support zsh completion

devscripts/zsh-completion.in

@@ -0,0 +1,28 @@
+#compdef youtube-dl
+
+__youtube_dl() {
+    local curcontext="$curcontext" fileopts diropts cur prev
+    typeset -A opt_args
+    fileopts="{{fileopts}}"
+    diropts="{{diropts}}"
+    cur=$words[CURRENT]
+    case $cur in
+        :)
+            _arguments '*: :(::ytfavorites ::ytrecommended ::ytsubscriptions ::ytwatchlater ::ythistory)'
+        ;;
+        *)
+            prev=$words[CURRENT-1]
+            if [[ ${prev} =~ ${fileopts} ]]; then
+                _path_files
+            elif [[ ${prev} =~ ${diropts} ]]; then
+                _path_files -/
+            elif [[ ${prev} == "--recode-video" ]]; then
+                _arguments '*: :(mp4 flv ogg webm mkv)'
+            else
+                _arguments '*: :({{flags}})'
+            fi
+        ;;
+    esac
+}
+
+__youtube_dl

devscripts/zsh-completion.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+import os
+from os.path import dirname as dirn
+import sys
+
+sys.path.append(dirn(dirn((os.path.abspath(__file__)))))
+import youtube_dl
+
+ZSH_COMPLETION_FILE = "youtube-dl.zsh"
+ZSH_COMPLETION_TEMPLATE = "devscripts/zsh-completion.in"
+
+
+def build_completion(opt_parser):
+    opts = [opt for group in opt_parser.option_groups
+            for opt in group.option_list]
+    opts_file = [opt for opt in opts if opt.metavar == "FILE"]
+    opts_dir = [opt for opt in opts if opt.metavar == "DIR"]
+
+    fileopts = []
+    for opt in opts_file:
+        if opt._short_opts:
+            fileopts.extend(opt._short_opts)
+        if opt._long_opts:
+            fileopts.extend(opt._long_opts)
+
+    diropts = []
+    for opt in opts_dir:
+        if opt._short_opts:
+            diropts.extend(opt._short_opts)
+        if opt._long_opts:
+            diropts.extend(opt._long_opts)
+
+    flags = [opt.get_opt_string() for opt in opts]
+
+    with open(ZSH_COMPLETION_TEMPLATE) as f:
+        template = f.read()
+
+    template = template.replace("{{fileopts}}", "|".join(fileopts))
+    template = template.replace("{{diropts}}", "|".join(diropts))
+    template = template.replace("{{flags}}", " ".join(flags))
+
+    with open(ZSH_COMPLETION_FILE, "w") as f:
+        f.write(template)
+
+parser = youtube_dl.parseOpts()[0]
+build_completion(parser)