/**
 * @file Workspace.tsx
 * @description Merged workspace page combining lanes (agent work units) and runs
 * (CLI spawns: Claude Code or Codex, determined per lane). The workspace shown
 * is picked in the sidebar's project tree and named by `?lane=<id>` (mirrored to
 * `agenthub.workspace.selected`, so a bare /workspace reopens the last one).
 * Shows the selected lane's one-row header, pipeline map and run console (1, 2
 * or 4 panes, each split pane with its own header), and the right panel —
 * Files · Changes · Sessions. Runs are tied to lanes: starting a run
 * posts to POST /api/lanes/:id/start with tool-appropriate fields. When a cwd
 * isn't owned by any lane, calls POST /api/lanes/ensure first. Polls GET
 * /api/sessions?status=active alongside the run list so Claude Code sessions
 * started outside the dashboard also appear in the active-runs list.
 *
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */
/* =============================================================================
 * MODULE_GUIDE — extended in-file reference (comments only; safe to read, never executed)
 * =============================================================================
 * ## Design constraints
 * - Local-first: no telemetry leaves the machine unless the user configures webhooks.
 * - Fail-safe hooks path on the server must never block Claude Code; UI mirrors that
 *   philosophy by degrading gracefully (empty states, stale badges, reconnect loops).
 * - Destructive flows stay behind explicit confirmation modals and server-side gates.
 * - Internationalization: user-visible strings belong in i18n JSON, not literals here.
 * - The console never writes a lane's stage: no POST /api/lanes/:id/stage calls.
 *
 * ## Internal dependencies
 * - `../lib/api` — REST client including lanes and run endpoints.
 * - `../lib/types` — Lane, Lane Counts, run handles, etc.
 * - `../lib/eventBus` — WebSocket subscription.
 * - `../components/lanes/` — LaneCard, PipelineMap, DestructiveLaneModal.
 * - `../components/run/` — RunConsole, RunSetup, RunHistory, ActiveRunsSwitcher.
 *
 * ## Public surface
 * - `Workspace` — merged page; see TSDoc on the symbol for behavior.
 *
 * ============================================================================= */
/* -----------------------------------------------------------------------------
 * EXPORT CATALOG
 * **Workspace**
 *   The main exported page component. Merges lanes and runs into one workspace.
 *
 * ----------------------------------------------------------------------------- */

import { useCallback, useEffect, useMemo, useState, useSyncExternalStore } from "react";
import { useLocation, useSearchParams } from "react-router-dom";
import { useTranslation } from "react-i18next";
import {
  ArrowLeft,
  Plus,
  Square,
  Columns2,
  Grid2x2,
  Layers,
  PanelLeftClose,
  PanelRightClose,
  Maximize2,
  FolderTree,
  GitCompare,
  History,
  X,
} from "lucide-react";
import { api } from "../lib/api";
import type { CwdSuggestion, RunListResponse } from "../lib/api";
import type { Lane, LaneFeature, ProofFeature, Session } from "../lib/types";
import { eventBus } from "../lib/eventBus";
import { keepIfSame } from "../lib/keepIfSame";
import { useLanes } from "../hooks/useLanes";
import { useAiTools } from "../hooks/useAiTools";
import { AiToolIcon } from "../components/AiToolIcon";
import { LaneConsolePane } from "../components/run/LaneConsolePane";
import PipelineMap from "../components/lanes/PipelineMap";
import LaneCard, {
  since,
  LIVENESS_DOT,
  LaneToolsMenu,
  LaneRouterRow,
} from "../components/lanes/LaneCard";
import { AddLaneModal } from "../components/lanes/AddLaneModal";
import { LaneChangesPanel } from "../components/lanes/LaneChangesPanel";
import { WorkspaceSessionsTab } from "../components/lanes/WorkspaceSessionsTab";
import { WorkspaceHome } from "../components/lanes/WorkspaceHome";
import { DestructiveLaneModal } from "../components/lanes/DestructiveLaneModal";
import { readSplitViewState, writeSplitViewState } from "../lib/splitViewStorage";
import type { SplitViewState, SplitLayout } from "../lib/splitViewStorage";

/** localStorage key for the Changes panel's open/closed state. */
const CHANGES_OPEN_KEY = "agenthub.workspace.changesOpen";
/** localStorage key for how wide the Changes panel is. */
const CHANGES_SIZE_KEY = "agenthub.workspace.changesSize";
/** localStorage key for the right panel's activity-bar tab. */
const PANEL_TAB_KEY = "agenthub.workspace.panelTab";
/** localStorage key for the last workspace shown, restored on a bare /workspace. */
const SELECTED_KEY = "agenthub.workspace.selected";

const PANEL_TABS = [
  { id: "files", Icon: FolderTree },
  { id: "changes", Icon: GitCompare },
  { id: "sessions", Icon: History },
] as const;
type PanelTab = (typeof PANEL_TABS)[number]["id"];

/** The three widths the Changes panel cycles through, then closed. Reading a
 *  diff and watching a console want opposite amounts of room, and which one is
 *  "work" changes several times an hour — hence ONE control that steps
 *  30/70 → 50/50 → full → closed, rather than a width button beside a
 *  collapse button that both live in the panel's tightest corner. */
const CHANGES_SIZES = ["compact", "half", "full"] as const;
type ChangesSize = (typeof CHANGES_SIZES)[number];
const CHANGES_WIDTH: Record<ChangesSize, string> = {
  compact: "w-[30%]",
  half: "w-1/2",
  // The console beside it is HIDDEN, not unmounted: a live run's terminal
  // and a half-typed prompt must survive a round trip through full width.
  full: "w-full",
};
/** The icon the one resize control shows AT each size: what the next click
 *  gives you — an even split, the full width, then closed. */
const CHANGES_NEXT_ICON: Record<ChangesSize, typeof Columns2> = {
  compact: Columns2,
  half: Maximize2,
  full: PanelRightClose,
};

