# retoor <retoor@molodetz.nl>
import logging
from xml.sax.saxutils import escape

import defusedxml.ElementTree as SafeET
from fastapi import APIRouter, Request
from fastapi.responses import PlainTextResponse, Response

from molodetz import config
from molodetz.cache import TTLCache
from molodetz.constants import TOPICS
from molodetz.database import db, public_people
from molodetz.docs_prose import DOCS_PAGES
from molodetz.seo import base_url

router = APIRouter()
logger = logging.getLogger(__name__)
_sitemap_cache = TTLCache(ttl=config.SITEMAP_TTL, max_size=4)
PER_TABLE_CAP = 5000
STATIC_PATHS = ("/", "/flyers", "/memes", "/people", "/join", "/terms", "/privacy", "/docs")


@router.get("/robots.txt")
async def robots(request: Request):
    base = base_url(request)
    body = "\n".join(
        [
            "User-agent: *",
            "Disallow: /admin",
            "Disallow: /auth",
            "Disallow: /notifications",
            "Disallow: /profile",
            "Allow: /",
            f"Sitemap: {base}/sitemap.xml",
            "",
        ]
    )
    return PlainTextResponse(body)


def build_sitemap(base):
    urls = [(path, None) for path in STATIC_PATHS]
    urls += [(f"/{topic}", None) for topic in TOPICS]
    if "posts" in db.tables:
        rows = list(db["posts"].find(deleted_at=None, status="published", order_by=["-published_at"], _limit=PER_TABLE_CAP + 1))
        if len(rows) > PER_TABLE_CAP:
            logger.warning("sitemap truncated posts at %d", PER_TABLE_CAP)
            rows = rows[:PER_TABLE_CAP]
        urls += [(f"/posts/{row['slug']}", row.get("updated_at")) for row in rows]
    urls += [(f"/people/{person['username']}", None) for person in public_people()[:PER_TABLE_CAP]]
    urls += [(f"/docs/{page['slug']}", None) for page in DOCS_PAGES if not page.get("admin")]
    parts = ['<?xml version="1.0" encoding="UTF-8"?>', '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">']
    for path, modified in urls:
        entry = f"<url><loc>{escape(base + path)}</loc>"
        if modified:
            entry += f"<lastmod>{escape(modified[:10])}</lastmod>"
        parts.append(entry + "</url>")
    parts.append("</urlset>")
    xml = "\n".join(parts)
    SafeET.fromstring(xml.encode("utf-8"))
    return xml


@router.get("/sitemap.xml")
async def sitemap(request: Request):
    base = base_url(request)
    xml = _sitemap_cache.get(base)
    if xml is None:
        xml = build_sitemap(base)
        _sitemap_cache.set(base, xml)
    return Response(xml, media_type="application/xml")