import { TestCase } from "./framework/test_case.js";
import { smallState, cityOf } from "./framework/helpers.js";
import { key } from "../shared/hex.js";
import { FAMINE, NEWS_FAMINE } from "../shared/data.js";

// A region in famine: its food store has run dry and the day's need went unmet.
function starve(state, city) {
  state._resourceShortages = new Map([[city.id, { food: 1 }]]);
}

export class FamineTest extends TestCase {
  test_famine_begins_when_food_runs_out() {
    const state = smallState();
    const city = cityOf(state, 0);
    this.assertFalse(state.isFamine(city), "a fed region is not in famine");
    starve(state, city);
    state._tickFamine();
    this.assertTrue(state.isFamine(city), "running out of food starts a famine");
  }

  test_famine_kills_one_percent_a_day() {
    const state = smallState();
    const city = cityOf(state, 0);
    const before = state.regionPopulation(city);
    this.assertGreater(before, 0, "the region has people");
    starve(state, city);
    state._tickFamine();
    const after = state.regionPopulation(city);
    this.assertApprox(after, before * (1 - FAMINE.dailyMortality), before * 0.01);
  }

  test_famine_is_announced_once_per_occurrence() {
    const state = smallState();
    const city = cityOf(state, 0);
    starve(state, city);
    state._tickFamine();
    state._tickFamine();
    let news = state.news.filter((entry) => entry.type === NEWS_FAMINE);
    this.assertEqual(news.length, 1, "a lasting famine is announced only once");
    this.assertEqual(news[0].region, city.name, "the region is named");
    this.assertEqual(news[0].civ, city.civ, "so is its nation");

    // Food comes back: the famine ends silently...
    state._resourceShortages = new Map();
    state._tickFamine();
    this.assertFalse(state.isFamine(city), "food ends the famine");
    // ...and a later famine is fresh news.
    starve(state, city);
    state._tickFamine();
    news = state.news.filter((entry) => entry.type === NEWS_FAMINE);
    this.assertEqual(news.length, 2, "a new famine is announced afresh");
  }

  test_the_snapshot_ships_the_famine() {
    const state = smallState();
    const city = cityOf(state, 0);
    starve(state, city);
    state._tickFamine();
    const snapshot = state.snapshot(0);
    const stats = snapshot.cityStats.find((entry) => entry.id === city.id);
    this.assertTrue(stats.famine, "the famine is shipped to the client");
  }

  test_a_drained_food_store_starts_a_famine() {
    const state = smallState();
    const city = cityOf(state, 0);
    // The region's people far outnumber what its land can feed, so the day's
    // harvest and every reachable store fall short of the need.
    for (const coords of state.regionTiles(city)) {
      const k = key(coords.x, coords.y);
      state.tilePopulation.set(k, (state.tilePopulation.get(k) || 0) * 1000);
    }
    state._tickResources();
    this.assertTrue(state.isFamine(city), "the resource tick starts the famine");
    this.assertGreater(
      state.news.filter((entry) => entry.type === NEWS_FAMINE).length,
      0,
      "the world is told"
    );
  }
}