add the switcher script

switcher.sh

@@ -0,0 +1,123 @@
+#!/usr/bin/env bash
+
+if test "$BASH" = "" || "$BASH" -uc "a=();true \"\${a[@]}\"" 2>/dev/null; then
+    # Bash 4.4, Zsh
+    set -euo pipefail
+else
+    # Bash 4.3 and older chokes on empty arrays with set -u.
+    set -eo pipefail
+fi
+shopt -s nullglob globstar
+
+app_name=${1:-}
+direction=${2:-next}
+
+function echo_help {
+    echo "Usage: $0 window_class [direction]"
+    echo "Focuses one of the opened windows with the passed window_class on the condition of i3wm being currently running."
+    echo "If the window of such class is already focused, then another one will be focused, appropriate to the passed direction."
+    echo " window_class is a Window Manager window class"
+    echo " direction denotes which window should be focused; possible values are next or previous, next being the default."
+    echo ""
+    echo "Examples:"
+    echo " $0 Firefox"
+    echo " $0 Firefox previous"
+    echo " $0 Code previous"
+}
+
+if [ -z "$I3SOCK" ]
+then
+    echo "i3wm is not running"
+    exit 127
+fi
+
+if [ "$app_name" = '-h' ] || [ "$app_name" = '--help' ]
+then
+    echo_help
+    exit 0
+fi
+
+# Check if the app name was passed and if not show an error to the user
+if [ -z "$app_name" ]
+then
+    echo "You need to pass an app name as the first param!"
+    exit 1
+fi
+
+# Check if the direction is a valid argument
+if [ "$direction" != 'next' ] && [ "$direction" != 'previous' ]
+then
+    echo "Invalid direction passed! Expected 'next' or 'previous'."
+    exit 2
+fi
+
+# Check if i3-msg is installed also silencing all of the output
+if ! command -v i3-msg >/dev/null
+then
+    echo "i3-msg is needed for this script to work!"
+    exit 3
+fi
+
+# Check if jq is installed also silencing all of the output
+if ! command -v jq >/dev/null
+then
+    echo "jq is needed for this script to work!"
+    exit 3
+fi
+
+# Get all the opened windows
+all_windows=$(i3-msg -t get_tree | jq ".nodes | map(.nodes[]) | map(.nodes[]) | map(recurse(.nodes[]))[] | select(.window_properties != null)")
+# Get all of the windows that belong to the $app_name
+app_windows=$(echo "$all_windows" | jq "select(.window_properties.class == \"$app_name\")")
+
+# Check if any windows were found and exit if not.
+if [ -z "$app_windows" ]
+then
+    echo "No windows for said app found"
+    exit 4
+fi
+
+# From now on I drop the app_ prefix in the variable naming schema, since variables will refer to
+# app windows only.
+mapfile -t windows_ids < <(echo "$app_windows" | jq '.id')
+windows_count=${#windows_ids[@]}
+windows_count=$(((windows_count - 1)))
+
+focused_window_id=$(echo "$app_windows" | jq "select(.focused == true) | .id")
+if [ -n "$focused_window_id" ]
+then
+    # The app is already focused, so we need to focus its next/previous instance
+    for focused_index in "${!windows_ids[@]}"
+    do
+        # Current ID is that of the focused window, just break to save the index and go on.
+        if [ "$focused_window_id" = "${windows_ids[$focused_index]}" ]
+        then
+            break;
+        fi
+    done
+else
+    # The app is not focused yet, so we need to do some hackery! Since we do some calculations and
+    # bounds checking below, -1 is appropriate here.
+    # If the user wants the next window, then the first one is appropriate.
+    # If they want a previous one, then the last one will be used.
+    focused_index=-1
+fi
+
+if [ "$direction" = "next" ]
+then
+    new_focused_index=$(((focused_index + 1)))
+else
+    new_focused_index=$(((focused_index - 1)))
+fi
+
+if [ "$new_focused_index" -gt "$windows_count" ]
+then
+    # The calculated index is bigger than the windows count, so wrap around, wrap around my child!
+    new_focused_index=0
+elif [ "$new_focused_index" -lt 0 ]
+then
+    # Same as above, but this time wrap around backwards.
+    new_focused_index=$windows_count
+fi
+
+i3-msg "[con_id=\"${windows_ids[$new_focused_index]}\"] focus"