Reg link insertion

links.py

from __future__ import unicode_literals
import re

from regulations3k.models import Part, Section
from regulations3k.scripts.ecfr_importer import LEGACY_PARTS

REG_BASE = '/policy-compliance/rulemaking/regulations/{}/'
SECTION_RE = re.compile('(?:\N{SECTION SIGN}|Section|12 CFR)\W+([^\s]+)')
PARTS_RE = re.compile(
    r'(?P<part>\d{4})[.-](?P<section>[0-9A-Z]+)(?P<ids>\([a-zA-Z0-9)(]+)?')
ID_RE = re.compile(r'\(([a-zA-Z0-9]{1,4})\)')


def get_url(section_reference):
    if not PARTS_RE.match(section_reference):
        return
    parts = PARTS_RE.match(section_reference).groupdict()
    part = parts.get('part')
    if part not in LEGACY_PARTS:
        return
    part_url = REG_BASE.format(part)
    if not parts.get('section'):
        return part_url
    section_url = "{}{}/".format(part_url, parts.get('section'))
    if not parts.get('ids'):
        return section_url
    paragraph_id = "-".join(ID_RE.findall(parts.get('ids')))
    if paragraph_id:
        return "{}#{}".format(section_url, paragraph_id)
    else:
        return section_url


def insert_section_links(regdown):
    """Turn internal section references into links."""
    section_refs = SECTION_RE.findall(regdown)
    index_head = 0
    for i, ref in enumerate(section_refs):
        url = get_url(ref)
        if url:
            link = '<a href="{}" data-linktag="{}">{}</a> '.format(url, i, ref)
            regdown = (
                regdown[:index_head] +
                regdown[index_head:].replace(ref, link, 1))
            index_head = regdown.index(link) + len(link)
    return regdown


def insert_links(reg=None):
    if reg is None:
        parts = Part.objects.all()
    else:
        parts = Part.objects.filter(part_number=reg)
    live_versions = [part.effective_version for part in parts]
    if not live_versions:
        return
    live_sections = Section.objects.filter(subpart__version__in=live_versions)
    for section in live_sections:
        print("Inserting links in section {}".format(section))
        section.contents = insert_section_links(section.contents)
        section.save()


def run(*args):
    if args:
        insert_links(reg=args[0])
    else:
        insert_links()