Focus next window in Sway

sway-focus-next.sh

# ====================================================================================== #
# Focus the next window on the current workspace in sway, e.g. for binding to Alt+Tab    #
# Depends: jq, sway                                                                      #
# License: AS IS                                                                         #
# Heavily inspired by i3 version https://gist.github.com/Nervengift/0ab9e6127ac17b8317ac #
# ====================================================================================== #
ws=$(swaymsg -t get_workspaces|jq "map(select(.focused))[]|.name")
windows=$(swaymsg -t get_tree|jq ".nodes|map(.nodes[])|map(select(.type==\"workspace\" and .name==$ws))[0]|[recurse(.nodes[])|select(.layout==\"none\")]|map({id: .id, focused: .focused})")

# https://stackoverflow.com/questions/53135035/jq-returning-null-as-string-if-the-json-is-empty
current=$(echo $windows | jq ".[]|select(.focused).id // empty")

if [[ -n $current ]]; then
  first=$(echo $windows | jq ".[0]|select(.focused==false).id")
  after=$(echo $windows | jq 'map(.id, if .focused then "F" else "" end) | join(" ") | split(" F") | last | split(" ") | map(select(. != "")) | first // empty')

  if [[ -n $after ]]; then
    next=$after
  else
    next=$first
  fi
  # Note, con_id, not "id". See: https://github.com/swaywm/sway/issues/4972#issuecomment-582213301
  swaymsg "[con_id=$next]" focus > /dev/null
fi