import "@fontsource/jetbrains-mono/400.css";
import "@fontsource/jetbrains-mono/500.css";
import "@fontsource/jetbrains-mono/600.css";
import "@fontsource/jetbrains-mono/700.css";
import { renderSidebar } from "./catalog.js";
import { ConnectionPool } from "./connections.js";
import { installDrawer, installDrawerSwipe, requestToggleDrawer } from "./drawer.js";
import { installHudKeybind } from "./debug.js";
import { installHelpKeybind, isHelpOpen } from "./help.js";
import { CommandSet, DEFAULT_LEADER, defineCommands, isTypingTarget } from "./commands.js";
import { isCommandBarOpen, openCommandBar } from "./commandBar.js";
import { DaemonLink } from "./daemonLink.js";
import { CatalogStore } from "./events.js";
import { installRestartOverlay } from "./restartOverlay.js";
import { shouldRetryClose } from "./reconnect.js";
import {
  createSession,
  fetchNames,
  getDaemonInfo,
  projects as fetchProjects,
} from "./api.js";
import {
  buildFastForwardRequest,
  fastForwardSeed,
  resolveFastForward,
} from "./fastForward.js";
import { FALLBACK_PRESETS } from "./spawnForm.js";
import { openSpawnModal } from "./spawnModal.js";
import { spawnSimilarProjectSeed, spawnSimilarSeed } from "./spawnSimilar.js";
import { mountHud, type Hud } from "./hud.js";
import { emptyLayout, type Layout, openSessions } from "./layout.js";
import { createMultiView, type MultiView } from "./multiview.js";
import { loadLayout, saveLayout } from "./persistence.js";
import { createPreviewSchedule } from "./previewSchedule.js";
import {
  FOCUS_PANE_EVENT,
  FOCUS_SIDEBAR_EVENT,
  OPEN_SPAWN_EVENT,
  SESSION_SELECT_EVENT,
  SPAWN_SIMILAR_EVENT,
} from "./catalog.js";
import { initTheme } from "./theme.js";
import { sessionName, type Project, type Session, type SpawnPreset } from "./types.js";
import { installViewportSizing } from "./viewport.js";
import "./styles.css";

initTheme();
installViewportSizing();
installHudKeybind();
installHelpKeybind();
registerServiceWorker();

// Register the PWA service worker so the app is installable and the shell loads
// offline. Production only — in dev the SW would fight Vite's HMR.
function registerServiceWorker(): void {
  if (import.meta.env.DEV) return;
  if (!("serviceWorker" in navigator)) return;
  window.addEventListener("load", () => {
    void navigator.serviceWorker.register("/sw.js").catch(() => {
      // Best-effort: a failed registration must never break the app.
    });
  });
}

const rootEl = document.getElementById("app");
if (!rootEl) {
  throw new Error("missing #app");
}
const root: HTMLElement = rootEl;

// Dev-only: `?kit` renders the standalone design kit instead of the app shell,
// so the component system can be reviewed as a whole. Stripped from production
// builds by Vite (dynamic import behind import.meta.env.DEV).
if (import.meta.env.DEV && location.search.includes("kit")) {
  void import("./kit.js").then((m) => root.replaceChildren(m.renderKit()));
} else {
  void bootApp();
}

async function bootApp(): Promise<void> {

const store = new CatalogStore();

// The daemon's home dir, for the command bar's `~/…` directory abbreviation.
// Absolute paths are a fine fallback until it lands.
let homeDir: string | undefined;
void getDaemonInfo()
  .then((info) => (homeDir = info.home_dir))
  .catch(() => {
    /* absolute paths are a fine fallback */
  });

// The daemon's identity and liveness: names the release in the sidebar's status
// dot, and blocks the UI behind the restart overlay while the daemon is away
// (docs/RESTART.md). The events socket is the trigger — it dies first.
const link = new DaemonLink();
installRestartOverlay(link);
store.subscribeConnection((up) => (up ? link.noteConnected() : link.noteDisconnected()));
void link.start();

store.start();