// ── Page ──────────────────────────────────────────────────────────────

/** One pane, two side by side, four in a grid — the conventional icons for
 *  each, so the toggle reads at a glance without spending three words on it. */
const LAYOUT_CHOICES = [
  { n: 1 as const, Icon: Square },
  { n: 2 as const, Icon: Columns2 },
  { n: 4 as const, Icon: Grid2x2 },
];

function SplitLayoutToggle({
  splitView,
  setLayout,
}: {
  splitView: SplitViewState;
  setLayout: (layout: SplitLayout) => void;
}) {
  const { t: tLanes } = useTranslation("lanes");

  return (
    <div className="flex items-center gap-1.5">
      {LAYOUT_CHOICES.map(({ n, Icon }) => {
        // The count still reaches assistive tech and the tooltip — only the
        // rendered word is gone, and the icon says the same thing in the
        // shape every other app uses for it.
        const label = tLanes("splitView.paneCount", { count: n });
        return (
          <button
            key={n}
            type="button"
            aria-pressed={splitView.layout === n}
            aria-label={label}
            title={label}
            onClick={() => setLayout(n)}
            className={`rounded border p-1.5 ${
              splitView.layout === n
                ? "border-accent bg-accent/15 text-accent"
                : "border-border text-fg-secondary hover:border-border-light"
            }`}
          >
            <Icon className="h-3.5 w-3.5" />
          </button>
        );
      })}
    </div>
  );
}

/** A split pane's one-line header: which lane, which slot, the run's model,
 *  and — for slots 1–3 — a button that kills that pane's own tmux session
 *  (`DELETE /api/run/<runId>`). Slot 0 is the lane's run and has no close. */
function PaneHeader({
  lane,
  slot,
  runId,
  model,
}: {
  lane: Lane | null;
  slot: number;
  runId: string | null;
  model: string | null;
}) {
  const { t } = useTranslation("lanes");
  const tools = useAiTools();
  return (
    <div
      data-testid={`pane-header-${slot}`}
      className="flex h-6 shrink-0 items-center gap-1.5 rounded border border-border bg-surface-2 px-2 text-[11px] text-fg-muted"
    >
      {lane && (
        <AiToolIcon
          tool={{ id: lane.tool, label: tools.label(lane.tool) }}
          className="h-3.5 w-3.5 !p-0"
        />
      )}
      <span className="min-w-0 truncate font-medium text-fg-secondary">
        {lane ? lane.title || lane.cwd.split("/").pop() : ""}
      </span>
      <span className="shrink-0">{t("pane.slot", { n: slot })}</span>
      {model && <span className="min-w-0 truncate">{model}</span>}
      {slot > 0 && runId && (
        <button
          type="button"
          onClick={() => void api.run.kill(runId).catch(() => undefined)}
          aria-label={t("pane.close")}
          title={t("pane.close")}
          className="ml-auto shrink-0 rounded p-0.5 hover:bg-surface-4 hover:text-status-danger"
        >
          <X className="h-3 w-3" />
        </button>
      )}
    </div>
  );
}

function ConsoleArea({
  lanes,
  selectedLaneId,
  splitView,
  setLayout,
  binaryStatus,
  cwdSuggestions,
  activeRuns,
  externalSessions,
  wsConnected,
  defaultCwd,
  onHasActiveRunChange,
  onLaneCreated,
  onLaneIdChange,
  showToggle = true,
  resumeRequest,
  attachRequest,
}: {
  lanes: Lane[];
  selectedLaneId: number | null;
  splitView: SplitViewState;
  setLayout: (layout: SplitLayout) => void;
  binaryStatus: Record<string, { found: boolean; path: string | null }> | null;
  cwdSuggestions: CwdSuggestion[];
  activeRuns: RunListResponse | null;
  externalSessions: Session[];
  wsConnected: boolean;
  defaultCwd: string;
  onHasActiveRunChange: (val: boolean) => void;
  onLaneCreated: (lane: Lane) => void;
  onLaneIdChange: (id: number | null) => void;
  showToggle?: boolean;
  /** A session to resume in slot 0, from the Sessions tab. */
  resumeRequest: { sessionId: string; model: string | null; nonce: number } | null;
  /** A live run to attach slot 0 to, from the sidebar (`?run=`). */
  attachRequest: { runId: string; nonce: string } | null;
}) {
  // Every split pane shows the SELECTED lane, each in its own tmux session
  // (slot = pane index). Tracking what each pane shows lets the others leave
  // that run out of their Active runs, so no terminal is attached twice.
  const [paneRunIds, setPaneRunIds] = useState<(string | null)[]>([]);
  const onPaneHandle = useCallback((i: number, id: string | null) => {
    setPaneRunIds((prev) => {
      if (prev[i] === id) return prev;
      const next = [...prev];
      next[i] = id;
      return next;
    });
  }, []);
  const paneHandlers = useMemo(
    () => [0, 1, 2, 3].map((i) => (id: string | null) => onPaneHandle(i, id)),
    [onPaneHandle]
  );
  const hiddenFor = useMemo(
    () =>
      [0, 1, 2, 3].map((i) =>
        paneRunIds.filter((id, j): id is string => j !== i && j < splitView.layout && !!id)
      ),
    [paneRunIds, splitView.layout]
  );

