#!/bin/bash

if [ -z "$1" ]; then
  >&2 echo 'too few arguments'
  exit 1
fi

Groeszen='
Es_kommt_ein_Schiff_geladen:19
Macht_hoch_die_Tuer:18
Freuet_euch_allezeit:17
Lobsinget_Gott_dem_Herrn:17
Stern_ueber_Bethlehem_:20
Freut_euch_von_Herzen:18
Drei_Koenige_wandern:17
Als_die_Welt_verloren:17
Die_Nacht_ist_vorgedrungen:18
Das_grosze_Wunder_hat_ganz_klein_begonnen:17.5
'

if printf '%s\n' "$1" \
| grep -q '/\([^/]\+\)/\1\.ly$'; then

  base="${1%/*.ly}"

  sed '
    s@\(include "\)\(\(artikulation\|stimmen\|texte\)\.ly"\)@\1'"${base}"'/\2@
    t
    s@\(include "\)\(\(artikulation\|stimmen\|texte\)\.pre"\)@\1'"${base##*/}"'_\2@
  ' \
  <"$1" \
  | case "${base##*/}" in
    'Es_kommt_ein_Schiff_geladen')
      sed 's/%STR_[1-4]%//g'
    ;;
    'Macht_hoch_die_Tuer')
      sed 's/%STR_[1-3]%//g'
    ;;
    *)
      cat
    ;;
  esac \
  | if Groesze=$(
    printf '%s\n' "${Groeszen}" \
    | grep "^${base##*/}:"
  ); then
    sed '
      /^\s*\\layout\s\+{\s*$/ a #(layout-set-staff-size '"${Groesze#*:}"')
    '
  else
    cat
  fi

elif [ -z "${1##*/Macht_hoch_die_Tuer/stimmen.ly}" ]; then

  sed '
    /%fermate$/ s/2\([_^]\?\\fermata\)\? /4 s /
  ' "$1"

else

  >&2 printf 'unknown input "%s"\n' "$1"
  exit 1

fi