#!/usr/bin/env python3

from contextlib import contextmanager
from dataclasses import dataclass
from datetime import datetime
import locale
from operator import attrgetter
from pathlib import Path
import re
from sys import argv
from typing import Iterator, Optional

from helpers import relative_path


# TODO: change some jargon:
# - event => concert
# - canceled => warning


LICENSE_URLS = {
    'CC0': 'https://creativecommons.org/publicdomain/zero',
    'CC BY': 'https://creativecommons.org/licenses/by',
    'CC BY-SA': 'https://creativecommons.org/licenses/by-sa',
}

LICENSE_RE = re.compile(
    '('+'|'.join(LICENSE_URLS.keys())+')' + ' ([0-9.]+)'
)


@dataclass
class LicenseInfo:
    tag: str
    version: str

    @classmethod
    def deserialize(cls, info):
        if info is None:
            return None
        return cls(*LICENSE_RE.fullmatch(info).groups())

    def format(self):
        url = f'{LICENSE_URLS[self.tag]}/{self.version}/'

        return f'<a href="{url}" target="_blank">{self.tag}</a>'


@dataclass
class Illustration:
    file: str
    alt_text: str
    source_name: str
    source_link: Optional[str]
    license_info: Optional[LicenseInfo]

    @classmethod
    def deserialize(cls, d):
        return cls(d['pic_file'],
                   d['pic_alt'],
                   d['pic_src'],
                   d['pic_link'],
                   LicenseInfo.deserialize(d['pic_license']))


@dataclass
class Concert:
    time: datetime
    place: str
    address: str
    pieces: Iterator[str]
    instructions: str
    illustration: Illustration
    warning: Optional[str]

    @classmethod
    def deserialize(cls, d):
        return cls(
            time=datetime.strptime(d['time'], '%d/%m/%Y %Hh%M'),
            place=d['place'],
            address=d['address'],
            pieces=d['pieces'],
            instructions=d['instructions'],
            illustration=Illustration.deserialize(d),
            warning=d['warning']
        )


def optional(line):
    return f'(?:{line})?'


CONCERT_LINES = (
    r'QUAND : (?P<time>[^\n]+)\n',
    r'O[UÙ] : (?P<place>[^\n]+)\n',
    'ADRESSE :\n',
    '(?P<address>.+?)\n',
    'PROGRAMME :\n',
    '(?P<pieces>.+?)\n',
    'INSTRUCTIONS :\n',
    '(?P<instructions>.+?)\n',
    'ILLUSTRATION :\n',
    r'fichier : (?P<pic_file>[^\n]+)\n',
    r'légende : (?P<pic_alt>[^\n]+)\n',
    r'source : (?P<pic_src>[^\n]+)\n',
    optional(r'lien : (?P<pic_link>[^\n]+)\n'),
    optional(r'licence : (?P<pic_license>[^\n]+)\n'),
    optional(r'AVERTISSEMENT : (?P<warning>[^\n]+)\n'),
)

CONCERT_RE = re.compile(''.join(CONCERT_LINES), flags=re.DOTALL)


def guess_language(filename):
    parent = str(Path(filename).parent)
    if parent == '.':
        return 'fr'
    return parent


def read_concerts(filename):
    with open(filename) as f:
        concerts = (
            Concert.deserialize(match)
            for match in re.finditer(CONCERT_RE, f.read())
        )
        return tuple(sorted(concerts, key=attrgetter('time')))


def split_concerts(concerts, threshold):
    for i, c in enumerate(concerts):
        if c.time > threshold:
            return concerts[:i], concerts[i:]

    return concerts, ()


LOCALIZED_TEXT = {
    'en': {
        'past': 'Past concerts',
        'next': 'Next concerts',
        'alt': 'Illustration:',
        'hint': 'Click on a concert to obtain more information.',
    },
    'fr': {
        'past': 'Concerts passés',
        'next': 'Prochains concerts',
        'alt': 'Illustration :',
        'hint': "Cliquez sur un concert pour obtenir plus d'informations.",
    }
}

THUMBNAILS_TEMPLATE = '''\
  <h1>{heading}</h1>
  <div class="events {time}">
{thumbnails}
  </div>\
'''

THUMBNAIL_TEMPLATE = '''\
    <div class="{eventclasses}">
      <a class="thumbnail" href="#{eventid}">
        <img src="{pic_file}" alt="{pic_alt}">
        <p class="summary">
          {summary}
        </p>
      </a>
      <div class="credits">
        <span>
          {credits}
        </span>
      </div>
    </div>\
'''


