romp - random music player

#!/bin/bash
# RandOm Music Player #########################################################
# v.1
# by mahatman2
#{{{ FEATURES ROADMAP #########################################################
# Current:
#   - definable begin path
#   - descend directory tree, play music files with `play` (from SoX)
#   - debug stuff
#   - exit playing with ^C
# Future:
#   - shuffle music files while playing (repeat/no-repeat)
#   - begin on track
#   > Shortcut Keys
#      - skip to next track
#      - pause/play
#}}} ##########################################################################
## config variables {{{
exclude=""
ls_opts="-l" # just list files, no hiddens
player="$(which play)"
file_formats="au\|snd\|a?iff?\|mp2\|mp3\|ra\|sf\|smp\|voc\|wav\|wve\|ogg\|wma\|m4a\|flac"
debug=0
## }}}
## functions {{{
Help() {
    cat <<EOF
    usage: $0 -[xhdb] [folder]
    -x [pattern]:   Exclude this pattern in file names.
    -b [track]:     Begin on track [track]
    -h:             Show this help.
    -d:             Debug.
    [folder]:       Play files in this folder.
                    ----DEFAULT: use current folder.
EOF
exit 0
}
Debug() { # <message>
    if [[ $debug == 1 ]]; then
        echo "$@" >&2;
        2>&1;
    fi
}
GetRandom() { # [lo=0] <hi> #TODO:[randosity]
    if [[ -z $1 ]]; then
        Debug "You need at least one argument!"
        return -1
    fi
    if [[ -z $2 ]]; then
        lo=0; hi=$1;
        Debug "GetRandom: lo defaulting to 0; hi = $hi"
    else
        lo=$1; hi=$2;
        Debug "GetRandom: lo = $lo; hi = $hi"
    fi
    # returns a value: {lo..hi}
    rand_number=$[(RANDOM % (hi+1 - lo)) + lo]
    Debug "GetRandom: number returned: $rand_number"
    return $rand_number
}
Branch() { # return 0 for continuing down, return # for stop
    number_dirs=$(ls -l | grep '^d' | wc -l)
    Debug "Branch: number_dirs = $number_dirs"
    # if no more branches, return 1
    if [[ $number_dirs == 0 ]]; then
        Debug "Branch: Directory at the end of tree. Return 1."
        return 1
    fi

    GetRandom $number_dirs
    random_dir_number=$?
    # if the random number is 0, stay here
    if [[ $random_dir_number == 0 ]]; then
        Debug "Branch: random_dir is this one."
        return 2
    fi

    random_dir="$(ls $ls_opts|\
        awk -v n=$random_dir_number '/^d/{i++;if(i==n){for(j=9;j<=NF;j++){printf "%s ",$j} }}')"

    # if it's something we don't want, go again
    if [[ "$exclude" =~ "*$random_dir*" ]]; then
        Debug "Branch: The directory "$random_dir" is in the \$exclude list. Retrying.."
        Branch
    fi

    # else, cd to the dir && return 0
    Debug "Branch: echo \"$random_dir\"; return 0"
    echo $random_dir; return 0
}
## }}}
## option parsing {{{
while getopts 'hdx:b:' opt; do
    case $opt in
        h)  Help                                    ;;
        d)  debug=1                                 ;;
        x)
            exclude="$OPTARG"
            Debug "$exclude will be excluded from path."
            ;;
        b)
            begin_on="$OPTARG"
            Debug "Begginning on track ${begin_on}..."
            ;;
        \?) echo "Invalid options: -$OPTARG" >&2    ;;
    esac
done
shift $((OPTIND-1))
# cd to folder passed after options (if exists)
if [[ -n "$1" ]]; then
    Debug "Romping from $(realpath ${1}).."
    cd ${1}
fi
##}}}
## Climb the tree {{{
Debug "Climb: Begin tree-climbing.."
while true; do
    path="$(Branch)";
    if [[ $? -ne 0 ]]; then
        Debug "Climb: Finished climbing the tree!"
        Debug "PWD = $PWD"
        # Make sure there are music files in this folder
        ls -l | grep -v '^d\|^total' && break || Debug "Oops, I lied! This folder has no music."
    fi
    cd "$path";
    Debug "Climb: PWD = $PWD"
done
##}}}
## Play music in this folder {{{
currentSong=1
IFS=$'\n'
list_Songs=( $(ls -1 | grep -i $file_formats) )
Debug "List of songs: ${list_Songs[@]}"
trap "exit" SIGINT
for song in ${list_Songs[@]}; do
    # TODO: enable 'skip'
    #trap "continue" SIGTSTP
    if [[ $begin_on -gt 1 ]]; then
        ((begin_on-=1))
        ((currentSong+=1))
        Debug "Skipping \"$song\" (-b flag; $begin_on more to skip)"
        continue
    fi
    [[ $debug -ne 0 ]] || clear
    echo "Romping in $PWD"
    echo "==============================================="
    echo "Playing: $song"
    echo "( $currentSong / ${#list_Songs[@]} )"
    echo "+++++++++++++++++++++++++++++++++++++++++++++++"
    $player "$song" || (Debug "Skipping \"$song\" (unrecognized format)"; continue)
    ((currentSong+=1))
done
#}}}