import os
import string

from bs4 import BeautifulSoup
from bs4.element import NavigableString, Tag

from field_mappings import field_mappings


def _read_line(tr):
    for td in tr.find_all('td'):
        label = td.text.strip().split('\n')[0].strip(u'\xa0' + string.whitespace)
        names = [c.attrs['name'] for c in td.children if isinstance(c, Tag) and 'name' in c.attrs]
        if names:
            name = names[0].split('_', 1)[-1]
            yield name, label


def extract_title_and_fieldsets(model):
    filename = os.path.join(os.path.dirname(__file__),
                            'original_forms/%s.html' % model.__name__)
    try:
        with open(filename, 'r') as f:
            cont = f.read()
    except IOError:
        return None, []

    html_doc = cont.decode('utf-8')
    soup = BeautifulSoup(html_doc, 'html.parser')
    forms = soup.find_all('form')
    [form] = [f for f in forms if (u'method', u'post') in f.attrs.items()]
    # children are either tags or strings...
    assert set(type(c) for c in form.children) == {Tag, NavigableString}
    # ... and all strings are empty
    assert all(not c.strip() for c in form.children if isinstance(c, NavigableString))

    title = soup.find('h1', {'class': 'firstHeading'})
    title = title.text if title else None
    fieldsets = [dict(
        legend=fieldset.find('legend').text if fieldset.find('legend') else '',
        lines=[list(_read_line(tr)) for tr in fieldset.find_all('tr')])
        for fieldset in form.find_all('fieldset')]

    return title, fieldsets


def get_names_labels(fieldsets):
    for fieldset in fieldsets:
        for line in fieldset['lines']:
            for name, label in line:
                yield name, label


def print_title_and_fieldsets(model):
    title, fieldsets = extract_title_and_fieldsets(model)
    print '#### %s ####\n' % title
    for fieldset in fieldsets:
        print fieldset['legend']
        for line in fieldset['lines']:
            print '  ' + ' | '.join('%s : %s' % (id, label) for id, label in line)


def extract_verbose_names(model):
    title, fieldsets = extract_title_and_fieldsets(model)
    names_to_labels = dict(get_names_labels(fieldsets))

    field_names = [f.name for f in model._meta.fields if f.name != 'id']

    matches = {}
    field_names_to_old = field_mappings[model]
    for name in field_names:
        old_name = field_names_to_old[name]
        label = names_to_labels.get(old_name, None)
        if label:
            matches[name] = label
            del names_to_labels[old_name]
    for name, label in matches.items():
        field_names.remove(name)
    non_matched = field_names, names_to_labels
    return title, matches, non_matched