From e1a6ad216711a894aa6d81c303dff6be6e8053a3 Mon Sep 17 00:00:00 2001
From: Olivier Mangin <olivier@mangin.com>
Date: Fri, 12 May 2017 19:02:35 -0400
Subject: [PATCH] Adds basic tag completion.

---
 pubs/commands/tag_cmd.py |  8 +++++---
 pubs/completion.py       | 23 ++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/pubs/commands/tag_cmd.py b/pubs/commands/tag_cmd.py
index c37eac4..b5031f9 100644
--- a/pubs/commands/tag_cmd.py
+++ b/pubs/commands/tag_cmd.py
@@ -24,16 +24,17 @@ from ..uis import get_ui
 from .. import pretty
 from .. import color
 from ..utils import resolve_citekey
-from ..completion import CiteKeyCompletion
+from ..completion import CiteKeyOrTagCompletion, TagModifierCompletion
 
 
 def parser(subparsers, conf):
     parser = subparsers.add_parser('tag', help="add, remove and show tags")
     parser.add_argument('citekeyOrTag', nargs='?', default=None,
-                        help='citekey or tag.').completer = CiteKeyCompletion(conf)
+                        help='citekey or tag.').completer = CiteKeyOrTagCompletion(conf)
     parser.add_argument('tags', nargs='?', default=None,
                         help='If the previous argument was a citekey, then '
-                             'a list of tags separated by a +.')
+                             'a list of tags separated by + and -.'
+                        ).completer = TagModifierCompletion(conf)
     # TODO find a way to display clear help for multiple command semantics,
     #      indistinguisable for argparse. (fabien, 201306)
     return parser
@@ -71,6 +72,7 @@ def _tag_groups(tags):
             minus_tags.append(tag[1:])
     return set(plus_tags), set(minus_tags)
 
+
 def command(conf, args):
     """Add, remove and show tags"""
 
diff --git a/pubs/completion.py b/pubs/completion.py
index 3752cb3..f05fe36 100644
--- a/pubs/completion.py
+++ b/pubs/completion.py
@@ -1,4 +1,4 @@
-from . import repo
+import re
 try:
     import argcomplete
 except ModuleNotFoundError:
@@ -14,6 +14,8 @@ except ModuleNotFoundError:
 
     argcomplete = FakeModule()
 
+from . import repo
+
 
 def autocomplete(parser):
     argcomplete.autocomplete(parser)
@@ -36,3 +38,22 @@ class CiteKeyCompletion(BaseCompleter):
     def _complete(self, **kwargs):
         rp = repo.Repository(self.conf)
         return rp.citekeys
+
+
+class CiteKeyOrTagCompletion(BaseCompleter):
+
+    def _complete(self, **kwargs):
+        rp = repo.Repository(self.conf)
+        return rp.citekeys.union(rp.get_tags())
+
+
+class TagModifierCompletion(BaseCompleter):
+
+    regxp = r"[^:+-]*$"  # prefix of tag after last separator
+
+    def _complete(self, prefix, **kwargs):
+        tags = repo.Repository(self.conf).get_tags()
+        start, _ = re.search(self.regxp, prefix).span()
+        partial_expr = prefix[:start]
+        t_prefix = prefix[start:]
+        return [partial_expr + t for t in tags if t.startswith(t_prefix)]