// Dev-only: `?mock` seeds a representative catalog so the UI can be reviewed
// without a running daemon. Stripped from production builds by Vite.
if (import.meta.env.DEV && location.search.includes("mock")) {
  void import("./mock.js").then((m) => m.seedMock(store));
}

// ---- persistent shell: sidebar (list) + content (welcome | attach) ----

const shellEl = document.createElement("div");
shellEl.className = "app-shell";
shellEl.dataset.route = "catalog";

// Forward-declared so the sidebar's drag hook can reach the controller (created
// after the welcome renderer). The hook only fires on user interaction, by which
// point `mv` is assigned.
let mv: MultiView;

// Preview timing (docs/PREVIEW.md): the first move shows at once, and a burst
// — j held down, or the pointer sweeping the whole list — is coalesced so it
// costs a couple of pane mounts instead of one per row walked.
const schedulePreview = createPreviewSchedule((sessionId) => {
  ensureMultiView();
  mv?.previewSession(sessionId);
  updateShellRoute();
});

const sidebar = renderSidebar(store, {
  onLeafDrag: (id, e) => mv?.beginSessionDrag(id, e),
  link,
  onPreview: schedulePreview,
});
const content = document.createElement("section");
content.className = "content";

// Mobile (issue #35): the sidebar is an off-canvas drawer toggled by the ☰ in
// the pane header (and the welcome state). `installDrawer` owns the close rules (session tap, Spawn, Spawn
// similar, backdrop); on desktop the class it toggles is inert.
const backdrop = document.createElement("div");
backdrop.className = "mv-backdrop";
const drawer = installDrawer(shellEl, sidebar.el, backdrop);
installDrawerSwipe(drawer);

shellEl.append(sidebar.el, content, backdrop);
root.replaceChildren(shellEl);

// The pool owns attach connections independently of the route: navigating away
// parks a session (keeps it streaming); navigating back re-mounts it instantly.
// It can mount several panes at once — the layout tree decides how many. For now
// the tree only ever holds a single leaf (splits/tabs arrive in epic #37); this
// routes the existing single-session view through that model.
// `mv` is forward-declared above (the sidebar drag hook needs it); the pool's
// disconnect callback below also references it.
let hud: Hud | undefined;
const pool = new ConnectionPool({
  onFocusChange: () => {
    // Sidebar highlighting is driven by the multi-view controller; the pool only
    // nudges the HUD here.
    hud?.refresh();
  },
  // Both the explicit disconnect (⏻) and a session ending on its own close the
  // pane — drop its leaf (collapsing the split) and tear down the socket. A dead
  // pane is never left lying around.
  onRequestClose: (id) => closePane(id),
  onClosed: (id) => closePane(id),
  shouldReconnect: (id, code) => shouldRetryClose(id, code, store.snapshot().sessions),
});

// Session death used to reach the UI on two uncoordinated channels — the row
// from the events socket, the pane from `ws.onclose` — so either could happen
// without the other. The catalog is the authority: a pane for a session that is
// no longer listed gets closed here.
store.subscribe((state) => {
  for (const id of mv?.openSessions() ?? []) {
    if (!state.sessions.has(id)) closePane(id);
  }
});

function closePane(id: string): void {
  pool.close(id);
  mv?.closeSession(id);
  updateShellRoute();
}

// Debug HUD (#20): a fixed-corner overlay on the active session's inferred
// fields, off by default (Ctrl+Shift+D, or `?hud` in dev).
hud = mountHud(root, store, () => pool.focused());

// ---- layout state ----
// Single source of truth for what's mounted: tabs of split trees. The hash route
// is just a deep-link into it (`#/attach/:id` focuses/opens a session). Restored
// from localStorage per device (issue #34); dead sessions self-prune on attach.
const layout: Layout = loadLayout() ?? emptyLayout();