  return (
    <>
      {showToggle && <SplitLayoutToggle splitView={splitView} setLayout={setLayout} />}
      {splitView.layout === 1 ? (
        <LaneConsolePane
          lanes={lanes}
          laneId={selectedLaneId}
          onHandleChange={paneHandlers[0]}
          showLaneSelector={false}
          onLaneIdChange={onLaneIdChange}
          onLaneCreated={onLaneCreated}
          binaryStatus={binaryStatus}
          cwdSuggestions={cwdSuggestions}
          activeRuns={activeRuns}
          externalSessions={externalSessions}
          wsConnected={wsConnected}
          defaultCwd={defaultCwd}
          onHasActiveRunChange={onHasActiveRunChange}
          resumeRequest={resumeRequest}
          attachRequest={attachRequest}
        />
      ) : (
        <div
          className={`grid flex-1 min-h-0 gap-3 ${
            splitView.layout === 2 ? "grid-cols-2" : "grid-cols-2 grid-rows-2"
          }`}
        >
          {Array.from({ length: splitView.layout }, (_, i) => (
            <div key={i} className="flex min-h-0 min-w-0 flex-col gap-1">
              <PaneHeader
                lane={lanes.find((l) => l.id === selectedLaneId) ?? null}
                slot={i}
                runId={paneRunIds[i] ?? null}
                model={activeRuns?.items.find((r) => r.id === paneRunIds[i])?.model ?? null}
              />
              <LaneConsolePane
                lanes={lanes}
                laneId={selectedLaneId}
                slot={i}
                hiddenRunIds={hiddenFor[i]}
                onHandleChange={paneHandlers[i]}
                showLaneSelector={false}
                onLaneIdChange={onLaneIdChange}
                onLaneCreated={onLaneCreated}
                binaryStatus={binaryStatus}
                cwdSuggestions={cwdSuggestions}
                activeRuns={activeRuns}
                externalSessions={externalSessions}
                wsConnected={wsConnected}
                defaultCwd={defaultCwd}
                resumeRequest={i === 0 ? resumeRequest : null}
                attachRequest={i === 0 ? attachRequest : null}
              />
            </div>
          ))}
        </div>
      )}
    </>
  );
}

export function Workspace() {
  const { t: tLanes } = useTranslation("lanes");
  const wsConnected = useSyncExternalStore(eventBus.onConnection, () => eventBus.connected);
  const [searchParams, setSearchParams] = useSearchParams();

  // Lane state: the list is the shared store the sidebar reads too; the
  // selection is the URL's `?lane=` (the sidebar sets it, so does a
  // notification click), falling back to the last one shown, then the first.
  const { lanes, loaded: lanesLoaded, refresh: refreshLanes } = useLanes();
  const laneParam = searchParams.get("lane");
  // `?run=` — a live session picked in the sidebar; the location key makes a
  // second pick of the same session a new request.
  const location = useLocation();
  const runParam = searchParams.get("run");
  const attachRequest = useMemo(
    () => (runParam ? { runId: runParam, nonce: location.key } : null),
    [runParam, location.key]
  );
  const paramId = laneParam === null ? null : Number(laneParam);
  const fallbackId = (() => {
    if (!lanesLoaded) return null;
    let stored: number | null = null;
    try {
      stored = Number(window.localStorage.getItem(SELECTED_KEY));
    } catch {
      /* disabled storage */
    }
    return lanes.find((l) => l.id === stored)?.id ?? lanes[0]?.id ?? null;
  })();
  const selectedLaneId =
    paramId !== null && lanes.some((l) => l.id === paramId) ? paramId : fallbackId;
  const setSelectedLaneId = useCallback(
    (id: number | null) =>
      setSearchParams(
        (prev) => {
          const next = new URLSearchParams(prev);
          // A run belongs to its lane: another lane opens on its home.
          if (next.get("lane") !== String(id)) next.delete("run");
          if (id === null) next.delete("lane");
          else next.set("lane", String(id));
          return next;
        },
        { replace: true }
      ),
    [setSearchParams]
  );
  // Name the fallback in the URL, so the sidebar highlights it and F5 keeps it.
  // Only a URL naming NO lane is rewritten: one naming a lane the list has not
  // caught up with yet (just created) must survive until the refetch lands.
  useEffect(() => {
    if (!lanesLoaded || selectedLaneId === null) return;
    try {
      window.localStorage.setItem(SELECTED_KEY, String(selectedLaneId));
    } catch {
      /* disabled storage */
    }
    if (paramId === null) setSelectedLaneId(selectedLaneId);
  }, [lanesLoaded, selectedLaneId, paramId, setSelectedLaneId]);
  const [laneActionError, setLaneActionError] = useState<string | null>(null);
  const [destructive, setDestructive] = useState<{
    lane: Lane;
    action: "reset" | "remove";
  } | null>(null);
  const [addLaneOpen, setAddLaneOpen] = useState(false);
  // Fields the Add-lane modal opens with when it was opened from a lane's git
  // bar ("new lane here"): one provisioning path for every lane, prefilled.
  const [addLanePrefill, setAddLanePrefill] = useState<{
    sourceRepo?: string;
    branch?: string;
  } | null>(null);
  const [viewedFeatureSlug, setViewedFeatureSlug] = useState<string | null>(null);
  const [features, setFeatures] = useState<LaneFeature[]>([]);
  const [pipelineTemplates, setPipelineTemplates] = useState<
    { id: string; name: string; nodes: { id: string }[] }[]
  >([]);
  const [viewedFeature, setViewedFeature] = useState<LaneFeature | null>(null);
  const [proofFeatures, setProofFeatures] = useState<ProofFeature[]>([]);
  const [resumeRequest, setResumeRequest] = useState<{
    sessionId: string;
    model: string | null;
    nonce: number;
  } | null>(null);

