from docutils import nodes
from sphinx.util.compat import Directive
from collections import defaultdict

def taglist_html(self, node):
    env = app.builder.env
    if not hasattr(env, 'tags_db'): return
    
    self.body.append("""
        <script langage=javascript>
        var cur = null;
        var cura = null;
        function change(a1, div1){
          nexta = document.getElementById(a1)
          next = document.getElementById(div1)
          if (cur != null) { cur.style.display = 'none'; cura.style.fontWeight = 'normal'; }
          if (cur != next) { next.style.display = 'block'; nexta.style.fontWeight = 'bold'; cur = next; cura = nexta; }
          else cur = null
        }
        </script>
        """)

    for tag in sorted(env.tags_db):
        tid = tag.replace(' ','_')
        self.body.append(""" <a id=a_%s href="javascript:change('a_%s', 'div_%s')">%s</a> &nbsp;""" % (tid, tid, tid, tag))

    for tag in env.tags_db:
        tid = tag.replace(' ','_')
        self.body.append('<div id=div_%s style="display:none;"><br>' % (tid,))
        for f in sorted(env.tags_db[tag], lambda f,g: cmp(f[1], g[1])):
            uri = app.builder.get_relative_uri(node.docname, f[0]) + '#' + f[1]
            self.body.append('<a href="%s">%s</a><br>' % (uri, f[1]))
        self.body.append('</div>')

class taglist_node(nodes.Element): pass

class taglist(Directive):
    def run(self):
        a = taglist_node()
        a.docname = app.builder.env.docname
        return [a]

def purge_tags(app, env, docname):
    if not hasattr(env, 'tags_db'): return

    for tag in env.tags_db:
        for f in [f for f in env.tags_db[tag]]:
            if f[0]==docname: env.tags_db[tag].remove(f)

def autodoc_process_docstring(app, what, name, obj, options, lines):
    env = app.builder.env
    if not hasattr(env, 'tags_db'):
        env.tags_db = defaultdict(set)

    if what == 'function' and hasattr(obj, 'tags'):
        for tag in obj.tags:
            env.tags_db[tag].add((env.docname, name))

def setup(app_):
    global app
    app = app_

    app.add_node(taglist_node, html=(taglist_html, lambda a,b:None))
    app.add_directive('taglist', taglist)
    app.connect('env-purge-doc', purge_tags)
    app.connect('autodoc-process-docstring', autodoc_process_docstring)