logbook

#!/bin/bash
#
# simple logbook aka journal aka work logger for lazy hoomans
#
set -e
PROG=${0##*/}
_err() { echo -e "$PROG:" "$@" >&2 ; exit 1; }

_default_editor() {
  if [ -z "$EDITOR" ]; then
    command -v ed >/dev/null && EDITOR=ed
    [ -z "$EDITOR" ] && command -v nano >/dev/null && EDITOR=nano
    [ -z "$EDITOR" ] && command -v vi >/dev/null && EDITOR=vi
    [ -z "$EDITOR" ] && _err "EDITOR is not set"
  fi
  case "$EDITOR" in
    "subl "*|*"/subl "|subl|*"/subl")
      # set cursor to end of file in sublime
      case "$EDITOR" in
        *"{}"*) ;;
        *) EDITOR="$EDITOR \"{}:999999\"" ;;
      esac
      ;;
  esac
  echo $EDITOR
}

_default_reader() {
  PAGER=${PAGER:-less}
  if [ "$PAGER" = less ]; then
    PAGER="$PAGER -I -K -s --tilde"
  fi
  echo "$PAGER"
}

LOGFILE=
LOGDIR=
LOGDIR_NAME=${LOGBOOK_LOGDIR_NAME:-.logbook}
DEFAULT_LOGDIR=${LOGBOOK_DEFAULT_LOGDIR:-~/$LOGDIR_NAME}
LOGFILE_PATTERN=${LOGBOOK_LOGFILE_PATTERN:-"%Y-%m-%d.md"}
EDIT_CMD=${LOGBOOK_EDIT_CMD:-$(_default_editor)}
READ_CMD=${LOGBOOK_READ_CMD:-$(_default_reader)}
GREP_CMD=${LOGBOOK_GREP_CMD:-grep -i -R -F --color}
USE_DEFAULT_LOGDIR=true
UTC=false
COMMAND=

_need2() { [ -z "$2" ] && _err "missing value for $1"; }

while [ $# -gt 0 ]; do case "$1" in
  -h|-help|--help|help) cat << _END
Simple journaling for lazy hoomans.
Usage:
  $PROG [options] [edit]             # Edit today's entry
  $PROG [options] edit [<entry>]     # Edit today's entry or specific entry
  $PROG [options] read [<entry>]     # Read today's entry or specific entry
  $PROG [options] add [--] <s>...    # Append line <s>... to today's entry
  $PROG [options] ls                 # List entries
  $PROG [options] grep <greparg>...  # Search entries
  $PROG [options] logdir             # Print path of log directory
  $PROG [options] logfile            # Print path of today's entry
Options:
  -C <dir>     Use <dir> as log directory (instead of searching for it.)
  -f <file>    Use <file> as log entry (instead of automatically selecting one.)
  -P <pattern> Set and override LOGBOOK_LOGFILE_PATTERN.
  -E <cmd>     Set and override LOGBOOK_EDIT_CMD.
  -D <dir>     Set and override LOGBOOK_DEFAULT_LOGDIR.
  -utc         Use log-entry filenames based on UTC instead of local time.
  -no-default  Do not fall back to LOGBOOK_DEFAULT_LOGDIR if log dir was not found.
  -h, -help    Show help on stdout and exit.
Environment variables:
  LOGBOOK_LOGDIR_NAME ($LOGDIR_NAME)
    Name of logbook directories
  LOGBOOK_DEFAULT_LOGDIR (${DEFAULT_LOGDIR/$HOME/~})
    Directory to use for log entires when logbook is invoked outside of
    a directory with a LOGBOOK_LOGDIR_NAME directory.
  LOGBOOK_LOGFILE_PATTERN ($LOGFILE_PATTERN)
    Filename pattern to use for log files, passed to the "date" program.
    See \`date --help\` for info on possible patterns.
  LOGBOOK_EDIT_CMD ($EDIT_CMD)
    Command invoked to edit a log entry. Substitutes "{}" for the log file.
    If "{}" is not present, passes the log file as an argument.
  LOGBOOK_READ_CMD ($READ_CMD)
    Command invoked to read a log entry. Substitutes "{}" for the log file.
    If "{}" is not present, passes the log file as an argument.
  LOGBOOK_GREP_CMD ($GREP_CMD)
    Command invoked to search a log directory. Substitutes "{}" for the log
    directory. Runs in the log directory as working directory.
Examples:
  Edit today's entry:
    $PROG
  Append a line to today's entry:
    $PROG add Bought cat food
  Keep logs per week instead of per day:
    export LOGBOOK_LOGFILE_PATTERN="%Y-week_%U.txt"
  Edit logs in a macOS application:
    export LOGBOOK_EDIT_CMD="open -a TextEdit"
_END
    exit ;;
  -f)          _need2 "$@"; LOGFILE=$2; shift; shift ;;
  -C)          _need2 "$@"; LOGDIR=$2; shift; shift ;;
  -P)          _need2 "$@"; LOGBOOK_LOGFILE_PATTERN=$2 ; shift; shift ;;
  -E)          _need2 "$@"; LOGBOOK_EDIT_CMD=$2 ; shift; shift ;;
  -D)          _need2 "$@"; LOGBOOK_DEFAULT_LOGDIR=$2 ; shift; shift ;;
  -utc)        UTC=true; shift ;;
  -no-default) USE_DEFAULT_LOGDIR=false; shift ;;
  --)          shift ; break ;;
  -*)          _err "unknown option: $1" ;;
  *)
    [ -z "$COMMAND" ] || break
    COMMAND=$1; shift
    [ "$COMMAND" = grep ] && break
    ;;
esac; done


