/**
 * @file TerminalView.test.tsx
 * @description Tests for the xterm.js-backed terminal view: verifies it opens
 * a WS connection to the right URL, writes incoming binary frames to the
 * mocked terminal, forwards typed input as outgoing binary frames, and
 * re-attaches after the socket drops (server restart) but not after `exit`,
 * and recolours live on a dark-theme change without re-attaching.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */
import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
import { render, cleanup, act, fireEvent, screen, waitFor } from "@testing-library/react";
import { TerminalView } from "../TerminalView";

const writeMock = vi.fn();
const onDataHandlers: Array<(d: string) => void> = [];
const openMock = vi.fn();
const disposeMock = vi.fn();
const wheelHandlerMock = vi.fn();
const keyHandlerMock = vi.fn();
const focusMock = vi.fn();
const pasteMock = vi.fn();
const dropImageMock = vi.fn();
vi.mock("../../../lib/api", () => ({
  api: { run: { dropImage: (f: Blob) => dropImageMock(f) } },
}));
const loadAddonMock = vi.fn();
// Mutable stand-ins for the two live terminal facts the wheel handler reads.
const termState = {
  modes: { mouseTrackingMode: "none" as "none" | "x10" | "vt200" | "drag" | "any" },
  buffer: { active: { type: "alternate" as "normal" | "alternate" } },
  cols: 131,
  rows: 28,
};
const onResizeHandlers: Array<() => void> = [];
const termOptions: { theme?: unknown } = {};
const ctorArgs: Array<{ theme?: unknown }> = [];

vi.mock("@xterm/xterm", () => ({
  Terminal: vi.fn().mockImplementation((opts: { theme?: unknown }) => ({
    ...(ctorArgs.push(opts), {}),
    options: termOptions,
    get modes() {
      return termState.modes;
    },
    get buffer() {
      return termState.buffer;
    },
    get cols() {
      return termState.cols;
    },
    get rows() {
      return termState.rows;
    },
    onResize: (fn: () => void) => {
      onResizeHandlers.push(fn);
      return { dispose: vi.fn() };
    },
    open: openMock,
    write: writeMock,
    onData: (fn: (d: string) => void) => {
      onDataHandlers.push(fn);
      return { dispose: vi.fn() };
    },
    dispose: disposeMock,
    loadAddon: loadAddonMock,
    attachCustomWheelEventHandler: wheelHandlerMock,
    attachCustomKeyEventHandler: keyHandlerMock,
    focus: focusMock,
    paste: pasteMock,
  })),
}));
// jsdom loads no stylesheet, so stand in for the CSS-variable probe.
vi.mock("../../../lib/terminalTheme", () => ({
  terminalThemeFor: (id: string) => ({ background: `bg-${id}` }),
}));
vi.mock("@xterm/addon-fit", () => ({
  FitAddon: vi.fn().mockImplementation(() => ({ fit: vi.fn() })),
}));
vi.mock("@xterm/addon-canvas", () => ({
  CanvasAddon: vi.fn().mockImplementation(() => ({ __canvas: true, dispose: vi.fn() })),
}));

class MockWebSocket {
  static instances: MockWebSocket[] = [];
  url: string;
  sent: unknown[] = [];
  onopen: (() => void) | null = null;
  onmessage: ((e: { data: unknown }) => void) | null = null;
  onclose: (() => void) | null = null;
  readyState = 1; // OPEN — the component only sends on an open socket
  static OPEN = 1;
  constructor(url: string) {
    this.url = url;
    MockWebSocket.instances.push(this);
  }
  send(data: unknown) {
    this.sent.push(data);
  }
  close() {
    this.onclose?.();
  }
}
// @ts-expect-error test override
global.WebSocket = MockWebSocket;

describe("TerminalView", () => {
  beforeEach(() => {
    termState.modes.mouseTrackingMode = "none";
    termState.buffer.active.type = "alternate";
    termState.cols = 131;
    termState.rows = 28;
    MockWebSocket.instances = [];
    onDataHandlers.length = 0;
    onResizeHandlers.length = 0;
    writeMock.mockClear();
    wheelHandlerMock.mockClear();
    keyHandlerMock.mockClear();
    loadAddonMock.mockClear();
    openMock.mockClear();
    focusMock.mockClear();
    disposeMock.mockClear();
    ctorArgs.length = 0;
    delete termOptions.theme;
    localStorage.clear();
  });

  afterEach(cleanup);

  it("opens a WS connection to the run's ws-pty path, carrying its own size", () => {
    // The size rides on the attach URL, not on a `resize` message sent after
    // it: tmux resizes the window to the newest client, so attaching at the
    // server's default 80x24 makes claude redraw its UI at 80 columns and
    // leaves that width in the scrollback (issue #33).
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    expect(MockWebSocket.instances).toHaveLength(1);
    expect(MockWebSocket.instances[0]!.url).toBe(
      "ws://localhost:4820/ws-pty/agenthub-lane-1?cols=131&rows=28"
    );
  });

