// ── The server list, and the module's landing page ────────────────────────
//
// R8: the list is what `/rust` renders, and `/rust/servers/:id` hangs beneath
// it. The route is registered with an empty path in `entry.jsx` — core turns
// that into the module's own namespace root — so this page's address is the one
// an operator links to when they mean "our Rust servers".
//
// An ordinary React component. Nothing about being inside a module changes how
// you write one; the only differences are where React comes from (core, via the
// aliases in `vite.config.js`, so the import below looks completely normal and is
// not) and where the chrome comes from (`../../core.js`, the shared UI kit).
//
// **Render `PublicLayout` yourself, and pass a `shell`.** Core wraps public
// routes in its maintenance gate and nothing else, so a page that omits the
// layout renders bare; without a `shell` it renders full-bleed with the footer
// riding up underneath it. Name a width, never a class — the classes are core's
// (MODULE_API.md §3.3).
//
// **This page never calls a game server.** Every field it renders comes from
// this module's own tables, written by the ingest cursor, which is what lets it
// render "offline, last seen an hour ago" instead of an error page when a shard
// is down. The site's availability does not depend on the game's.

import { Link } from 'react-router-dom'
import { EmptyState, ErrorState, Loading, PageHeader, PublicLayout, useAsync } from '../../core.js'
import { ago, count, day } from '../../lib/format.js'
import api from '../../api.js'

/** The "last reported" line, which has three cases and not one. */
function reported(server) {
  if (!server.lastSeenAt) return 'This server has never reported.'
  if (server.stale) return `Last reported ${ago(server.lastSeenAt)} — out of date, so it is shown as offline.`
  return `Last reported ${ago(server.lastSeenAt)}.`
}

export default function Servers() {
  // `useAsync` is core's fetch/loading/error hook, and the components below are
  // its states. Using them rather than rolling your own is what makes a module
  // page indistinguishable from a core one while it loads and while it fails.
  //
  // It loads once, deliberately. The DETAIL page polls, because that is where
  // somebody watching a server sits; a list is a place people pass through.
  const { data, loading, error } = useAsync(() => api.servers.list(), [])
  const servers = data ? data.servers : []

  return (
    <PublicLayout shell="mid">
      <PageHeader
        // `lead`, not `subtitle`. PageHeader takes `eyebrow`, `title`, `lead` and
        // `center`, and an unknown prop on a React component is silently dropped
        // — so a page written with `subtitle` renders its title and nothing else,
        // on a site where every core page has a line under its heading.
        title="Servers"
        lead="Every Rust server this community runs, as each one last reported itself"
      />

      {loading && <Loading />}
      {error && <ErrorState error={error} />}

      {/* An operator who has configured no servers is not an error and not an
          empty game — it is an install that is not finished. Saying so beats a
          blank page that looks like a failure. */}
      {data && servers.length === 0 && (
        <EmptyState
          title="No servers yet"
          message="An administrator adds a Rust server, and its sidecar, from the admin panel."
        />
      )}

      {servers.length > 0 && (
        <div style={{ display: 'grid', gap: 12 }}>
          {servers.map((server) => (
            // The whole row is the link. A server's name being the only clickable
            // part is the thing people miss on a list of cards, and `a.card`
            // already carries core's own hover treatment.
            <Link
              key={server.id}
              to={`/rust/servers/${encodeURIComponent(server.id)}`}
              className="card"
              style={{
                display: 'flex',
                justifyContent: 'space-between',
                alignItems: 'baseline',
                gap: '1rem',
                padding: '16px 20px',
              }}
            >
              <span>
                <strong style={{ color: 'var(--ink)' }}>{server.name}</strong>
                <span className="sans" style={{ display: 'block', color: 'var(--dim)', fontSize: '0.78rem', marginTop: 4 }}>
                  {[
                    server.level || null,
                    server.worldSize ? `size ${count(server.worldSize)}` : null,
                    server.wipedAt ? `wiped ${day(server.wipedAt)}` : null,
                  ]
                    .filter(Boolean)
                    .join(' · ')}
                </span>
                <span className="sans" style={{ display: 'block', color: 'var(--dim)', fontSize: '0.74rem', marginTop: 2 }}>
                  {/* `lastSeenAt`, never `updatedAt`. The second is when THIS
                      site last wrote the row — which a failed poll does too — so
                      a page reading it told a reader that a server down for three
                      days had reported just now. And `stale` is a first-class
                      part of the answer rather than something inferred from a
                      timestamp: the server decides what counts as stale, because
                      the server knows how often a sidecar is supposed to check in. */}
                  {reported(server)}
                </span>
              </span>
              <span
                className="sans"
                style={{ whiteSpace: 'nowrap', color: server.online ? 'var(--mode-live, #5fb98a)' : 'var(--dim)' }}
              >
                {server.online
                  ? `${count(server.players)}${server.maxPlayers ? ` / ${count(server.maxPlayers)}` : ''} online`
                  : 'Offline'}
              </span>
            </Link>
          ))}
        </div>
      )}
    </PublicLayout>
  )
}