Battle-for-Tismo/shared/game_state.js

// Authoritative game model. It owns the generated world, cities, units,
// territory, population, the economy, combat and diplomacy, and is completely
// free of any rendering or transport concerns, so the Node server can own it
// and both sides can share the data catalogue. Clients never run this class
// against a live game; they render snapshots of it and send orders back.
//
// The behaviour is split across the modules in ./game_state/ and composed onto
// the prototype below. Everything still lives on the one GameState object, so
// methods can freely call each other through `this`; the split is purely about
// keeping each concern in a file small enough to read.

import { MapTopology, key } from "./hex.js";
import { MapGenerator } from "./map_generator.js";
import { TerrainStats } from "./terrain_stats.js";
import { HexPathfinder } from "./hex_pathfinder.js";
import { randomSeed } from "./rng.js";
import {
  PROTO_UNITS,
  BUILDINGS,
  GOVERNMENTS,
  TECHNOLOGIES,
  MAP_CONFIG,
} from "./data.js";
import {
  MAX_NEWS,
  UNIT_VISION,
  TERRITORY_VISION,
  HOURS_PER_DAY,
  DAYS_PER_YEAR,
  HOURS_PER_YEAR,
  CONTROLLED_SPEED_MULTIPLIER,
  DEFAULT_UNIT_SPEED,
  MIN_STEP_COST,
  TRAINING_QUEUE_LIMIT,
  DEFENDER_DEFENSE_MULTIPLIER,
} from "./game_state/constants.js";
import { worldMethods } from "./game_state/world.js";
import { territoryMethods } from "./game_state/territory.js";
import { economyMethods } from "./game_state/economy.js";
import { movementMethods } from "./game_state/movement.js";
import { combatMethods } from "./game_state/combat.js";
import { statusMethods } from "./game_state/statuses.js";
import { diplomacyMethods } from "./game_state/diplomacy.js";
import { orderMethods } from "./game_state/orders.js";
import { visibilityMethods } from "./game_state/visibility.js";
import { serializationMethods } from "./game_state/serialization.js";

export {
  MAX_NEWS,
  UNIT_VISION,
  TERRITORY_VISION,
  HOURS_PER_DAY,
  DAYS_PER_YEAR,
  HOURS_PER_YEAR,
  CONTROLLED_SPEED_MULTIPLIER,
  DEFAULT_UNIT_SPEED,
  MIN_STEP_COST,
  TRAINING_QUEUE_LIMIT,
  DEFENDER_DEFENSE_MULTIPLIER,
};

export class GameState {
  constructor() {
    this.mapConfig = MAP_CONFIG;
    this.civilisations = [];
    this.protoUnits = PROTO_UNITS.slice();
    this.protoBuildings = BUILDINGS.slice();
    this.governments = GOVERNMENTS.slice();
    this.technologies = TECHNOLOGIES.slice();

    this.seed = 0;
    this.topology = null;
    this.tiles = {};
    this.terrainStats = null;
    this.landCells = [];
    this.totalHours = 0;

    this._configured = false;
    this._generator = null;
    this._pathfinder = new HexPathfinder();
    this._minMovementCost = 1.0;
    this._maxStepLength = 1.0;
    this._listeners = [];

    this._resetCollections();
  }

  // Recreates every per-game collection, index and counter. Shared by the
  // constructor and `configure`, so a fresh instance and a restarted game
  // always start from exactly the same shape.
  _resetCollections() {
    this.cities = [];
    this.units = [];
    this.territory = new Map();
    // Which city's region each land tile belongs to: the nearest city, used to
    // attribute population, GDP and tax to the city that develops the land.
    this.tileRegion = new Map();
    this._regionByCity = new Map();
    // Tiles carrying a road (pre-generated city network).
    this.roads = new Set();
    this.tilePopulation = new Map();
    // Per-tile GDP-per-capita multiplier, lowered by pillaging (default 1).
    this.tileGdpPenalty = new Map();
    // Absolute GDP-per-capita lost to fighting on a tile, and the hour its
    // recovery may begin. A tile leaves both maps once it has recovered.
    this.tileBattleGdpDeficit = new Map();
    this.tileBattleRecoveryStart = new Map();
    this.budgets = new Map();
    this.training = new Map();
    this.research = new Map();
    this.culture = new Map();
    this.government = new Map();
    this.researched = new Map();
    this.explored = new Map();
    this.visible = new Map();
    // Diplomatic relations, stored as a set of canonical "a:b" keys of pairs
    // at war. Every other pair is at peace by default.
    this.wars = new Set();
    // One record per war, keyed like `wars`: when it started and the military
    // and civilian casualties each side has suffered so far.
    this.conflicts = new Map();
    this.news = [];

