"""Waste collection schedules."""

import os
import re
from collections import defaultdict
from datetime import date, datetime, time, timedelta

import httpx
import lxml.html

from . import uk_time
from .event import Event
from .utils import make_waste_dir

ttl_hours = 12


async def get_html(data_dir: str, postcode: str, uprn: str) -> str:
    """Get waste schedule."""
    now = datetime.now()
    waste_dir = os.path.join(data_dir, "waste")

    make_waste_dir(data_dir)

    existing_data = os.listdir(waste_dir)
    existing = [f for f in existing_data if f.endswith(".html")]
    if existing:
        recent_filename = max(existing)
        recent = datetime.strptime(recent_filename, "%Y-%m-%d_%H:%M.html")
        delta = now - recent

    if existing and delta < timedelta(hours=ttl_hours):
        return open(os.path.join(waste_dir, recent_filename)).read()

    now_str = now.strftime("%Y-%m-%d_%H:%M")
    filename = f"{waste_dir}/{now_str}.html"

    forms_base_url = "https://forms.n-somerset.gov.uk"
    url = "https://forms.n-somerset.gov.uk/Waste/CollectionSchedule"
    async with httpx.AsyncClient() as client:
        r = await client.post(
            url,
            data={
                "PreviousHouse": "",
                "PreviousPostcode": "-",
                "Postcode": postcode,
                "SelectedUprn": uprn,
            },
        )
        form_post_html = r.text
        pattern = r'<h2>Object moved to <a href="([^"]*)">here<\/a>\.<\/h2>'
        m = re.search(pattern, form_post_html)
        if m:
            r = await client.get(forms_base_url + m.group(1))
    html = r.text
    open(filename, "w").write(html)
    return html


def parse_waste_schedule_date(day_and_month: str) -> date:
    """Parse waste schedule date."""
    today = date.today()
    fmt = "%A %d %B %Y"
    d = datetime.strptime(f"{day_and_month} {today.year}", fmt).date()
    if d < today:
        d = datetime.strptime(f"{day_and_month} {today.year + 1}", fmt).date()
    return d


def parse(root: lxml.html.HtmlElement) -> list[Event]:
    """Parse waste schedule."""
    tbody = root.find(".//table/tbody")
    assert tbody is not None
    by_date = defaultdict(list)
    for e_service, e_next_date, e_following in tbody:
        assert e_service.text and e_next_date.text and e_following.text
        service = e_service.text
        next_date = parse_waste_schedule_date(e_next_date.text)
        following_date = parse_waste_schedule_date(e_following.text)

        by_date[next_date].append(service)
        by_date[following_date].append(service)

    return [
        Event(
            name="waste_schedule",
            date=uk_time(d, time(6, 30)),
            title="Backwell: " + ", ".join(services),
        )
        for d, services in by_date.items()
    ]