dotfiles/.local/bin/slatectx-get-context-name

#!/bin/bash

set -e

XDG_CONFIG_HOME="${XDG_CONFIG_HOME:-$HOME/.config}"

# Derive name from the session type

get_from_session() {
	SESSION_TYPE="$(slatectx-guess-session-type)"

	case "$SESSION_TYPE" in
		wayland)
			printf "y%s-%s\n" "$( printf "%s" "$WAYLAND_DISPLAY" | sed 's/^wayland-//' )" "$(slatectx-get-workspace)" ;;
		x11)
			printf "x%s-%s\n" "$( printf "%s" "$WAYLAND_DISPLAY" | sed 's/^://' )" "$(slatectx-get-workspace)" ;;
		tmux)
			printf "t-%s\n" "$( printf "%s" "$TMUX" | awk -F, '{ print $2 }' )" ;;
		xdg-*)
			printf "%s-%s\n" "$SESSION_TYPE" "$XDG_SESSION_ID" ;;
		*)
			printf "%s\n" "$SESSION_TYPE";;
	esac
}

get_label_from_path() {
	cat "$XDG_CONFIG_HOME/slatectx/ctx-from-path.rules" "$XDG_CONFIG_HOME/slatectx/ctx-from-path.$(hostname).rules" 2>&- | \
	grep -v '^#' | \
	awk -v "here=${1/#$HOME/\~}" '{ match(here, $0, out); if (out[1]) { name=out[1] ; for ( i=2; out[i] ; i++) { name = name "///" out[i] } ; print name ; exit 0 } }'
}

shorten() {
	# This is not supposed to see untrusted data
	# it must be fast and produce a short output
	md5sum | sed -E 's/(.{8}).*/_\1/'
}

show_help() {
	cat <<EOF
Usage: slatectx-get-context-name [auto|by-session|by-path] [options...]

slatectx-get-context-name derives an identifier for a slatetx context based on the current envoirenment.

The context name can be based on the current session and workspace or on the current path (either the real pwd or slatectx-pwd).

COMMANDS:
	Note, that only one of them can be used,
	if multiple are specified the last one is used and others are ignored
	
	by-session
		Only derive the context name from the current session.
		
	by-path
		Only derive the context name from the given path (defaults to the pwd).
		Will return an empty result if the given path does not map to a context name.
		
	auto
		The current default, will try deriving a context name
		from the session and then use that information with
		slatectx-pwd to get a more specific by path context.
		If the path lookup fails, it falls back to a by-session.

OPTIONS:
	--not-by-path
		Avoids path information for context name derivation.
		Used by slatectx-pwd. Currently equivalent to by-session

	--not-by-session
		Avoids the session information for context name derivation.

	--path <path>
		Manually give a path to be used instead of one derived from
		the pwd or slatectx-pwd

	--label
		Itended for debugging.
		Instead of hashing, print out the cleartext label,
		derived from the path.
		Do NOT use this for identifying contexts.

	--no-override
		Disable the SLATECTX_CONTEXT_NAME envoirenment variable.
		Do NOT turn this off when using this command for figuring out the
		current context.
		The intention behind this option is to make the logic in this script
		useable for more sophisticated scripts operting across contexts.

CONFIGURATION FILES:

	Note: \$XDG_CONFIG_HOME is usually your ~/.config

	\$XDG_CONFIG_HOME/slatectx/ctx-from-path.rules
	\$XDG_CONFIG_HOME/slatectx/ctx-from-path.<hostname>.rules
		These files contain one (awk) regex per line.
		When a regex matches the caputure groups will be
		joined together to form a label for the context.
		(which will be hashed to keep them in a resonable
		length with known save characters)
		Lines starting with a # will be treated as comments.

		Examples:
		# A ~/Notes folder gets its own context
		(^~/Notes)
		# Some folders in our \$HOME have a context for each subfolder
		^~/(Development|Documents|Experiments)/([^/*]*)
	
ENVOIRNMENT:
	SLATECTX_CONTEXT_NAME
		if set its contents will be returned
		This behaviour can be disabled with the --no-override option.
	
EOF
}

COMMAND="auto"
PATH_ARG="$PWD"
GET_LABEL=""
USE_SLATECTX_PWD="y"

while [[ "$#" -gt 0 ]]; do
	case "$1" in
		by-session|--not-by-path) COMMAND="from-session"; shift 1;;
		by-path|--not-by-session) COMMAND="from-path"; shift 1;;
		auto) COMMAND="auto"; shift 1;;

		--no-override) SLATECTX_CONTEXT_NAME=""; shift 1;;

		--label) GET_LABEL="y"; shift 1;;

		--path) PATH_ARG="$2"; USE_SLATECTX_PWD=""; shift 2;;
		
		--help) show_help; exit 0;;
		*) printf "Unknown option: %s\n" "$1" >&2; exit 1;;
	esac
done

# If we already have a context name from the envoirenment, return it

if [ -n "$SLATECTX_CONTEXT_NAME" ]; then
	printf "%s\n" "$SLATECTX_CONTEXT_NAME"
	exit 0
fi

PATH_ARG="$(realpath "${PATH_ARG/#~/$HOME}" 2>&-)"

case "$COMMAND" in
	from-session) get_from_session ;;
	from-path)
		LABEL="$(get_label_from_path "$PATH_ARG")"
		if [[ -n "$GET_LABEL" ]] || [[ -z "$LABEL" ]] ; then
			printf "%s\n" "$LABEL"
		else
			printf "%s" "$LABEL" | shorten
		fi
	;;
	auto)
		SLATECTX_CONTEXT_NAME="$(get_from_session)"
		[ -n "$USE_SLATECTX_PWD" ] && PATH_ARG="$(slatectx-pwd get --context "$SLATECTX_CONTEXT_NAME" || true)"
		if [ -n "$PATH_ARG" ] && [ -d "$PATH_ARG" ]; then
			PWD_LABEL="$(get_label_from_path "$PATH_ARG")"
			if [ -n "$PWD_LABEL" ]; then
				if [ -n "$GET_LABEL" ] ; then
					printf "%s\n" "$PWD_LABEL"
				else
					printf "%s" "$PWD_LABEL" | shorten
				fi
				exit
			fi
		fi
		printf "%s\n" "$SLATECTX_CONTEXT_NAME"
	;;
esac