feat: add bash completionHEADmaster

Completes the flags, and directories for --archive-dir in both the
--opt value and --opt=value forms. --target offers only "me": real chat
handles would need a network round-trip inside a tab press, and
--list-chats already answers that question.

Installed by hand, nothing automates it. A new flag has to be added to
opts in the completion as well.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/tg_backup.bash-completion b/tg_backup.bash-completion
new file mode 100644
index 0000000..5aca64f
--- /dev/null
+++ b/tg_backup.bash-completion
@@ -0,0 +1,39 @@
+#   bash completion for tg_backup.py
+#
+#   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.
+
+_tg_backup() {
+    local cur prev opts
+    cur=${COMP_WORDS[COMP_CWORD]}
+    prev=${COMP_WORDS[COMP_CWORD-1]}
+    opts="--target --archive-dir --list-chats --force-target --self-check --help"
+
+    # --archive-dir takes a directory. Handles both "--archive-dir <tab>" and
+    # the --opt=value form, where bash leaves the = in prev.
+    case $prev in
+        --archive-dir)
+            _filedir -d
+            return
+            ;;
+    esac
+    if [[ $cur == --archive-dir=* ]]; then
+        cur=${cur#--archive-dir=}
+        _filedir -d
+        return
+    fi
+
+    # --target is a chat: no local source of completions without hitting the
+    # network, so offer only the one value that is not chat-specific.
+    if [[ $prev == --target || $cur == --target=* ]]; then
+        [[ $cur == --target=* ]] && cur=${cur#--target=}
+        COMPREPLY=($(compgen -W "me" -- "$cur"))
+        return
+    fi
+
+    COMPREPLY=($(compgen -W "$opts" -- "$cur"))
+}
+complete -F _tg_backup tg_backup.py tg_backup