/* @vitest-environment jsdom */

import { act, fireEvent, renderHook } from '@testing-library/react';
import { afterEach, describe, expect, it, vi } from 'vitest';

import type { CanvasLayer, CanvasViewport } from './ImageCanvasEditorTypes';
import { useImageCanvasViewportControls } from './useImageCanvasViewportControls';

function createLayer(overrides: Partial<CanvasLayer>): CanvasLayer {
  const id = overrides.id ?? 'layer-a';
  return {
    id,
    resourceId: `resource-${id}`,
    title: id,
    src: `data:image/png;base64,${id}`,
    x: 100,
    y: 120,
    width: 200,
    height: 100,
    originalWidth: 200,
    originalHeight: 100,
    zIndex: 1,
    sourceType: 'uploaded',
    ...overrides,
  };
}

function setElementBox(
  element: HTMLElement,
  box: { width: number; height: number; left?: number; top?: number },
) {
  Object.defineProperty(element, 'clientWidth', {
    configurable: true,
    value: box.width,
  });
  Object.defineProperty(element, 'clientHeight', {
    configurable: true,
    value: box.height,
  });
  element.getBoundingClientRect = () =>
    ({
      x: box.left ?? 0,
      y: box.top ?? 0,
      left: box.left ?? 0,
      top: box.top ?? 0,
      right: (box.left ?? 0) + box.width,
      bottom: (box.top ?? 0) + box.height,
      width: box.width,
      height: box.height,
      toJSON: () => ({}),
    }) as DOMRect;
}

function createViewportLayers() {
  return [
    createLayer({ id: 'one', x: 0, y: 0, width: 400, height: 300 }),
    createLayer({ id: 'two', x: 600, y: 100, width: 200, height: 200 }),
  ];
}

function renderViewportControls({
  captureCanvasHistory = vi.fn(),
  layers = createViewportLayers(),
}: {
  captureCanvasHistory?: () => void;
  layers?: CanvasLayer[];
} = {}) {
  const viewportElement = document.createElement('div');
  setElementBox(viewportElement, { width: 900, height: 640 });
  document.body.append(viewportElement);

  const minimapElement = document.createElement('div');
  minimapElement.className = 'genarrative-image-canvas__minimap';
  setElementBox(minimapElement, {
    left: 20,
    top: 30,
    width: 160,
    height: 120,
  });
  document.body.append(minimapElement);

  const canvasViewportRef = { current: viewportElement };
  const hook = renderHook(() =>
    useImageCanvasViewportControls({
      canvasViewportRef,
      layers,
      captureCanvasHistory,
    }),
  );

  return {
    ...hook,
    viewportElement,
    captureCanvasHistory,
  };
}

function createMinimapDragState(minimapScale: number) {
  return {
    kind: 'minimap' as const,
    pointerId: 1,
    startClientX: 100,
    startClientY: 100,
    startViewport: { x: -100, y: -50, scale: 1 },
    minimapScale,
    moved: true,
  };
}

function expectViewport(viewport: CanvasViewport, expected: CanvasViewport) {
  expect(viewport.x).toBeCloseTo(expected.x);
  expect(viewport.y).toBeCloseTo(expected.y);
  expect(viewport.scale).toBeCloseTo(expected.scale);
}

describe('useImageCanvasViewportControls', () => {
  afterEach(() => {
    vi.restoreAllMocks();
    vi.unstubAllGlobals();
    document.body.replaceChildren();
  });

  it('owns canvas size, minimap model and canvas point helpers', () => {
    const { result } = renderViewportControls();

    expect(result.current.canvasSize).toEqual({ width: 900, height: 640 });
    expect(result.current.minimapModel?.layers).toHaveLength(2);
    expect(result.current.getCanvasDropPoint(260, 190)).toEqual({
      x: 260,
      y: 190,
    });
    const worldPoint = result.current.getCanvasPointFromClient(260, 190);
    expect(worldPoint.x).toBeCloseTo(1040);
    expect(worldPoint.y).toBeCloseTo(240);
  });

  it('fits layers and zooms from the viewport center', () => {
    const captureCanvasHistory = vi.fn();
    const { result } = renderViewportControls({ captureCanvasHistory });

    act(() => {
      result.current.fitLayers();
    });
    expectViewport(result.current.viewport, {
      x: 50,
      y: 170,
      scale: 1,
    });
    expect(captureCanvasHistory).toHaveBeenCalledTimes(1);