  it("omits the size when the terminal has none yet (a collapsed console is 0x0)", () => {
    termState.cols = 0;
    termState.rows = 0;
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    expect(MockWebSocket.instances[0]!.url).toBe("ws://localhost:4820/ws-pty/agenthub-lane-1");
  });

  it("paints the chosen DARK theme and recolours live without re-attaching", () => {
    localStorage.setItem("theme", "light"); // app in light mode: terminal stays dark
    localStorage.setItem("agenthub.theme.dark", "apple-dark");
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    expect(ctorArgs[0]!.theme).toEqual({ background: "bg-apple-dark" });

    act(() => {
      localStorage.setItem("agenthub.theme.dark", "darcula");
      window.dispatchEvent(new Event("agenthub-theme"));
    });
    expect(termOptions.theme).toEqual({ background: "bg-darcula" });
    expect(MockWebSocket.instances).toHaveLength(1);
    expect(disposeMock).not.toHaveBeenCalled();
  });

  it("writes incoming WS data to the terminal", () => {
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    const ws = MockWebSocket.instances[0]!;
    ws.onopen?.();
    ws.onmessage?.({ data: "hello" });
    expect(writeMock).toHaveBeenCalledWith("hello");
  });

  it("decodes binary ArrayBuffer frames (server sends PTY output as binary)", () => {
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    const ws = MockWebSocket.instances[0]!;
    ws.onopen?.();
    const bytes = new TextEncoder().encode("hello-binary").buffer;
    ws.onmessage?.({ data: bytes });
    expect(writeMock).toHaveBeenCalledWith("hello-binary");
  });

  it("forwards terminal keystrokes as outgoing WS sends", () => {
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    const ws = MockWebSocket.instances[0]!;
    onDataHandlers[0]!("ls -la\r");
    expect(ws.sent).toEqual(["ls -la\r"]);
  });

  it("swallows wheel events xterm would otherwise turn into arrow keys", () => {
    termState.modes.mouseTrackingMode = "none";
    termState.buffer.active.type = "alternate";
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    expect(wheelHandlerMock).toHaveBeenCalledTimes(1);
    // false = xterm skips its alt-screen wheel→cursor-key emulation, which in a
    // claude pane would walk the prompt history instead of scrolling.
    expect(wheelHandlerMock.mock.calls[0]![0]!(new Event("wheel"))).toBe(false);
  });

  it("lets the wheel through once the pane's program tracks the mouse", () => {
    // tmux with `mouse on` sets this; the wheel must reach it as a real SGR
    // report, so returning false here would kill scrolling entirely.
    termState.modes.mouseTrackingMode = "any";
    termState.buffer.active.type = "alternate";
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    expect(wheelHandlerMock.mock.calls[0]![0]!(new Event("wheel"))).toBe(true);
  });

  it("lets the wheel through on a normal buffer, where xterm scrolls scrollback", () => {
    termState.modes.mouseTrackingMode = "none";
    termState.buffer.active.type = "normal";
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    expect(wheelHandlerMock.mock.calls[0]![0]!(new Event("wheel"))).toBe(true);
  });

  it("treats x10 tracking as no wheel tracking (x10 never reports the wheel)", () => {
    termState.modes.mouseTrackingMode = "x10";
    termState.buffer.active.type = "alternate";
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    expect(wheelHandlerMock.mock.calls[0]![0]!(new Event("wheel"))).toBe(false);
  });

  it("keeps Shift+Tab in the terminal instead of letting focus escape", () => {
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    const handler = keyHandlerMock.mock.calls[0]![0]! as (e: KeyboardEvent) => boolean;

    const shiftTab = new KeyboardEvent("keydown", { key: "Tab", shiftKey: true });
    const preventShiftTab = vi.spyOn(shiftTab, "preventDefault");
    // true = xterm still processes it and sends ESC[Z; only the browser's
    // focus-moving default is suppressed.
    expect(handler(shiftTab)).toBe(true);
    expect(preventShiftTab).toHaveBeenCalled();

    const plainTab = new KeyboardEvent("keydown", { key: "Tab" });
    const preventPlainTab = vi.spyOn(plainTab, "preventDefault");
    expect(handler(plainTab)).toBe(true);
    expect(preventPlainTab).not.toHaveBeenCalled();
  });

  it("takes the keyboard as soon as it mounts", () => {
    // The terminal IS the page here — without this the first thing typed after
    // opening a lane went nowhere until the user clicked the pane.
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    expect(focusMock).toHaveBeenCalled();
  });