  // Run state kept at page level: shared across every pane, or drives the
  // lane strip itself rather than any one pane's form.
  const [activeRuns, setActiveRuns] = useState<RunListResponse | null>(null);
  // Claude Code sessions running outside the dashboard (a `claude` the user
  // started in a terminal tab). They are not dashboard runs, so the run list
  // would otherwise show nothing while two agents are working.
  const [externalSessions, setExternalSessions] = useState<Session[]>([]);
  const [binaryStatus, setBinaryStatus] = useState<Record<
    string,
    { found: boolean; path: string | null }
  > | null>(null);
  const [cwdSuggestions, setCwdSuggestions] = useState<CwdSuggestion[]>([]);
  const [defaultCwd, setDefaultCwd] = useState<string>("");
  const [paneHasActiveRun, setPaneHasActiveRun] = useState(false);

  // Split view state
  const [splitView, setSplitView] = useState<SplitViewState>(() => readSplitViewState());
  const [panelTab, setPanelTab] = useState<PanelTab>(() => {
    try {
      const saved = window.localStorage.getItem(PANEL_TAB_KEY) as PanelTab | null;
      return saved && PANEL_TABS.some((x) => x.id === saved) ? saved : "changes";
    } catch {
      return "changes";
    }
  });
  useEffect(() => {
    try {
      window.localStorage.setItem(PANEL_TAB_KEY, panelTab);
    } catch {
      /* the panel just forgets its tab between visits */
    }
  }, [panelTab]);
  // Whether the Changes panel is open. A viewer preference, so it lives in
  // localStorage and never reaches the server — same rule as the lane strip's
  // order (client/src/lib/laneOrderStorage.ts).
  const [changesOpen, setChangesOpen] = useState(() => {
    try {
      return window.localStorage.getItem(CHANGES_OPEN_KEY) === "1";
    } catch {
      return false;
    }
  });
  useEffect(() => {
    try {
      window.localStorage.setItem(CHANGES_OPEN_KEY, changesOpen ? "1" : "0");
    } catch {
      /* private mode / disabled storage: the panel just forgets between visits */
    }
  }, [changesOpen]);
  const [changesSize, setChangesSize] = useState<ChangesSize>(() => {
    try {
      const saved = window.localStorage.getItem(CHANGES_SIZE_KEY) as ChangesSize | null;
      return saved && CHANGES_SIZES.includes(saved) ? saved : "compact";
    } catch {
      return "compact";
    }
  });
  useEffect(() => {
    try {
      window.localStorage.setItem(CHANGES_SIZE_KEY, changesSize);
    } catch {
      /* same as above: a forgotten width, not an error */
    }
  }, [changesSize]);
  const nextChangesSize =
    CHANGES_SIZES[(CHANGES_SIZES.indexOf(changesSize) + 1) % CHANGES_SIZES.length]!;
  const changesNextLabel =
    changesSize === CHANGES_SIZES[CHANGES_SIZES.length - 1]
      ? tLanes("changes.collapse")
      : tLanes("changes.resize", { size: tLanes(`changes.size.${nextChangesSize}`) });

  const setLayout = useCallback((layout: SplitLayout) => {
    setSplitView((prev) => {
      const paneLaneIds = Array.from({ length: layout }, (_, i) => prev.paneLaneIds[i] ?? null);
      const next = { layout, paneLaneIds };
      writeSplitViewState(next);
      return next;
    });
  }, []);

  // Probe the CLI of every tool a lane uses — fresh on the server, so a CLI
  // installed since the page loaded clears its missing-binary banner. Claude is
  // always probed: the console's no-lane state runs it.
  const laneToolsKey = Array.from(new Set(["claude", ...lanes.map((l) => l.tool || "claude")]))
    .sort()
    .join(",");
  useEffect(() => {
    const tools = laneToolsKey.split(",");
    Promise.all(tools.map((tool) => api.run.binary(tool)))
      .then((found) =>
        setBinaryStatus(Object.fromEntries(tools.map((tool, i) => [tool, found[i]!])))
      )
      // Fetch failure (server unreachable, proxy misrouted, etc.) isn't proof
      // a CLI is missing from PATH — leave the probe unresolved rather than
      // showing a misleading "binary missing" banner for an unrelated fault.
      .catch(() => undefined);
  }, [laneToolsKey]);

  useEffect(() => {
    api.lanes
      .pipelines()
      .then((r) => setPipelineTemplates(r.pipelines))
      .catch(() => undefined);
    api.run
      .cwds()
      .then((r) => {
        setCwdSuggestions(r.items);
        // Pre-fill cwd with the user's home directory — a neutral default.
        // Spawning in the dashboard's own cwd would make ad-hoc runs inherit
        // this repo's project context (.claude/agents, skills, rules,
        // CLAUDE.md, .mcp.json), which is almost never what an ad-hoc run
        // wants and can bloat the initial request (issue #202). Fall back to
        // the dashboard cwd when no home suggestion exists. The user can
        // change it; we just don't want an invisible default.
        const home = r.items.find((s) => s.kind === "home");
        const dashboard = r.items.find((s) => s.kind === "dashboard");
        const preferred = home || dashboard;
        if (preferred) {
          setDefaultCwd(preferred.path);
        }
      })
      .catch(() => undefined);
  }, []);

  // Clean up stale pane lane IDs when lanes load
  useEffect(() => {
    if (!lanes.length) return;
    setSplitView((prev) => {
      const paneLaneIds = prev.paneLaneIds.map((id) =>
        id !== null && lanes.some((l) => l.id === id) ? id : null
      );
      if (paneLaneIds.every((id, i) => id === prev.paneLaneIds[i])) return prev;
      const next = { ...prev, paneLaneIds };
      writeSplitViewState(next);
      return next;
    });
  }, [lanes]);

