Started a famine when a region's food runs out

client/css/style.css

@@ -1493,6 +1493,7 @@ input:focus, select:focus { border-color: var(--accent); }
   border-top: 1px solid rgba(255, 255, 255, 0.05);
 }
 .politics-penalty { color: #f0b060; }
+.famine-warning { color: #e05a4a; font-weight: 600; }
 .ethnic-chart { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; margin-top: 8px; }
 .ethnic-legend { display: flex; flex-direction: column; gap: 4px; font-size: 13px; }
 .ethnic-legend-row { display: flex; align-items: center; gap: 8px; }

client/js/game_screen/panels.js

@@ -14,6 +14,7 @@ import {
   NEWS_WAR,
   NEWS_TECHNOLOGY,
   NEWS_JOIN,
+  NEWS_FAMINE,
   ECONOMY,
   EFFECT_PRODUCTION,
   APPROVAL,
@@ -1639,8 +1640,10 @@ export const panelMethods = {
       debt: cityStats.debt || 0,
       currencies: stats.currencies || [],
       approval: cityStats.approval,
-      // What the region's people went short of over the last day.
+      // What the region's people went short of over the last day, and whether
+      // they are starving.
       shortage: cityStats.shortage || {},
+      famine: !!cityStats.famine,
       // The region's reserves, their value and its daily consumption.
       resources: cityStats.resources || null,
       // The trade taxes the region generated over the last day.
@@ -1678,7 +1681,8 @@ export const panelMethods = {
         cityStats.approval,
         this._taxMultiplier(cityStats.approval),
         this.civilisations,
-        cityStats.shortage || {}
+        cityStats.shortage || {},
+        !!cityStats.famine
       );
       this.cityModal.renderResources(cityStats.resources || null);
     }
@@ -1905,6 +1909,12 @@ export const panelMethods = {
     // else taking control of a nation is the neutral notice (Mouth_08).
     if (entry.type === NEWS_TECHNOLOGY && entry.civ === this.localCiv) {
       audio.play("complete");
+    } else if (entry.type === NEWS_FAMINE) {
+      // A famine concerns everyone, so it raises the alert notice regardless of
+      // whose region it strikes.
+      audio.play("notification");
+      this.feed.push(describeNews(entry, this.civilisations), { alert: true });
+      return;
     } else if (entry.type === NEWS_JOIN && entry.civ !== this.localCiv) {
       audio.play("notification");
     }

client/js/modals/city.js

@@ -101,7 +101,8 @@ export class CityModal {
       view.approval,
       view.taxMultiplier,
       view.civs || [],
-      view.shortage || {}
+      view.shortage || {},
+      !!view.famine
     );
     this.renderResources(view.resources);
     this.renderEconomy(view.cash || {}, view.cashValue || 0, view.currencies || [], view.debt || 0);
@@ -110,14 +111,22 @@ export class CityModal {
 
   // The region's people: their ethnic makeup and their government approval,
   // which decides how much tax they pay and how fast they build. `shortage`
-  // reports the resources they went short of over the last day and by how much.
-  renderPeople(makeup, approval, taxMultiplier, civs, shortage = {}) {
+  // reports the resources they went short of over the last day and by how much;
+  // `famine` says whether they are starving.
+  renderPeople(makeup, approval, taxMultiplier, civs, shortage = {}, famine = false) {
     if (!this.$peopleList || !this.$peopleList.length) return;
     this.$peopleList.empty();
     const value = approval === undefined || approval === null ? 0.5 : approval;
     if (this.$peopleSub && this.$peopleSub.length) {
       this.$peopleSub.text(`Government approval ${Math.round(value * 100)}%`);
     }
+    if (famine) {
+      this.$peopleList.append(
+        $("<div class='desc famine-warning'></div>").text(
+          "Famine! The region has run out of food and its people are dying."
+        )
+      );
+    }
     if (makeup && makeup.length > 0) {
       this.$peopleList.append(ethnicityChart(makeup, civs || []));
     } else {

client/js/modals/format.js

@@ -146,6 +146,8 @@ export function describeNews(entry, civs) {
       const kind = entry.kind === "export" ? "export tariff" : "import tariff";
       return `${adjective(entry.civ)} leaders set the ${kind} on ${resource} to ${rate}`;
     }
+    case "famine":
+      return `${people(entry.civ)} are starving in ${entry.region}: a famine has begun`;
     default:
       return entry.type;
   }

shared/data/relations.js

@@ -19,3 +19,5 @@ export const NEWS_JOIN = "join";
 // A government changed an import or export tariff. The involved trading
 // parties see it in the news feed.
 export const NEWS_TARIFF = "tariff";
+// A region's food ran out: a famine has begun. Reported to every nation.
+export const NEWS_FAMINE = "famine";

shared/data/resources.js

@@ -107,6 +107,13 @@ export const RESOURCE_MARKET = {
   maxMultiplier: 1.8,
 };
 
+// A region whose food store runs dry and cannot feed its people is in famine:
+// the whole world is told the day it begins, and the region loses this share of
+// its people every day until food comes back.
+export const FAMINE = {
+  dailyMortality: 0.01,
+};
+
 // The physical rules of the resource economy. Every per-person figure and every
 // energy-per-material ratio below is fixed by the design; the prices above are
 // what we tune against them.

