// Co-performance in the room page (WAI co-performance): what the room's statements say, shown
// as they arrive, and what this page sends or asks for.
//
// - The floor: the turn schedule in effect (WPT1) and its handovers (WPH1), who holds the floor
//   now and the turns ahead, in microseconds or bars at a tempo; the marks the room's clock
//   signs (WPM1) for an object out of turn or late.
// - What's next: each participant's intents (WPI1) as upcoming lines, and, once the instant has
//   passed, what played: kept, diverged or missed, read from the participant's own captions and
//   chats under the room's policy (WPP1); an AI participant's marked as an AI system's.
// - The audience: the selection window open now (WPW1), and, for a viewer whose grant carries
//   the audience-input power, its options or a prompt box; each window's commitment (WPK1) and
//   selection (WPS1) with its credits.
// - Fidelity: the clock's last fidelity statement (WPF1), each participant's kept of announced.
//
// A lead (a grant with the direct power) asks the room's clock to state a schedule, a handover
// or a window, and a fidelity statement, through the room service; the holder of a turn may
// hand it over. A performer's page sends media only while it holds the floor, a guard inside
// each turn, so that what it plays arrives in its turn; `playOutOfTurn` lifts that for a
// moment, as a pickup that starts before the bar line does.
//
// What a page shows is its own reading. The room's verification (co-performance §9, with
// wai-live-web's `Room.coVerify`) is what decides.

const GUARD_US = 150_000; // a performer's media starts this far into its turn and stops this far before its end
const STATEMENT_KIND = 0x01; // `meta` (live-events §4.2)
const TYPE_BIT = { prompt: 1, sketch: 2, vote: 4, movement: 8 };

export class Co {
  constructor(o) {
    Object.assign(this, o); // wai, log, $, nameOf, isAi, roomNow, me, grantOf, present, emit, emitDetached, api
    this.policy = JSON.parse(this.wai.coPolicy(o.policyBytes));
    this.windowUs = (this.policy.window_ms || 120) * 1000;
    this.schedules = []; // in the order held
    this.handovers = [];
    this.intents = [];
    this.said = {}; // principal -> [{t, text, digest}]
    this.marks = { out_of_turn: 0, late: 0, records: [] };
    this.windows = new Map(); // digest -> window
    this.inputs = new Map(); // digest -> input
    this.fidelity = null;
    this.sent = {}; // window digest -> inputs this page sent
    this.outOfTurnUntil = 0;
    this.lateNext = 0;
    this.statements = 0;
    this.requests = [];
  }

  // ---------------------------------------------------------------------------- the records

  // A record the room accepted (`v`, room.offer's view) and its bytes.
  onRecord(v, bytes) {
    if (v.kind_name === "chat" || v.kind_name === "caption") {
      (this.said[v.principal] = this.said[v.principal] || []).push({ t: v.t, text: v.payload && v.payload.text, digest: v.digest });
      return;
    }
    if (v.kind_name !== "meta") return;
    const s = JSON.parse(this.wai.coEventStatement(bytes));
    if (!s || !s.statement) return;
    this.statements++;
    const at = { t: v.t, principal: v.principal, digest: v.digest };
    switch (s.statement) {
      case "schedule": this.schedules.push({ ...s, ...at, order: this.statements }); break;
      case "handover": this.onHandover(s, at); break;
      case "intent": this.intents.push({ ...s, ...at }); break;
      case "mark":
        if (s.out_of_turn) this.marks.out_of_turn++;
        if (s.late) this.marks.late++;
        this.marks.records.push({ ...s, t: v.t });
        break;
      case "window": this.windows.set(v.digest, { ...s, ...at, inputs: [], commit: null, selection: null }); break;
      case "input": {
        this.inputs.set(v.digest, { ...s, ...at });
        const w = this.windows.get(s.window);
        if (w) w.inputs.push(v.digest);
        break;
      }
      case "commit": { const w = this.windows.get(s.window); if (w) w.commit = { ...s, ...at }; break; }
      case "selection": { const w = this.windows.get(s.window); if (w) w.selection = { ...s, ...at }; break; }
      case "fidelity": this.fidelity = { ...s, ...at }; break;
    }
    this.render();
  }

  onHandover(s, at) {
    const turn = this.turnAt(s.at);
    if (!turn || !turn.holders.includes(s.to)) return; // the room's verifier refuses it; nothing to show
    this.handovers.push({ ...s, ...at, schedule: turn.schedule.digest, segment: turn.segment, turn: turn.index, order: this.statements });
  }

