#!/usr/bin/env python3
"""Rebuild the data payload inside 274-transect.html from 274-lookup.md.

The HTML is self-contained: it carries its data in a <script id="data"> block so
it opens straight from disk. This script re-reads the roster table out of
274-lookup.md, joins the route line and district bands, and writes the payload back
into the HTML in place. The page's markup, CSS and JS are left untouched.

    python3 274-transect-build.py

Inputs : 274-lookup.md (roster, source of truth), 274-route.json, 274-districts.json
Output : 274-transect.html (data block replaced)
"""
import io, json, os, re, sys

HERE = os.path.dirname(os.path.abspath(__file__))
p = lambda n: os.path.join(HERE, n)
CHOME = re.compile(r'[一二三四五六七八九十百]+丁目$')


def roster(path):
    hdr, rows = None, []
    for line in io.open(path, encoding='utf-8'):
        if line.startswith('| km | Name |'):
            hdr = [c.strip() for c in line.strip().strip('|').split('|')]
            continue
        if hdr and line.startswith('| ') and line.count('|') >= 13:
            c = [x.strip() for x in line.strip().strip('|').split('|')]
            if re.match(r'^\d+\.\d+$', c[0]):
                rows.append(dict(zip(hdr, c)))
    if not rows:
        sys.exit('no roster rows found in %s' % path)
    return rows


def oaza_of(address, cities):
    a = address or ''
    for c in cities:
        if a.startswith(c):
            a = a[len(c):]
            break
    return CHOME.sub('', a).strip() or '—'


def main():
    bands = json.load(io.open(p('274-districts.json'), encoding='utf-8'))
    route = json.load(io.open(p('274-route.json'), encoding='utf-8'))
    cities = sorted({b['city'] for b in bands if b.get('city')}, key=len, reverse=True)

    items = []
    for r in roster(p('274-lookup.md')):
        items.append(dict(
            km=float(r['km']), name=r['Name'], obj=r['Object'],
            kana=r.get('Kana', ''), romaji=r.get('Romaji', ''), kind=r['Kind'],
            off=float(r['Off (m)'] or 0), lat=float(r['Lat']), lon=float(r['Lon']),
            L=r.get('Length', ''), y=r.get('Built', ''), g=r.get('Grade', ''),
            addr=r.get('Address', ''), addrk=r.get('Address kana', ''),
            oaza=oaza_of(r.get('Address', ''), cities),
            city=next((c for c in cities if (r.get('Address') or '').startswith(c)), '')))
    items.sort(key=lambda o: (o['km'], o['obj']))

    payload = json.dumps(dict(route=route, items=items, bands=bands),
                         ensure_ascii=False, separators=(',', ':'))
    html = io.open(p('274-transect.html'), encoding='utf-8').read()
    new, n = re.subn(r'(<script id="data" type="application/json">).*?(</script>)',
                     lambda m: m.group(1) + payload + m.group(2), html, count=1, flags=re.S)
    if not n:
        sys.exit('data block not found in 274-transect.html')
    io.open(p('274-transect.html'), 'w', encoding='utf-8').write(new)
    print('%d entries, %d district bands, %d route points -> 274-transect.html'
          % (len(items), len(bands), len(route)))


if __name__ == '__main__':
    main()