// PROCITY Lane B — credits.js  ⟨R41 §41.5, THE CREDITS SURFACE⟩
//
// PROCITY had no attribution surface at all. It ships OpenStreetMap data (ODbL 1.0 — "keep the
// © OpenStreetMap contributors credit visible", web/assets/towns/SOURCES.md's own words) and a
// vendored MIT three.js, and both obligations were live and undischarged. It is also the gate in
// front of 4,472 more licence-clean motion clips on the fleet (100STYLE CC BY 4.0 · CMU · ACCAD
// CC BY 3.0) that R41 could not spend for exactly this reason (ROUND41 ruling 2). So: build the
// surface, then a later round can spend them by appending rows to a data file.
//
// ── THE THREE PROPERTIES THIS FILE IS BUILT TO HOLD ──────────────────────────────────────────────
//
// 1. ZERO DRAWS, structurally. Everything here is DOM. The renderer never sees a credits object,
//    there is no geometry, no material, no texture and no render pass — so the street draw budget
//    (291/300 at night, ROUND41 ruling 4: nine draws of margin, no lane spends any) cannot move.
//    It is the same mechanism the R19 town selector and the R39 fog map use: chrome the composer
//    never renders. Measured as an A/B against a control tree anyway — see B-progress R41.
//
// 2. CLASSIC-GATED BY CONSTRUCTION, not by a flag test. There is NO `classic` check in this file.
//    The shell dynamic-imports this module only on a non-classic boot and hands the result to
//    `hud.setCredits()`; under `?classic=1` the module is never fetched, `setCredits` is never
//    called, and the HUD's DOM, key handlers and fetch surface are byte-identical to R40. That is
//    the null-provider idiom the R40 `#pc-street` row rides, and the R40 playtest harness before it.
//
// 3. LAZY, so an unopened panel costs nothing. `assets/credits.json` is fetched on FIRST OPEN, not
//    at boot: a boot that never opens the panel makes no request at all, so the default boot's fetch
//    surface is unchanged too. Under `?noassets=1` the asset law forbids the fetch outright and the
//    panel says so honestly rather than fetching anyway or inventing a built-in copy — a boot with
//    no assets loaded has, correctly, almost nothing to attribute.
//
// ── THE DATA FILE IS THE PRODUCT ─────────────────────────────────────────────────────────────────
// `web/assets/credits.json`, schema `procity-credits/1`. EVERY lane appends its own entries there;
// no lane needs to touch this file to be credited. The full schema, the field rules and a paste-ready
// row for the three CC-BY motion libraries are in docs/LANES/LANE_B_NOTES.md §41.
//
// This renderer makes exactly two editorial decisions and both are licence-driven:
//   • entries whose attribution is a LICENCE OBLIGATION (`required: true`) sort to the top and are
//     rendered with the required text verbatim, in a box, so it cannot be skimmed past;
//   • entries carrying a `flag` (an open licence question — an unverified source, or art a human
//     must clear before release) are rendered in amber. A flag that only exists in a lane note is a
//     flag nobody sees; R25's lesson (the licence line that went silent while the gate still said OK)
//     is that the print IS the mechanism.
// Everything else is presented as the data file states it. This file never decides a licence.

const CREDITS_URL = 'assets/credits.json';