// Debounced persist — the controller calls this after every layout change.
let saveTimer: number | undefined;
function scheduleSave(): void {
  clearTimeout(saveTimer);
  saveTimer = window.setTimeout(() => saveLayout(layout), 400);
}

function infoFor(sessionId: string) {
  const s = store.snapshot().sessions.get(sessionId);
  return s ? { name: sessionName(s), command: s.command } : undefined;
}

/** Drive the shell's responsive layout off whether any pane is open. */
function updateShellRoute(): void {
  // A preview is not an open pane (docs/PREVIEW.md), so the mobile shell does
  // not swap the list out for a terminal on the way past a row.
  const hasPanes = (mv?.openSessions() ?? openSessions(layout)).size > 0;
  shellEl.dataset.route = hasPanes ? "attach" : "catalog";
}

function renderWelcome(): HTMLElement {
  const el = document.createElement("div");
  el.className = "empty content-welcome";
  el.innerHTML = `
    <div class="empty-glyph" aria-hidden="true">⌘</div>
    <div class="empty-title">No session open</div>
    <p class="empty-hint">
      Pick a session from the list, or start a new one. Open sessions keep
      streaming in the background — switching back is instant.
    </p>
    <p class="empty-hint">Press <kbd>?</kbd> for keyboard shortcuts.</p>
    <div class="empty-actions"></div>`;
  const actions = el.querySelector(".empty-actions") as HTMLElement;
  // Mobile-only: with no pane open there is no pane header to carry the ☰, so
  // the drawer would be swipe-only. CSS hides this on desktop.
  const sessions = document.createElement("button");
  sessions.type = "button";
  sessions.className = "btn btn-ghost welcome-sessions";
  sessions.textContent = "☰ Sessions";
  sessions.addEventListener("click", () => requestToggleDrawer());
  actions.appendChild(sessions);
  const spawn = document.createElement("button");
  spawn.type = "button";
  spawn.className = "btn btn-primary";
  spawn.textContent = "+ Spawn session";
  spawn.title = "Draft pane: n — fast-forward spawn: N";
  spawn.addEventListener("click", () => requestOpenSpawn());
  actions.appendChild(spawn);
  return el;
}

function renderNotFound(raw: string): HTMLElement {
  const el = document.createElement("div");
  el.className = "not-found";
  el.innerHTML = `
    <h1>Unknown route</h1>
    <p><code>#${raw.replace(/[<&]/g, "")}</code> doesn't match anything.</p>
    <a class="btn btn-primary" href="#/">Back to catalog</a>`;
  return el;
}

// The multi-view controller renders tabs + splits inside the content pane and
// mounts a live attach into each session leaf.
mv = createMultiView({
  pool,
  layout,
  sidebar,
  infoFor,
  onDisconnect: closePane,
  renderWelcome,
  // A spawn fills a pane with its new session; the shell route may flip from
  // catalog (no sessions) to attach.
  onOpenSessionsChange: updateShellRoute,
  onLayoutChange: scheduleSave,
});
let contentShowsMv = false;
/** Put the multi-view in the content pane, without rendering it. A preview
 *  renders once, on its own terms (`docs/PREVIEW.md`); a render here would
 *  first re-mount the pane it is about to replace, and that mount takes the
 *  keyboard away from the list being walked. */
function ensureMultiView(): void {
  if (!contentShowsMv) {
    content.replaceChildren(mv.el);
    contentShowsMv = true;
  }
}
function showMultiView(): void {
  ensureMultiView();
  mv.render();
  updateShellRoute();
}

// Spawn affordances: the sidebar's footer button, its empty state, and
// `?mock&spawn` all open the spawn modal; "Spawn similar" seeds one from the
// cloned session (see spawnSimilar.ts).
function requestOpenSpawn(): void {
  // The session lands in a new tab, not a split of the pane you were reading
  // (#100). "Spawn similar" and the fast-forward key below deliberately keep
  // the old behaviour: both act on the session in front of you, so a split
  // beside it is the point.
  // The session you were last on preselects its project: `n` then Enter spawns
  // another session there without touching the picker.
  const current = focusedSession();
  openSpawnModal({
    seed: current ? spawnSimilarProjectSeed(current) : undefined,
    onSuccess: (session) => mountSpawned(session, { newTab: true }),
  });
}

