import { describe, it, expect } from 'vitest';

import {
  classifyTier,
  computeHeat,
  DEFAULT_RECOMMENDER_SETTINGS,
} from '@/lib/services/berth-recommender.service';

describe('classifyTier', () => {
  it('"A" when there is no interest history at all', () => {
    expect(classifyTier({ activeInterestCount: 0, lostCount: 0, maxActiveStage: 0 })).toBe('A');
  });
  it('"B" when only lost interests exist (no active)', () => {
    expect(classifyTier({ activeInterestCount: 0, lostCount: 2, maxActiveStage: 0 })).toBe('B');
  });
  it('"C" when an active interest is in an early stage', () => {
    expect(classifyTier({ activeInterestCount: 1, lostCount: 0, maxActiveStage: 3 })).toBe('C');
  });
  it('"C" even when a prior interest was lost, if there is an active one', () => {
    expect(classifyTier({ activeInterestCount: 1, lostCount: 5, maxActiveStage: 2 })).toBe('C');
  });
  it('"D" when an active interest is at deposit or beyond', () => {
    expect(classifyTier({ activeInterestCount: 1, lostCount: 0, maxActiveStage: 6 })).toBe('D');
    expect(classifyTier({ activeInterestCount: 1, lostCount: 0, maxActiveStage: 8 })).toBe('D');
  });
  it('still "C" at eoi_signed (stage 5) - tier D only kicks in at deposit', () => {
    expect(classifyTier({ activeInterestCount: 1, lostCount: 0, maxActiveStage: 5 })).toBe('C');
  });
});

describe('computeHeat', () => {
  const w = DEFAULT_RECOMMENDER_SETTINGS;
  const NOW = new Date('2026-05-05T00:00:00Z');

  it('zero heat when nothing in history', () => {
    const h = computeHeat(
      {
        latestFallthroughAt: null,
        totalInterestCount: 0,
        eoiSignedCount: 0,
        fallthroughMaxStage: 0,
      },
      w,
      NOW,
    );
    expect(h.total).toBe(0);
  });

  it('full recency for a fall-through within the last 30 days', () => {
    const h = computeHeat(
      {
        latestFallthroughAt: new Date('2026-04-25T00:00:00Z'),
        totalInterestCount: 0,
        eoiSignedCount: 0,
        fallthroughMaxStage: 1,
      },
      w,
      NOW,
    );
    // recency component should be the full heat_weight_recency (30)
    expect(h.recency).toBeCloseTo(30, 1);
  });

  it('zero recency for an ancient fall-through (>1 year)', () => {
    const h = computeHeat(
      {
        latestFallthroughAt: new Date('2024-01-01T00:00:00Z'),
        totalInterestCount: 0,
        eoiSignedCount: 0,
        fallthroughMaxStage: 1,
      },
      w,
      NOW,
    );
    expect(h.recency).toBe(0);
  });

  it('full furthest-stage when the fall-through reached deposit', () => {
    const h = computeHeat(
      {
        latestFallthroughAt: null,
        totalInterestCount: 0,
        eoiSignedCount: 0,
        fallthroughMaxStage: 6, // deposit_10pct
      },
      w,
      NOW,
    );
    expect(h.furthestStage).toBeCloseTo(40, 1);
  });

  it('saturates interest-count at 5+', () => {
    const h = computeHeat(
      {
        latestFallthroughAt: null,
        totalInterestCount: 10,
        eoiSignedCount: 0,
        fallthroughMaxStage: 0,
      },
      w,
      NOW,
    );
    expect(h.interestCount).toBeCloseTo(15, 1); // full weight
  });

  it('saturates EOI-count at 3+', () => {
    const h = computeHeat(
      {
        latestFallthroughAt: null,
        totalInterestCount: 0,
        eoiSignedCount: 5,
        fallthroughMaxStage: 0,
      },
      w,
      NOW,
    );
    expect(h.eoiCount).toBeCloseTo(15, 1);
  });

  it('total ≈ 100 when everything is maxed', () => {
    const h = computeHeat(
      {
        latestFallthroughAt: new Date('2026-04-25T00:00:00Z'),
        totalInterestCount: 5,
        eoiSignedCount: 3,
        fallthroughMaxStage: 6,
      },
      w,
      NOW,
    );
    expect(h.total).toBeGreaterThanOrEqual(99);
    expect(h.total).toBeLessThanOrEqual(100);
  });

  it('respects tunable per-port weights (skewed toward recency)', () => {
    const skewed = {
      heatWeightRecency: 100,
      heatWeightFurthestStage: 0,
      heatWeightInterestCount: 0,
      heatWeightEoiCount: 0,
    };
    const recent = computeHeat(
      {
        latestFallthroughAt: new Date('2026-04-25T00:00:00Z'),
        totalInterestCount: 0,
        eoiSignedCount: 0,
        fallthroughMaxStage: 0,
      },
      skewed,
      NOW,
    );
    expect(recent.total).toBeCloseTo(100, 1);

    const old = computeHeat(
      {
        latestFallthroughAt: new Date('2024-01-01T00:00:00Z'),
        totalInterestCount: 5,
        eoiSignedCount: 3,
        fallthroughMaxStage: 6,
      },
      skewed,
      NOW,
    );
    expect(old.total).toBe(0);
  });

  it('zero-weights guard (no division-by-zero blow-up)', () => {
    const zeros = {
      heatWeightRecency: 0,
      heatWeightFurthestStage: 0,
      heatWeightInterestCount: 0,
      heatWeightEoiCount: 0,
    };
    const h = computeHeat(
      {
        latestFallthroughAt: new Date(),
        totalInterestCount: 5,
        eoiSignedCount: 3,
        fallthroughMaxStage: 6,
      },
      zeros,
      NOW,
    );
    expect(h.total).toBe(0);
  });
});