// @vitest-environment happy-dom
import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";

import { addTab, emptyLayout, leaves, type Layout } from "./layout.js";
import { splitLeaf } from "./layout.js";
import { createMultiView, type MultiView } from "./multiview.js";
import type { ConnectionPool } from "./connections.js";
import type { SidebarHandle } from "./catalog.js";

function stubFetch(): void {
  vi.stubGlobal(
    "fetch",
    vi.fn(async (input: RequestInfo | URL) => {
      const url = String(input);
      const body = url.includes("/api/info")
        ? { hostname: "h", version: "0", home_dir: "/home/user", presets: [] }
        : url.includes("/api/projects")
          ? []
          : url.includes("/api/names")
            ? { names: ["cello"] }
            : undefined;
      return new Response(JSON.stringify(body), { status: 200 });
    }),
  );
}

function fakePool(): ConnectionPool {
  return {
    setVisible() {},
    setFocus() {},
  } as unknown as ConnectionPool;
}

function fakeSidebar(): SidebarHandle {
  return {
    el: document.createElement("aside"),
    setActive() {},
    setHighlights() {},
    setPreview() {},
    focusList() {},
    hasListFocus() {
      return false;
    },
    dispose() {},
  };
}

function makeMv(layout: Layout): MultiView {
  return createMultiView({
    pool: fakePool(),
    layout,
    sidebar: fakeSidebar(),
    infoFor: () => ({ name: "sess", command: "bash" }),
    onDisconnect: () => {},
    renderWelcome: () => document.createElement("div"),
  });
}

/** Drain the microtask queue so any pending async work lands. */
async function flush(): Promise<void> {
  for (let i = 0; i < 20; i++) await Promise.resolve();
}

describe("multiview empty panes", () => {
  beforeEach(() => {
    stubFetch();
    document.body.replaceChildren();
  });

  afterEach(() => {
    vi.unstubAllGlobals();
  });

  it("renders a placeholder, not a spawn form", async () => {
    const layout = emptyLayout();
    const tab = layout.tabs[0];
    const first = splitLeaf(tab, "", "s1", "row", true);
    tab.focusedLeafId = splitLeaf(tab, first, null, "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();
    await flush();

    expect(mv.el.querySelectorAll(".mv-pane")).toHaveLength(2);
    expect(mv.el.querySelector(".mv-pane-empty")).toBeTruthy();
    expect(mv.el.querySelector(".spawn-form")).toBeNull();
  });
});

describe("multiview pane-drag swap", () => {
  beforeEach(() => {
    stubFetch();
    document.body.replaceChildren();
  });

  afterEach(() => {
    vi.unstubAllGlobals();
    vi.restoreAllMocks();
  });

  /** Drag `sourcePane`'s title onto `targetPane`'s center, as the real pane
   *  drag handler does — modelled after the pointer sequence in runDrag()/
   *  updateDock() in multiview.ts, since neither is exposed on MultiView. */
  async function dragPaneOntoCenter(sourcePane: HTMLElement, targetPane: HTMLElement): Promise<void> {
    // The real drag-start gate requires the pointerdown target to sit inside
    // an `.attach-header` (attach.ts's session title bar), which the fake pool
    // never mounts; stand one in for the gate check itself.
    const marker = document.createElement("div");
    marker.className = "attach-header";
    sourcePane.appendChild(marker);

    vi.spyOn(targetPane, "getBoundingClientRect").mockReturnValue({
      left: 100,
      top: 0,
      width: 100,
      height: 100,
      right: 200,
      bottom: 100,
      x: 100,
      y: 0,
      toJSON() {},
    } as DOMRect);
    (document as unknown as { elementsFromPoint: (x: number, y: number) => Element[] }).elementsFromPoint = () => [
      targetPane,
    ];

    marker.dispatchEvent(
      new PointerEvent("pointerdown", { clientX: 0, clientY: 0, bubbles: true, cancelable: true }),
    );
    window.dispatchEvent(
      new PointerEvent("pointermove", { clientX: 150, clientY: 50, bubbles: true, cancelable: true }),
    );
    window.dispatchEvent(new PointerEvent("pointerup", { clientX: 150, clientY: 50, bubbles: true, cancelable: true }));
    await flush();
  }