  // Both setters go through `keepIfSame`: these fire every 5 s below, and a
  // fresh-but-identical payload would otherwise re-render the lane strip, the
  // lane card and the whole console area on every tick for nothing.
  const refreshList = useCallback(() => {
    api.run
      .list()
      .then((r) => setActiveRuns(keepIfSame(r)))
      .catch(() => undefined);
    api.sessions
      // Attach/resume go through `claude`, so a Codex session is not offered
      // (filtered by the server, before its limit).
      .list({ status: "active", limit: 50, sort_by: "updated_at", sort_desc: true, tool: "claude" })
      .then((r) => setExternalSessions(keepIfSame(r.sessions)))
      .catch(() => undefined);
  }, []);

  // Background poll so the run list and history reflect external changes
  // (server-boot reconciliation, sibling tabs, direct DB edits) even when
  // no WS event fires. Lighter than typical WS gaps; aggressive enough that
  // status flips appear within seconds without needing a manual refresh.
  useEffect(() => {
    refreshList();
    const tick = setInterval(() => {
      refreshList();
    }, 5000);
    return () => clearInterval(tick);
  }, [refreshList]);

  // Refresh whenever the tab regains focus / visibility - typical when the
  // user comes back from running `claude` in a terminal and wants to see the
  // current state of every run without waiting for the next poll.
  useEffect(() => {
    const onFocus = () => refreshList();
    const onVis = () => {
      if (document.visibilityState === "visible") refreshList();
    };
    window.addEventListener("focus", onFocus);
    document.addEventListener("visibilitychange", onVis);
    return () => {
      window.removeEventListener("focus", onFocus);
      document.removeEventListener("visibilitychange", onVis);
    };
  }, [refreshList]);

  const currentLane = selectedLaneId !== null ? lanes.find((l) => l.id === selectedLaneId) : null;
  // Only claude lanes carry a pipeline (codex and antigravity emit no hooks),
  // and only while a template is installed — none ships, so it is dormant.
  const noPipeline =
    !!currentLane && (currentLane.tool !== "claude" || currentLane.pipeline_nodes.length === 0);

  // Feature list follows the selected lane, resets the viewer on lane switch.
  useEffect(() => {
    setViewedFeatureSlug(null);
    setViewedFeature(null);
    if (currentLane === null || currentLane === undefined) {
      setFeatures([]);
      return;
    }
    api.lanes.features
      .list(currentLane.id)
      .then((data) => setFeatures(data.features))
      .catch(() => setFeatures([]));
  }, [currentLane?.id]);

  // Fetch the archived snapshot when the picker selects one — read-only, never
  // touches the live lane.
  useEffect(() => {
    if (!currentLane || !viewedFeatureSlug) {
      setViewedFeature(null);
      return;
    }
    let cancelled = false;
    api.lanes.features
      .show(currentLane.id, viewedFeatureSlug)
      .then((data) => {
        if (!cancelled) setViewedFeature(data.feature);
      })
      .catch(() => {
        if (!cancelled) setViewedFeature(null);
      });
    return () => {
      cancelled = true;
    };
  }, [currentLane?.id, viewedFeatureSlug]);

  // Proof gallery follows the selected lane.
  useEffect(() => {
    if (!currentLane) {
      setProofFeatures([]);
      return;
    }
    api.lanes.proof
      .list(currentLane.id)
      .then((data) => setProofFeatures(data.features))
      .catch(() => setProofFeatures([]));
  }, [currentLane?.id, viewedFeatureSlug]);

  // Resolve the active feature slug: either the user-selected one, or the lane's active_feature_id
  const activeFeatureSlug =
    viewedFeatureSlug ??
    (currentLane?.active_feature_id
      ? features.find((f) => f.id === currentLane?.active_feature_id)?.slug
      : null);
  const proofFeature = activeFeatureSlug
    ? proofFeatures.find((f) => f.slug === activeFeatureSlug)
    : null;

  // Viewport locked only when a live run is showing (TerminalView needs locked
  // viewport for chat scrolling). The config-card screen needs normal page flow
  // so the form is fully reachable on short windows. A full-width Changes panel
  // hides that form anyway, and without a locked height it shrinks to its
  // content — the editor inside it collapsed to a few lines (no live run).
  // A workspace opens on its HOME (WorkspaceHome); `?run=` opens a session —
  // the console, panes and Changes panel, which the home only hides (CSS), so
  // a live terminal never unmounts behind it.
  const home = !!currentLane && !runParam;
  const viewportLocked =
    !home && (paneHasActiveRun || (!!currentLane && changesOpen && changesSize === "full"));

  const handleLaneAction = async (id: number, action: string, body?: Record<string, unknown>) => {
    setLaneActionError(null);
    try {
      if (action === "reset" || action === "remove" || action === "purge") {
        await api.lanes.action(id, action, {
          confirm: true,
          expect: body?.expect,
          ...(body?.force === true ? { force: true } : {}),
        });
      } else {
        await api.lanes.action(id, action, body);
      }
      if (action === "remove") await refreshLanes();
    } catch (err) {
      setLaneActionError(err instanceof Error ? err.message : tLanes("actionErrorUnknown"));
    }
  };