  it("tells its owner when the pane exited, so the setup form can come back", () => {
    // A double Ctrl+C out of `claude` ends the tmux session; the dead pane used
    // to sit there until the user found the "New run" button.
    const onExit = vi.fn();
    render(
      <TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" onExit={onExit} />
    );
    MockWebSocket.instances[0]!.onmessage?.({ data: '{"type":"exit","code":0}' });
    expect(onExit).toHaveBeenCalledTimes(1);
  });

  it("renders through the canvas addon, not xterm's DOM renderer", () => {
    // The DOM renderer aligns a row with one `letter-spacing`, which holds only
    // while every glyph shares a font. Vietnamese diacritics and CJK fall to a
    // fallback face with a different advance, so glyphs shove their neighbours
    // and the row's tail spills onto the row below — buffer clean, painting
    // wrong. The canvas renderer draws each cell at a fixed position instead.
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    expect(loadAddonMock.mock.calls.some(([a]) => (a as { __canvas?: boolean }).__canvas)).toBe(
      true
    );
  });

  describe("size reporting (tmux must never be wider than the terminal)", () => {
    // A tmux pane wider than xterm wraps each over-long row's tail onto the
    // next row's left margin, and tmux never repaints a row it believes
    // unchanged — the stray characters glued to the left edge after scrolling.
    it("reports its size when the socket opens", () => {
      render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
      const ws = MockWebSocket.instances[0]!;
      ws.onopen?.();
      expect(ws.sent).toContain(JSON.stringify({ type: "resize", cols: 131, rows: 28 }));
    });

    it("reports a size change xterm made on its own, with no container resize", () => {
      // Webfont load and page zoom both move cols without resizing the element
      // ResizeObserver watches, which is why onResize is the hook.
      render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
      const ws = MockWebSocket.instances[0]!;
      ws.onopen?.();
      ws.sent.length = 0;
      termState.cols = 129;
      onResizeHandlers.forEach((fn) => fn());
      expect(ws.sent).toEqual([JSON.stringify({ type: "resize", cols: 129, rows: 28 })]);
    });

    it("never reports a collapsed console's zero size", () => {
      // The Workspace console collapses with CSS, so the container can be 0×0
      // while mounted; resizing the real tmux pane to that would wreck it.
      render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
      const ws = MockWebSocket.instances[0]!;
      ws.sent.length = 0;
      termState.cols = 0;
      termState.rows = 0;
      onResizeHandlers.forEach((fn) => fn());
      ws.onopen?.();
      expect(ws.sent).toEqual([]);
    });
  });

  it("re-attaches after the socket drops (a server restart must not freeze the pane)", () => {
    vi.useFakeTimers();
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    MockWebSocket.instances[0]!.close();
    vi.advanceTimersByTime(1600);
    expect(MockWebSocket.instances).toHaveLength(2);
    vi.useRealTimers();
  });

  it("does not re-attach once the server reported the pane exited", () => {
    vi.useFakeTimers();
    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
    const ws = MockWebSocket.instances[0]!;
    ws.onmessage?.({ data: '{"type":"exit","code":0}' });
    ws.close();
    vi.advanceTimersByTime(5000);
    expect(MockWebSocket.instances).toHaveLength(1);
    vi.useRealTimers();
  });

  it("pastes the server-side path of a dropped image into the pane", async () => {
    dropImageMock.mockReset().mockResolvedValue({ path: "/tmp/agenthub-drops-1/ab.png" });
    pasteMock.mockClear();
    render(<TerminalView runId="r1" wsBaseUrl="ws://x" />);
    const img = new File([new Uint8Array([137, 80])], "shot.png", { type: "image/png" });
    const target = screen.getByTestId("terminal-view");
    fireEvent.dragEnter(target, { dataTransfer: { types: ["Files"], files: [img] } });
    expect(screen.getByTestId("terminal-drop")).toHaveTextContent("Drop image to attach");
    fireEvent.drop(target, { dataTransfer: { types: ["Files"], files: [img] } });
    await waitFor(() => expect(pasteMock).toHaveBeenCalledWith("/tmp/agenthub-drops-1/ab.png "));
    expect(dropImageMock).toHaveBeenCalledWith(img);
    await waitFor(() => expect(screen.queryByTestId("terminal-drop")).toBeNull());
  });

  it("uploads nothing for a dropped non-image and says why", async () => {
    dropImageMock.mockReset();
    pasteMock.mockClear();
    render(<TerminalView runId="r1" wsBaseUrl="ws://x" />);
    const txt = new File(["hi"], "a.txt", { type: "text/plain" });
    fireEvent.drop(screen.getByTestId("terminal-view"), {
      dataTransfer: { types: ["Files"], files: [txt] },
    });
    expect(await screen.findByText("Only images can be dropped here")).toBeInTheDocument();
    expect(dropImageMock).not.toHaveBeenCalled();
    expect(pasteMock).not.toHaveBeenCalled();
  });
});