// src/web/public/tile-grid.js

/**
 * @fileoverview The tile grid: 1 to 9 live sessions side by side in one
 * window, each in its own TerminalTile (terminal-tile.js), laid out by count
 * (window.CodemanTileGrid, constants.js). Desktop only; see
 * docs/tile-grid-plan.md.
 *
 * While the grid is open the main terminal (terminal-ui.js) is PARKED: hidden,
 * its socket closed, and every path that would write to it, fetch for it or
 * reconnect it stands aside (`_tilesOwnTerminal()`). `activeSessionId` always
 * names the FOCUSED tile's session, so everything keyed on it (files panel,
 * respawn and Ralph panels, subagent windows, voice, image paste, the tab
 * highlight) follows focus without knowing tiles exist.
 *
 * Every capture a tile fetches goes through the grid's one TileLoadQueue,
 * because each is a synchronous tmux call on the server.
 *
 * @dependency terminal-tile.js (window.TerminalTile, window.TileLoadQueue)
 * @dependency constants.js (window.CodemanTileGrid, SPLIT_PANE_MIN_WIDTH)
 * @loadorder 7.6 of 16, loaded after terminal-split.js and before respawn-ui.js
 */

// Per-device tile font size (a tile is a fraction of the screen).
const TILE_GRID_FONT_KEY = 'codeman-tile-font-size';
// Trailing debounce for refitting tiles after the grid area changes size, so a
// window drag sends each tile's PTY one resize, not one per frame.
const TILE_GRID_REFIT_MS = 150;

/** The grid's state. `has(id)` answers only while it is open. */
class TileGridModel {
  constructor() {
    this.open = false;
    // Session ids in reading order (row-major).
    this.ids = [];
    // id -> { tile: TerminalTile, el: HTMLElement }
    this.tiles = new Map();
    this.focusedId = null;
    this.cols = 0;
    this.rows = 0;
    this.queue = null;
    this.resizeObserver = null;
    this.refitTimer = null;
  }

  has(id) {
    return this.open && this.tiles.has(id);
  }
}

Object.assign(CodemanApp.prototype, {
  /**
   * True while the grid owns the terminal area and the main terminal is parked.
   * Every main-terminal path that would write, fetch, resize or reconnect checks
   * this and stands aside.
   */
  _tilesOwnTerminal() {
    return !!this._tileGrid?.open;
  },

  /** The open grid's TerminalTile for a session, or null. */
  _tileFor(sessionId) {
    return this._tileGrid?.open ? (this._tileGrid.tiles.get(sessionId)?.tile ?? null) : null;
  },

  /** Desktop only, never in a solo (popped-out) window; same gate as the split. */
  canOpenTileGrid() {
    return !this.isSoloWindow && window.innerWidth >= SPLIT_PANE_MIN_WIDTH;
  },

  _tileGridFontSize() {
    let saved = NaN;
    try {
      saved = parseInt(localStorage.getItem(TILE_GRID_FONT_KEY), 10);
    } catch {
      /* Storage unavailable: the default below. */
    }
    return saved >= 10 && saved <= 24 ? saved : window.CodemanTileGrid.TILE_FONT_SIZE_DEFAULT;
  },

  /** Ctrl +/- while the grid is open: every tile, then each tile's PTY (a font change is a size change, #464). */
  setTileFontSize(size) {
    try {
      localStorage.setItem(TILE_GRID_FONT_KEY, String(size));
    } catch {
      /* Per-device convenience only. */
    }
    for (const { tile } of this._tileGrid?.tiles.values() || []) {
      tile.fontSize = size;
      if (!tile.terminal) continue;
      tile.terminal.options.fontSize = size;
      tile.fit();
    }
  },

  _tileLoadQueue() {
    const grid = this._tileGrid;
    if (!grid.queue) {
      grid.queue = new window.TileLoadQueue({
        // The focused tile first, then reading order.
        rank: (tile) => (tile.sessionId === grid.focusedId ? -1 : grid.ids.indexOf(tile.sessionId)),
        // A quiet "loading" state on a tile until its capture has landed.
        onChange: (tile, state) => {
          const entry = grid.tiles.get(tile.sessionId);
          if (entry?.tile === tile) entry.el.classList.toggle('tile--loading', state !== 'idle');
        },
      });
    }
    return grid.queue;
  },

