// Wave 4B — LIVE GRADE-SHIFT timeline helper + component (source-asserted).
// Locks the color law (green toward / amber against / dim flat), the revision
// strike-through, and the <3-point self-hide.

const fs = require('fs');
const path = require('path');
const {
  buildGradeTimeline,
  classifyMove,
  cleanHistory,
  TOWARD_COLOR,
  AGAINST_COLOR,
  FLAT_COLOR,
  MIN_POINTS,
} = require('../../web/src/lib/gradeShift');

const read = (rel) => fs.readFileSync(path.join(__dirname, '..', '..', 'web', 'src', rel), 'utf8');

describe('gradeShift helper — color law', () => {
  it('color tokens are green / amber / dim (never red)', () => {
    expect(TOWARD_COLOR).toBe('var(--g-a)');
    expect(AGAINST_COLOR).toBe('var(--amber)');
    expect(FLAT_COLOR).toBe('var(--text-1)');
    for (const c of [TOWARD_COLOR, AGAINST_COLOR, FLAT_COLOR]) {
      expect(c).not.toBe('var(--miss)');
    }
  });

  it('OVER: line up = TOWARD (green), line down = AGAINST (amber), no move = FLAT (dim)', () => {
    expect(classifyMove(0.5, 'Over')).toEqual({ dir: 'toward', color: TOWARD_COLOR });
    expect(classifyMove(-0.5, 'Over')).toEqual({ dir: 'against', color: AGAINST_COLOR });
    expect(classifyMove(0, 'Over')).toEqual({ dir: 'flat', color: FLAT_COLOR });
  });

  it('UNDER inverts the sign: line down = TOWARD (green), line up = AGAINST (amber)', () => {
    expect(classifyMove(-0.5, 'Under')).toEqual({ dir: 'toward', color: TOWARD_COLOR });
    expect(classifyMove(0.5, 'Under')).toEqual({ dir: 'against', color: AGAINST_COLOR });
  });
});

describe('gradeShift helper — timeline assembly', () => {
  it('self-hides below 3 real captured points', () => {
    expect(buildGradeTimeline({ history: null }).show).toBe(false);
    expect(buildGradeTimeline({ history: [{ t: '1', line: 5.5 }] }).show).toBe(false);
    expect(buildGradeTimeline({ history: [{ t: '1', line: 5.5 }, { t: '2', line: 5.5 }] }).show).toBe(false);
    expect(buildGradeTimeline({ history: [{ t: '1', line: 5.5 }, { t: '2', line: 6 }, { t: '3', line: 6.5 }] }).show).toBe(true);
  });

  it('drops non-numeric points (Number(null)===0 guard)', () => {
    const tl = buildGradeTimeline({ history: [{ t: '1', line: 5.5 }, { t: '2', line: null }, { t: '3', line: 6.5 }] });
    expect(tl.points.length).toBe(2); // the null point is dropped, not coerced to 0
    expect(cleanHistory([{ line: null }, { line: 3 }])).toHaveLength(1);
  });

  it('net move on an OVER that rose reads TOWARD (green)', () => {
    const tl = buildGradeTimeline({ history: [{ t: '1', line: 5.5 }, { t: '2', line: 6 }, { t: '3', line: 6.5 }], side: 'Over' });
    expect(tl.net.dir).toBe('toward');
    expect(tl.net.color).toBe(TOWARD_COLOR);
    expect(tl.firstLine).toBe(5.5);
    expect(tl.lastLine).toBe(6.5);
  });

  it('net move on an OVER that fell reads AGAINST (amber)', () => {
    const tl = buildGradeTimeline({ history: [{ t: '1', line: 6.5 }, { t: '2', line: 6 }, { t: '3', line: 5.5 }], side: 'Over' });
    expect(tl.net.dir).toBe('against');
    expect(tl.net.color).toBe(AGAINST_COLOR);
  });

  it('a revision surfaces the ORIGINAL grade struck (from) alongside the new (to)', () => {
    const tl = buildGradeTimeline({
      history: [{ t: '1', line: 5.5 }, { t: '2', line: 6 }, { t: '3', line: 6.5 }],
      grade: 'B',
      revisedFrom: 'A',
    });
    expect(tl.revision).toEqual({ from: 'A', to: 'B' });
  });

  it('no revision when there was no prior grade or it is unchanged', () => {
    const base = [{ t: '1', line: 5.5 }, { t: '2', line: 6 }, { t: '3', line: 6.5 }];
    expect(buildGradeTimeline({ history: base, grade: 'A' }).revision).toBeNull();
    expect(buildGradeTimeline({ history: base, grade: 'A', revisedFrom: 'A' }).revision).toBeNull();
  });

  it('accepts the snapshot field name revised_from_grade too', () => {
    const tl = buildGradeTimeline({
      history: [{ t: '1', line: 5.5 }, { t: '2', line: 6 }, { t: '3', line: 6.5 }],
      grade: 'C',
      revised_from_grade: 'B',
    });
    expect(tl.revision).toEqual({ from: 'B', to: 'C' });
  });

  it('MIN_POINTS matches the LineSparkline floor of 3', () => {
    expect(MIN_POINTS).toBe(3);
  });
});

describe('GradeShift component', () => {
  const src = read('components/vyndr/GradeShift.tsx');
  it('self-hides on !tl.show (returns null)', () => {
    expect(src).toContain('if (!tl.show) return null');
  });
  it('renders the original grade struck-through when revised', () => {
    expect(src).toContain('tl.revision');
    expect(src).toContain('line-through');
    expect(src).toContain('tl.revision.from');
    expect(src).toContain('tl.revision.to');
  });
  it('is a data surface — mono, no glitch classes', () => {
    expect(src).toContain('mono');
    expect(src).not.toMatch(/wm-tear|glitch-shift|head-tear|glitch-hover/);
  });
});

describe('GradeResultCard mounts the timeline', () => {
  const src = read('components/vyndr/GradeResultCard.tsx');
  it('imports and renders GradeShift with the optional history fields', () => {
    expect(src).toContain("import GradeShift from '@/components/vyndr/GradeShift'");
    expect(src).toContain('<GradeShift');
    expect(src).toContain('history?: Array<{ t: string; line: number }> | null');
    expect(src).toContain('revisedFrom');
  });
});