  // Mirrors `agenthub lanes pipeline <template> <id>`: same PATCH, same
  // stage-mismatch warning when the current declared stage matches no node
  // in the newly chosen template.
  const handlePipelineChange = async (id: number, pipeline: string) => {
    setLaneActionError(null);
    try {
      const { lane } = await api.lanes.update(id, { pipeline });
      await refreshLanes();
      // `stage` defaults to the DB sentinel "idle" until a driving session ever
      // calls `agenthub stage` — that's the normal state for most lanes and never
      // matches a real pipeline node, so it isn't a mismatch worth surfacing.
      if (lane.stage !== "idle" && !lane.pipeline_nodes.some((n) => n.state === "current")) {
        setLaneActionError(
          tLanes("pipelinePicker.stageMismatch", {
            stage: lane.stage,
            pipeline: lane.pipeline,
            nodes: lane.pipeline_nodes.map((n) => n.id).join(", "),
          })
        );
      }
    } catch (err) {
      setLaneActionError(err instanceof Error ? err.message : tLanes("actionErrorUnknown"));
    }
  };

  return (
    <div
      className={
        viewportLocked
          ? "h-[calc(100vh-4rem)] lg:h-[calc(100vh-4.5rem)] flex flex-col gap-5"
          : "space-y-5"
      }
    >
      {/* Workspaces are picked in the sidebar's project tree; this page shows
          the selected one. With none at all, one banner offers to create it. */}
      <div className="flex min-h-0 flex-1 flex-col gap-4">
        {lanesLoaded && lanes.length === 0 && (
          /* With no lanes the strip was a dashed tile beside a stray sentence,
             which reads as a half-rendered row rather than a state. One banner
             instead — and a compact one on purpose: the run setup form below
             is what the user actually needs the height for. */
          <button
            type="button"
            data-testid="lane-empty"
            onClick={() => setAddLaneOpen(true)}
            className="card flex w-full shrink-0 flex-wrap items-center gap-4 border-dashed px-5 py-4 text-left transition-colors hover:border-accent/50 hover:bg-surface-2"
          >
            <span className="flex h-10 w-10 shrink-0 items-center justify-center rounded-xl bg-surface-4 text-fg-muted">
              <Layers className="h-5 w-5" />
            </span>
            <div className="min-w-0 flex-1">
              <span className="block text-sm font-medium text-fg-primary">
                {tLanes("empty.title")}
              </span>
              <p className="mt-0.5 text-xs text-fg-muted">
                {tLanes("empty.body")}{" "}
                <code className="rounded bg-surface-2 px-1.5 py-0.5 text-[11px] text-fg-secondary">
                  agenthub lanes add --cwd $(pwd)
                </code>
              </p>
            </div>
            <span className="flex shrink-0 items-center gap-1.5 text-xs font-medium text-accent">
              <Plus className="h-4 w-4" />
              {tLanes("add")}
            </span>
          </button>
        )}