  _tileGridSection() {
    let section = document.getElementById('tileGrid');
    if (!section) {
      section = document.createElement('section');
      section.id = 'tileGrid';
      section.className = 'tile-grid';
      section.setAttribute('aria-label', 'Tiled sessions');
      const wrap = document.querySelector('.terminal-wrap');
      wrap?.parentElement?.insertBefore(section, wrap.nextSibling);
    }
    return section;
  },

  /**
   * Opens the grid on `ids` (unknown, detached and duplicate ids are skipped;
   * at most TILE_GRID_MAX), focusing `focusedId` or the first. Already open, it
   * adds what is missing and moves focus. `auto: false` makes the focus a human
   * selection (it acknowledges that session's idle alert).
   *
   * Parks the main terminal first: `_cleanupPreviousSession()` runs ONCE, while
   * its snapshot of the session it shows is still right, and closes its socket.
   *
   * @returns {boolean} whether the grid is open afterwards
   */
  openTileGrid(ids, { focusedId = null, auto = true } = {}) {
    if (!this.canOpenTileGrid()) return false;
    const grid = (this._tileGrid ||= new TileGridModel());
    const max = window.CodemanTileGrid.TILE_GRID_MAX;
    const wanted = [];
    for (const id of ids || []) {
      if (typeof id !== 'string' || wanted.includes(id)) continue;
      if (!this.sessions.has(id) || this.detachedSessions?.has(id)) continue;
      wanted.push(id);
      if (wanted.length === max) break;
    }
    if (wanted.length === 0) return grid.open;
    const focus = wanted.includes(focusedId) ? focusedId : wanted[0];

    if (grid.open) {
      for (const id of wanted) this.addTile(id);
      if (grid.has(focus)) this._selectTiledSession(focus, { auto });
      return true;
    }

    this._cleanupPreviousSession(focus);
    grid.open = true;
    grid.ids = [];
    grid.focusedId = focus;
    document.querySelector('.main')?.classList.add('tiles-active');
    const section = this._tileGridSection();
    this.hideWelcome();
    // Mount every tile and lay the grid out BEFORE any tile connects, so each
    // first fit measures its real cell; the focused tile connects first, so
    // its capture is the one the queue starts with.
    for (const id of wanted) this._mountTile(id);
    this._applyTileLayout();
    for (const id of [focus, ...wanted.filter((id) => id !== focus)]) this._connectTile(id);
    if (!grid.resizeObserver && typeof ResizeObserver !== 'undefined') {
      // The main terminal's observer watches a node that is now hidden; this one
      // catches window resizes, sidebar toggles and rail drags for the grid.
      grid.resizeObserver = new ResizeObserver(() => this._scheduleTileGridRefit());
      grid.resizeObserver.observe(section);
    }
    this._installTileGridWidthGate();
    this._selectTiledSession(focus, { auto });
    this._updateConnectionIndicator?.();
    return true;
  },

  /**
   * Leaves the grid: every tile destroyed (sockets closed, xterms disposed,
   * queued loads dropped), the main terminal unparked.
   *
   * `keepStored` remembers the grid for one-click return (toggleTileGrid).
   * `reselect` shows the focused session in the single view through a forced
   * reload; pass false when the caller selects something itself.
   *
   * The main terminal's cached content for EVERY tiled id is invalidated: it was
   * written before the grid opened, possibly hours ago, and selectSession paints
   * a snapshot as its first frame.
   */
  closeTileGrid({ keepStored = true, reselect = true } = {}) {
    const grid = this._tileGrid;
    if (!grid?.open) return;
    const focusedId = grid.focusedId;
    const ids = grid.ids.slice();
    this._tileGridRemembered = keepStored ? { ids, focusedId } : null;
    // Closed BEFORE the tiles go: each destroy() updates the header's connection
    // state, which must read the main terminal again, not half-destroyed tiles.
    grid.open = false;
    clearTimeout(grid.refitTimer);
    grid.refitTimer = null;
    grid.resizeObserver?.disconnect();
    grid.resizeObserver = null;
    for (const { tile, el } of grid.tiles.values()) {
      grid.queue?.drop(tile);
      tile.destroy();
      el.remove();
    }
    grid.tiles.clear();
    grid.ids = [];
    grid.focusedId = null;
    document.querySelector('.main')?.classList.remove('tiles-active');
    const section = document.getElementById('tileGrid');
    if (section) {
      section.style.gridTemplateColumns = '';
      section.style.gridTemplateRows = '';
    }
    // As _redock does: the tiles sized these PTYs, so the main terminal's
    // record of the last size it sent no longer describes them.
    this._lastResizeDims = null;
    for (const id of ids) {
      this._xtermSnapshots?.delete(id);
      try {
        localStorage.removeItem(`codeman-xs-${id}`);
      } catch {
        /* Nothing stored. */
      }
      this.terminalBufferCache?.delete(id);
    }
    this._updateConnectionIndicator?.();
    if (reselect) this._selectAfterTileGrid(focusedId);
  },

