import { describe, expect, it } from 'vitest';
import type { AnimationTrack } from '../../src/core/model/Asset';
import {
  clampMove,
  clampPan,
  clampScroll,
  DEFAULT_VIEW,
  frameAt,
  frameCentreX,
  frameToX,
  keyAt,
  keysWithin,
  MAX_CELL_WIDTH,
  maxScrollY,
  MIN_CELL_WIDTH,
  revealRow,
  ROW_HEIGHT,
  rowAt,
  rowCentreY,
  rowTop,
  RULER_HEIGHT,
  rulerStep,
  scrollByThumb,
  scrollThumb,
  type TimelineView,
  xToFrame,
  zoomCells,
} from '../../src/editor/animation/timelineView';

const TRACKS: AnimationTrack[] = [
  {
    id: 'a',
    target: '',
    property: 'x',
    keys: [
      { frame: 0, value: 0 },
      { frame: 4, value: 40 },
    ],
  },
  { id: 'b', target: '', property: 'y', keys: [{ frame: 2, value: 0 }] },
];

describe('timeline geometry', () => {
  it('maps frames to cells and back', () => {
    const view: TimelineView = { panX: 10, cellWidth: 20, scrollY: 0 };
    expect(frameToX(view, 0)).toBe(10);
    expect(frameToX(view, 3)).toBe(70);
    expect(frameCentreX(view, 3)).toBe(80);
    expect(xToFrame(view, 80)).toBe(3.5);
    expect(frameAt(view, 89)).toBe(3);
    expect(frameAt(view, 90)).toBe(4);
  });

  it('never answers a frame below 0', () => {
    expect(frameAt({ panX: 0, cellWidth: 16, scrollY: 0 }, -40)).toBe(0);
  });

  it('finds rows below the ruler and nothing beyond the last', () => {
    expect(rowAt(RULER_HEIGHT - 1, 2)).toBe(-1);
    expect(rowAt(RULER_HEIGHT, 2)).toBe(0);
    expect(rowAt(RULER_HEIGHT + ROW_HEIGHT, 2)).toBe(1);
    expect(rowAt(RULER_HEIGHT + 2 * ROW_HEIGHT, 2)).toBe(-1);
  });

  it('zooms about the pointer, so the frame under it stays put', () => {
    const view: TimelineView = { panX: -100, cellWidth: 16, scrollY: 0 };
    const x = 200;
    const before = xToFrame(view, x);
    const zoomed = zoomCells(view, 1.5, x);
    expect(zoomed.cellWidth).toBe(24);
    expect(xToFrame(zoomed, x)).toBeCloseTo(before);
  });

  it('keeps the cell width within its bounds', () => {
    expect(zoomCells(DEFAULT_VIEW, 100, 0).cellWidth).toBe(MAX_CELL_WIDTH);
    expect(zoomCells(DEFAULT_VIEW, 0.001, 0).cellWidth).toBe(MIN_CELL_WIDTH);
  });

  it('zooms out far enough that an hour of video at 30 fps fits a screen (#407)', () => {
    const out = zoomCells(DEFAULT_VIEW, 1e-6, 0);
    expect(frameToX(out, 3600 * 30)).toBeLessThanOrEqual(2200);
  });

  it('does not let frame 0 drift right of the left edge', () => {
    expect(clampPan({ panX: 30, cellWidth: 16, scrollY: 0 }).panX).toBe(0);
    expect(clampPan({ panX: -30, cellWidth: 16, scrollY: 0 }).panX).toBe(-30);
  });

  it('labels the ruler with a step that keeps the numbers apart', () => {
    expect(rulerStep({ panX: 0, cellWidth: 48, scrollY: 0 })).toBe(1);
    expect(rulerStep({ panX: 0, cellWidth: 16, scrollY: 0 })).toBe(5);
    expect(rulerStep({ panX: 0, cellWidth: 4, scrollY: 0 })).toBe(10);
    expect(rulerStep({ panX: 0, cellWidth: 0.1, scrollY: 0 })).toBe(500);
    expect(rulerStep({ panX: 0, cellWidth: MIN_CELL_WIDTH, scrollY: 0 })).toBe(2000);
  });
});

describe('picking keys', () => {
  const view: TimelineView = { panX: 0, cellWidth: 16, scrollY: 0 };

  it('hits the key drawn at the centre of its cell', () => {
    expect(keyAt(view, TRACKS, { x: frameCentreX(view, 4), y: rowCentreY(0) })).toEqual({
      trackId: 'a',
      frame: 4,
    });
    expect(keyAt(view, TRACKS, { x: frameCentreX(view, 2), y: rowCentreY(1) })).toEqual({
      trackId: 'b',
      frame: 2,
    });
  });

  it('misses an empty cell and the ruler', () => {
    expect(keyAt(view, TRACKS, { x: frameCentreX(view, 2), y: rowCentreY(0) })).toBeNull();
    expect(keyAt(view, TRACKS, { x: frameCentreX(view, 4), y: RULER_HEIGHT / 2 })).toBeNull();
  });

  it('a band catches every key whose diamond centre it spans, across rows', () => {
    const a = { x: frameToX(view, 1), y: RULER_HEIGHT };
    const b = { x: frameToX(view, 5), y: RULER_HEIGHT + 2 * ROW_HEIGHT };
    expect(keysWithin(view, TRACKS, a, b)).toEqual([
      { trackId: 'a', frame: 4 },
      { trackId: 'b', frame: 2 },
    ]);
    // Spanned the other way round it is the same band.
    expect(keysWithin(view, TRACKS, b, a)).toHaveLength(2);
  });