  // ------------------------------------------------------------------------------ the floor

  scheduleAt(x) {
    for (let i = this.schedules.length - 1; i >= 0; i--) if (this.schedules[i].from <= x) return this.schedules[i];
    return null;
  }

  // The turn running at room-clock `x` (§6.2), with its holder at `x` (§6.3).
  turnAt(x) {
    const s = this.scheduleAt(x);
    if (!s) return null;
    for (let i = 0; i < s.segments.length; i++) {
      const g = s.segments[i];
      const L = g.turn_us;
      if (!L) continue;
      if (g.start <= x && x < g.start + g.turns * L) {
        const n = Math.floor((x - g.start) / L);
        const scheduled = g.holders[n % g.holders.length];
        const h = this.handovers.filter((h) => h.schedule === s.digest && h.segment === i && h.turn === n && h.at <= x).sort((a, b) => a.at - b.at || a.order - b.order).pop();
        return { schedule: s, segment: i, index: n, start: g.start + n * L, end: g.start + (n + 1) * L, scheduled, holder: h ? h.to : scheduled, holders: g.holders, role: g.pairs ? (n % 2 ? "response" : "call") : "solo", mode: s.mode, of: g.turns };
      }
    }
    return null;
  }

  // The turns ahead of `x`, under the schedule in effect at each.
  turnsAhead(x, n) {
    const out = [];
    let y = x;
    for (let i = 0; i < n; i++) {
      const t = this.turnAt(y);
      if (!t) {
        // The next segment or schedule to start, if any.
        const next = this.nextStart(y);
        if (next == null) break;
        y = next;
        continue;
      }
      out.push(t);
      y = t.end;
    }
    return out;
  }

  nextStart(y) {
    let best = null;
    for (const s of this.schedules) for (const g of s.segments) if (g.start > y && (best == null || g.start < best)) best = g.start;
    return best;
  }

  // Whether this page sends its media now: unless a schedule governs it and another holds the
  // floor, or the turn is within its guard of its start or end (§6.4).
  sends(x) {
    if (x < this.outOfTurnUntil) return true;
    const t = this.turnAt(x);
    if (!t || !t.holders.includes(this.me().principal)) return true;
    return t.holder === this.me().principal && x >= t.start + GUARD_US && x < t.end - GUARD_US;
  }

  // A moment out of turn, on purpose: a pickup before the bar line.
  playOutOfTurn(ms) {
    this.outOfTurnUntil = this.roomNow() + ms * 1000;
  }

  // The due instant the next audio object states is `ms` earlier than its capture: it arrives
  // that much later than its due instant.
  stampNextLate(ms) {
    this.lateNext = ms * 1000;
  }

  takeLate() {
    const l = this.lateNext;
    this.lateNext = 0;
    return l;
  }

  // ------------------------------------------------------------------------------- intents

  // What played for an intent so far (§5.4, text intents): the author's chat or caption nearest
  // its instant within the policy's window.
  outcome(i, now) {
    if (i.form !== "text") return i.at + this.windowUs < now ? "announced" : "upcoming";
    const near = (this.said[i.principal] || []).filter((x) => Math.abs(x.t - i.at) <= this.windowUs).sort((a, b) => Math.abs(a.t - i.at) - Math.abs(b.t - i.at))[0];
    if (near) return near.text === i.text ? "kept" : "diverged";
    return now > i.at + this.windowUs ? "missed" : "upcoming";
  }

