/**
 * @file LaneConsolePane.tsx
 * @description One console tab's body: a TerminalView on the tab's tmux
 * session (`agenthub-lane-<id>[-<slot>]`), or — with no run — an empty pane
 * whose button goes back to the workspace home, where a session starts with a
 * prompt (a pane has no run form; the tab bar's `+`, `ConsoleTabs.tsx`, starts
 * a bare CLI or a shell). No header of its own: the tab bar is the console's
 * header. The Workspace page keeps one per live session (slot 0–9) mounted, the
 * inactive ones hidden with CSS.
 *
 * The pane is bound to the lane it shows: switching `laneId` swaps it to the
 * new lane's own live session for its slot, or an empty pane — never the
 * previous lane's terminal. `attachRequest` (a run picked in the sidebar or a
 * tab) attaches to that tmux session only; nothing is started or resumed.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import { useEffect, useRef, useState } from "react";
import { useTranslation } from "react-i18next";
import { AlertCircle, Plus } from "lucide-react";
import { api } from "../../lib/api";
import type { RunHandle, RunListResponse } from "../../lib/api";
import type { Lane } from "../../lib/types";
import { useAiTools } from "../../hooks/useAiTools";
import { TerminalView } from "./TerminalView";

export interface LaneConsolePaneProps {
  lanes: Lane[];
  laneId: number | null;
  binaryStatus: Record<string, { found: boolean; path: string | null }> | null;
  activeRuns: RunListResponse | null;
  onHasActiveRunChange?: (active: boolean) => void;
  /** Which tab this is: slot 0 is the lane's own session, 1–3
   *  `agenthub-lane-<id>-<slot>`. */
  slot?: number;
  /** A live run to show in this pane (a session picked in the sidebar or a
   *  tab). It attaches to that tmux session only. */
  attachRequest?: { runId: string; nonce: string } | null;
  /** Opens the workspace home, where a new session is started. */
  onNewSession?: () => void;
  /** The pane's run exited (the tab bar opens another tab, or the home). */
  onRunExit?: () => void;
  /** The terminal takes the keyboard when it appears (default). */
  autoFocus?: boolean;
}

/** The tmux session a lane's tab owns (see server/lib/pty-run.js). */
function paneRunId(laneId: number, slot: number): string {
  return slot ? `agenthub-lane-${laneId}-${slot}` : `agenthub-lane-${laneId}`;
}

export function LaneConsolePane({
  lanes,
  laneId,
  binaryStatus,
  activeRuns,
  onHasActiveRunChange,
  slot = 0,
  attachRequest,
  onNewSession,
  onRunExit,
  autoFocus,
}: LaneConsolePaneProps) {
  const { t } = useTranslation("run");
  const [handle, setHandle] = useState<RunHandle | null>(null);
  const [error, setError] = useState<string | null>(null);

  const currentLane = laneId !== null ? lanes.find((l) => l.id === laneId) : null;
  const aiTools = useAiTools();
  // The tool of the run on screen — a session's own, which need not be the
  // workspace's; the workspace's with no run.
  const paneTool = handle?.tool ?? currentLane?.tool ?? "claude";

  useEffect(() => {
    onHasActiveRunChange?.(handle !== null);
  }, [handle, onHasActiveRunChange]);

  // `activeRuns` is re-fetched every few seconds by the page, so reading it
  // through a ref keeps the lane-switch effect below off its identity.
  const latest = useRef(activeRuns);
  latest.current = activeRuns;

  // A pane's terminal belongs to the lane it shows, so switching lanes swaps
  // it — to the new lane's own live session for this slot, if it has one.
  const autoAttachedForLane = useRef<number | null>(null);
  useEffect(() => {
    setError(null);
    const own = laneId === null ? null : paneRunId(laneId, slot);
    setHandle(latest.current?.items.find((r) => r.id === own && r.status === "running") ?? null);
    autoAttachedForLane.current = null;
  }, [laneId, slot]);

