// -----------------------------------------------------------------------------
// Rent-Ka — Rental listings aggregator (Canada, outside Québec)
// Author: Simon-Pierre Boucher — contact@spboucher.ai
// pages/Ville.tsx: programmatic SEO pages — /cities, /city/:ville[/:type]
// The server renders the same content as HTML (rentka/seo.py); here, the
// interactive version with the app's listing cards.
// -----------------------------------------------------------------------------
import { useEffect, useState } from "react";
import { Link, useParams } from "react-router-dom";
import { Listing } from "../api";
import ListingCard from "../components/ListingCard";

interface VilleRow {
  city: string;
  slug: string;
  n: number;
  avg_price: number | null;
}

interface VilleData {
  city: string;
  slug: string;
  unit_type: string | null;
  n: number;
  avg: number | null;
  med: number | null;
  types: { unit_type: string; slug: string; n: number }[];
  listings: Listing[];
  neighbors: VilleRow[];
}

const fmt = (p: number | null) =>
  p == null ? "—" : `$${Math.round(p).toLocaleString("en-CA")}`;

async function get<T>(path: string): Promise<T> {
  const res = await fetch(path);
  if (!res.ok) throw new Error(`${res.status}`);
  return res.json();
}

export function VillesPage() {
  const [villes, setVilles] = useState<VilleRow[] | null>(null);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    get<{ villes: VilleRow[] }>("/api/seo/villes")
      .then((r) => setVilles(r.villes))
      .catch((e) => setError(String(e)));
  }, []);

  return (
    <div className="container">
      <span className="kicker">Directory — rentals by city</span>
      <h1>Rentals by city</h1>
      <p className="sub">
        Every Canadian city where Rent-Ka tracks rentals, with the number of
        active listings and the average rent.
      </p>
      {error && <div className="notice">⚠️ {error}</div>}
      {!villes && !error && <div className="notice">Loading…</div>}
      {villes && (
        <ul className="ville-list" style={{ marginTop: 24, lineHeight: 2 }}>
          {villes.map((v) => (
            <li key={v.slug}>
              <Link to={`/city/${v.slug}`}>{v.city}</Link>
              {" — "}
              {v.n} listing{v.n > 1 ? "s" : ""}
              {v.avg_price != null && <> · average rent {fmt(v.avg_price)}</>}
            </li>
          ))}
        </ul>
      )}
    </div>
  );
}

export default function VillePage() {
  const { ville = "", type } = useParams();
  const [data, setData] = useState<VilleData | null>(null);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    setData(null);
    setError(null);
    const qs = type ? `?type=${encodeURIComponent(type)}` : "";
    get<VilleData>(`/api/seo/ville/${encodeURIComponent(ville)}${qs}`)
      .then(setData)
      .catch((e) =>
        setError(e.message === "404" ? "Unknown city or type." : String(e)));
    window.scrollTo(0, 0);
  }, [ville, type]);

  if (error)
    return (
      <div className="container">
        <h1>Page not found</h1>
        <div className="notice">
          ⚠️ {error} <Link to="/cities">See all cities</Link>
        </div>
      </div>
    );
  if (!data)
    return (
      <div className="container">
        <div className="notice">Loading…</div>
      </div>
    );

  const what = data.unit_type ? `${data.unit_type} rentals` : "Rentals";
  return (
    <div className="container">
      <span className="kicker">
        <Link to="/cities">Cities</Link> — {data.city}
      </span>
      <h1>
        {what} in {data.city}
      </h1>
      <p className="sub">
        {data.n} active listing{data.n > 1 ? "s" : ""}
        {data.avg != null && <> · average rent {fmt(data.avg)}</>}
        {data.med != null && <> · median {fmt(data.med)}</>}
      </p>

      {!data.unit_type && data.types.length > 1 && (
        <p style={{ display: "flex", flexWrap: "wrap", gap: 8 }}>
          {data.types.map((t) => (
            <Link key={t.slug} className="pill" to={`/city/${data.slug}/${t.slug}`}>
              {t.unit_type} ({t.n})
            </Link>
          ))}
        </p>
      )}
      {data.unit_type && (
        <p>
          <Link to={`/city/${data.slug}`}>
            ← All rentals in {data.city}
          </Link>
        </p>
      )}

      <div className="grid" style={{ marginTop: 24 }}>
        {data.listings.map((l) => (
          <ListingCard key={l.uid} l={l} />
        ))}
      </div>

      {data.neighbors.length > 0 && (
        <>
          <h2 style={{ marginTop: 40 }}>Other cities</h2>
          <p style={{ display: "flex", flexWrap: "wrap", gap: 8 }}>
            {data.neighbors.map((v) => (
              <Link key={v.slug} className="pill" to={`/city/${v.slug}`}>
                {v.city} ({v.n})
              </Link>
            ))}
          </p>
        </>
      )}
    </div>
  );
}