  // Announce a line `inMs` ahead, and say `say` (the line itself unless given) at its instant,
  // as a caption a machine made when this page is an AI participant.
  async announce({ text, inMs = 1500, spanMs = 1000, say }) {
    const at = this.roomNow() + inMs * 1000;
    const p = this.wai.coEncode(JSON.stringify({ statement: "intent", at, span: spanMs * 1000, form: "text", text }));
    const view = await this.emit(STATEMENT_KIND, p);
    // Said a little before its instant, so that a timer that fires late still says it within
    // the policy's window of it (§5.4).
    const spoken = new Promise((resolve) => {
      setTimeout(async () => {
        try { resolve(await this.say(say == null ? text : say)); } catch (e) { resolve({ error: String(e) }); }
      }, Math.max(0, (at - this.roomNow()) / 1000 - 20));
    });
    this.spoken = spoken;
    return { at, intent: view.digest, spoken };
  }

  // ------------------------------------------------------------------------------ audience

  myGrant() {
    return this.grantOf(this.me().principal);
  }

  audienceLimit() {
    const g = this.myGrant();
    const a = g && g.attrs.find((x) => x[0] === "audience_input");
    return a ? Number(a[1]) : 0;
  }

  isLead() {
    const g = this.myGrant();
    return !!g && (g.powers & 2) !== 0;
  }

  openWindow(now) {
    const open = [...this.windows.values()].filter((w) => w.close > now);
    return open[open.length - 1] || null;
  }

  // An input to window `window` (§7.3): a vote's `option`, or a prompt's `text`.
  async input({ window, type, option, text }) {
    const p = this.wai.coEncode(JSON.stringify({ statement: "input", window, type, option, text }));
    const view = await this.emit(STATEMENT_KIND, p);
    this.sent[window] = (this.sent[window] || 0) + 1;
    this.render();
    return view;
  }

  // An input signed as this page's next record and sent, but not kept in its chain: for a test
  // that the relay withholds what §7.3 refuses, which nobody then receives.
  async inputDetached(desc) {
    let p;
    try { p = this.wai.coEncode(JSON.stringify({ statement: "input", ...desc })); } catch {
      // A body that does not read: a vote with a byte too many.
      const w = this.wai.coEncode(JSON.stringify({ statement: "input", window: desc.window, type: "vote", option: 0 }));
      p = new Uint8Array(w.length + 1);
      p.set(w);
    }
    return this.emitDetached(STATEMENT_KIND, p);
  }

  // ------------------------------------------------------------------- asking the room's clock

  async ask(path, body) {
    const r = await this.api(path, body || {});
    this.requests.push({ path, status: r.status, body: r.body });
    if (r.status !== 200) this.log(`co: ${path} answered ${r.status} ${JSON.stringify(r.body)}`);
    return r;
  }

  // Two-or-more holders trading turns of `seconds` (mode `mark` or `refuse`), starting soon.
  startTurns({ seconds = 4, turns = 4, mode = "mark", holders, pairs = false }) {
    const hs = holders || this.present().filter((p) => this.isPublisher(p));
    return this.ask("/co/schedule", { mode, beat_us: 0, beats_per_bar: 0, segments: [{ length: Math.round(seconds * 1e6), turns, pairs, holders: hs }] });
  }

  passFloor() {
    const t = this.turnAt(this.roomNow() + 400_000);
    if (!t) return Promise.resolve({ status: 0, body: { error: "no turn" } });
    const i = t.holders.indexOf(t.holder);
    return this.ask("/co/handover", { to: t.holders[(i + 1) % t.holders.length] });
  }

  openVote({ question, options = 3, seconds = 8 }) {
    return this.ask("/co/window", { rule: "plurality", options, k: 1, seconds, question });
  }

  askPrompts({ question, seconds = 8, k = 1, rule = "draw" }) {
    return this.ask("/co/window", { rule, types: ["prompt"], options: 0, k, seconds, question });
  }

  stateFidelity() {
    return this.ask("/co/fidelity", {});
  }

  // ------------------------------------------------------------------------------- the view

