// tests/reward_core.test.mjs
import { describe, it, expect, vi } from 'vitest';
import { runReward } from '../src/reward/reward_core.mjs';

describe('reward_core.mjs', () => {
  it('parses reward score from valid numeric output', async () => {
    const sample = {
      question: 'Q',
      context: [{ content: 'ctx' }],
      gen: { answer: 'A', raw: 'A' },
    };

    const provider = {
      generate: vi.fn(async () => '0.87\nHigh quality explanation'),
    };

    const result = await runReward(
      {
        question: sample.question,
        context: sample.context,
        gen: sample.gen,
      },
      provider,
    );

    expect(result.score).toBeCloseTo(0.87, 5);
    expect(result.ok).toBe(true);
  });

  it('handles invalid or missing score by falling back to 0 and ok=false', async () => {
    const sample = {
      question: 'Q',
      context: [{ content: 'ctx' }],
      gen: { answer: 'A', raw: 'A' },
    };

    const provider = {
      // no valid 0–1 number present
      generate: vi.fn(async () => 'no numeric score here\ntext'),
    };

    const result = await runReward(
      {
        question: sample.question,
        context: sample.context,
        gen: sample.gen,
      },
      provider,
    );

    expect(result.score).toBe(0);
    expect(result.ok).toBe(false);
  });

  it('treats score >= 0.5 as success and < 0.5 as failure', async () => {
    const sample = {
      question: 'Q',
      context: [{ content: 'ctx' }],
      gen: { answer: 'A', raw: 'A' },
    };

    const highProvider = {
      generate: vi.fn(async () => '0.9\nGreat answer'),
    };

    const lowProvider = {
      generate: vi.fn(async () => '0.2\nWeak answer'),
    };

    const high = await runReward(
      {
        question: sample.question,
        context: sample.context,
        gen: sample.gen,
      },
      highProvider,
    );
    const low = await runReward(
      {
        question: sample.question,
        context: sample.context,
        gen: sample.gen,
      },
      lowProvider,
    );

    expect(high.ok).toBe(true);
    expect(low.ok).toBe(false);
  });
});