        {/* The selected lane's pipeline — the thing you actually come to this
            page to read, beside the list rather than stacked under it.
            The section itself is ALWAYS rendered, even with no lane selected:
            `ConsoleArea` lives inside it, and a conditional wrapper would give
            the console two render sites, so every flip of `currentLane` (lanes
            arriving on mount, a lane removed, a refetch re-picking the
            selection) unmounted the terminal and wiped a half-typed prompt.
            Same rule as RunConsole's own collapse — hide with CSS, never by
            unmounting. */}
        {/* Detail and the Changes panel share one row: the panel is a reading
            surface for the same lane the console is driving, so it sits beside
            it rather than under it. It collapses to a rail instead of
            unmounting nothing — there is no live subscription inside it, so
            unmounting is safe and keeps a closed panel from polling. */}
        {home && currentLane && (
          <WorkspaceHome
            lane={currentLane}
            onRenamed={() => void refreshLanes()}
            onMenuAction={(action) => {
              if (action === "new-here") {
                setAddLanePrefill({ sourceRepo: currentLane.source_repo || currentLane.cwd });
                setAddLaneOpen(true);
              } else if (action === "reset" || action === "remove") {
                setDestructive({ lane: currentLane, action });
              } else if (action === "started") {
                setSearchParams({
                  lane: String(currentLane.id),
                  run: `agenthub-lane-${currentLane.id}`,
                });
              }
            }}
          />
        )}
        <div className={`flex min-h-0 flex-1 gap-4${home ? " hidden" : ""}`}>
          <section
            data-testid="lane-detail"
            className={`flex min-h-0 min-w-0 flex-1 flex-col ${currentLane ? "card p-4" : ""}${
              currentLane && changesOpen && changesSize === "full" ? " hidden" : ""
            }`}
          >
            {/* One header row, not two. The pipeline picker, the stage badges,
              the feature picker and the router select used to sit on a second
              row below this one; every one of them is a per-lane control that
              belongs beside the lane's own name, and stacking them cost a whole
              row of height on a panel whose point is the pipeline map further
              down. The pipeline's NAME is no longer interpolated into
              `laneHeader` either — the picker right next to it already says it.
              They stay gated on `showInfo`, same as before the merge. */}
            {currentLane && (
              <div className="mb-3 flex flex-wrap items-center gap-2">
                <span className="flex shrink-0 items-center gap-1.5 text-[11px] font-medium uppercase tracking-wide text-fg-secondary">
                  <span className={`h-2 w-2 rounded-full ${LIVENESS_DOT[currentLane.liveness]}`} />
                  {currentLane.liveness === "dead"
                    ? tLanes("statusDead")
                    : tLanes(`status.${currentLane.status}`, { defaultValue: currentLane.status })}
                </span>
                {/* Back to the workspace's home; renaming lives on the sidebar
                  row and the home's title, so here the name is only read. */}
                <button
                  type="button"
                  data-testid="workspace-back-home"
                  onClick={() => setSearchParams({ lane: String(currentLane.id) })}
                  title={tLanes("home.back")}
                  aria-label={tLanes("home.back")}
                  className="shrink-0 rounded p-0.5 text-fg-muted hover:bg-surface-4 hover:text-fg-primary"
                >
                  <ArrowLeft className="h-4 w-4" />
                </button>
                <span
                  title={currentLane.cwd}
                  className="min-w-0 truncate text-sm font-semibold text-fg-primary"
                >
                  {currentLane.title || currentLane.cwd}
                </span>
                {/* A lane with no pipeline (non-claude, or no template
                    installed): no time-at-stage, no pipeline or feature
                    picker, no map. */}
                {!noPipeline && (
                  <span className="shrink-0 tabular-nums text-xs text-fg-muted">
                    {since(currentLane.stage_seconds)}
                  </span>
                )}
                {!noPipeline && (
                  <select
                    data-testid="pipeline-picker"
                    aria-label={tLanes("pipelinePicker.label")}
                    className="rounded border border-border bg-surface-1 px-2 py-0.5 text-xs text-fg-secondary disabled:opacity-60"
                    value={currentLane.pipeline}
                    disabled={!!viewedFeature}
                    title={
                      viewedFeature
                        ? tLanes("features.viewingArchived", { slug: viewedFeature.slug })
                        : undefined
                    }
                    onChange={(e) => void handlePipelineChange(currentLane.id, e.target.value)}
                  >
                    {(pipelineTemplates.length
                      ? pipelineTemplates
                      : [
                          {
                            id: currentLane.pipeline,
                            name: currentLane.pipeline_name,
                            nodes: [],
                          },
                        ]
                    ).map((p) => (
                      <option key={p.id} value={p.id}>
                        {p.nodes.length ? `${p.name} (${p.nodes.length})` : p.name}
                      </option>
                    ))}
                  </select>
                )}
                {/* `agy` has no endpoint to point at a router. */}
                <LaneRouterRow lane={currentLane} />
                {/* No stage chip and no "auto: <stage>" chip here: the
                        PipelineMap right below this header already draws both
                        — the declared node as the current ring, the detected
                        one as its amber badge — so the chips were a second,
                        smaller copy of the same two facts. */}
                {!noPipeline && features.length > 0 && (
                  <select
                    data-testid="feature-picker"
                    className="rounded border border-border bg-surface-1 px-2 py-0.5 text-xs"
                    value={viewedFeatureSlug ?? ""}
                    onChange={(e) => setViewedFeatureSlug(e.target.value || null)}
                  >
                    <option value="">{tLanes("features.live")}</option>
                    {features.map((f) => (
                      <option key={f.slug} value={f.slug}>
                        {f.slug}
                        {f.archived_at ? ` (${tLanes("features.archived")})` : ""}
                      </option>
                    ))}
                  </select>
                )}
                <div className="ml-auto flex items-center gap-2">
                  {/* Per-lane actions (mcp sync, sync-base check)
                    belong beside the lane they act on, not in a page header. */}
                  <LaneToolsMenu lane={currentLane} />
                  <SplitLayoutToggle splitView={splitView} setLayout={setLayout} />
                </div>
              </div>
            )}
            {currentLane && (
              <div className="max-h-[45vh] shrink-0 overflow-y-auto">
                {/* No margin when the card rendered nothing (see LaneCard). */}
                <div className="mb-3 has-[>div:empty]:mb-0">
                  <LaneCard
                    lane={currentLane}
                    onAction={(a, b) => handleLaneAction(currentLane.id, a, b)}
                    childWorktrees={lanes.filter(
                      (l) => l.source_repo === currentLane.cwd && l.id !== currentLane.id
                    )}
                    onSelectLane={setSelectedLaneId}
                  />
                </div>
                {!noPipeline && (
                  <div className="mb-3">
                    <PipelineMap
                      nodes={
                        viewedFeature ? viewedFeature.pipeline_nodes : currentLane.pipeline_nodes
                      }
                      detectedSignal={viewedFeature ? undefined : currentLane.detected_signal}
                    />
                    {viewedFeature && (
                      <p data-testid="feature-viewer-banner" className="mb-2 text-xs text-fg-muted">
                        {tLanes("features.viewingArchived", { slug: viewedFeature.slug })}
                      </p>
                    )}
                  </div>
                )}
                {proofFeature &&
                  (Object.keys(proofFeature.groups).length > 0 || proofFeature.ticket_report) && (
                    <div data-testid="proof-gallery" className="mt-2">
                      {proofFeature.ticket_report && (
                        <a
                          href={`/api/lanes/${currentLane.id}/proof/${proofFeature.ticket_report}`}
                          target="_blank"
                          rel="noreferrer"
                          className="text-xs text-fg-muted"
                        >
                          {tLanes("proof.ticketReport")}
                        </a>
                      )}
                      {Object.entries(proofFeature.groups).map(([group, images]) => (
                        <div key={group} className="mt-1">
                          <span className="text-xs text-fg-muted">
                            {group} · {images.length}
                          </span>
                          <div className="flex flex-wrap gap-1">
                            {images.slice(0, 8).map((img) => (
                              <img
                                key={img}
                                loading="lazy"
                                className="h-16 w-16 rounded object-cover"
                                src={api.lanes.proof.imageUrl(
                                  currentLane.id,
                                  proofFeature.slug,
                                  group,
                                  img
                                )}
                                alt={img}
                              />
                            ))}
                            {images.length > 8 && (
                              <span className="text-xs text-fg-muted">+{images.length - 8}</span>
                            )}
                          </div>
                        </div>
                      ))}
                    </div>
                  )}
              </div>
            )}
            <div
              className={`flex min-h-0 flex-1 flex-col gap-2 ${
                currentLane ? "border-t border-border pt-3" : ""
              }`}
            >
              {/* `showToggle`: the lane header carries its own split toggle; with
                no lane there is no header, so the console shows one instead. */}
              <ConsoleArea
                lanes={lanes}
                selectedLaneId={selectedLaneId}
                splitView={splitView}
                setLayout={setLayout}
                binaryStatus={binaryStatus}
                cwdSuggestions={cwdSuggestions}
                activeRuns={activeRuns}
                externalSessions={externalSessions}
                wsConnected={wsConnected}
                defaultCwd={defaultCwd}
                onHasActiveRunChange={setPaneHasActiveRun}
                onLaneCreated={() => void refreshLanes()}
                onLaneIdChange={setSelectedLaneId}
                showToggle={!currentLane}
                resumeRequest={resumeRequest}
                attachRequest={attachRequest}
              />
            </div>
          </section>

