// @vitest-environment happy-dom
import { act, cleanup, fireEvent, render, screen } from "@testing-library/react";
import { afterEach, describe, expect, it, vi } from "vitest";

import { leaves } from "../../layout.js";
import { createLayoutStore } from "../../stores/layoutStore.js";
import type { Session } from "../../types.js";
import { MultiView } from "./MultiView.js";

vi.mock("../terminal/TerminalPane.js", () => ({
  TerminalPane: ({ sessionId }: { sessionId: string }) => <div data-testid={`terminal-${sessionId}`} />,
}));

vi.mock("../structured/StructuredPane.js", () => ({
  StructuredPane: ({ sessionId }: { sessionId: string }) => <div data-testid={`structured-${sessionId}`} />,
}));

afterEach(cleanup);

function store() {
  return createLayoutStore({
    load: () => null,
    save: vi.fn(),
    scheduler: { setTimer: () => 1, clearTimer: () => {} },
  });
}

function session(id: string, over: Partial<Session> = {}): Session {
  return {
    id,
    cwd: "/home/n",
    command: "claude",
    env: {},
    metadata: {},
    status: "Running",
    created_at: "2026-01-01T00:00:00Z",
    ...over,
  } as Session;
}

describe("MultiView", () => {
  it("shows the empty state when the active tab has no panes", () => {
    const s = store();
    render(<MultiView store={s} />);
    expect(screen.getByText(/No session open/)).toBeTruthy();
  });

  it("renders a pane per leaf, dispatching to the terminal or structured body", () => {
    const s = store();
    s.getState().openSession("s1");
    s.getState().openSessionBeside("s2");
    const sessions = new Map([
      ["s1", session("s1")],
      ["s2", session("s2", { view: "Structured" })],
    ]);
    render(<MultiView store={s} sessions={sessions} />);
    expect(screen.getByTestId("terminal-s1")).toBeTruthy();
    expect(screen.getByTestId("structured-s2")).toBeTruthy();
  });

  it("split right adds a second pane to the tree", () => {
    const s = store();
    s.getState().openSession("s1");
    render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);
    fireEvent.click(screen.getByTitle("Split right"));
    expect(screen.getAllByText("Empty pane")).toHaveLength(1);
  });

  it("close pane removes it", () => {
    const s = store();
    s.getState().openSession("s1");
    const leafId = leaves(s.getState().layout.tabs[0].root)[0].id;
    s.getState().splitFocused(leafId, "row"); // adds an empty leaf beside s1
    render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);
    // splitFocused(after: true) puts the fresh empty leaf second — close it.
    fireEvent.click(screen.getAllByTitle("Close pane")[1]);
    expect(screen.queryByText("Empty pane")).toBeNull();
    expect(screen.getByTestId("terminal-s1")).toBeTruthy();
  });

  it("prunes a leaf whose session no longer exists, once the live set is known", () => {
    const s = store();
    s.getState().openSession("s1");
    s.getState().openSessionBeside("dead");
    render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);
    expect(screen.getByTestId("terminal-s1")).toBeTruthy();
    expect(screen.queryByTestId("terminal-dead")).toBeNull();
  });

  it("does not touch the layout while the live set is still unknown", () => {
    const s = store();
    s.getState().openSession("s1");
    render(<MultiView store={s} />);
    expect(screen.getByTestId("terminal-s1")).toBeTruthy();
  });

  describe("preview mode (docs/PREVIEW.md)", () => {
    it("shows a session no pane holds in a throwaway tab, marked as a preview", () => {
      const s = store();
      s.getState().openSession("s1");
      render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);

      act(() => s.getState().previewSession("s9"));
      // s1's own tab is still in the strip — the preview never touched it.
      expect(screen.getByText("Tab 1 · 1")).toBeTruthy();
      const pane = document.querySelector('[data-session-id="s9"]');
      expect(pane).toBeTruthy();
      expect(pane!.querySelector(".bg-preview-tint")).toBeTruthy();
      expect(screen.getByText("preview")).toBeTruthy();
    });

    it("puts the layout back byte for byte once the preview ends", () => {
      const s = store();
      s.getState().openSession("s1");
      render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);
      const before = JSON.stringify(s.getState().layout);

      act(() => s.getState().previewSession("s9"));
      act(() => s.getState().previewSession(null));

      expect(JSON.stringify(s.getState().layout)).toBe(before);
      expect(screen.queryByText("preview")).toBeNull();
    });

    it("does not grab the keyboard while previewing", () => {
      const s = store();
      s.getState().openSession("s1");
      render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);

      act(() => s.getState().previewSession("s9"));
      const pane = document.querySelector('[data-session-id="s9"]') as HTMLElement;
      expect(pane.querySelector('[data-testid="terminal-s9"]')).toBeTruthy();
      // TerminalPane's `focus` prop is verified by TerminalPane's own tests;
      // here the preview must never end up as the active-tab's accent pane.
      expect(pane.className).not.toContain("border-accent");
    });

    it("clicking into a previewed pane commits it: no more preview, nothing moves a second time", () => {
      const s = store();
      s.getState().openSession("s1");
      render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);

      act(() => s.getState().previewSession("s9"));
      const pane = document.querySelector('[data-session-id="s9"]') as HTMLElement;
      fireEvent.pointerDown(pane);

      expect(s.getState().preview).toBeNull();
      expect(screen.queryByText("preview")).toBeNull();
      expect(leaves(s.getState().layout.tabs[1].root).map((l) => l.sessionId)).toEqual(["s9"]);
    });
  });
});