  // The single view after the grid closes: the session the grid was focused on,
  // replayed fresh (forceReload drops the stale snapshot and nulls
  // activeSessionId BEFORE _cleanupPreviousSession, so nothing wrong is saved),
  // or, if that session is gone, the same fallback as closing the active tab.
  _selectAfterTileGrid(sessionId) {
    if (sessionId && this.sessions.has(sessionId)) {
      this.selectSession(sessionId, { forceReload: true, auto: true });
      return;
    }
    this.activeSessionId = null;
    try {
      localStorage.removeItem('codeman-active-session');
    } catch {
      /* Nothing stored. */
    }
    const next = this.sessionOrder.find((id) => this.sessions.has(id));
    if (next) {
      this.selectSession(next, { auto: true });
    } else {
      this.terminal?.clear();
      this.showWelcome();
    }
  },

  /** Adds one session as a tile (open grid only). Returns whether it was added. */
  addTile(sessionId) {
    const grid = this._tileGrid;
    if (!grid?.open || grid.tiles.has(sessionId)) return false;
    if (grid.ids.length >= window.CodemanTileGrid.TILE_GRID_MAX) return false;
    if (!this._mountTile(sessionId)) return false;
    this._applyTileLayout();
    this._connectTile(sessionId);
    this._scheduleTileGridRefit();
    return true;
  },

  /**
   * Removes one tile; the session keeps running. When it held focus, `refocus`
   * moves focus to the neighbouring tile (next in grid order, else previous).
   * The last tile leaving closes the grid: with `refocus` the single view then
   * shows that session, without it the caller decides what comes next.
   */
  removeTile(sessionId, { refocus = true, auto = true } = {}) {
    const grid = this._tileGrid;
    const entry = grid?.open ? grid.tiles.get(sessionId) : null;
    if (!entry) return false;
    if (grid.ids.length === 1) {
      this.closeTileGrid({ keepStored: false, reselect: refocus });
      return true;
    }
    const wasFocused = grid.focusedId === sessionId;
    const neighbor = window.CodemanTileGrid.tileNeighbor(grid.ids, sessionId);
    grid.queue?.drop(entry.tile);
    entry.tile.destroy();
    entry.el.remove();
    grid.tiles.delete(sessionId);
    grid.ids.splice(grid.ids.indexOf(sessionId), 1);
    this._applyTileLayout();
    this._scheduleTileGridRefit();
    if (wasFocused) {
      grid.focusedId = null;
      if (refocus && neighbor) this._selectTiledSession(neighbor, { auto });
    }
    return true;
  },

  _mountTile(sessionId) {
    const grid = this._tileGrid;
    const session = this.sessions.get(sessionId);
    if (!session || this.detachedSessions?.has(sessionId)) return false;
    const el = document.createElement('div');
    el.className = 'tile';
    el.dataset.sessionId = sessionId;
    const body = document.createElement('div');
    body.className = 'tile-body';
    el.appendChild(body);
    // Pressing a tile is a human selection: it focuses the tile and
    // acknowledges its idle alert (the already-focused tile hits
    // selectSession's early return, which acknowledges too). pointerdown, not
    // click, so focus moves before the press reaches xterm, and never
    // preventDefault: xterm's own mousedown focuses its textarea and starts
    // selections.
    el.addEventListener('pointerdown', () => {
      if (this._tileGrid?.has(sessionId)) this.selectSession(sessionId);
    });
    this._tileGridSection().appendChild(el);
    const tile = new window.TerminalTile(sessionId, body, {
      mode: session.mode,
      fontSettings: this.loadAppSettingsFromStorage?.() || {},
      detachedSessions: this.detachedSessions,
      scheduleLoad: (t, kind, run) => this._tileLoadQueue().schedule(t, kind, run),
      scrollback: window.CodemanTileGrid.TILE_SCROLLBACK,
      fontSize: this._tileGridFontSize(),
      boundedLoad: true,
      onExit: (code) => this._onTileExit(sessionId, tile, code),
    });
    grid.tiles.set(sessionId, { tile, el });
    grid.ids.push(sessionId);
    return true;
  },

