drive-between-the-lines/src/sim/quests.test.ts

import { describe, expect, it } from 'vitest';
import { generateWorld } from './world';
import { placeBases, baseAt } from './bases';
import { buildGraph, findRoute } from './routing';
import { createIntel, observe, summariseRoute, survey, hasSeen } from './intel';
import { createAreas, createHeat, stepHeat } from './heat';
import {
  accept,
  createQuests,
  MISSION_SHAPE,
  MISSION_TYPES,
  offersAt,
  rewardFor,
  stepQuest,
} from './quests';

const world = generateWorld(1337);
const graph = buildGraph(world.roads);
const bases = placeBases(world.roads, world.spawn);
const areas = createAreas(world.roads, world.extent);

describe('bases', () => {
  it('puts one where the player starts, so the loop is available at once', () => {
    expect(baseAt(bases, world.spawn.x, world.spawn.z)).not.toBeNull();
  });

  it('spreads the rest out, so no single choke point can strand the player', () => {
    const spacing: number[] = [];
    for (let i = 0; i < bases.length; i++) {
      for (let j = i + 1; j < bases.length; j++) {
        spacing.push(Math.hypot(bases[i]!.x - bases[j]!.x, bases[i]!.z - bases[j]!.z));
      }
    }
    expect(Math.min(...spacing)).toBeGreaterThan(100);
  });

  it('reaches every base by road from every other', () => {
    for (const from of bases) {
      for (const to of bases) {
        if (from === to) continue;
        expect(findRoute(graph, from.nodeId, to.nodeId)).not.toBeNull();
      }
    }
  });
});

describe('routing', () => {
  it('finds a route whose segments actually chain together', () => {
    const route = findRoute(graph, bases[0]!.nodeId, bases[2]!.nodeId)!;
    expect(route.nodes[0]).toBe(bases[0]!.nodeId);
    expect(route.nodes.at(-1)).toBe(bases[2]!.nodeId);
    expect(route.segments).toHaveLength(route.nodes.length - 1);
    for (let i = 0; i < route.segments.length; i++) {
      const s = world.roads.segments[route.segments[i]!]!;
      const pair = [s.a, s.b];
      expect(pair).toContain(route.nodes[i]);
      expect(pair).toContain(route.nodes[i + 1]);
    }
  });

  it('reports true metres, and no longer than the straight line is short', () => {
    const route = findRoute(graph, bases[0]!.nodeId, bases[1]!.nodeId)!;
    const straight = Math.hypot(bases[0]!.x - bases[1]!.x, bases[0]!.z - bases[1]!.z);
    expect(route.length).toBeGreaterThanOrEqual(straight - 1e-6);
    const summed = route.segments.reduce((t, id) => t + world.roads.segments[id]!.length, 0);
    expect(route.length).toBeCloseTo(summed, 6);
  });

  it('takes a detour when the direct road is weighted as expensive', () => {
    const direct = findRoute(graph, bases[0]!.nodeId, bases[1]!.nodeId)!;
    const avoided = new Set(direct.segments);
    const detour = findRoute(graph, bases[0]!.nodeId, bases[1]!.nodeId, (id, length) =>
      avoided.has(id) ? length * 100 : length,
    )!;
    // Loops in the network mean an alternative exists and costs more.
    expect(detour.segments).not.toEqual(direct.segments);
    expect(detour.length).toBeGreaterThan(direct.length);
  });
});

describe('intel', () => {
  it('starts blank and only records what was observed', () => {
    const intel = createIntel(world.roads, world.extent);
    const heat = createHeat(world.roads, areas);
    expect(hasSeen(intel, 4)).toBe(false);
    observe(intel, heat, 4, 10);
    expect(hasSeen(intel, 4)).toBe(true);
    expect(hasSeen(intel, 5)).toBe(false);
  });

  it('remembers what a road was, not what it has since become', () => {
    const intel = createIntel(world.roads, world.extent);
    const heat = createHeat(world.roads, areas);
    observe(intel, heat, 0, 0);
    expect(intel.rememberedLevel[0]).toBe('clear');

    for (let m = 0; m < 400; m++) stepHeat(heat, { dt: 1 / 60, segmentId: 0, distance: 1 , areaId: null}, areas);
    expect(heat.level[0]).toBe('turret');
    // The player was not there to see it escalate.
    expect(intel.rememberedLevel[0]).toBe('clear');
  });

  it('surveys a whole area at once, which is what recon is for', () => {
    const intel = createIntel(world.roads, world.extent);
    const heat = createHeat(world.roads, areas);
    const node = world.roads.nodes[24]!;
    const mapped = survey(intel, heat, world.roads, node.x, node.z, 5);
    expect(mapped).toBeGreaterThan(1);
    expect(intel.seenAt.filter((t) => t >= 0)).toHaveLength(mapped);
  });

  it('summarises a route by its worst road and how much is unscouted', () => {
    const intel = createIntel(world.roads, world.extent);
    const heat = createHeat(world.roads, areas);
    const route = findRoute(graph, bases[0]!.nodeId, bases[1]!.nodeId)!;

    expect(summariseRoute(intel, route.segments, 0).unknownCount).toBe(route.segments.length);

