Determine monitor in better way on bspwm and i3

Addresses #3

This ensures that -m will work even when the focused workspace on a
monitor is empty.

tdrop

@@ -146,25 +146,44 @@ update_geometry_settings_for_monitor() {
 	#    monitor IF the monitor has changed since the last time the dropdown
 	#    was used
 
-	# determine curent monitor
-	wininfo=$(xwininfo -id "$(xdotool getactivewindow)")
-	window_x=$(echo "$wininfo" | awk '/Absolute.*X/ {print $4}')
-	window_y=$(echo "$wininfo" | awk '/Absolute.*Y/ {print $4}')
-	monitors_info=$(xrandr --query | awk '/ connected/ {gsub("primary ",""); print}')
-	while read -r monitor; do
-		monitor_geo=$(echo "$monitor" | awk '{print $3}')
+	# it is conceivable that a user may want to use -m but not -a, so
+	# get the wm from with
+	# in this function
+	wm=$(get_window_manager)
+	if [[ $wm == bspwm ]]; then
+		current_monitor=$(bspc query -m -M)
+	elif [[ $wm == i3 ]]; then
+		# I'd rather not make jq a dependency
+		current_monitor=$(i3-msg -t get_workspaces | sed 's/{"num"/\n/g' | awk -F ',' '/focused":true/ {sub(".*output",""); gsub("[:\"]",""); print $1}')
+	fi
+
+	if [[ -n $current_monitor ]]; then
+		monitor_geo=$(xrandr --query | awk "/$current_monitor/ {gsub(\"primary \",\"\"); print \$3}")
 		x_begin=$(echo "$monitor_geo" | awk -F '+' '{print $2}')
 		y_begin=$(echo "$monitor_geo" | awk -F '+' '{print $3}')
 		x_width=$(echo "$monitor_geo" | awk -F 'x' '{print $1}')
 		y_height=$(echo "$monitor_geo" | awk -F 'x|+' '{print $2}')
-		x_end=$((x_begin+x_width))
-		y_end=$((y_begin+y_height))
-		if [[ $window_x -ge $x_begin ]] && [[ $window_x -lt $x_end ]] && \
-			[[ $window_y -ge $y_begin ]] && [[ $window_y -lt $y_end ]]; then
-			current_monitor=$(echo "$monitor" | awk '{print $1}')
-			break
-		fi
-	done <<< "$monitors_info"
+	else
+		# determine current monitor in generic (hacky) way
+		wininfo=$(xwininfo -id "$(xdotool getactivewindow)")
+		window_x=$(echo "$wininfo" | awk '/Absolute.*X/ {print $4}')
+		window_y=$(echo "$wininfo" | awk '/Absolute.*Y/ {print $4}')
+		monitors_info=$(xrandr --query | awk '/ connected/ {gsub("primary ",""); print}')
+		while read -r monitor; do
+			monitor_geo=$(echo "$monitor" | awk '{print $3}')
+			x_begin=$(echo "$monitor_geo" | awk -F '+' '{print $2}')
+			y_begin=$(echo "$monitor_geo" | awk -F '+' '{print $3}')
+			x_width=$(echo "$monitor_geo" | awk -F 'x' '{print $1}')
+			y_height=$(echo "$monitor_geo" | awk -F 'x|+' '{print $2}')
+			x_end=$((x_begin+x_width))
+			y_end=$((y_begin+y_height))
+			if [[ $window_x -ge $x_begin ]] && [[ $window_x -lt $x_end ]] && \
+				[[ $window_y -ge $y_begin ]] && [[ $window_y -lt $y_end ]]; then
+				current_monitor=$(echo "$monitor" | awk '{print $1}')
+				break
+			fi
+		done <<< "$monitors_info"
+	fi
 
 	# update x and y offsets, so that will appear on correct screen
 	# (required for some WMs apparently, but not for others)