  _connectTile(sessionId) {
    this._tileGrid?.tiles
      .get(sessionId)
      ?.tile.connect()
      .catch(() => {
        /* Best-effort, as the split's Pane B: live output arrives once the socket opens. */
      });
  },

  /**
   * A tile's socket stopped for good. 4009 (the session exited) keeps the tile
   * with its "session ended" marker; 4003 (refused), 4004 (session gone) and
   * 4010 (another socket took over) remove it.
   */
  _onTileExit(sessionId, tile, code) {
    if (this._tileGrid?.tiles.get(sessionId)?.tile !== tile) return;
    if (code === 4009) return;
    this.removeTile(sessionId, { refocus: true, auto: true });
  },

  /** Columns x rows for the current tile count, applied to the grid section. */
  _applyTileLayout() {
    const grid = this._tileGrid;
    const section = this._tileGridSection();
    const rect = section.getBoundingClientRect?.() || { width: 0, height: 0 };
    const { cols, rows } = window.CodemanTileGrid.computeTileLayout({
      count: grid.ids.length,
      width: rect.width || window.innerWidth,
      height: rect.height || window.innerHeight,
    });
    grid.cols = cols;
    grid.rows = rows;
    section.style.gridTemplateColumns = `repeat(${cols}, minmax(0, 1fr))`;
    section.style.gridTemplateRows = `repeat(${rows}, minmax(0, 1fr))`;
  },

  // Refits every tile once the grid area has settled: one xterm resize and one
  // PTY resize together per tile (#464), on the trailing edge.
  _scheduleTileGridRefit() {
    const grid = this._tileGrid;
    if (!grid?.open) return;
    clearTimeout(grid.refitTimer);
    grid.refitTimer = setTimeout(() => {
      grid.refitTimer = null;
      if (!grid.open) return;
      // The 3-tile layout depends on the width (3x1 or 2x2).
      this._applyTileLayout();
      for (const { tile } of grid.tiles.values()) tile.fit();
    }, TILE_GRID_REFIT_MS);
  },

  // Narrowing the window past the desktop gate returns to the single view of the
  // focused session; the grid is remembered.
  _installTileGridWidthGate() {
    if (this._tileGridWidthGateInstalled || !window.matchMedia) return;
    this._tileGridWidthGateInstalled = true;
    const mq = window.matchMedia(`(min-width: ${SPLIT_PANE_MIN_WIDTH}px)`);
    mq.addEventListener('change', (e) => {
      if (!e.matches && this._tileGrid?.open) this.closeTileGrid({ keepStored: true, reselect: true });
    });
  },

  _paintTileFocus() {
    const grid = this._tileGrid;
    for (const [id, { el }] of grid?.tiles || []) el.classList.toggle('focused', id === grid.focusedId);
  },