  it("swaps the two panes' sessions when one is dropped on the other's centre", async () => {
    const layout = emptyLayout();
    const tab = layout.tabs[0];
    const leaf1 = splitLeaf(tab, "", "s1", "row", true);
    const leaf2 = splitLeaf(tab, leaf1, "s2", "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();
    await flush();

    const paneOf = (leafId: string) => mv.el.querySelector(`[data-leaf-id="${leafId}"]`) as HTMLElement;
    await dragPaneOntoCenter(paneOf(leaf1), paneOf(leaf2));

    expect(leaves(tab.root).find((l) => l.id === leaf1)?.sessionId).toBe("s2");
    expect(leaves(tab.root).find((l) => l.id === leaf2)?.sessionId).toBe("s1");
    expect(tab.focusedLeafId).toBe(leaf2);
  });
});

describe("openSessionBeside newTab (#100)", () => {
  beforeEach(() => {
    stubFetch();
    document.body.replaceChildren();
  });

  afterEach(() => {
    vi.unstubAllGlobals();
  });

  it("opens its own tab instead of splitting the focused session", async () => {
    const layout = emptyLayout();
    const tab = layout.tabs[0];
    const first = splitLeaf(tab, "", "s1", "row", true);
    tab.focusedLeafId = first;
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    mv.openSessionBeside("s2", { newTab: true });
    await flush();

    expect(layout.tabs).toHaveLength(2);
    // The tab you were reading is untouched: still one pane, still its session.
    const original = leaves(layout.tabs[0].root);
    expect(original).toHaveLength(1);
    expect(original[0].sessionId).toBe("s1");
    // The new session is alone in the new, now-active tab.
    const fresh = leaves(layout.tabs[1].root);
    expect(fresh).toHaveLength(1);
    expect(fresh[0].sessionId).toBe("s2");
    expect(layout.activeTabId).toBe(layout.tabs[1].id);
  });

  it("still splits when newTab is not asked for", async () => {
    const layout = emptyLayout();
    const tab = layout.tabs[0];
    tab.focusedLeafId = splitLeaf(tab, "", "s1", "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    mv.openSessionBeside("s2");
    await flush();

    expect(layout.tabs).toHaveLength(1);
    expect(leaves(tab.root)).toHaveLength(2);
  });
});

describe("multiview closeSession tab cleanup (#137)", () => {
  beforeEach(() => {
    stubFetch();
    document.body.replaceChildren();
  });

  afterEach(() => {
    vi.unstubAllGlobals();
  });

  it("closes the tab when its last session goes away", () => {
    const layout = emptyLayout();
    const first = layout.tabs[0];
    first.focusedLeafId = splitLeaf(first, "", "s1", "row", true);
    const second = addTab(layout);
    second.focusedLeafId = splitLeaf(second, "", "s2", "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    mv.closeSession("s2");

    expect(layout.tabs).toHaveLength(1);
    expect(layout.tabs[0].id).toBe(first.id);
    expect(layout.activeTabId).toBe(first.id);
  });

  it("closes a background tab without stealing focus from the active one", () => {
    const layout = emptyLayout();
    const background = layout.tabs[0];
    background.focusedLeafId = splitLeaf(background, "", "s1", "row", true);
    const active = addTab(layout);
    active.focusedLeafId = splitLeaf(active, "", "s2", "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    mv.closeSession("s1");

    expect(layout.tabs).toHaveLength(1);
    expect(layout.tabs[0].id).toBe(active.id);
    expect(layout.activeTabId).toBe(active.id);
  });

  it("keeps a tab that still holds another pane", () => {
    const layout = emptyLayout();
    const tab = layout.tabs[0];
    const first = splitLeaf(tab, "", "s1", "row", true);
    tab.focusedLeafId = splitLeaf(tab, first, "s2", "row", true);
    addTab(layout);
    layout.activeTabId = tab.id;
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    mv.closeSession("s2");

    expect(layout.tabs).toHaveLength(2);
    expect(leaves(tab.root)).toHaveLength(1);
  });

  it("keeps a tab holding an empty pane", async () => {
    const layout = emptyLayout();
    const tab = layout.tabs[0];
    const s1 = splitLeaf(tab, "", "s1", "row", true);
    splitLeaf(tab, s1, null, "row", true);
    addTab(layout);
    layout.activeTabId = tab.id;
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();
    await flush();

