import Queue
import collections
import threading
import urllib
import xmlrpclib

from xml.etree import ElementTree as ET

from docutils import nodes, utils
from docutils.parsers.rst import Directive, directives
from sphinx.domains import Domain

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

class Fields(Directive):
    """Fetches and lists the fields linked to a specific action.

    Required argument: external ID of the action

    Options:

    view
        defaults to "form"
    fields
        comma-separated whitelist of fields. By default, lists all
        fields returned by fields_view_get
    """
    required_arguments = 1
    option_spec = {
        'view': directives.unchanged,
        'only': directives.unchanged,
    }
    def __init__(self, name, arguments, options, content, lineno,
                 content_offset, block_text, state, state_machine):
        super(Fields, self).__init__(
            name, arguments, options, content, lineno,
            content_offset, block_text, state, state_machine)
        xid = arguments[0]
        self.future_fields = self._get_fields(xid, options.get('view') or 'form')

    def run(self):
        try:
            fields = self.future_fields.get(timeout=30)
        except Queue.Empty:
            return [self.state_machine.reporter.error(
                "Timed out while fetching fields related to action [%s]" % self.arguments[0]
            )]
        if fields is None:
            return [self.state_machine.reporter.warning(
                "Could not find any field related to the action [%s]" % self.arguments[0]
            )]
        whitelist = set(self.options.get('only', '').split())
        return [nodes.field_list('', *(
            nodes.field('',
                nodes.field_name(text=v['string'] or k),
                nodes.field_body('',
                    # keep help formatting around (e.g. newlines for lists)
                    nodes.line_block('', *(
                        nodes.line(text=line)
                        for line in v['help'].split('\n')
                    ))
                )
            )
            for k, v in fields.iteritems()
            # if there's a whitelist, only display whitelisted fields
            if not whitelist or k in whitelist
            # only display if there's a help text
            if v.get('help')
        ))]

    def _get_fields(self, xid, view='form'):
        q = Queue.Queue(1)
        _submit(q, xid, view)
        return q

class Action(Directive):
    required_arguments = 1
    final_argument_whitespace = True
    has_content = True

    def run(self):
        self.assert_has_content()
        external_id = self.arguments[0]
        text = "action button"
        node = nodes.reference(
            refuri='https://demo.odoo.com?{}'.format(urllib.urlencode({
                'module': external_id
            })),
            classes=['btn', 'btn-primary', 'btn-lg', 'btn-block', 'center-block']
        )
        self.state.nested_parse(self.content, self.content_offset, node)
        return [node]

class OdooDemoDomain(Domain):
    name = 'demo'
    label = 'Odoo Demo'
    directives = {
        'fields': Fields,
        'action': Action,
    }

FETCH_THREADS = 4
launcher_lock = threading.Lock()
launcher = None
work_queue = Queue.Queue()
Task = collections.namedtuple('Task', 'result xid view')
def _submit(result_queue, xid, view='form'):
    global launcher
    # enqueue task before checking launcher, that way if the launcher
    # is already started (likely) a worker can immediately get to work
    work_queue.put(Task(result_queue, xid, view))

    with launcher_lock:
        if launcher is None:
            launcher = threading.Thread(target=_launcher, name="Fetch threads launcher")
            launcher.daemon = True
            launcher.start()

def _launcher():
    info = xmlrpclib.ServerProxy('https://demo.odoo.com/start').start()
    url, db, username, password = \
        info['host'], info['database'], info['user'], info['password']

    uid = xmlrpclib.ServerProxy('{}/xmlrpc/2/common'.format(url))\
                   .authenticate(db, username, password, {})

    for i in range(FETCH_THREADS):
        # daemon because Launcher is daemon
        threading.Thread(target=_fetch_fields, kwargs={
            'db': db,
            'uid': uid,
            'password': password,
            'url': '{}/xmlrpc/2/object'.format(url)
        }, name="fields_get fetcher thread %d/%d" % (i, FETCH_THREADS)).start()

def _fetch_fields(url, db, uid, password):
    server = xmlrpclib.ServerProxy(url)
    while True:
        task = work_queue.get()

        # resolve xid
        model, id_ = server.execute_kw(
            db, uid, password,
            'ir.model.data', 'xmlid_to_res_model_res_id', [task.xid])
        if not id_: # didn't find xid
            result = None
        elif model != 'ir.actions.act_window': # we only handle action windows, rest is unknown
            result = None
        else:
            action = server.execute_kw(db, uid, password, model, 'read', [id_, ['res_model', 'views']])
            view_id = next((id_ for type, id_ in action['views'] if type == task.view), False)
            fvg = server.execute_kw(
                db, uid, password,
                action['res_model'], 'fields_view_get', [], {
                    'view_id': view_id,
                    'view_type': task.view
                })
            result = collections.OrderedDict()
            # reorder fields to be in view order, and add @help from view if any
            arch = ET.fromstring(fvg['arch'])
            for node in arch.iter(tag='field'):
                field = node.get('name')

                result[field] = fvg['fields'][field]
                # bit trashy but should work well enough to update
                # @string and @help
                result[field].update(node.attrib)
                if node.get('nolabel'):
                    # native @string suppressed, look for <label
                    # for=@name>.  invisible means a field could have
                    # multiple <label> but that's basically impossible
                    # to handle so jusr get the first one
                    label = arch.find(".//label[@for='%s']" % field)
                    if label is not None:
                        result[field]['string'] = label.get('string')

        task.result.put(result)
        work_queue.task_done()