    act(() => {
      result.current.updateScaleFromCenter(2);
    });
    expectViewport(result.current.viewport, {
      x: -350,
      y: 20,
      scale: 2,
    });
    expect(captureCanvasHistory).toHaveBeenCalledTimes(2);
  });

  it('animates, retargets from the current frame and lets manual input cancel the transition', () => {
    const rafCallbacks = new Map<number, FrameRequestCallback>();
    let nextFrameId = 0;
    vi.spyOn(window, 'requestAnimationFrame').mockImplementation((callback) => {
      nextFrameId += 1;
      rafCallbacks.set(nextFrameId, callback);
      return nextFrameId;
    });
    const cancelAnimationFrameSpy = vi
      .spyOn(window, 'cancelAnimationFrame')
      .mockImplementation((frameId) => {
        rafCallbacks.delete(frameId);
      });
    vi.stubGlobal(
      'matchMedia',
      vi.fn(() => ({ matches: false })) as unknown as typeof window.matchMedia,
    );
    const { result, viewportElement, captureCanvasHistory } =
      renderViewportControls();
    const targetViewport = { x: 120, y: -80, scale: 1.25 };
    const runNextFrame = (timestamp: number) => {
      const entry = rafCallbacks.entries().next().value as
        | [number, FrameRequestCallback]
        | undefined;
      expect(entry).toBeTruthy();
      if (!entry) {
        return;
      }
      rafCallbacks.delete(entry[0]);
      entry[1](timestamp);
    };

    act(() => {
      result.current.animateViewportTo(targetViewport);
    });
    expectViewport(result.current.viewport, {
      x: -260,
      y: 70,
      scale: 0.5,
    });

    act(() => runNextFrame(0));
    act(() => runNextFrame(210));
    expect(result.current.viewport.x).toBeGreaterThan(-260);
    expect(result.current.viewport.x).toBeLessThan(120);
    expect(result.current.viewport.scale).toBeGreaterThan(0.5);
    expect(result.current.viewport.scale).toBeLessThan(1.25);

    const retargetedViewport = { x: 420, y: 260, scale: 1.6 };
    act(() => {
      result.current.animateViewportTo(retargetedViewport);
    });
    expect(cancelAnimationFrameSpy).toHaveBeenCalled();
    act(() => runNextFrame(300));
    act(() => runNextFrame(720));
    expectViewport(result.current.viewport, retargetedViewport);
    expect(captureCanvasHistory).not.toHaveBeenCalled();

    act(() => {
      result.current.animateViewportTo({ x: 600, y: 400, scale: 2 });
    });
    act(() => runNextFrame(800));
    act(() => {
      fireEvent.wheel(viewportElement, { deltaY: 40 });
    });
    expect(cancelAnimationFrameSpy).toHaveBeenCalled();
    expect(rafCallbacks.size).toBe(0);
  });

  it('finishes viewport animation immediately when reduced motion is requested', () => {
    const requestAnimationFrameSpy = vi.spyOn(window, 'requestAnimationFrame');
    vi.stubGlobal(
      'matchMedia',
      vi.fn(() => ({ matches: true })) as unknown as typeof window.matchMedia,
    );
    const { result } = renderViewportControls();
    const targetViewport = { x: 20, y: 30, scale: 0.8 };

    act(() => {
      result.current.animateViewportTo(targetViewport);
    });

    expectViewport(result.current.viewport, targetViewport);
    expect(requestAnimationFrameSpy).not.toHaveBeenCalled();
  });

  it('keeps ordinary mouse wheel vertical and maps Shift wheel to horizontal', () => {
    const { result, viewportElement } = renderViewportControls();

    act(() => {
      fireEvent.wheel(viewportElement, {
        deltaX: 0,
        deltaY: 120,
        clientX: 260,
        clientY: 190,
      });
    });
    expectViewport(result.current.viewport, {
      x: -260,
      y: -50,
      scale: 0.5,
    });

    act(() => {
      fireEvent.wheel(viewportElement, {
        shiftKey: true,
        deltaX: 0,
        deltaY: 80,
        clientX: 260,
        clientY: 190,
      });
    });
    expectViewport(result.current.viewport, {
      x: -340,
      y: -50,
      scale: 0.5,
    });
  });

  it('does not pan the canvas when a generation prompt receives wheel input', () => {
    const { result, viewportElement } = renderViewportControls();
    const prompt = document.createElement('textarea');
    viewportElement.append(prompt);
    const initialViewport = result.current.viewport;

    const wheelEvent = new WheelEvent('wheel', {
      bubbles: true,
      cancelable: true,
      deltaY: 120,
      clientX: 260,
      clientY: 190,
    });
    act(() => {
      prompt.dispatchEvent(wheelEvent);
    });

