muccadoro

#!/usr/bin/env bash

set -o nounset -o pipefail

# Before doing anything, check if the required programs are installed.  See
# <https://stackoverflow.com/q/592620>.  Some of these can probably be reasonably assumed
# to be present, but err on the side of caution.
for prog in awk cowsay figlet notify-send stty tput; do
   if ! hash "$prog" 2>/dev/null; then
      printf 'muccadoro: %s: command not found\n' "$prog" >&2
      exit 127
   fi
done

declare -i silly=1

# https://mywiki.wooledge.org/BashFAQ/035#getopts
# https://wiki.bash-hackers.org/howto/getopts_tutorial
while getopts ':s' opt; do
   case $opt in
      s) (( ++silly ));;
   esac
done
shift "$((OPTIND-1))" # Shift off the options and optional --.

# One pomodoro lasts "$1" minutes.  The default duration is 25 minutes.
declare -i duration=$((${1:-25}*60)) num_pomodoros=4

(( silly %= 5 ))
if (( silly )); then
   declare -i silliness=$((2**(4-silly)))
   # `apps` stands for appearances, of course.
   declare -a apps=('' '-b' '-d' '-g' '-p' '-s' '-t' '-w' '-e oO' '-e Oo' '-e ><' '-e -o'
      '-e o-' '-e >o' '-e o<')
   num_apps=${#apps[@]}
   cowtell() {
      app_num=$((RANDOM % (silliness * num_apps)))
      (( app_num >= num_apps )) && app_num=0
      cowsay -n ${apps[app_num]}
   }
else
   cowtell() {
      cowsay -n
   }
fi

summary=

# Standard output must be a terminal.  See <https://unix.stackexchange.com/q/91638>.  Save
# the original stdout to file descriptor 3 (see <https://unix.stackexchange.com/q/80988>).
exec 3>&1 &>/dev/tty

# Save the current terminal settings.
initial_tty_settings=$(stty -g)

# Revert all changed terminal settings (FIXME: restore everything from saved settings) and
# print a summary.
cleanup() {
   tput rmcup
   tput cnorm
   stty "$initial_tty_settings"
   [[ $summary ]] && echo -ne "$summary" >&3
}

trap cleanup EXIT

# Switch to the alternate screen.  See <https://unix.stackexchange.com/q/27941>, xterm(1),
# terminfo(5), and <https://stackoverflow.com/q/11023929>.
tput smcup

# TODO: explain.  See
# <http://www.unix.com/shell-programming-and-scripting/176837-bash-hide-terminal-cursor.html>.
tput civis

# Don't echo characters typed on the tty.  See <https://unix.stackexchange.com/a/28620>.
stty -echo

# Output empty lines before the message so the message is displayed at the bottom of the
# terminal.  See <https://stackoverflow.com/a/29314659>.  Also, instead of `clear`ing
# (which causes flickering), pad all lines of the message with spaces all the way to the
# right edge of the terminal, thereby overwriting any currently displayed characters.  See
# <https://stackoverflow.com/questions/9394408>.  TODO: probably just use Bash and not
# awk.
pad() {
   awk -v lines="$(tput lines)" -v cols="$(tput cols)" '
      NR!=1 && FNR==1 { n=lines-NR; for(; n>0; n--) printf "%-"cols"s\n", "" }
      NR==FNR { next }
      { printf "%-"cols"s\n", $0 }' <(echo "$1"){,}
}

pp() {
   tput cup 0 0 # TODO: explain.
   pad "$1"
}

ppp() {
   tput cup 0 0
   # FIXME: probably just check once if we have lolcat.
   pad "$1" | { lolcat 2>/dev/null || cat; }
}

declare -a lyrics
declare -i line_index=0
lyrics=(
   "Can't stop, addicted to the shindig;"
   "Chop Top, he says I'm gonna win big;"
   "Choose not a life of imitation;"
   "Distant cousin to the reservation;"
   "Defunct the pistol that you pay for;"
   "This punk, the feeling that you stay for;"
   "In time I want to be your best friend;"
   "East side lovers living on the west end;"
   "Knocked out but boy you better come to;"
   "Don't die, you know the truth as some do;"
   "Go write your message on the pavement;"
   "Burn so bright I wonder what the wave meant;"
)

declare -i state=0

cant-stop() {
   (( state == 2 )) && return
   state=2
   tty_settings=$(stty -g)
   trap '' INT
   stty susp undef
   pp "$(cowsay -e '><' -W $(($(tput cols)-3)) ${lyrics[line_index]})"

   ((++line_index)); ((line_index%=${#lyrics[@]}))
   sleep 2 & wait $!
   stty "$tty_settings"
   count-state
}

