todo

#!/bin/sh
# Part of sh-todo:
# https://github.com/asb/sh-todo
set -e

. ~/.sh-todo

SCRIPTNAME=$(basename $0)

# Return 0 if $2 contains all tags in $1 and 1 otherwise. Returns 0 in the 
# case that $1 is empty.
match_tags() {
  WANTEDTAGS=$1
  LINETAGS="$2 "
  for TAG in $WANTEDTAGS; do
    if [ "${LINETAGS#*$TAG }" = "$LINETAGS" ]; then
      return 1
    fi
  done
  return 0
}

output_line() {
  LINE=$1
  if [ "${LINE#DONE }" != "$LINE" ]; then
    printf "• $BEGIN_DONE%s$END_DONE\n" "${LINE#DONE }"
  else
    printf "• %s\n" "${LINE#TODO }"
  fi
}

parse_linetags() {
  LINETAGS="${1#*\[}"
  if [ "$LINETAGS" != "$LINE" ]; then
    LINETAGS="${LINETAGS%]*} "
  else
    LINETAGS=""
  fi
  printf "%s" "$LINETAGS"
}

# If given a todo, then add that to the list of tasks. Otherwise, print all 
# todo items which have the given tags
do_todo() {
  [ -e "$TODO_F" ] || touch "$TODO_F"
  if [ -z "$INPUT" ]; then # No todo given, so print current tasks with matching tags
    while read -r LINE; do
      if match_tags "$ARGTAGS" "$(parse_linetags "$LINE")"; then
        output_line "$LINE"
      fi
    done < "$TODO_F"
  else # Must be adding a new todo
    printf "TODO %s%s\n" "$INPUT" "${ARGTAGS:+ [$ARGTAGS]}" >> "$TODO_F"
  fi
  exit 0
}

# Mark any tasks matching the given pattern as done. Tags can also be 
# specified to limit the scope of the match
do_todone() {
  if [ -z "$INPUT" ]; then
    printf "Error: no todo to mark done specified\n" >&2
    exit 1
  fi

  > "$TODO_F.tmp"

  HAD_MATCH=0
  while read -r LINE; do
    if [ "${LINE#TODO *$INPUT}" != "$LINE" ] && match_tags "$ARGTAGS" "$(parse_linetags "$LINE")"; then
      HAD_MATCH=1
      TASK="${LINE#TODO }"
      LINE=$(printf "DONE %s ($(date "+%Y-%m-%d %R"))" "$TASK")
      output_line "$LINE"
      printf "%s\n" "$LINE" >> "$TODONE_F"
    fi
    printf "%s\n" "$LINE" >> "$TODO_F.tmp"
  done < "$TODO_F"

  if [ $HAD_MATCH -eq 0 ]; then
    printf "Error: no tasks matched the given pattern\n" >&2
    rm "$TODO_F.tmp"
    exit 1
  fi

  mv "$TODO_F.tmp" "$TODO_F"
}

# Remove all DONE lines with the given tags from $TODO_F. All such lines will 
# already have been added to $TODONE_F
do_todone_archive() {
  > "$TODO_F.tmp"

  while read -r LINE; do
    if [ "${LINE#DONE }" != "$LINE" ] && match_tags "$ARGTAGS" "$(parse_linetags "$LINE")"; then
      output_line "$LINE"
    else
      printf "%s\n" "$LINE" >> "$TODO_F.tmp"
    fi;
  done < "$TODO_F"

  mv "$TODO_F.tmp" "$TODO_F"
}

# Show a formatted list of completed tasks (can be limited by specifying 
# desired tags).
# This function uses tac which is non-POSIX, as is the -d argument to date
do_todone_view() {
  TAC=tac
  #TAC="tail -r" # For OSX/BSD

  $TAC "$TODONE_F" | while read -r LINE; do
    if ! match_tags "$ARGTAGS" "$(parse_linetags "$LINE")"; then
      continue;
    fi
    TRIMLINE=${LINE%(*)} # strip the timestamp
    TIMESTAMP=${LINE#"$TRIMLINE("}
    TIMESTAMP=${TIMESTAMP%)}

    DATE=${TIMESTAMP%% [0-9][0-9]:[0-9][0-9]}
    TIME=${TIMESTAMP#"$DATE "}

    if [ "$DATE" != "$LASTDATE" ]; then
      printf "\n$(date -d"$DATE" "+%A %d %B %Y")\n\n"
    fi
    printf "• %s($TIME)\n" "${TRIMLINE#DONE }"
    LASTDATE=$DATE
  done | less
}

# Parse arguments
ARGTAGS=""
INPUT=""
for ARG in "$@"; do
  if [ "${ARG#@}" != "$ARG" ]; then
    ARGTAGS="${ARGTAGS:+$ARGTAGS }$ARG"
  else
    INPUT="${INPUT:+$INPUT }$ARG"
  fi
done

if [ "$SCRIPTNAME" = "todo" ]; then
  do_todo
elif [ "$SCRIPTNAME" = "todone" ]; then
  do_todone
elif [ "$SCRIPTNAME" = "todone-archive" ]; then
  do_todone_archive
elif [ "$SCRIPTNAME" = "todone-view" ]; then
  do_todone_view
else
  printf "Error: this is a multicall script, but was called with unrecognised script name '%s'\n" "$SCRIPTNAME" >&2
  exit 1
fi