  it('a band over one row leaves the other alone', () => {
    const a = { x: frameToX(view, 0), y: RULER_HEIGHT };
    const b = { x: frameToX(view, 10), y: RULER_HEIGHT + ROW_HEIGHT - 1 };
    expect(keysWithin(view, TRACKS, a, b).map((k) => k.trackId)).toEqual(['a', 'a']);
  });

  it("skips an object's head between the rows (#408)", () => {
    const lanes = [null, TRACKS[0]!, null, TRACKS[1]!];
    expect(keyAt(view, lanes, { x: frameCentreX(view, 4), y: rowCentreY(0) })).toBeNull();
    expect(keyAt(view, lanes, { x: frameCentreX(view, 4), y: rowCentreY(1) })).toEqual({
      trackId: 'a',
      frame: 4,
    });
    expect(keyAt(view, lanes, { x: frameCentreX(view, 2), y: rowCentreY(3) })?.trackId).toBe('b');
    const all = keysWithin(view, lanes, { x: 0, y: RULER_HEIGHT }, { x: frameToX(view, 10), y: rowTop(4) });
    expect(all.map((k) => k.trackId)).toEqual(['a', 'a', 'b']);
  });

  it('finds the key of a row scrolled up, and nothing under the ruler (#413)', () => {
    const scrolled: TimelineView = { ...view, scrollY: ROW_HEIGHT };
    expect(keyAt(scrolled, TRACKS, { x: frameCentreX(view, 2), y: rowCentreY(0) })?.trackId).toBe('b');
    expect(rowAt(RULER_HEIGHT - 1, 2, ROW_HEIGHT)).toBe(-1);
    const band = keysWithin(
      scrolled,
      TRACKS,
      { x: 0, y: RULER_HEIGHT },
      { x: frameToX(view, 10), y: rowTop(1) },
    );
    expect(band).toEqual([{ trackId: 'b', frame: 2 }]);
  });

  it('a move never takes a key before frame 0', () => {
    const keys = [
      { trackId: 'a', frame: 2 },
      { trackId: 'b', frame: 5 },
    ];
    expect(clampMove(keys, -5)).toBe(-2);
    expect(clampMove(keys, 3)).toBe(3);
    expect(clampMove([], -3)).toBe(0);
  });
});

describe('scrolling the rows (#413)', () => {
  // Room for 4 rows below the ruler, and 10 of them: 6 rows' worth to scroll.
  const height = RULER_HEIGHT + 4 * ROW_HEIGHT;
  const at = (scrollY: number): TimelineView => ({ ...DEFAULT_VIEW, scrollY });

  it('scrolls no further than the last row coming up to the bottom edge, and not above the first', () => {
    expect(maxScrollY(10, height)).toBe(6 * ROW_HEIGHT);
    expect(clampScroll(at(10_000), 10, height).scrollY).toBe(6 * ROW_HEIGHT);
    expect(clampScroll(at(-40), 10, height).scrollY).toBe(0);
    expect(maxScrollY(3, height)).toBe(0);
    expect(clampScroll(at(50), 3, height).scrollY).toBe(0);
  });

  it('brings a picked row into view, just far enough, and leaves one in view alone', () => {
    expect(revealRow(at(0), 9, 10, height).scrollY).toBe(6 * ROW_HEIGHT);
    expect(revealRow(at(0), 5, 10, height).scrollY).toBe(2 * ROW_HEIGHT);
    expect(revealRow(at(6 * ROW_HEIGHT), 1, 10, height).scrollY).toBe(ROW_HEIGHT);
    expect(revealRow(at(2 * ROW_HEIGHT), 3, 10, height).scrollY).toBe(2 * ROW_HEIGHT);
    // Half hidden under the ruler is out of view.
    expect(revealRow(at(ROW_HEIGHT / 2), 0, 10, height).scrollY).toBe(0);
  });

  it('shows a thumb only while the rows do not fit, from top to bottom of its track', () => {
    expect(scrollThumb(at(0), 4, height)).toBeNull();
    const top = scrollThumb(at(0), 10, height)!;
    const bottom = scrollThumb(at(6 * ROW_HEIGHT), 10, height)!;
    expect(top.top).toBe(RULER_HEIGHT);
    expect(top.height).toBeCloseTo((4 * ROW_HEIGHT * 4) / 10);
    expect(bottom.top + bottom.height).toBeCloseTo(height);
  });

  it('a thumb dragged its whole travel scrolls the whole way, and no further', () => {
    const thumb = scrollThumb(at(0), 10, height)!;
    const travel = height - RULER_HEIGHT - thumb.height;
    expect(scrollByThumb(0, travel, 10, height)).toBeCloseTo(6 * ROW_HEIGHT);
    expect(scrollByThumb(0, travel / 2, 10, height)).toBeCloseTo(3 * ROW_HEIGHT);
    expect(scrollByThumb(0, 10 * travel, 10, height)).toBe(6 * ROW_HEIGHT);
    expect(scrollByThumb(ROW_HEIGHT, -10 * travel, 10, height)).toBe(0);
  });

  it('zooming keeps the rows where they were scrolled to', () => {
    expect(zoomCells(at(40), 2, 0).scrollY).toBe(40);
  });
});