    expect(result.current.viewport).toEqual(initialViewport);
    expect(wheelEvent.defaultPrevented).toBe(false);
  });

  it('handles native two-axis wheel pan, ctrl wheel zoom and minimap movement', () => {
    const rafCallbacks: FrameRequestCallback[] = [];
    vi.spyOn(window, 'requestAnimationFrame').mockImplementation(
      (callback: FrameRequestCallback) => {
        rafCallbacks.push(callback);
        return rafCallbacks.length;
      },
    );
    vi.spyOn(window, 'cancelAnimationFrame').mockImplementation(() => {});
    const { result, viewportElement } = renderViewportControls();

    act(() => {
      fireEvent.wheel(viewportElement, {
        deltaX: 40,
        deltaY: 120,
        clientX: 260,
        clientY: 190,
      });
    });
    expectViewport(result.current.viewport, {
      x: -300,
      y: -50,
      scale: 0.5,
    });

    act(() => {
      fireEvent.wheel(viewportElement, {
        ctrlKey: true,
        deltaY: -120,
        clientX: 260,
        clientY: 190,
      });
    });
    expectViewport(result.current.viewport, {
      x: -356,
      y: -74,
      scale: 0.55,
    });

    const beforeDrag = result.current.viewport;
    act(() => {
      result.current.updateViewportFromMinimapDrag(
        createMinimapDragState(result.current.minimapModel?.scale ?? 1),
        104,
        103,
      );
    });
    act(() => {
      rafCallbacks.shift()?.(performance.now());
    });
    expect(result.current.viewport).not.toEqual(beforeDrag);

    const beforeClick = result.current.viewport;
    act(() => {
      result.current.moveViewportFromMinimapPointer(100, 90);
    });
    expect(result.current.viewport).not.toEqual(beforeClick);
  });

  it('coalesces minimap drag viewport updates into one animation frame', () => {
    const rafCallbacks: FrameRequestCallback[] = [];
    const requestAnimationFrameSpy = vi
      .spyOn(window, 'requestAnimationFrame')
      .mockImplementation((callback: FrameRequestCallback) => {
        rafCallbacks.push(callback);
        return rafCallbacks.length;
      });
    vi.spyOn(window, 'cancelAnimationFrame').mockImplementation(() => {});
    const { result } = renderViewportControls();

    const initialViewport = result.current.viewport;
    const dragState = createMinimapDragState(
      result.current.minimapModel?.scale ?? 1,
    );
    act(() => {
      result.current.updateViewportFromMinimapDrag(dragState, 104, 103);
      result.current.updateViewportFromMinimapDrag(dragState, 112, 109);
    });

    expect(requestAnimationFrameSpy).toHaveBeenCalledTimes(1);
    expect(result.current.viewport).toEqual(initialViewport);

    act(() => {
      rafCallbacks.shift()?.(performance.now());
    });
    const coalescedViewport = result.current.viewport;
    expect(coalescedViewport).not.toEqual(initialViewport);

    act(() => {
      result.current.updateViewportFromMinimapDrag(dragState, 104, 103);
    });
    act(() => {
      rafCallbacks.shift()?.(performance.now());
    });
    expect(result.current.viewport).not.toEqual(coalescedViewport);
  });

  it('flushes a pending minimap drag before the next animation frame', () => {
    const rafCallbacks: FrameRequestCallback[] = [];
    const cancelAnimationFrameSpy = vi
      .spyOn(window, 'cancelAnimationFrame')
      .mockImplementation(() => {});
    vi.spyOn(window, 'requestAnimationFrame').mockImplementation(
      (callback: FrameRequestCallback) => {
        rafCallbacks.push(callback);
        return rafCallbacks.length;
      },
    );
    const { result } = renderViewportControls();
    const initialViewport = result.current.viewport;
    const dragState = createMinimapDragState(
      result.current.minimapModel?.scale ?? 1,
    );

    act(() => {
      result.current.updateViewportFromMinimapDrag(dragState, 104, 103);
      result.current.updateViewportFromMinimapDrag(dragState, 112, 109);
    });
    act(() => {
      result.current.flushMinimapViewportDrag();
    });

    expect(cancelAnimationFrameSpy).toHaveBeenCalledTimes(1);
    const flushedViewport = result.current.viewport;
    expect(flushedViewport).not.toEqual(initialViewport);

    act(() => {
      rafCallbacks.shift()?.(performance.now());
    });
    expect(result.current.viewport).toEqual(flushedViewport);
  });
});