@contextmanager
def tmplocale(lang):
    old_lang, encoding = locale.getlocale()
    try:
        locale.setlocale(locale.LC_TIME, (lang, encoding))
        yield
    finally:
        locale.setlocale(locale.LC_TIME, (old_lang, encoding))


def format_credits(illustration):
    credits = illustration.source_name

    if illustration.source_link is not None:
        credits = (f'<a href="{illustration.source_link}" target="_blank">'
                   f'{illustration.source_name}'
                   '</a>')

    if illustration.license_info is not None:
        credits += ' / ' + illustration.license_info.format()

    return credits


def format_thumbnail(concert, imgdir, lang):
    eventclasses = ('event',)
    with tmplocale(lang):
        day = f'{concert.time.day} {concert.time.strftime("%B %Y")}'
    summary = f'{concert.place}<br>{day}'

    if concert.warning is not None:
        eventclasses += ('canceled',)
        summary = (f'<span class="canceled">{concert.warning}</span>\n'
                   f'          {summary}')

    alt_prefix = LOCALIZED_TEXT[lang]['alt']

    return THUMBNAIL_TEMPLATE.format_map({
        'eventclasses': ' '.join(eventclasses),
        'eventid': f'concert-{concert.time.strftime("%F")}',
        'pic_file': Path(imgdir, 'concerts', concert.illustration.file),
        'pic_alt': f'{alt_prefix} {concert.illustration.alt_text}',
        'summary': summary,
        'credits': format_credits(concert.illustration)
    })


def print_thumbnails_section(concerts, imgdir, section, lang):
    if not concerts:
        return

    thumbnails = '\n'.join(
        format_thumbnail(c, imgdir, lang) for c in concerts
    )

    print(THUMBNAILS_TEMPLATE.format(heading=LOCALIZED_TEXT[lang][section],
                                     time=section,
                                     thumbnails=thumbnails))


def print_thumbnails(concerts, imgdir, lang):
    today = datetime.fromordinal(
        datetime.today().date().toordinal()
    )
    past_concerts, next_concerts = split_concerts(concerts, today)

    print('<div id="event-list">')
    print_thumbnails_section(next_concerts, imgdir, 'next', lang)
    print_thumbnails_section(past_concerts, imgdir, 'past', lang)
    print('</div>')


DETAILS_TEMPLATE = '''\
  <div class="{concertclasses}" id="{concertid}">
{details}
  </div>\
'''


DATE_FORMATTERS = {
    'en': {
        'date': lambda d: d.strftime('%A %B %-d, %Y'),
        'time': lambda d: d.strftime('%I:%M %p'),
    },
    'fr': {
        'date': lambda d: d.strftime('%A %-d %B %Y').capitalize(),
        'time': lambda d: d.strftime('%Hh%M'),
    },
}


def detail_block(tag, classes, content):
    opener = f'<{tag} class="{" ".join(classes)}">'
    closer = f'</{tag}>'

    if isinstance(content, str):
        return f'    {opener}{content}{closer}'

    return '\n'.join((
        '    '+opener,
        *('      '+line for line in content),
        '    '+closer,
    ))


def break_lines(lines):
    return tuple(line+'<br>' for line in lines[:-1]) + (lines[-1],)


TOUCHUPS = (
    (re.compile('([0-9])(st|nd|rd|th|er|ère|nde|ème)'), r'\1<sup>\2</sup>'),
    (re.compile('(https://[^ ]+)'), r'<a href="\1" target="_blank">\1</a>'),
    (re.compile('([^ ]+@[^ ]+)'), r'<a href="mailto:\1">\1</a>'),
)


def touchup_plaintext(plaintext):
    text = plaintext
    for regexp, repl in TOUCHUPS:
        text = regexp.sub(repl, text)
    return text


def print_concert_details(concert, lang):
    concert_id = f'concert-{concert.time.strftime("%F")}'
    classes = ('details',)
    blocks = []

    if concert.warning is not None:
        classes += ('canceled',)
        blocks.append(
            detail_block('p', ('canceled',), concert.warning)
        )

    with tmplocale(lang):
        day = DATE_FORMATTERS[lang]['date'](concert.time)
    hour = DATE_FORMATTERS[lang]['time'](concert.time)

    address_lines = break_lines(concert.address.splitlines())
    piece_list = tuple(
        f'<li>{touchup_plaintext(line)}</li>'
        for line in concert.pieces.splitlines()
    )

    blocks.extend((
        detail_block('p', ('detail', 'date'), day),
        detail_block('p', ('detail', 'time'), hour),
        detail_block('p', ('detail', 'place'), address_lines),
        detail_block('ol', ('detail', 'program'), piece_list),
    ))

    instructions = [
        f'    <p>{touchup_plaintext(line)}</p>'
        for line in concert.instructions.splitlines()
    ]

    print(f'  <div class="{" ".join(classes)}" id="{concert_id}">')
    print('\n'.join(blocks+instructions))
    print('  </div>')


def print_details(concerts, lang):
    print('<div id="event-details">')
    print(f'  <p class="hint">{LOCALIZED_TEXT[lang]["hint"]}</p>')

    for c in concerts:
        print_concert_details(c, lang)

    print('</div>')


def main(concerts_src):
    imgdir = relative_path(to='images', ref=concerts_src)
    lang = guess_language(concerts_src)

    concerts = read_concerts(concerts_src)
    print_thumbnails(concerts, imgdir, lang)
    print_details(concerts, lang)


if __name__ == '__main__':
    main(argv[1])