path: root/session.bash

# session.bash - A session management script for Bash
# Copyright (C) 2021, 2022 Soni L.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

# note: consider adding the following to your PS1:
PS1='{$([[ "${HISTFILE#~/.bash_history.}" != "$HISTFILE" ]] && printf "@ " || printf "/ ")${HISTFILE#~/.bash_history.}} '"$PS1"

if [[ "$HISTFILE" = ~/.bash_history ]]; then
	HISTFILE="$HISTFILE".default
fi

# simple interface to history/"session" management
# usage: session <name>
# switches HISTFILE to ~/.bash_history.<name>
session() {
	local session sessioncwd sessionflags
	if [[ "$1" =~ ^[a-z][a-z0-9]*$ ]]; then
		if [[ "${HISTFILE#~/.bash_history.}" != "$HISTFILE" ]]; then
			session="${HISTFILE#~/.bash_history.}"
			sessioncwd="$(grep -s ' # '"$session"'$' ~/.bash_session_cwd | tail -n 1)"
			sessionflags="${sessioncwd% # *}"
			sessionflags="${sessionflags##* # }"
			if (eval "$sessionflags" && test -v NOHIST); then
				history -c
			fi
		fi
		# remove session switch from history
		history -d -1 >/dev/null 2>/dev/null || true
		# write/append history
		if shopt -q histappend; then history -a; else history -w; fi
		# clear history
		history -c
		# set HISTFILE
		HISTFILE=~/.bash_history."$1"
		# load new session's history
		history -r
		# see setsessioncwd()
		eval "$(grep -s ' # '"$1"'$' ~/.bash_session_cwd | tail -n 1)"
	else
		echo "invalid session"
		false
	fi
}

# NOHIST handling - clear history on session exit
# FIXME: what happens if another plugin wants to hook EXIT?! (they get replaced/overridden - this could be a problem)
trap '
	if [[ "${HISTFILE#~/.bash_history.}" != "$HISTFILE" ]]; then
		session="${HISTFILE#~/.bash_history.}"
		sessioncwd="$(grep -s '\'' # '\''"$session"'\''$'\'' ~/.bash_session_cwd | tail -n 1)"
		sessionflags="${sessioncwd% # *}"
		sessionflags="${sessionflags##* # }"
		if (eval "$sessionflags" && test -v NOHIST); then
			history -c
		fi
	fi
' exit
# setup completion for session(), using only builtins
complete -C 'source <(printf "%s" '\''
	set -- ~/.bash_history."$2"*
	flag=0
	[[ -e "$1" ]] && for f in "${@#~/.bash_history.}" ; do
		if [[ "$f" =~ ^[a-z][a-z0-9]*$ ]] ; then
			((flag)) && printf "\n"
			printf "%s" "$f"
			flag=1
		fi
	done
'\'')' session

# sets the current cwd as the default cwd for the session
setsessioncwd() {
	local session
	# guard against relative HISTFILE
	if [[ "${HISTFILE#~/.bash_history.}" != "$HISTFILE" ]]; then
		session="${HISTFILE#~/.bash_history.}"
		if [[ "$session" =~ ^[a-z][a-z0-9]*$ ]]; then
			printf 'cd %q # %s\n' "$PWD" "$session" >>~/.bash_session_cwd
		else
			echo "invalid session"
			false
		fi
	else
		echo "invalid session"
		false
	fi
}

# saves the current working directory into the current history.
# does NOT save to the history *file*.
savecwd() {
	history -s "$(printf 'cd %q' "$PWD")"
}

echo "session.bash  Copyright (C) 2021, 2022 Soni L."
echo "SPDX-License-Identifier: AGPL-3.0-or-later."
echo "This software is made with love by a queer trans person."