  /**
   * Focuses a tiled session: the tile branch of selectSession. Moving focus is
   * an `activeSessionId` change plus `xterm.focus()`: no fetch, no replay. It
   * runs the panel refresh a normal switch runs and skips everything bound to
   * the main terminal (cleanup, replay, resize, its socket, local echo). Only a
   * USER-initiated selection (`auto` not true) acknowledges the idle alert.
   *
   * @param {string} sessionId
   * @param {{auto?: boolean, focus?: boolean}} [options] - `focus: false` leaves
   *   DOM focus where it is (an app-driven reconcile must not steal it)
   */
  _selectTiledSession(sessionId, options = {}) {
    const grid = this._tileGrid;
    const entry = grid?.open ? grid.tiles.get(sessionId) : null;
    if (!entry) return;
    const userInitiated = options.auto !== true;
    // Aborts any in-flight normal select at its next _isStaleSelect check.
    const selectGen = ++this._selectGeneration;
    this._hideWebviewLayer?.();
    this.activeSessionId = sessionId;
    grid.focusedId = sessionId;
    this._activateFileBrowserSession?.(sessionId);
    try {
      localStorage.setItem('codeman-active-session', sessionId);
    } catch {
      /* Per-device convenience only. */
    }
    // The SSE subscription follows the focused session as in the single view;
    // its terminal frames are dropped by the parking guards.
    this._updateSseSubscription?.(sessionId);
    this.hideWelcome();
    if (userInitiated) this.markIdleAlertSeen(sessionId);
    this._paintTileFocus();
    this._updateActiveTabImmediate?.(sessionId);
    this.closeSessionSidebarOnHandheld?.();
    this.renderSessionTabs?.();
    const activeTab = document.querySelector(`.session-tab.active[data-id="${sessionId}"]`);
    if (activeTab) {
      activeTab.classList.add('tab-glow');
      activeTab.addEventListener('animationend', () => activeTab.classList.remove('tab-glow'), { once: true });
    }
    this.updateAttachmentHistoryBadge?.();
    if (this.attachmentHistoryDrawerOpen) this.loadAttachmentHistory?.(sessionId);
    if (typeof KeyboardAccessoryBar !== 'undefined') KeyboardAccessoryBar.refreshForActiveSession();
    this.refreshHostWakeBanner?.(sessionId);
    this.currentSessionWorkingDir = this.sessions.get(sessionId)?.workingDir || null;
    const idleCb = typeof requestIdleCallback === 'function' ? requestIdleCallback : (cb) => setTimeout(cb, 16);
    idleCb(() => this._refreshSessionPanels(sessionId, selectGen));
    // The keyboard follows focus: shortcuts, voice and paste act on this tile.
    this._noteFocusedTile(entry.tile);
    if (options.focus !== false) entry.tile.terminal?.focus();
  },

  /** Header connection state while tiles own the terminal: every live tile socket open, or not. */
  _tileGridSocketState() {
    for (const { tile } of this._tileGrid?.tiles.values() || []) {
      // A tile stopped for good (its session exited) has nothing to reconnect.
      if (tile._stoppedCode !== null && tile._stoppedCode !== undefined) continue;
      if (!tile._wsReady) return 'reconnecting';
    }
    return 'connected';
  },

  /**
   * handleInit (page state reloaded, or SSE back after a server restart) with
   * the grid open: tiles whose sessions are gone or popped out are removed, the
   * rest are KEPT (never rebuilt) and told to reconnect now instead of waiting
   * out their backoff, and focus stays on a live tile.
   *
   * @returns {boolean} whether the grid is still open (handleInit then skips
   *   restoring the main terminal)
   */
  _reconcileTileGrid() {
    const grid = this._tileGrid;
    if (!grid?.open) return false;
    for (const id of grid.ids.slice()) {
      if (!this.sessions.has(id) || this.detachedSessions?.has(id)) this.removeTile(id, { refocus: false });
    }
    if (!grid.open) return false;
    // Only a focus that is gone moves: re-selecting the same tile would hide an
    // active web tab on every SSE blip (_selectTiledSession hides the web layer),
    // which the single view's reconnect never does.
    if (!grid.has(grid.focusedId)) this._selectTiledSession(grid.ids[0], { auto: true });
    for (const { tile } of grid.tiles.values()) tile.reconnectNow();
    return true;
  },
});

// A tiled session deleted (here or elsewhere) loses its tile; if it held focus,
// the neighbouring tile takes it (`auto`: the app chose, so no idle alert is
// spent). Done BEFORE the original handler, so activeSessionId no longer names
// the deleted id and its welcome-screen handoff stays out of it. The last tile
// closes the grid without a reselect, and the original handler then shows the
// welcome screen as in the single view. A close started from this tab
// (closeSession, in _closingSessions) owns its own follow-up: only the tile goes.
const _tileGridOriginalOnSessionDeleted = CodemanApp.prototype._onSessionDeleted;
CodemanApp.prototype._onSessionDeleted = function (data) {
  const grid = this._tileGrid;
  if (grid?.has(data.id)) {
    const wasFocused = grid.focusedId === data.id;
    const neighbor = window.CodemanTileGrid.tileNeighbor(grid.ids, data.id);
    this.removeTile(data.id, { refocus: false });
    if (wasFocused && grid.open && neighbor && !this._closingSessions?.has(data.id)) {
      this._selectTiledSession(neighbor, { auto: true });
    }
  }
  return _tileGridOriginalOnSessionDeleted.call(this, data);
};