const CSS = `
#pc-credits{position:fixed;inset:0;z-index:40;display:none;align-items:center;justify-content:center;
  background:rgba(8,6,4,.72);font:13px/1.55 -apple-system,Segoe UI,Roboto,sans-serif;color:#f4efe6}
#pc-credits.on{display:flex}
#pc-credits-box{width:min(760px,92vw);max-height:86vh;overflow-y:auto;background:rgba(20,16,10,.97);
  border:1px solid rgba(255,215,94,.35);border-radius:14px;padding:18px 20px 22px;pointer-events:auto;
  box-shadow:0 18px 60px rgba(0,0,0,.6)}
#pc-credits h2{font-size:15px;color:#ffd75e;margin:0 0 2px;font-weight:600;letter-spacing:.06em}
#pc-credits .pc-cr-sub{opacity:.72;margin:0 0 14px;font-size:12px}
#pc-credits .pc-cr-note{opacity:.85;margin:0 0 16px;padding-bottom:14px;border-bottom:1px solid rgba(255,244,230,.13)}
#pc-credits .pc-cr-e{padding:11px 0;border-top:1px solid rgba(255,244,230,.09)}
#pc-credits .pc-cr-e:first-of-type{border-top:0}
#pc-credits .pc-cr-h{display:flex;gap:9px;align-items:baseline;flex-wrap:wrap}
#pc-credits .pc-cr-n{font-weight:600;color:#ffe9b0}
#pc-credits .pc-cr-k{font-size:10px;letter-spacing:.09em;text-transform:uppercase;opacity:.5}
#pc-credits .pc-cr-lic{font-size:12px;opacity:.8}
#pc-credits .pc-cr-u{opacity:.82;margin:4px 0 0}
#pc-credits .pc-cr-src{font-size:12px;opacity:.62;margin:3px 0 0}
#pc-credits .pc-cr-att{margin:7px 0 0;padding:7px 10px;border-left:3px solid #ffd75e;
  background:rgba(255,215,94,.09);border-radius:0 6px 6px 0}
#pc-credits .pc-cr-att b{color:#ffd75e;font-size:10px;letter-spacing:.09em;display:block;margin-bottom:2px}
#pc-credits .pc-cr-flag{margin:7px 0 0;padding:7px 10px;border-left:3px solid #ff9a6a;
  background:rgba(255,154,106,.09);border-radius:0 6px 6px 0;color:#ffcdb4;font-size:12px}
#pc-credits .pc-cr-flag b{color:#ff9a6a;font-size:10px;letter-spacing:.09em;display:block;margin-bottom:2px}
#pc-credits .pc-cr-foot{margin-top:16px;padding-top:12px;border-top:1px solid rgba(255,244,230,.13);
  font-size:12px;opacity:.6;display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}
#pc-credits button{background:rgba(20,16,10,.7);color:#f4efe6;border:1px solid rgba(255,215,94,.35);
  border-radius:8px;padding:4px 12px;font:12px/1.3 -apple-system,Segoe UI,Roboto,sans-serif;cursor:pointer}
#pc-credits button:hover{border-color:rgba(255,215,94,.7);color:#ffd75e}
`;

const KIND_LABEL = {
  engine: 'engine', data: 'map data', motion: 'motion', mesh: 'models', texture: 'textures',
  audio: 'audio', stock: 'cover art', tool: 'tools', font: 'type',
};

const esc = (s) => String(s == null ? '' : s)
  .replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');

/**
 * createCredits({ noassets, releasePointer }) → { toggle, open, close, dispose, get isOpen, state }
 * Builds nothing but a hidden overlay shell; the list is rendered on first open, after the fetch.
 * Never throws: a missing, 404ing or malformed data file degrades to a stated line, not an error.
 *
 * `releasePointer` frees the pointer lock on open, so the panel is clickable and WASD stops moving
 * a player who is reading. It is the SAME contract the dig card, the sell card and the F8 note ride,
 * which is why the shell's `unlock` handler carries one more term: an unlock that is us opening the
 * credits must not walk you out of a shop (index.html, [Lane B R41]). F2/Esc work locked or not.
 */
export function createCredits({ noassets = false, releasePointer = null } = {}) {
  if (!document.getElementById('pc-credits-style')) {
    const st = document.createElement('style');
    st.id = 'pc-credits-style'; st.textContent = CSS;
    document.head.appendChild(st);
  }
  const root = document.createElement('div');
  root.id = 'pc-credits';
  root.innerHTML = '<div id="pc-credits-box"></div>';
  document.body.appendChild(root);
  const box = root.querySelector('#pc-credits-box');

  let open = false, loaded = false, data = null, err = null;

  // one fetch per session, on first open. `force-cache` matches the towns-index discipline.
  function load() {
    if (loaded) return Promise.resolve();
    loaded = true;
    if (noassets) { err = 'noassets'; return Promise.resolve(); }
    return fetch(CREDITS_URL, { cache: 'force-cache' })
      .then((r) => (r.ok ? r.json() : Promise.reject(new Error('HTTP ' + r.status))))
      .then((j) => {
        if (!j || !Array.isArray(j.entries)) throw new Error('bad shape');
        data = j;
      })
      .catch((e) => { err = String((e && e.message) || e); });   // stated in the panel, never thrown
  }