/** The session the operator was last on, if any. Shared by the plain spawn
 *  modal seed and fast-forward's project pick: both should land on "where I
 *  currently am". */
function focusedSession(): Session | undefined {
  const focused = mv?.focusedSessionId() ?? null;
  return focused ? store.snapshot().sessions.get(focused) : undefined;
}

/** The focused session's project — its base repo for a worktree session, its
 *  cwd otherwise (same rule as spawnSimilarProjectSeed). */
function focusedProjectCwd(): string | undefined {
  const s = focusedSession();
  if (!s) return undefined;
  return s.worktree ? s.worktree.base_repo : s.cwd;
}
document.addEventListener(OPEN_SPAWN_EVENT, () => requestOpenSpawn());
document.addEventListener(SPAWN_SIMILAR_EVENT, (ev) => {
  const s = (ev as CustomEvent<Session>).detail;
  openSpawnModal({ seed: spawnSimilarSeed(s), onSuccess: (session) => mountSpawned(session) });
});

/** Show a freshly spawned session: bring the multi-view up (the shell may still
 *  be on the catalog route) and give the session a pane. */
function mountSpawned(session: Session, placement?: { newTab?: boolean }): void {
  showMultiView();
  mv.openSessionBeside(session.id, placement);
  updateShellRoute();
}

// Fast-forward spawn (#67): the spawn modal's keystroke neighbour spawns
// immediately with every default resolved — most recent project, its last
// command (or the first non-custom preset), a fresh name, worktree on with
// a new branch named after that name. Anything unresolvable (no projects
// known yet, no command, no generated name) opens the form pre-filled with
// what did resolve instead.
async function requestFastForward(): Promise<void> {
  const [discovered, name] = await Promise.all([
    fetchProjects().catch(() => [] as Project[]),
    fetchNames(1)
      .then((batch) => batch.names[0])
      .catch(() => undefined),
  ]);
  let presets: SpawnPreset[] = FALLBACK_PRESETS;
  try {
    const info = await getDaemonInfo();
    if (info.presets?.length) presets = info.presets;
  } catch {
    /* keep fallbacks */
  }
  const resolved = resolveFastForward(discovered, presets, name, focusedProjectCwd());
  const req = buildFastForwardRequest(resolved);
  if (req) {
    try {
      const session = await createSession(req);
      // Mount it, the way the TUI's fast path attaches. Without this the
      // keystroke creates a session and leaves the UI untouched, so it reads
      // as a dead key (#67 review).
      mountSpawned(session);
      return;
    } catch {
      // A failed POST degrades to the same pre-filled form as an
      // unresolvable default — never a silent dead keystroke.
    }
  }
  openSpawnModal({
    seed: fastForwardSeed(resolved),
    onSuccess: (session) => mountSpawned(session),
  });
}

// The global half of the command registry (#148). Two sets, because they
// differ in one thing: the help overlay owns the keyboard while it is up, so
// the plain keys go deaf behind it while the focus chord does not — an
// attached terminal must never be able to trap the focus keys.
//
// `n` opens the spawn modal, `N` fast-forwards a spawn (#67). Both are plain
// keys, so `isTypingTarget` keeps them out of form fields and the terminal's
// hidden textarea.
const spawnKeys = new CommandSet(
  defineCommands({
    "spawn.open": () => requestOpenSpawn(),
    "spawn.fastForward": () => void requestFastForward(),
  }),
);

// Ctrl+Shift+H moves the keyboard between the session list and the pane, the
// web counterpart of the TUI's `ctrl-w h`. It has to be a chord: an attached
// terminal owns every plain keystroke, so nothing unmodified could ever get
// the focus back out of it.
//
// This set also owns the leader (`ctrl-a`, the TUI's default): it holds the
// key as a partial chord and takes select-all off it, so the escape hatch
// docs/COMMAND-BAR.md describes has somewhere to land (#149).
const focusKeys = new CommandSet(
  defineCommands({
    "focus.toggle": () => {
      if (sidebar.hasListFocus()) {
        pool.focusTerminal();
      } else {
        drawer.open(); // no-op on desktop; on mobile the list is off-canvas
        sidebar.focusList();
      }
    },
  }),
  { leader: DEFAULT_LEADER },
);