          {currentLane &&
            (changesOpen ? (
              <aside
                id="lane-changes-panel"
                data-testid="lane-changes-card"
                className={`card flex shrink-0 flex-col p-3 ${CHANGES_WIDTH[changesSize]}`}
              >
                {/* Activity bar: Files · Changes · Sessions, then the resize control. */}
                <div className="mb-2 flex items-center gap-1" role="toolbar">
                  {PANEL_TABS.map(({ id, Icon }) => (
                    <button
                      key={id}
                      type="button"
                      data-testid={`panel-tab-${id}`}
                      aria-pressed={panelTab === id}
                      onClick={() => setPanelTab(id)}
                      title={tLanes(`panel.${id}`)}
                      aria-label={tLanes(`panel.${id}`)}
                      className={`flex h-7 w-7 items-center justify-center rounded-md transition-colors ${
                        panelTab === id
                          ? "bg-accent/15 text-accent"
                          : "text-fg-muted hover:bg-surface-4 hover:text-fg-primary"
                      }`}
                    >
                      <Icon className="h-4 w-4" />
                    </button>
                  ))}
                  <button
                    type="button"
                    data-testid="lane-changes-resize"
                    onClick={() => {
                      // Past the widest step the next state is "gone", which
                      // is what the rail button reopens at `compact`.
                      if (changesSize === CHANGES_SIZES[CHANGES_SIZES.length - 1]) {
                        setChangesOpen(false);
                        setChangesSize("compact");
                      } else {
                        setChangesSize(nextChangesSize);
                      }
                    }}
                    // The control names the same region the rail button does,
                    // so a screen reader reads one panel that is open or
                    // closed rather than two unrelated buttons.
                    aria-expanded
                    aria-controls="lane-changes-panel"
                    aria-label={changesNextLabel}
                    title={changesNextLabel}
                    className="ml-auto flex h-6 w-6 items-center justify-center rounded-md text-fg-muted transition-colors hover:bg-surface-4 hover:text-fg-primary"
                  >
                    {/* Icon-only, and it draws the width the click LANDS on,
                        not the current one — the label the tooltip carries. */}
                    {(() => {
                      const Next = CHANGES_NEXT_ICON[changesSize];
                      return <Next className="h-4 w-4" />;
                    })()}
                  </button>
                </div>
                {panelTab === "sessions" ? (
                  <WorkspaceSessionsTab
                    lane={currentLane}
                    onResume={(session) =>
                      setResumeRequest({
                        sessionId: session.id,
                        model: session.model,
                        nonce: Date.now(),
                      })
                    }
                  />
                ) : (
                  <LaneChangesPanel
                    laneId={currentLane.id}
                    tab={panelTab}
                    full={changesSize === "full"}
                    // A sibling worktree forks from the lane's SOURCE repo when
                    // it has one (this lane is itself a worktree of it); an
                    // adopted lane is its own repo.
                    onNewLane={(branch) => {
                      setAddLanePrefill({
                        sourceRepo: currentLane.source_repo || currentLane.cwd,
                        branch,
                      });
                      setAddLaneOpen(true);
                    }}
                  />
                )}
              </aside>
            ) : (
              <button
                type="button"
                data-testid="lane-changes-expand"
                onClick={() => setChangesOpen(true)}
                aria-expanded={false}
                aria-controls="lane-changes-panel"
                aria-label={tLanes("changes.expand")}
                title={tLanes("changes.expand")}
                className="card flex w-9 shrink-0 flex-col items-center gap-2 py-3 text-fg-muted transition-colors hover:text-fg-primary"
              >
                <PanelLeftClose className="h-4 w-4" />
                <span className="text-[10px] uppercase tracking-wide [writing-mode:vertical-rl]">
                  {tLanes("changes.title")}
                </span>
              </button>
            ))}
        </div>
      </div>

      <AddLaneModal
        open={addLaneOpen}
        cwdSuggestions={cwdSuggestions}
        prefill={addLanePrefill}
        onClose={() => {
          setAddLaneOpen(false);
          setAddLanePrefill(null);
        }}
        onAdded={(lane) => {
          void refreshLanes();
          setSelectedLaneId(lane.id);
        }}
      />

      {destructive && (
        <DestructiveLaneModal
          lane={destructive.lane}
          action={destructive.action}
          open
          onClose={() => setDestructive(null)}
          onConfirm={async (body) => {
            const { lane, action } = destructive;
            setDestructive(null);
            setLaneActionError(null);
            try {
              await api.lanes.action(lane.id, action, {
                confirm: true,
                expect: body.expect,
                ...(body.force === true ? { force: true } : {}),
              });
              await refreshLanes();
              if (action === "remove") setSearchParams({});
            } catch (err) {
              setLaneActionError(err instanceof Error ? err.message : String(err));
            }
          }}
        />
      )}

      {laneActionError && (
        <p
          role="alert"
          className="rounded border border-status-danger bg-status-danger/40 px-3 py-2 text-sm text-status-danger"
        >
          {tLanes("actionError", { message: laneActionError })}
        </p>
      )}
    </div>
  );
}