  render() {
    const $ = this.$;
    const sec = $("co");
    if (!sec) return;
    sec.hidden = false;
    const now = this.roomNow();
    const me = this.me();
    const name = (p) => (p === me.principal ? "you" : this.nameOf(p)) + (this.isAi(p) ? " (AI system)" : "");
    const s = (us) => `${(us / 1e6).toFixed(1)} s`;
    // The floor.
    const t = this.turnAt(now);
    const nowEl = $("co-now");
    if (nowEl) {
      nowEl.textContent = t
        ? `${name(t.holder)} ${t.holder === me.principal ? "hold" : "holds"} the floor · ${s(t.end - now)} left · turn ${t.index + 1} of ${t.of}${t.role === "solo" ? "" : ` (${t.role})`} · out of turn is ${t.mode === "refuse" ? "refused" : "marked"}`
        : this.schedules.length ? "The floor is open: no turn runs now." : "No turn schedule yet: the floor is open.";
      nowEl.dataset.holder = t ? t.holder : "";
    }
    const turnsEl = $("co-turns");
    if (turnsEl) {
      turnsEl.replaceChildren(...this.turnsAhead(now, 6).map((x) => {
        const li = document.createElement("li");
        li.dataset.holder = x.holder;
        li.textContent = `${x.start <= now ? "now" : `in ${s(x.start - now)}`}: ${name(x.holder)}${x.holder !== x.scheduled ? " (handed over)" : ""}${x.role === "solo" ? "" : `, ${x.role}`}`;
        return li;
      }));
    }
    const marksEl = $("co-marks");
    if (marksEl) marksEl.textContent = this.marks.out_of_turn + this.marks.late ? `Marked by the room's clock: ${this.marks.out_of_turn} out of turn, ${this.marks.late} late.` : "";
    // What's next.
    const intentsEl = $("co-intents");
    if (intentsEl) {
      const shown = this.intents.filter((i) => i.at + i.span > now - 20e6).slice(-8);
      intentsEl.replaceChildren(...shown.map((i) => {
        const li = document.createElement("li");
        const o = this.outcome(i, now);
        li.dataset.outcome = o;
        li.dataset.intent = i.digest;
        const what = i.form === "text" ? `“${i.text}”` : i.form === "object" ? `an object ${i.digest.slice(0, 8)}` : i.form;
        li.textContent = o === "upcoming" ? `${name(i.principal)} · next, in ${s(Math.max(0, i.at - now))}: ${what}` : `${name(i.principal)} · ${what} · ${o}`;
        return li;
      }));
    }
    // The audience.
    const w = this.openWindow(now);
    const q = $("co-question");
    if (q) q.textContent = w ? `${w.question || "The audience is asked"} · closes in ${s(w.close - now)}` : "No window is open.";
    const form = $("co-input");
    const limit = this.audienceLimit();
    const present = this.present().includes(me.principal);
    if (form) {
      const take = w && limit > 0 && present;
      form.hidden = !take;
      if (take && form.dataset.window !== w.digest) {
        form.dataset.window = w.digest;
        const opts = $("co-options");
        opts.replaceChildren();
        if (w.rule === "plurality") {
          for (let o = 0; o < w.options; o++) {
            const b = document.createElement("button");
            b.type = "button";
            b.textContent = `Option ${o + 1}`;
            b.dataset.option = String(o);
            b.addEventListener("click", () => this.input({ window: w.digest, type: "vote", option: o }).catch((e) => this.log(`co: ${e}`)));
            opts.appendChild(b);
          }
        }
        $("co-prompt-row").hidden = w.rule === "plurality";
      }
      const left = w ? limit - (this.sent[w.digest] || 0) : 0;
      if ($("co-left")) $("co-left").textContent = take ? `${left} of ${limit} input${limit === 1 ? "" : "s"} left` : "";
      for (const b of form.querySelectorAll("button")) b.disabled = left <= 0;
    }
    const selEl = $("co-selections");
    if (selEl) {
      const done = [...this.windows.values()].filter((x) => x.selection).slice(-4);
      selEl.replaceChildren(...done.map((x) => {
        const li = document.createElement("li");
        li.dataset.window = x.digest;
        const sel = x.selection;
        const picks = sel.picks.map((p, n) => {
          const c = sel.credits[n];
          if (p.option != null) return `option ${p.option + 1}, credited to its ${c.count} voter${c.count === 1 ? "" : "s"} together`;
          const inp = this.inputs.get(p.input);
          return `“${inp && inp.text != null ? inp.text : p.input.slice(0, 8)}”, credited to ${name(c.party)}`;
        });
        li.textContent = `${x.question || "a window"}: ${picks.length ? picks.join("; ") : "nothing selected"} (${x.commit ? x.commit.count : 0} input${x.commit && x.commit.count === 1 ? "" : "s"} committed, ${sel.rule})`;
        return li;
      }));
    }
    // Fidelity.
    const fEl = $("co-fidelity");
    if (fEl && this.fidelity) {
      fEl.replaceChildren(...this.fidelity.entries.map((e) => {
        const li = document.createElement("li");
        li.dataset.principal = e.principal;
        li.textContent = `${name(e.principal)}: kept ${e.kept} of ${e.announced} announced (${e.diverged} diverged, ${e.missed} missed)`;
        return li;
      }));
    }
    const lead = $("co-lead");
    if (lead) lead.hidden = !this.isLead();
    const pass = $("co-pass");
    if (pass) pass.hidden = !(t && (t.holder === me.principal || this.isLead()));
  }

