# HG changeset patch
# User Ludovic Chabant <ludovic@chabant.com>
# Date 1437458205 25200
# Node ID d5885c6d64bd98e22d1d27f4677570ddcaf632e2
# Parent  3b6cbadd0c64298c011fa76a61a925754bcbbd09
themes: Add a `link` sub-command to install a theme via a symbolic link.

diff -r 3b6cbadd0c64 -r d5885c6d64bd piecrust/commands/builtin/themes.py
--- a/piecrust/commands/builtin/themes.py	Mon Jul 20 22:25:39 2015 -0700
+++ b/piecrust/commands/builtin/themes.py	Mon Jul 20 22:56:45 2015 -0700
@@ -40,6 +40,15 @@
                 help="Copies a theme to the website for customization.")
         p.set_defaults(sub_func=self._overrideTheme)
 
+        p = subparsers.add_parser(
+                'link',
+                help="Installs a theme as a link to an already existing "
+                     "theme on disk.")
+        p.add_argument(
+                'theme_dir',
+                help="The directory of the theme to link.")
+        p.set_defaults(sub_func=self._linkTheme)
+
     def checkedRun(self, ctx):
         if not hasattr(ctx.args, 'sub_func'):
             ctx.parser.parse_args(['themes', '--help'])
@@ -131,3 +140,24 @@
                 os.makedirs(os.path.dirname(c[1]))
             shutil.copy2(c[0], c[1])
 
+    def _linkTheme(self, ctx):
+        if not os.path.isdir(ctx.args.theme_dir):
+            logger.error("Invalid theme directory: %s" % ctx.args.theme_dir)
+            return 1
+
+        theme_dir = os.path.join(ctx.app.root_dir, THEME_DIR)
+
+        if os.path.islink(theme_dir):
+            logger.debug("Unlinking: %s" % theme_dir)
+            os.unlink(theme_dir)
+        elif os.path.isdir(theme_dir):
+            logger.warning("A theme already exists, and will be overwritten. "
+                           "Are you sure? [Y/n]")
+            ans = input()
+            if len(ans) > 0 and ans.lower() not in ['y', 'yes']:
+                return 1
+
+            shutil.rmtree(theme_dir)
+
+        os.symlink(ctx.args.theme_dir, theme_dir)
+