# extract file extension from LOGFILE_PATTERN
FILEEXT=$(basename "$LOGFILE_PATTERN")
FILEEXT=${FILEEXT##*.}
[ -n "$FILEEXT" ] && FILEEXT=.$FILEEXT


_find_logdir() {
  LOGDIR=$PWD
  while true; do
    [ -z "$LOGDIR" -o -d "$LOGDIR/$LOGDIR_NAME" ] && break
    LOGDIR=${LOGDIR%/*}  # shave off last path component
  done
  if [ -d "$LOGDIR/$LOGDIR_NAME" ]; then
    LOGDIR=$LOGDIR/$LOGDIR_NAME
  else
    # expand tilde in DEFAULT_LOGDIR
    case "$DEFAULT_LOGDIR" in
      ~/*) DEFAULT_LOGDIR=${DEFAULT_LOGDIR/~/$HOME} ;;
    esac
    if $USE_DEFAULT_LOGDIR && [ -d "$DEFAULT_LOGDIR" ]; then
      LOGDIR=$DEFAULT_LOGDIR
    else
      cat <<EOF >&2
$PROG: No log directory found.
I looked for a directory named "$LOGDIR_NAME" in the current directory and its parents.
EOF
      $USE_DEFAULT_LOGDIR &&
        echo "(Default directory \"${DEFAULT_LOGDIR/$HOME/~}\" does not exist.)" >&2
      exit 1
    fi
  fi
}


_logfile() {
  local DATECMD=date
  $UTC && DATECMD="$DATE_ARGS -u"
  $DATECMD "+$LOGFILE_PATTERN"
}


_logfile_name() {
  basename "$1" "$FILEEXT"
}


_cmd_ls() {
  [ -z "$1" ] || _err "unexpected extra argument: $1"

  # determine TTY size
  local TERMSIZE COLS
  TERMSIZE=$(stty size 2>/dev/null || true)
  if [ -n "$TERMSIZE" ]; then
    #ROWS=${TERMSIZE% *}
    COLS=${TERMSIZE#* }
  fi
  COLS=${COLS:-60}

  local f excerpt excerptlen namelen name files

  namelen=0
  files=()
  for f in "$LOGDIR"/*$FILEEXT; do
    files+=( "$f" )
    name=$(basename "$f" "$FILEEXT")
    [ ${#name} -gt $namelen ] && namelen=${#name}
  done