  function entryHTML(e) {
    const kind = KIND_LABEL[e.kind] || e.kind || '';
    const lic = e.licence === 'unverified' ? 'licence unverified' : e.licence;
    const n = Number.isFinite(e.count) && e.count > 0 ? ` · ${e.count}` : '';
    let h = '<div class="pc-cr-e"><div class="pc-cr-h">'
      + `<span class="pc-cr-n">${esc(e.name)}</span>`
      + `<span class="pc-cr-k">${esc(kind)}${esc(n)}</span>`
      + `<span class="pc-cr-lic">${esc(lic)}</span></div>`;
    if (e.used_for) h += `<div class="pc-cr-u">${esc(e.used_for)}</div>`;
    if (e.attribution) {
      h += '<div class="pc-cr-att"><b>' + (e.required ? 'ATTRIBUTION REQUIRED' : 'ATTRIBUTION')
        + `</b>${esc(e.attribution)}</div>`;
    }
    if (e.source) h += `<div class="pc-cr-src">${esc(e.source)}</div>`;
    if (e.flag) h += `<div class="pc-cr-flag"><b>OPEN LICENCE QUESTION</b>${esc(e.flag)}</div>`;
    return h + '</div>';
  }

  function render() {
    let body;
    if (data) {
      // required attributions first, then everything else — data-file order inside each group.
      const es = data.entries.slice();
      const idx = new Map(es.map((e, i) => [e, i]));
      es.sort((a, b) => (!!b.required - !!a.required) || (idx.get(a) - idx.get(b)));
      const req = es.filter((e) => e.required).length;
      const flags = es.filter((e) => e.flag).length;
      body = `<p class="pc-cr-note">${esc(data.notice || '')}</p>`
        + es.map(entryHTML).join('')
        + '<div class="pc-cr-foot"><span>'
        + `${es.length} entries · ${req} with a required attribution`
        + (flags ? ` · ${flags} open licence question${flags === 1 ? '' : 's'}` : '')
        + `</span><span>${esc(data.schema || '')}${data.updated ? ' · ' + esc(data.updated) : ''}</span></div>`;
    } else if (err === 'noassets') {
      body = '<p class="pc-cr-note">This boot is running with <b>?noassets=1</b> — no textures, models,'
        + ' audio or town data have been loaded, and the asset law forbids fetching the credits file'
        + ' either. There is nothing on screen to attribute beyond three.js (MIT, vendored) and the'
        + ' game\'s own code. The full list ships at <b>web/assets/credits.json</b>.</p>';
    } else {
      body = `<p class="pc-cr-note">The credits file could not be read (<b>${esc(err || 'unknown')}</b>).`
        + ' It ships at <b>web/assets/credits.json</b>; nothing has been guessed to fill the gap.</p>';
    }
    box.innerHTML = '<h2>CREDITS &amp; LICENCES</h2>'
      + '<p class="pc-cr-sub">What PROCITY is built from, and what each source asks for in return.</p>'
      + body
      + '<div class="pc-cr-foot"><span>Esc or F2 to close</span>'
      + '<button id="pc-credits-close">CLOSE</button></div>';
    const btn = box.querySelector('#pc-credits-close');
    if (btn) btn.onclick = () => setOpen(false);
  }

  function setOpen(v) {
    if (v === open) return;
    open = v;
    root.classList.toggle('on', open);
    if (!open) return;
    if (releasePointer) { try { releasePointer(); } catch { /* pointer lock is a nicety, never a throw */ } }
    render();                                   // the "loading"/settled state, whichever we're in
    load().then(() => { if (open) render(); });  // then the real list (or the stated failure)
  }

  function onKey(e) {
    if (e.code === 'F2') { e.preventDefault(); setOpen(!open); }
    else if (e.code === 'Escape' && open) setOpen(false);
  }
  addEventListener('keydown', onKey);
  root.addEventListener('click', (e) => { if (e.target === root) setOpen(false); });   // click the scrim

  return {
    open: () => setOpen(true),
    close: () => setOpen(false),
    toggle: () => setOpen(!open),
    get isOpen() { return open; },
    // read-only diag for the QA harness: no fetch has happened until `loaded` is true
    get state() { return { open, loaded, entries: data ? data.entries.length : 0, error: err }; },
    dispose() { removeEventListener('keydown', onKey); root.remove(); },
  };
}