drills.lib

# vim: filetype=sh

INSTRUMENT=57
OUTDIR=$HOME/library/workout
mkdir -p $OUTDIR

function mcd { mkdir -p "$1"; cd "$1"; }

#
# create a directory for each drill, adding rotation number, drill number and permutations
#
# $1 drill name
# $2+ drill permutation patterns
#
function drill {
  DRILLNUM=$((DRILLNUM+1))
  dir="00.$(printf %02d $DRILLNUM).$1"
  mkdir "$dir"

  # join and normalise the permutations pattern
  # brace expansion uses spaces as separators, so we replace them with underscores
  pattern="${*:2}"
  pattern="${pattern// /_}"

  # make one file per permutation
  i=0
  for permutation in $(eval echo "$pattern"); do 
    i=$((i+1))
    echo -e ${permutation//_/\\n} > "$dir"/$(printf %04d $i)."${permutation//_/ }".txt
  done
}
function drillcd {
  drill $*
  cd "00.$(printf %02d $DRILLNUM).$1"
}
DRILLNUM=0

#
# convert an abc score to an mp3 file
#
# $1 abc score
# $2 output directory
# $3 output filename
# $4 transpose semitones (default 0)
# $5 transpose tempo % (default 100)
#
function make_mp3 {
  if [ -f "$2/$3" ]; then
    echo "$3 already exists; skipping"
    return
  fi
  mkdir -p "$2"
  echo "$1" | abc2midi /dev/stdin -o /dev/stdout \
        | timidity - --output-24bit -A800 -K${4:=0} -T${5:=100} -Ow -o - \
        | ffmpeg -loglevel error -i - -ac 1 -ab 64k "$2/$3"
}

#
# generate a set of mp3s by transposing the pitch and tempo of the score
#
# $1 set name
# $2 abc score in the key of C with a tempo of 100
# $3 pitches
#
function generate_scales {
  STEPS=$((12#${3:0:2} - 12#40))
  for PITCH in $3; do
    TEMPO=20 # percent
    while [ $TEMPO -le 400 ]; do
      make_mp3 "$2" $OUTDIR/$1/$PITCH $(printf %03d $TEMPO).$PITCH.${1/\//-}.mp3 $STEPS $TEMPO
      TEMPO=$((TEMPO+10))
    done
    STEPS=$((STEPS+1))
  done
}

#
# generate a set of mp3s by transposing the pitch and tempo of the score
#
# $1 drill name
# $2 abc score for the base position (fret=0)
# $* list of frets to transpose to
#
function generate_pattern_scales {
  for FRET in ${@:3}; do
    TEMPO=30 # percent
    while [ $TEMPO -le 240 ]; do
      make_mp3 "
        X:0
        M:4/4
        L:1/4
        Q:100
        K:C
        | [I:MIDI program 115]
        |cccc| [I:MIDI program $((INSTRUMENT - 1))]
        $2" "$1/fret=$FRET" $(printf %03d $TEMPO).mp3 $FRET $TEMPO
      TEMPO=$((TEMPO+30))
    done
  done
}

#
# generate a set of mp3s by transposing the tempo of the score
#
# $1 set name
# $2 abc score with a tempo of 100
#
function generate_tempos {
  TEMPO=20 # percent
  while [ $TEMPO -le 400 ]; do
    make_mp3 "$2" $OUTDIR/$1 \'$(printf %03d $TEMPO).${1/\//-}.mp3 0 $TEMPO
    TEMPO=$((TEMPO+10))
  done
}

# create a directory for each drill and one file defining each drill variable
function drill~ {
  mkdir -p $1;
  i=0
  for var in ${@:2}; do
    i=$((i+1))
    touch $1/$i.$var
  done
}

# create a set of drills for each scale key
function scale {
  for TONIC in 0 1 2 3 4 5 6 7 8 9 X Y; do
    drill $1/00.$TONIC/$2 ${@:3}
  done
}