlier releases but now gives different behavior in recent releases (via code review).

Perhaps if would be easier to keep track of the Latest ("recently added") album(s) by evaluating the album titles(s) while rebuilding / updating the library.

A field could be added to the MPD library (or similar data structure) to keep track of whether an album has already been added to the library or if it is new to the library since the last library update which would then be used to populate the Latest album list.

This would also bypass the various issues of sorting behaviors, track date tag usage, what file format the music library is stored on, network (NFS, CIFS) or USB shares, etc. that you mentioned.

[klassikmann]

@Sagnasty
I agree to your interpretation of LATEST as "recently added".

@rern
In the course of my investigations into the problem, I also made various inaccurate assumptions (e.g. different locales), but I was able to identify the problem with different tag values of "DATE" in the same album in the algorithm for calculating the LATEST counter beyond doubt. But I am not convinced that this is the only problem.