1 files changed, 132 insertions, 0 deletions
diff --git a/desktop/modules/status/statusctl b/desktop/modules/status/statusctl
new file mode 100755
index 0000000..6fbb689
--- /dev/null
+++ b/desktop/modules/status/statusctl
@@ -0,0 +1,132 @@
+#!/bin/bash
+#
+# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+# 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 General Public License for more details.
+#
+# Read, set and watch desktop modes. The modes are files under
+# XDG_RUNTIME_DIR holding 0 or 1; a missing file means off.
+#
+# This talks to the files, not to the shell, so it works while quickshell is
+# down. Setting a mode that way records the state without firing its effects;
+# the shell sees the change through its own watch and reasserts them.
+#
+#   statusctl <mode> get          prints 0 or 1
+#   statusctl <mode> set 0|1
+#   statusctl <mode> toggle
+#   statusctl <mode> watch        waybar JSON on every change
+
+set -u
+
+MODES="dnd presentation"
+DIR="${XDG_RUNTIME_DIR:-/tmp}"
+
+usage() {
+    printf 'usage: %s <%s> <get|set 0|1|toggle|watch>\n' \
+           "${0##*/}" "$(printf '%s' "$MODES" | tr ' ' '|')" >&2
+    exit 1
+}
+
+[[ $# -ge 2 ]] || usage
+
+mode="$1"
+action="$2"
+
+# A typo must fail loudly rather than read as a mode that happens to be off.
+case " $MODES " in
+    *" $mode "*) ;;
+    *) printf '%s: unknown mode: %s\n' "${0##*/}" "$mode" >&2; exit 1 ;;
+esac
+
+file="$DIR/status.$mode"
+
+read_mode() {
+    local v=""
+    # A missing file is the normal state before anything has written one and
+    # reads as off. Guarding on existence keeps the shell's redirection error
+    # off stderr: `2>/dev/null` on the command cannot suppress a failure of
+    # its own input redirect.
+    [[ -e "$file" ]] && v="$(tr -d '[:space:]' < "$file" 2>/dev/null)"
+    [[ "$v" == "1" ]] && printf '1' || printf '0'
+}
+
+# Write through a temporary file and rename, so no reader ever sees a
+# half-written value. This is also what FileView does on the QML side, and it
+# is why a watcher has to listen for moved_to as well as close_write.
+write_mode() {
+    local want="$1" tmp
+    tmp="$(mktemp "$DIR/.status.$mode.XXXXXX")" || exit 1
+    printf '%s\n' "$want" > "$tmp"
+    # The temp file is made in the same directory as the target, so this is a
+    # rename rather than a copy, and therefore atomic. A failure here has to
+    # be loud: reporting success on a write that did not land would leave the
+    # caller and the shell disagreeing about the mode, with an orphan temp
+    # file as the only trace.
+    mv -f "$tmp" "$file" || { rm -f "$tmp"; exit 1; }
+}
+
+emit() {
+    local state="$1"
+    printf '{"text": "", "alt": "%s", "class": "%s", "tooltip": "%s"}\n' \
+           "$state" "$state" "$(tooltip "$state")"
+}
+
+tooltip() {
+    case "$1" in
+        activated)   printf '%s: on' "$mode" ;;
+        deactivated) printf '%s: off' "$mode" ;;
+        down)        printf '%s: no state file' "$mode" ;;
+    esac
+}
+
+state_now() {
+    [[ -e "$file" ]] || { printf 'down'; return; }
+    [[ "$(read_mode)" == "1" ]] && printf 'activated' || printf 'deactivated'
+}
+
+case "$action" in
+    get)
+        read_mode
+        printf '\n'
+        ;;
+    set)
+        [[ $# -eq 3 ]] || usage
+        case "$3" in
+            0|1) write_mode "$3" ;;
+            *) usage ;;
+        esac
+        ;;
+    toggle)
+        [[ "$(read_mode)" == "1" ]] && write_mode 0 || write_mode 1
+        ;;
+    watch)
+        emit "$(state_now)"
+        # Watch the directory rather than the file: an atomic write replaces
+        # the file, so a watch held on the old inode dies with it. This is the
+        # same trap the mail watcher hit with Xapian.
+        #
+        # inotifywait must die with us. Piped straight into the while loop it
+        # would be a pipeline sibling, not a child, so a plain kill on this
+        # process (which is exactly how waybar stops and respawns its exec
+        # children on every reload) leaves it running, watching a directory
+        # nobody reads anymore. Process substitution makes it a real child
+        # whose PID we can hold and kill from a trap.
+        exec 3< <(inotifywait -q -m -e close_write,moved_to,delete --format '%f' "$DIR" 2>/dev/null)
+        watcher=$!
+        trap 'kill "$watcher" 2>/dev/null' EXIT TERM INT
+        while read -r changed <&3; do
+            [[ "$changed" == "status.$mode" ]] || continue
+            emit "$(state_now)"
+        done
+        ;;
+    *)
+        usage
+        ;;
+esac