    for (let m = 0; m < 400; m++) {
      stepHeat(heat, { dt: 1 / 60, segmentId: route.segments[0]!, distance: 1 , areaId: null}, areas);
    }
    for (const id of route.segments) observe(intel, heat, id, 100);

    const summary = summariseRoute(intel, route.segments, 400);
    expect(summary.unknownCount).toBe(0);
    expect(summary.worst).toBe('turret');
    expect(summary.stalest).toBeCloseTo(300, 6);
  });
});

describe('quest board', () => {
  it('always offers something new to go and look at', () => {
    const state = createQuests();
    const intel = createIntel(world.roads, world.extent);
    const offers = offersAt(state, world.roads, graph, intel, bases[0]!, 0, 1);
    expect(offers.length).toBeGreaterThan(0);
    expect(offers.some((o) => o.novel)).toBe(true);
  });

  it('offers both a known and an unknown target once somewhere has been visited', () => {
    const state = createQuests();
    const intel = createIntel(world.roads, world.extent);
    intel.visitedNodes.add(world.roads.nodes[10]!.id);
    intel.visitedNodes.add(world.roads.nodes[30]!.id);
    const offers = offersAt(state, world.roads, graph, intel, bases[0]!, 0, 7);
    expect(offers.some((o) => o.novel)).toBe(true);
    expect(offers.some((o) => !o.novel)).toBe(true);
  });

  it('pays more for an unknown target, or nobody would ever take one', () => {
    // Compared on the *same* route. An earlier version of this test compared
    // rates across whatever targets each board happened to offer, which mostly
    // measured route length: the reward has a fixed component, so a short trip
    // always looks better per kilometre whether or not it is novel.
    const route = findRoute(graph, bases[0]!.nodeId, bases[1]!.nodeId)!;
    for (const type of MISSION_TYPES) {
      expect(rewardFor(type, route, true)).toBeGreaterThan(rewardFor(type, route, false));
    }
  });

  it('never offers the base you are standing in as a target', () => {
    const state = createQuests();
    const intel = createIntel(world.roads, world.extent);
    for (const base of bases) {
      for (const offer of offersAt(state, world.roads, graph, intel, base, 0, 11)) {
        expect(offer.targetNode).not.toBe(base.nodeId);
      }
    }
  });
});

describe('mission lifecycle', () => {
  const start = () => {
    const state = createQuests();
    const intel = createIntel(world.roads, world.extent);
    const offer = offersAt(state, world.roads, graph, intel, bases[0]!, 0, 5)[0]!;
    accept(state, offer, bases[0]!);
    return state;
  };

  it('runs travel → work → return → hand in', () => {
    const state = start();
    expect(state.active!.stage).toBe('travel');

    expect(stepQuest(state, { dt: 1 / 60, distanceToTarget: 400, atBase: null, speed: 20 })).toBeNull();
    expect(stepQuest(state, { dt: 1 / 60, distanceToTarget: 5, atBase: null, speed: 20 })).toEqual({
      kind: 'arrived',
    });

    // Still rolling: no work gets done.
    stepQuest(state, { dt: 1, distanceToTarget: 5, atBase: null, speed: 20 });
    expect(state.active!.worked).toBe(0);

    let worked = null;
    for (let i = 0; i < MISSION_SHAPE[state.active!.type].work * 60 + 2 && !worked; i++) {
      worked = stepQuest(state, { dt: 1 / 60, distanceToTarget: 5, atBase: null, speed: 0 });
    }
    expect(worked).toEqual({ kind: 'worked', type: state.active!.type });
    expect(state.active!.stage).toBe('return');

    const done = stepQuest(state, {
      dt: 1 / 60,
      distanceToTarget: 900,
      atBase: bases[2]!,
      speed: 0,
    });
    expect(done?.kind).toBe('completed');
    expect(state.active).toBeNull();
    expect(state.completed).toBe(1);
    expect(state.parts).toBeGreaterThan(0);
  });

  it('accepts a hand-in at any base, so a blocked road home cannot strand you', () => {
    const state = start();
    stepQuest(state, { dt: 1 / 60, distanceToTarget: 5, atBase: null, speed: 0 });
    for (let i = 0; i < MISSION_SHAPE[state.active!.type].work * 60 + 2; i++) {
      stepQuest(state, { dt: 1 / 60, distanceToTarget: 5, atBase: null, speed: 0 });
    }
    const elsewhere = bases.find((b) => b.nodeId !== state.active!.originBase)!;
    expect(
      stepQuest(state, { dt: 1 / 60, distanceToTarget: 999, atBase: elsewhere, speed: 0 })?.kind,
    ).toBe('completed');
  });

  it('abandons half-finished work if you drive away', () => {
    const state = start();
    stepQuest(state, { dt: 1 / 60, distanceToTarget: 5, atBase: null, speed: 0 });
    stepQuest(state, { dt: 1, distanceToTarget: 5, atBase: null, speed: 0 });
    expect(state.active!.worked).toBeGreaterThan(0);

    stepQuest(state, { dt: 1 / 60, distanceToTarget: 200, atBase: null, speed: 25 });
    expect(state.active!.stage).toBe('travel');
    expect(state.active!.worked).toBe(0);
  });
});