// Ctrl+K opens the command bar (docs/COMMAND-BAR.md). It is a registry command
// like any other, so the `?` overlay lists it without a second list.
const barKeys = new CommandSet(
  defineCommands({
    "bar.open": () => {
      // Opening while a session is previewed discards the preview first, like
      // any other real change (docs/PREVIEW.md): the bar is not previewed into.
      schedulePreview.cancel();
      mv?.previewSession(null);
      openCommandBar({ sessions: [...store.snapshot().sessions.values()], homeDir });
    },
  }),
);

// Capture phase: an attached xterm swallows every keystroke it is given, so the
// bar's binding has to be seen ahead of the terminal (docs/COMMAND-BAR.md).
window.addEventListener(
  "keydown",
  (e) => {
    // The bar owns the keyboard while it is up; its own input handles the keys.
    if (isCommandBarOpen()) return;
    if (focusKeys.handle(e)) return;
    // The help overlay owns the keyboard while it is up.
    if (isHelpOpen()) return;
    // Opening the bar over a focused terminal is #152; until then the pane's
    // hidden textarea keeps its Ctrl+K, like any other typing target.
    if (!isTypingTarget(e.target) && barKeys.handle(e)) return;
    spawnKeys.handle(e);
  },
  true,
);


// Tab in the session list hands the keyboard to the pane; Escape in the pane
// hands it back — the pair the TUI gets from `tab` and `esc`.
document.addEventListener(FOCUS_PANE_EVENT, () => {
  // Handing the keyboard to a previewed pane is choosing it: the preview stops
  // being provisional rather than snapping back the moment the list blurs.
  const previewed = mv.previewedSessionId();
  if (previewed) focusSession(previewed);
  pool.focusTerminal();
});
document.addEventListener(FOCUS_SIDEBAR_EVENT, () => {
  drawer.open(); // no-op on desktop; on mobile the list is off-canvas
  sidebar.focusList();
});

/** Open/focus a session and reflect it in the shell chrome. Shared by the
 *  hash router and the sidebar's click-driven path (#133), which can't rely
 *  on `hashchange` alone — a split or drag can move focus without the hash
 *  changing, leaving a click back onto that session's row silently ignored. */
function focusSession(sessionId: string): void {
  schedulePreview.cancel();
  showMultiView();
  mv.openSession(sessionId);
  updateShellRoute();
}

document.addEventListener(SESSION_SELECT_EVENT, (e) => {
  focusSession((e as CustomEvent<string>).detail);
});

type Route =
  | { kind: "catalog" }
  | { kind: "attach"; sessionId: string }
  | { kind: "not-found"; raw: string };

function parseRoute(): Route {
  const hash = location.hash.replace(/^#/, "");
  if (hash === "" || hash === "/") return { kind: "catalog" };
  const m = hash.match(/^\/attach\/([^/?#]+)$/);
  if (m) return { kind: "attach", sessionId: decodeURIComponent(m[1]) };
  return { kind: "not-found", raw: hash };
}

function dispatch(): void {
  const route = parseRoute();
  switch (route.kind) {
    case "attach":
      // Deep-link: open/focus the session, then show the layout.
      focusSession(route.sessionId);
      return;
    case "not-found":
      shellEl.dataset.route = "notfound";
      pool.setVisible([]);
      pool.setFocus(null);
      content.replaceChildren(renderNotFound(route.raw));
      contentShowsMv = false;
      return;
    case "catalog":
      // Show the current layout (welcome if empty) — navigating to #/ no longer
      // tears panes down.
      showMultiView();
      return;
  }
}

window.addEventListener("hashchange", dispatch);
dispatch();

} // bootApp