    mv.closeSession("s1");

    expect(layout.tabs).toHaveLength(2);
    expect(leaves(tab.root)).toHaveLength(1);
  });

  it("never closes the only tab", () => {
    const layout = emptyLayout();
    const tab = layout.tabs[0];
    tab.focusedLeafId = splitLeaf(tab, "", "s1", "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    mv.closeSession("s1");

    expect(layout.tabs).toHaveLength(1);
    expect(layout.tabs[0].root).toBeNull();
    expect(layout.activeTabId).toBe(tab.id);
  });
});

describe("multiview mobile single pane", () => {
  /** Force the mobile media query on, whatever happy-dom's viewport says. */
  function forceMobile(): void {
    vi.spyOn(window, "matchMedia").mockImplementation(
      (query: string) =>
        ({
          matches: query.includes("859"),
          media: query,
          onchange: null,
          addEventListener() {},
          removeEventListener() {},
          addListener() {},
          removeListener() {},
          dispatchEvent: () => false,
        }) as unknown as MediaQueryList,
    );
  }

  beforeEach(() => {
    stubFetch();
    forceMobile();
    document.body.replaceChildren();
  });

  afterEach(() => {
    vi.unstubAllGlobals();
    vi.restoreAllMocks();
  });

  it("replaces the focused pane instead of splitting beside it", () => {
    const layout = emptyLayout();
    const tab = layout.tabs[0];
    tab.focusedLeafId = splitLeaf(tab, "", "s1", "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    mv.openSessionBeside("s2");

    const ls = leaves(tab.root);
    expect(ls).toHaveLength(1);
    expect(ls[0].sessionId).toBe("s2");
    expect(layout.tabs).toHaveLength(1);
  });

  it("keeps a spawned session in the current pane rather than a new tab", async () => {
    const layout = emptyLayout();
    const tab = layout.tabs[0];
    tab.focusedLeafId = splitLeaf(tab, "", "s1", "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    mv.openSessionBeside("s2", { newTab: true });
    await flush();

    expect(layout.tabs).toHaveLength(1);
    const ls = leaves(tab.root);
    expect(ls).toHaveLength(1);
    expect(ls[0].sessionId).toBe("s2");
  });

  it("renders one pane and no pane pills for a multi-leaf tab", () => {
    const layout = emptyLayout();
    const tab = layout.tabs[0];
    const first = splitLeaf(tab, "", "s1", "row", true);
    tab.focusedLeafId = splitLeaf(tab, first, "s2", "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    expect(mv.el.querySelectorAll(".mv-pane")).toHaveLength(1);
    expect(mv.el.querySelector(".mv-panebar")).toBeNull();
    expect(mv.el.querySelector(".mv-pill")).toBeNull();
  });

  it("collapses the tab bar even with several tabs", () => {
    const layout = emptyLayout();
    const first = layout.tabs[0];
    first.focusedLeafId = splitLeaf(first, "", "s1", "row", true);
    const second = addTab(layout);
    second.focusedLeafId = splitLeaf(second, "", "s2", "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    expect(mv.el.classList.contains("mv-mobile-solo")).toBe(true);
  });
});

describe("multiview solo tab bar", () => {
  beforeEach(() => {
    stubFetch();
    document.body.replaceChildren();
  });

  afterEach(() => {
    vi.unstubAllGlobals();
  });

  it("hides the tab bar while only one tab exists", () => {
    const layout = emptyLayout();
    const tab = layout.tabs[0];
    tab.focusedLeafId = splitLeaf(tab, "", "s1", "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    expect(mv.el.classList.contains("mv-solo-tab")).toBe(true);
  });

  it("shows the tab bar again once a second tab appears", () => {
    const layout = emptyLayout();
    const first = layout.tabs[0];
    first.focusedLeafId = splitLeaf(first, "", "s1", "row", true);
    const second = addTab(layout);
    second.focusedLeafId = splitLeaf(second, "", "s2", "row", true);
    const mv = makeMv(layout);
    document.body.appendChild(mv.el);
    mv.render();

    expect(mv.el.classList.contains("mv-solo-tab")).toBe(false);
  });
});