shared/game_state/resources.js

@@ -16,6 +16,7 @@ import {
   RESOURCE_RULES,
   RESOURCE_MARKET_BASE,
   RESOURCE_TRADE_RADIUS,
+  FAMINE,
   tileImprovementById,
   isResourceTileBuilding,
   MONEY,
@@ -38,6 +39,7 @@ import { buildingBuildCost } from "../rules.js";
 import { Random } from "../rng.js";
 import { TILE_IMPROVEMENT_HP, HOURS_PER_DAY } from "./constants.js";
 import { EFFECT_RESEARCH } from "../data/effects.js";
+import { NEWS_FAMINE } from "../data/relations.js";
 
 // A city keeps at least this many days of a material in stock before it will
 // sell any of it on; the rest is surplus a neighbour may buy.
@@ -81,6 +83,8 @@ export const resourceMethods = {
     }
     this.resourceLinks = [];
     this._resourceShortages = new Map();
+    // The regions whose food store has run dry and cannot feed their people.
+    this._famine = new Set();
     this._resourceVersion = 0;
     // What each nation imported and exported over the last simulated day, by
     // resource, from cross-nation deliveries only.
@@ -1274,6 +1278,10 @@ export const resourceMethods = {
     // stores -- home regions first, then foreign ones.
     this._consumeCityResources(components, market);
 
+    // A region that could not feed its people is in famine: it tells the world,
+    // and its people start dying.
+    this._tickFamine();
+
     // Every nation's buildings, units and works then wear out: the state draws
     // its stores and buys the rest, and an unpaid bill becomes unrest.
     for (let civ = 0; civ < this.civilisations.length; civ++) {
@@ -1528,6 +1536,49 @@ export const resourceMethods = {
     }
   },
 
+  // A region whose food ran out and could not be resupplied is in famine. The
+  // world is told the day it begins, once per famine rather than daily, and the
+  // region loses a share of its people every day it lasts. Food coming back ends
+  // it silently.
+  _tickFamine() {
+    for (const city of this.cities) {
+      const shortage = (this._resourceShortages && this._resourceShortages.get(city.id)) || {};
+      const starving = (shortage.food || 0) > 0;
+      const was = this._famine.has(city.id);
+      if (starving && !was) {
+        this._famine.add(city.id);
+        this._addNews({ type: NEWS_FAMINE, civ: city.civ, region: city.name });
+      } else if (!starving && was) {
+        this._famine.delete(city.id);
+      }
+      if (starving) this._applyFamineDeaths(city);
+    }
+  },
+
+  // Famine kills a fixed share of a region's people each day, spread over its
+  // tiles in proportion to where they live.
+  _applyFamineDeaths(city) {
+    let total = 0;
+    const tiles = [];
+    for (const coords of this.regionTiles(city)) {
+      const k = key(coords.x, coords.y);
+      const population = this.tilePopulation.get(k) || 0;
+      if (population <= 0) continue;
+      tiles.push({ k, population });
+      total += population;
+    }
+    if (total <= 0) return;
+    for (const tile of tiles) {
+      this.tilePopulation.set(tile.k, tile.population * (1 - FAMINE.dailyMortality));
+    }
+    this._populationVersion += 1;
+  },
+
+  // Whether a region is currently in famine, for its city panel.
+  isFamine(city) {
+    return !!(this._famine && this._famine.has(city.id));
+  },
+
   // A city buys a material from the stores it can reach over the transport
   // network. There is no global market: if no reachable store holds enough, the
   // rest is simply not bought. Suppliers in the buyer's own nation come first;

shared/game_state/serialization.js

@@ -442,8 +442,9 @@ export const serializationMethods = {
         cashValue: this.getRegionCashValue(city),
         debt: this.getRegionDebt(city),
         // What the region's people went short of over the last day, so the
-        // People tab can report it.
+        // People tab can report it, and whether they are starving.
         shortage: this.getRegionShortages(city),
+        famine: this.isFamine(city),
         // The region's reserves, their market value and the private sector's
         // daily consumption, for the Resources tab.
         resources: this.getRegionResourceInfo(city),

tests/famine_test.js

@@ -0,0 +1,81 @@
+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"
+    );
+  }
+}

tests/modals_test.js

@@ -230,6 +230,26 @@ export class CityModalTest extends TestCase {
     }
   }
 
+  async test_the_people_tab_warns_of_famine() {
+    const env = await setupDom();
+    try {
+      const modal = new CityModal();
+      modal.show({ id: 1, name: "Paris" }, {
+        budget: 1.0e15,
+        buildings: BUILDINGS,
+        levels: {},
+        ethnicMakeup: [],
+        famine: true,
+      });
+      this.assertTrue(
+        env.$("#city-people-list").text().includes("Famine"),
+        "the famine warning is shown"
+      );
+    } finally {
+      teardownDom(env);
+    }
+  }
+
   async test_tabs_switch_the_visible_page() {
     const env = await setupDom();
     try {
@@ -1060,5 +1080,9 @@ export class NewsModalTest extends TestCase {
       describeNews({ type: "technology", civ: 2, name: "Radio" }, civs),
       "New Zealand scientists have discovered Radio"
     );
+    this.assertEqual(
+      describeNews({ type: "famine", civ: 1, region: "Hanoi" }, civs),
+      "the Vietnamese are starving in Hanoi: a famine has begun"
+    );
   }
 }