add zsh completion script (#150)

scripts/completion_bash.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+# Copyright 2019 Mike Fährmann
+#
+# 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.
+
+"""Generate bash completion script from gallery-dl's argument parser"""
+
+import util
+from gallery_dl import option
+
+
+TEMPLATE = """_gallery_dl()
+{
+    local cur prev
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+
+    if [[ "${prev}" =~ ^(%(fileopts)s)$ ]]; then
+        COMPREPLY=( $(compgen -f -- "${cur}") )
+    elif [[ "${prev}" =~ ^(%(diropts)s)$ ]]; then
+        COMPREPLY=( $(compgen -d -- "${cur}") )
+    else
+        COMPREPLY=( $(compgen -W "%(opts)s" -- "${cur}") )
+    fi
+}
+
+complete -F _gallery_dl gallery-dl
+"""
+
+opts = []
+diropts = []
+fileopts = []
+for action in option.build_parser()._actions:
+
+    if action.metavar in ("DEST",):
+        diropts.extend(action.option_strings)
+
+    elif action.metavar in ("FILE", "CFG"):
+        fileopts.extend(action.option_strings)
+
+    for opt in action.option_strings:
+        if opt.startswith("--"):
+            opts.append(opt)
+
+PATH = util.path("data/completion/gallery-dl")
+with open(PATH, "w", encoding="utf-8") as file:
+    file.write(TEMPLATE % {
+        "opts"    : " ".join(opts),
+        "diropts" : "|".join(diropts),
+        "fileopts": "|".join(fileopts),
+    })