from collections import defaultdict

from docutils.parsers.rst import directives

from sphinx import addnodes
from sphinx.directives import ObjectDescription
from sphinx.domains import Domain
from sphinx.domains import Index
from sphinx.roles import XRefRole
from sphinx.util.nodes import make_refnode


class KeywordDirective(ObjectDescription):
    has_content = True
    required_arguments = 1

    def handle_signature(self, sig, signode):
        signode += addnodes.desc_name(text=sig)
        return sig

    def add_target_and_index(self, name_cls, sig, signode):
        signode['ids'].append('keyword' + '-' + sig)
        if 'noindex' not in self.options:
            crowbar = self.env.get_domain('crowbar')
            crowbar.add_keyword(sig)


class KeywordIndex(Index):
    name = 'keyword'
    localname = 'Keyword Index'
    shortname = 'Keyword'

    def generate(self, docnames=None):
        content = defaultdict(list)

        # sort the list of recipes in alphabetical order
        recipes = self.domain.get_objects()
        recipes = sorted(recipes, key=lambda recipe: recipe[0])

        # generate the expected output, shown below, from the above using the
        # first letter of the recipe as a key to group thing
        #
        # name, subtype, docname, anchor, extra, qualifier, description
        for name, dispname, typ, docname, anchor, _ in recipes:
            content[dispname[0].lower()].append(
                (dispname, 0, docname, anchor, docname, '', typ))

        # convert the dict to the sorted list of tuples expected
        content = sorted(content.items())

        return content, True


class CrowbarDomain(Domain):
    name = 'crowbar'
    label = 'Crowbar'
    roles = {
        'ref': XRefRole()
    }
    directives = {
        'keyword': KeywordDirective,
    }
    indices = {
        KeywordIndex,
    }
    initial_data = {
        'keywords': [],
    }

    def get_full_qualified_name(self, node):
        return '{}.{}'.format('keyword', node.arguments[0])

    def get_objects(self):
        for obj in self.data['keywords']:
            yield(obj)

    def resolve_xref(self, env, fromdocname, builder, typ, target, node,
                     contnode):
        match = [(docname, anchor)
                 for name, sig, typ, docname, anchor, prio
                 in self.get_objects() if sig == target]

        if len(match) > 0:
            todocname = match[0][0]
            targ = match[0][1]

            return make_refnode(builder, fromdocname, todocname, targ,
                                contnode, targ)
        else:
            print('Awww, found nothing')
            return None

    def add_keyword(self, signature):
        """Add a new keyword to the domain."""
        name = '{}.{}'.format('keyword', signature)
        anchor = 'keyword-{}'.format(signature)

        # name, dispname, type, docname, anchor, priority
        self.data['keywords'].append(
            (name, signature, 'Keyword', self.env.docname, anchor, 0))


def setup(app):
    app.add_domain(CrowbarDomain)

    return {
        'version': '0.1',
        'parallel_read_safe': True,
        'parallel_write_safe': True,
    }