# SIGTSTP handler.
on-tstp() {
   # Signal all processes in the process group $$ (the group leader) to continue.  See
   # kill(1), and <https://unix.stackexchange.com/q/139222>.  Pomodoros are not
   # interruptible.
   kill -CONT -- -$$
   if (( state == 1 )); then
      cant-stop
   fi
}
trap on-tstp TSTP

count-state() {
   # 130 is the exit status for termination by Ctrl-C.  See
   # <https://www.tldp.org/LDP/abs/html/exitcodes.html>.
   trap 'trap on-int INT; on-int; return 130' INT
   state=1
}

dead-state() {
   trap on-int INT
   state=0
}

pause-state() {
   trap on-int INT
   state=0
}

on-int() {
   if (( state==0 )); then
      # We are supposed to kill ourselves with SIGINT instead of using `exit`.  See
      # <https://mywiki.wooledge.org/SignalTrap#Special_Note_On_SIGINT>.
      trap - INT
      kill -INT $$
   elif (( state==1 )); then
      dead-state
   elif (( state==2 )); then
      count-state
   fi
}

# XXX: beware of bugs due to SIGINT (Ctrl-C) being received during the short timeframe in
# which another function invoked by this one is executing.  The `return 1` statement of
# the SIGINT trap will be ran in the context of the inner function.
pomodoro() {
   count-state
   while :; do
      # Handle signals immediately, not after `sleep` exits.  See
      # <https://mywiki.wooledge.org/SignalTrap#When_is_the_signal_handled.3F>.
      sleep 1 &
      # See <https://mywiki.wooledge.org/BashFAQ/002>.
      the_time=$((seconds/60)):$(printf '%02d' $((seconds%60)))
      # Keep in mind that almost everything causes new values to be assigned to `$?`:
      #    $ false
      #    $ (( $? )) && echo $?
      #    0
      #    $ false || { (( $? != 148 )) && echo $?; }
      #    0
      # In both cases, when `echo $?` is executed, `$?` is no longer 1.
      fail=$?
      if (( fail && fail != 148 )); then
         return $fail
      fi
      text=$(figlet -f small "$the_time" | cowtell)
      fail=$?
      if (( ! fail )); then
         pp "$text"
         fail=$?
         (( fail && fail != 148 )) && return $fail
      elif (( fail != 148 )); then
         return $fail
      fi
      wait
      seconds=$((planned_end_time - $(date +'%s')))
      ((seconds <= 0)) && return 0
   done
   return 1
}

flush-stdin() {
   # See <https://superuser.com/q/276531>.
   read -r -d '' -t 0.1 -n 1000
}

# FIXME: why `dummy` (https://wiki.bash-hackers.org/commands/builtin/read#press_any_key).
pause() {
   # See <https://wiki.bash-hackers.org/syntax/pe#use_an_alternate_value>.
   read -r -n 1${1:+ -t $1}
}

for (( n=1; n<=num_pomodoros; ++n )); do
   declare -i seconds=$duration
   declare -i start_time_secs=$(date +'%s')
   start_time=$(date --date "@$start_time_secs" +'%H:%M')
   planned_end_time=$((start_time_secs + duration))
   pomodoro
   fail=$?
   if (( fail == 130 )); then
      summary+="Abandoned: $start_time to $(date +'%H:%M')\n"
      # Pomodoros are atomic.
      pp "$(cowsay -d -W $(($(tput cols)-3)) 'You abandoned pomodoro '$n'.  Press any' \
         'key to restart it.')"
      pause
      (( --n ))
      continue
   elif (( fail )); then
      exit $fail
   fi
   pause-state
   tty_settings=$(stty -g)
   stty susp undef
   summary+="Pomodoro $n: $start_time to $(date +'%H:%M')\n"
   if (( n!=num_pomodoros )); then
      start_time=$(date +'%s')
      notify-send "You completed pomodoro $n.  Take a short break (3-5 minutes)."
      # TODO: it may be nice to create this message asynchronously with `lolcat -f` since
      # lolcat is a bit slow.  That's not a priority, though.
      ppp "$(cowsay -e '^^' -W $(($(tput cols)-3)) 'You completed pomodoro '$n'.  Take' \
         'a short break (3-5 minutes), then press any key to continue.')"
      flush-stdin
      if ! pause 180; then
         pp "$(cowsay -w -W $(($(tput cols)-3)) 'Press any key to continue.')"
         pause 120 || {
            notify-send -u critical 'Time to start the next pomodoro.'; pause;
         }
      fi
      break_duration=$((($(date +'%s')-start_time+30)/60))
      summary+="Break: about $break_duration minute"
      (( break_duration != 1 )) && summary+=s # plural
      summary+='\n'
   fi
   stty "$tty_settings"
done
notify-send "You completed all $num_pomodoros pomodoros!"

# vim: tw=90 sts=-1 sw=3 et