combat-hud-hub/scripts/main.js

// combat-hud-hub — module entry point (v0.1.0).
//
// Generic combat HUD host. Consumer modules (its-achievable, future
// ones) register sections via the public API; the hub aggregates
// built-in core sections + consumer-registered feeds.
//
// Soft dependencies:
// - foundry-hooks-lib: subscribed for combat lifecycle envelopes
//   (combatStart, combatEnd, combatRound, combatTurn,
//   createCombatant, deleteCombatant, dnd5e.rollAttackV2,
//   dnd5e.rollDamageV2). If missing, core sections hide.
// - battle-focus: read the active encounter via the public seam
//   (battle-focus.api.getActiveEncounter()). If missing, core
//   sections hide.
// Consumer-registered sections work whether or not either is present.

const MODULE_ID = "combat-hud-hub";
const MODULE_VERSION = "0.1.0";

const COMBAT_HOOK_NAMES = [
  "combatStart",
  "combatEnd",
  "combatRound",
  "combatTurn",
  "createCombatant",
  "deleteCombatant",
  "dnd5e.rollAttackV2",
  "dnd5e.rollDamageV2",
];

// ── Section registry ───────────────────────────────────────────────────
// Sections are named slots other modules register. Each section owns a
// label, an optional list of feed entries, and a render(slot, ctx) fn
// that produces the section's inner HTML. The HUD orchestrates when
// render is called (throttled to 1Hz).

const _sections = new Map();
let _feedBySection = new Map(); // sectionId -> [entry, ...]

const api = {
  id: MODULE_ID,
  version: MODULE_VERSION,
  addSection(spec) {
    if (!spec || typeof spec !== "object") throw new Error("addSection: spec required");
    if (!spec.id) throw new Error("addSection: spec.id required");
    if (typeof spec.render !== "function") throw new Error("addSection: spec.render must be a function");
    const id = spec.id;
    _sections.set(id, { id, label: spec.label ?? id, render: spec.render });
    if (!_feedBySection.has(id)) _feedBySection.set(id, []);
    // Wrap the consumer's render so it receives a context that includes
    // the section's feed entries. The consumer can destructure.
    const entry = _sections.get(id);
    const originalRender = entry.render;
    entry.render = (ctx) => {
      const feed = _feedBySection.get(id) ?? [];
      return originalRender({ ...(ctx ?? {}), feed, section: entry });
    };
    return id;
  },
  removeSection(id) {
    _sections.delete(id);
    _feedBySection.delete(id);
  },
  listSections() {
    return Array.from(_sections.values());
  },
  pushFeedEntry(sectionId, entry) {
    if (!_feedBySection.has(sectionId)) _feedBySection.set(sectionId, []);
    _feedBySection.get(sectionId).push(entry);
  },
  getHud() {
    return hudInstance;
  },
  openHud() { hudInstance?.open?.(); },
  closeHud() { hudInstance?.close?.(); },
};

// ── Built-in core sections ─────────────────────────────────────────────
// These only register when foundry-hooks-lib AND battle-focus are both
// present at ready. They expose round / current turn / per-PC damage /
// dice streak. Detail implementation comes in v0.2.0 — for v0.1.0 the
// hub ships the public seam and soft-dep wiring; core sections
// themselves land in the next slice.

function _maybeRegisterCoreSections() {
  const hooksLibMod = game.modules.get("foundry-hooks-lib");
  const battleFocusMod = game.modules.get("battle-focus");
  const hooksLibActive = !!hooksLibMod?.active;
  const battleFocusActive = !!battleFocusMod?.active;
  if (!hooksLibActive || !battleFocusActive) return false;

  // core-round: simple round counter
  api.addSection({
    id: "core-round",
    label: "Round",
    render: (_slot, ctx) => {
      const r = ctx?.round ?? 0;
      return `<div class="chh-round">Round ${r}</div>`;
    },
  });

  // core-current-turn: turn number + actor name
  api.addSection({
    id: "core-current-turn",
    label: "Turn",
    render: (_slot, ctx) => {
      const t = ctx?.turn ?? 0;
      const name = ctx?.currentTurn?.name ?? "—";
      return `<div class="chh-turn">Turn ${t}: ${name}</div>`;
    },
  });

  // core-damage: per-PC dealt/taken
  api.addSection({
    id: "core-damage",
    label: "Damage",
    render: (_slot, ctx) => {
      const rows = (ctx?.combatants ?? []).map(c =>
        `<li>${c.name}: dealt ${c.dealt ?? 0} / taken ${c.taken ?? 0}</li>`
      ).join("");
      return `<ul class="chh-damage">${rows}</ul>`;
    },
  });

  return true;
}

// ── HUD instance placeholder ───────────────────────────────────────────
// v0.1.0 ships a minimal stub so the seam works. Real ApplicationV2
// wiring (open, render, throttle) lands in v0.2.0 alongside the
// ported hud.js.

let hudInstance = null;
function _ensureHud() {
  if (hudInstance) return hudInstance;
  hudInstance = {
    _lastRenderAt: 0,
    _state: undefined,
    _renderCtx: undefined,
    forceRender(ctx) {
      this._lastRenderAt = Date.now();
      // Walk every registered section and invoke its render fn. The
      // wrapper installed by addSection passes `{ feed, section, ...ctx }`.
      const html = [];
      for (const entry of _sections.values()) {
        try {
          html.push(`<section data-section="${entry.id}">${entry.render(this._renderCtx)}</section>`);
        } catch (e) {
          console.warn(`[${MODULE_ID}] section ${entry.id} render threw:`, e);
        }
      }
      this._state = html.join("");
      return this._state;
    },
    open() {},
    close() {},
    setRenderCtx(ctx) { this._renderCtx = ctx; },
  };
  return hudInstance;
}

// ── Lifecycle ──────────────────────────────────────────────────────────

Hooks.once("init", () => {
  const mod = game.modules.get(MODULE_ID);
  mod.api = api;
  console.log(`[${MODULE_ID} v${MODULE_VERSION}] init`);
});

Hooks.once("ready", () => {
  // Ensure the HUD stub exists so getHud/openHud/closeHud are reachable.
  _ensureHud();

  // Register core sections if both soft-deps are present.
  const coreRegistered = _maybeRegisterCoreSections();

  // Subscribe to foundry-hooks-lib if active.
  const hooksLibMod = game.modules.get("foundry-hooks-lib");
  const hooksLibApi = hooksLibMod?.active ? hooksLibMod.api : null;
  if (hooksLibApi?.subscribeMany) {
    hooksLibApi.subscribeMany(COMBAT_HOOK_NAMES, () => {
      // v0.1.0: just record that we received an envelope. v0.2.0 will
      // translate envelopes into a render context + call forceRender.
      hudInstance._lastReceivedAt = Date.now();
    });
    console.log(`[${MODULE_ID} v${MODULE_VERSION}] ready (subscribed to foundry-hooks-lib v${hooksLibApi.version ?? "?"}, core sections: ${coreRegistered})`);
  } else {
    console.warn(`[${MODULE_ID}] foundry-hooks-lib not installed or not active; combat envelopes will not be received`);
  }
});

export { api };