### requires.py

from charms.reactive import hook
from charms.reactive import RelationBase
from charms.reactive import scopes


class HttpRequires(RelationBase):
    scope = scopes.UNIT

    @hook('{requires:http}-relation-{joined,changed}')
    def changed(self):
        conv = self.conversation()
        if conv.get_remote('port'):
            # this unit's conversation has a port, so
            # it is part of the set of available units
            conv.set_state('{relation_name}.available')
        if conv.get_remote('httpsport'):
            # this unit's conversation has a port, so
            # it is part of the set of available units
            conv.set_state('{relation_name}.available')

    @hook('{requires:http}-relation-{departed,broken}')
    def broken(self):
        conv = self.conversation()
        conv.remove_state('{relation_name}.available')

    def services(self):
        services = {}
        for conv in self.conversations():
            service_name = conv.scope.split('/')[0]
            service = services.setdefault(service_name, {
                'service_name': service_name,
                'hosts': [],
            })
            host = conv.get_remote('hostname') or \
                conv.get_remote('private-address')
            port = conv.get_remote('port')
            httpsport = conv.get_remote('httpsport')
            if host and port:
                service['hosts'].append({
                    'hostname': host,
                    'port': port,
                    'httpsport': httpsport,
                })
    return [s for s in services.values() if s['hosts']]