  snapshot() {
    const now = this.roomNow();
    return {
      now,
      policy: this.policy,
      schedules: this.schedules.map((s) => ({ digest: s.digest, mode: s.mode, from: s.from, segments: s.segments })),
      handovers: this.handovers.map((h) => ({ digest: h.digest, at: h.at, to: h.to })),
      turn: this.turnAt(now),
      marks: { out_of_turn: this.marks.out_of_turn, late: this.marks.late },
      intents: this.intents.map((i) => ({ digest: i.digest, principal: i.principal, at: i.at, text: i.text, outcome: this.outcome(i, now) })),
      windows: [...this.windows.values()].map((w) => ({ digest: w.digest, rule: w.rule, close: w.close, question: w.question, inputs: w.inputs.length, commit: w.commit && { count: w.commit.count, digest: w.commit.digest }, selection: w.selection && { picks: w.selection.picks, credits: w.selection.credits } })),
      fidelity: this.fidelity && { t: this.fidelity.t, through: this.fidelity.through, entries: this.fidelity.entries, digest: this.fidelity.digest },
      audience: { limit: this.audienceLimit(), sent: this.sent },
      lead: this.isLead(),
      requests: this.requests.map((r) => ({ path: r.path, status: r.status })),
    };
  }
}

// The wiring of the section's controls (index.html), once the page has a Co.
export function wireControls(co, $, fail) {
  const on = (id, f) => { const el = $(id); if (el) el.addEventListener("click", () => f().catch(fail)); };
  const num = (id, d) => Number(($(id) || {}).value || d);
  on("co-start", () => co.startTurns({ seconds: num("co-turn-s", 4), turns: num("co-turns-n", 4), mode: ($("co-mode") || {}).value || "mark" }));
  on("co-pass", () => co.passFloor());
  on("co-vote", () => co.openVote({ question: ($("co-q") || {}).value || "Which way next?", options: num("co-options-n", 3), seconds: num("co-window-s", 8) }));
  on("co-prompts", () => co.askPrompts({ question: ($("co-q") || {}).value || "What should happen next?", seconds: num("co-window-s", 8) }));
  on("co-fid", () => co.stateFidelity());
  const form = $("co-input");
  if (form) form.addEventListener("submit", (e) => {
    e.preventDefault();
    const el = $("co-prompt");
    const text = el.value.trim();
    if (!text || !form.dataset.window) return;
    el.value = "";
    co.input({ window: form.dataset.window, type: "prompt", text }).catch(fail);
  });
}

export { GUARD_US, TYPE_BIT };