diariet/src/engine.test.ts

import { describe, expect, it } from 'vitest';
import { buildRoster, createState, currentReport, reportsForDay, nextShift, routeReport, startGame, PER_DAY_COUNT, LAST_DAY } from './engine.ts';
import { REPORTS } from './data/content.ts';

// A fixed sequence, not a real PRNG — deterministic and enough entropy to
// exercise the shuffle without pulling in a dependency for tests only.
function fakeRng(seed: number): () => number {
  let s = seed;
  return () => {
    s = (s * 9301 + 49297) % 233280;
    return s / 233280;
  };
}

function stateWithRoster(roster: string[]) {
  return { ...startGame(createState()), roster };
}

describe('buildRoster', () => {
  it('draws exactly PER_DAY_COUNT reports per day from that day\'s pool', () => {
    const roster = buildRoster(fakeRng(1));
    expect(roster).toHaveLength(PER_DAY_COUNT * LAST_DAY);
    for (let day = 1; day <= LAST_DAY; day++) {
      const ids = roster.slice((day - 1) * PER_DAY_COUNT, day * PER_DAY_COUNT);
      expect(ids).toHaveLength(PER_DAY_COUNT);
      expect(new Set(ids).size).toBe(PER_DAY_COUNT); // no duplicates within a day
      for (const id of ids) {
        const report = REPORTS.find((r) => r.id === id);
        expect(report, `roster id ${id} has no matching report`).toBeTruthy();
        expect(report!.day).toBe(day);
      }
    }
  });

  it('each day\'s pool has more reports than get drawn, so variety is possible', () => {
    for (let day = 1; day <= LAST_DAY; day++) {
      const poolSize = REPORTS.filter((r) => r.day === day).length;
      expect(poolSize).toBeGreaterThan(PER_DAY_COUNT);
    }
  });

  it('different seeds produce different rosters', () => {
    const a = buildRoster(fakeRng(1));
    const b = buildRoster(fakeRng(99));
    expect(a).not.toEqual(b);
  });
});

describe('routing engine', () => {
  it('starts on a real report from shift one', () => {
    const state = startGame(createState());
    const report = currentReport(state);
    expect(state.phase).toBe('playing');
    expect(report).toBeTruthy();
    expect(report!.day).toBe(1);
  });

  it('advances and records a correct route', () => {
    const before = startGame(createState());
    const report = currentReport(before)!;
    const state = routeReport(before, report.correctRoute);
    expect(state.reportIndex).toBe(1);
    expect(state.decisions[0].correct).toBe(true);
    expect(state.trust).toBe(3);
  });

  it('penalizes an incorrect route', () => {
    const before = startGame(createState());
    const report = currentReport(before)!;
    const wrongRoute = (['avfarda', 'arkivera', 'utred', 'eskalera'] as const).find((r) => r !== report.correctRoute)!;
    const state = routeReport(before, wrongRoute);
    expect(state.decisions[0].correct).toBe(false);
    expect(state.trust).toBeLessThan(3);
    expect(state.insight).toBeGreaterThan(0);
  });

  it('escalating costs insight even when it is the correct route (d04, hand-picked into the roster)', () => {
    const roster = ['d01', 'd02', 'd03', 'd04', 'd05', ...buildRoster(fakeRng(2)).slice(PER_DAY_COUNT)];
    let state = stateWithRoster(roster);
    for (const route of ['avfarda', 'arkivera', 'utred'] as const) state = routeReport(state, route);
    expect(currentReport(state)?.id).toBe('d04');
    state = routeReport(state, 'eskalera');
    expect(state.lastDecision?.correct).toBe(true);
    expect(state.lastDecision?.trustCost).toBe(0);
    expect(state.lastDecision?.insightCost).toBe(1);
  });

  it('escalating a wrong report stacks the escalation cost on top of the wrong-route cost', () => {
    const roster = ['d01', 'd02', 'd03', 'd04', 'd05', ...buildRoster(fakeRng(3)).slice(PER_DAY_COUNT)];
    let state = stateWithRoster(roster);
    // d01's correct route is avfarda; eskalera is wrong here.
    state = routeReport(state, 'eskalera');
    expect(state.lastDecision?.correct).toBe(false);
    expect(state.lastDecision?.insightCost).toBe(2); // 1 for wrong + 1 for escalating
  });

  it('ends a shift and restores one trust point for the next', () => {
    let state = startGame(createState());
    const routes = reportsForDay(state, 1).map((report) => report.correctRoute);
    for (const route of routes) state = routeReport(state, route);
    expect(state.phase).toBe('shift-end');
    state = nextShift(state);
    expect(state.day).toBe(2);
    expect(state.trust).toBe(3);
  });

  it('has PER_DAY_COUNT reports available in every shift', () => {
    const state = startGame(createState());
    for (let day = 1; day <= LAST_DAY; day += 1) expect(reportsForDay(state, day)).toHaveLength(PER_DAY_COUNT);
  });

  it('every report has its own correct-route consequence', () => {
    for (const report of REPORTS) {
      expect(report.correctConsequence, `${report.id} is missing a correctConsequence`).toBeTruthy();
    }
  });

  it('loses on insight reaching the cap even with trust intact', () => {
    let state = startGame(createState());
    // Escalate every report regardless of correctness to ramp insight fast.
    for (let i = 0; i < 10 && state.phase === 'playing'; i++) state = routeReport(state, 'eskalera');
    expect(state.phase).toBe('lost');
    expect(state.insight).toBeGreaterThanOrEqual(5);
  });
});