  # max length of excerpt (-3 for 2 spaces + …)
  excerptlen=$(expr $COLS - $namelen - 3)

  for f in "${files[@]}"; do
    name=$(basename "$f" "$FILEEXT")
    excerpt=$(head -n3 "$f")
    excerpt=${excerpt/
/" "}
    if [ ${#excerpt} -ge $excerptlen ]; then
      excerpt=$(echo "$excerpt" | head -c$excerptlen)"…"
    fi
    printf "%-*s  %s\n" $namelen "$name" "$excerpt"
  done
}


_cmd_edit() {
  [ -z "$2" ] || _err "unexpected extra argument: $2"
  [ -n "$1" ] && LOGFILE=$LOGDIR/${1}$FILEEXT
  case "$EDIT_CMD" in
    *"{}"*)
      EDIT_CMD=${EDIT_CMD/\{\}/"$LOGFILE"}
      eval "exec $EDIT_CMD"
      ;;
    *)
      exec $EDIT_CMD "$LOGFILE"
      ;;
  esac
}


_cmd_read() {
  [ -z "$2" ] || _err "unexpected extra argument: $2"
  [ -n "$1" ] && LOGFILE=$LOGDIR/${1}$FILEEXT

  local NAME=$(basename "$(dirname "$LOGDIR")")
  [ -n "$NAME" ] && NAME=$NAME/
  NAME=$NAME$(_logfile_name "$LOGFILE")

  local ARGS=()
  case "$READ_CMD" in
    "less "*|*"/less "|less|*"/less")
      ARGS+=( "-Ps$NAME" ) ;;
  esac

  case "$READ_CMD" in
    *"{}"*)
      READ_CMD=${READ_CMD/\{\}/"$LOGFILE"}
      eval "exec $READ_CMD ${ARGS[@]}"
      ;;
    *)
      exec $READ_CMD "${ARGS[@]}" "$LOGFILE"
      ;;
  esac
}


_cmd_grep() {
  cd "$LOGDIR"
  case "$GREP_CMD" in
    *"{}"*)
      GREP_CMD=${GREP_CMD/\{\}/"$LOGDIR"}
      eval "exec $GREP_CMD $@"
      ;;
    *)
      exec $GREP_CMD $@ *$FILEEXT
      ;;
  esac
}


_cmd_append() {
  [ $# -gt 0 ] || _err "no message to append"
  if [ $(tail -c1 "$LOGFILE"|wc -l) = "0" ]; then
    # no newline at end
    echo >> "$LOGFILE"
  fi
  echo "$@" >> "$LOGFILE"
  echo "Added message to $(_logfile_name "$LOGFILE")"
}


_cmd_logdir() {
  [ -z "$1" ] || _err "unexpected extra argument: $1"
  echo "$LOGDIR"
}


_cmd_logfile() {
  [ -z "$1" ] || _err "unexpected extra argument: $1"
  echo "$LOGFILE"
}


# sort out LOGDIR and LOGFILE
if [ -z "$LOGFILE" ]; then
  [ -z "$LOGDIR" ] && _find_logdir
  LOGFILE=$LOGDIR/$(_logfile)
else
  LOGDIR=$(dirname "$LOGFILE")
fi
[ -e "$LOGDIR" ] || _err "log directory \"$LOGDIR\" does not exist"
[ -d "$LOGDIR" ] || _err "log directory \"$LOGDIR\" is not a directory"
# echo "LOGFILE $LOGFILE"
# echo "LOGDIR  $LOGDIR"

# Create directories, in case LOGFILE_PATTERN contains subdirectories.
# Note that _find_logdir already checked that LOGDIR exists.
mkdir -pv "${LOGFILE%/*}"

# call
case "$COMMAND" in
  e|ed|edit|"")  _cmd_edit "$@" ;;
  a|add|append)  _cmd_append "$@" ;;
  l|ls|list)     _cmd_ls "$@" ;;
  r|read|cat)    _cmd_read "$@" ;;
  g|grep|search) _cmd_grep "$@" ;;
  logfile)       _cmd_logfile "$@" ;;
  logdir)        _cmd_logdir "$@" ;;
  *)             _err "unrecognized command: $COMMAND" ;;
esac