  // Runs after the lane-switch effect above, so a sidebar pick that changes
  // lane AND run at once lands on the picked run, not the lane's own. Keyed on
  // `laneId` too: on a cold load the pane mounts before the lane list does,
  // and the switch effect then resets the pane to its own slot once `laneId`
  // arrives — the request must land after that. Only this lane's own tabs.
  useEffect(() => {
    if (!attachRequest || laneId === null) return;
    if (!new RegExp(`^agenthub-lane-${laneId}(-[1-9])?$`).test(attachRequest.runId)) return;
    let live = true;
    autoAttachedForLane.current = laneId;
    api.run
      .get(attachRequest.runId)
      .then((h) => {
        if (!live) return;
        setHandle(h);
        // A later attach that worked clears an earlier one's failure.
        setError(null);
      })
      .catch(
        (err: unknown) =>
          live &&
          setError(
            t("errors.attachFailed", { message: err instanceof Error ? err.message : "unknown" })
          )
      );
    return () => {
      live = false;
    };
    // A new request (nonce), or the lane it names arriving, attaches; a switch
    // to another lane drops `?run=` (Workspace), so it never replays one.
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [attachRequest?.nonce, laneId]);

  // The switch effect only sees whatever `activeRuns` the page had loaded at
  // that instant — null right after a remount. Re-check once the poll lands,
  // once per lane.
  useEffect(() => {
    if (handle || laneId === null) return;
    if (autoAttachedForLane.current === laneId) return;
    const own = paneRunId(laneId, slot);
    const running = activeRuns?.items.find((r) => r.id === own && r.status === "running");
    if (running) {
      autoAttachedForLane.current = laneId;
      setHandle(running);
    }
  }, [activeRuns, laneId, slot, handle]);

  return (
    <div data-testid="console-body" className="flex min-h-0 flex-1 flex-col gap-3">
      {/* Not probed yet (a tool the page has not probed, or a shell) is not "missing". */}
      {binaryStatus?.[paneTool] && !binaryStatus[paneTool].found && (
        <div className="mx-3 mt-2 rounded-lg border border-status-danger/40 bg-status-danger/10 px-4 py-3 text-sm text-status-danger flex items-center gap-2">
          <AlertCircle className="w-4 h-4 flex-shrink-0" />
          <span>
            {t("binary.missing", {
              cli: aiTools.byId(paneTool)?.command ?? paneTool,
              tool: aiTools.label(paneTool),
            })}
          </span>
        </div>
      )}

      {error && (
        <div className="mx-3 mt-2 rounded-lg border border-status-danger/40 bg-status-danger/10 px-4 py-3 text-sm text-status-danger flex items-center gap-2">
          <AlertCircle className="w-4 h-4 flex-shrink-0" />
          <span className="flex-1 break-all">{error}</span>
        </div>
      )}

      {!handle ? (
        <div
          data-testid="pane-no-run"
          className="m-3 flex flex-1 flex-col items-center justify-center gap-3 rounded-xl border border-dashed border-border p-6 text-center text-sm text-fg-muted"
        >
          <p>{t("emptyPane")}</p>
          {onNewSession && (
            <button type="button" onClick={onNewSession} className="btn-primary text-xs">
              <Plus className="h-3.5 w-3.5" />
              {t("actions.newSession")}
            </button>
          )}
        </div>
      ) : (
        <div className="flex-1 min-h-0 flex flex-col">
          <TerminalView
            runId={handle.id}
            wsBaseUrl={window.location.origin.replace(/^http/, "ws")}
            autoFocus={autoFocus}
            // The pane died (double Ctrl+C out of `claude`, `exit`, a crash) —
            // the tab bar moves on (another tab, or the home's prompt box)
            // rather than leaving a dead terminal the user has to click out of.
            onExit={() => {
              setHandle(null);
              onRunExit?.();
            }}
          />
        </div>
      )}
    </div>
  );
}