    this._nextUnitId = 1;
    this._nextCityId = 1;
    this._nextNewsId = 1;
    this._cityNamesUsed = new Map();
    this._usedCityNames = new Set();
    this._unitById = new Map();
    this._cityById = new Map();
    this._cityByCoords = new Map();
    this._cityAdjacent = new Map();
    this._territoryByCiv = new Map();
    this._gdpPerCapitaCache = new Map();
    // Per-civ factors that map generation picked so every nation starts with
    // the same population and GDP per capita (see _balanceStartingEconomy).
    this._populationBalance = new Map();
    this._perCapitaBalance = new Map();
    this._serializedTerritory = [];
    this._serializedExplored = new Map();
    this._neighbourCache = new Map();
    this._visibilityDirty = true;
  }

  onChanged(fn) {
    this._listeners.push(fn);
  }

  _emitChanged() {
    for (const fn of this._listeners) fn();
  }

  isConfigured() {
    return this._configured;
  }

  configure(civs, worldSeed = 0) {
    this.civilisations = civs.slice();
    this.seed = worldSeed !== 0 ? worldSeed | 0 : randomSeed();
    this.topology = new MapTopology(
      this.mapConfig.mapSize,
      this.mapConfig.topology === "cylindrical"
    );
    this._generator = new MapGenerator(this.mapConfig, this.topology);
    this._generator.generate(this.seed);
    this.tiles = this._generator.tiles;
    this.landCells = this._generator.landCells;
    this.terrainStats = new TerrainStats(this.tiles);
    this._minMovementCost = this.terrainStats.minMovementCostMultiplier();
    this._maxStepLength = this._computeMaxStepLength();

    this._resetCollections();
    for (let i = 0; i < this.civilisations.length; i++) {
      this.research.set(i, 0);
      this.culture.set(i, 0);
      this.government.set(i, 0);
      this.researched.set(i, new Set());
    }
    this.totalHours = 0;
    this._configured = true;

    this._placeSettlements();
    this._refreshStatuses();
    this._revealAll();
    this._refreshVisibility();
    this._visibilityDirty = false;
    this._emitChanged();
  }

  // ------------------------------------------------------------- lookups --

  findUnit(unitId) {
    return this._unitById.get(unitId) || null;
  }

  findCity(cityId) {
    return this._cityById.get(cityId) || null;
  }

  unitProto(unit) {
    const index = unit.proto;
    if (index < 0 || index >= this.protoUnits.length) return null;
    return this.protoUnits[index];
  }

  cityAt(coords) {
    return this._cityByCoords.get(key(coords.x, coords.y)) || null;
  }

  // Every unit standing on `coords`. Friendly units may stack, so a tile can
  // hold more than one.
  unitsAt(coords) {
    const result = [];
    for (const unit of this.units) {
      if (unit.coords.x === coords.x && unit.coords.y === coords.y) result.push(unit);
    }
    return result;
  }

  unitAt(coords) {
    return this.unitsAt(coords)[0] || null;
  }

  // The hostile units standing on `coords` (when seen by `civ`).
  enemyUnitsAt(coords, civ) {
    return this.unitsAt(coords).filter((unit) => unit.civ !== civ);
  }

  advanceHour() {
    this.advanceMovement(1.0);
    this.tickHour();
  }

  tickHour() {
    this.totalHours += 1;
    this._tickTraining();
    this._tickGarrisonHealing();
    if (this._visibilityDirty) {
      this._refreshVisibility();
      this._visibilityDirty = false;
    }
    if (this.totalHours % HOURS_PER_DAY === 0) {
      this._tickPopulation();
      this._tickBattleTiles();
      this._tickGdpRecovery();
      this._tickEconomy();
      this._refreshStatuses();
      this._applyDailyStatusEffects();
      this._resolveCombatRound();
    }
    this._tickBuildings();
    // A unit no longer sharing a tile with an enemy is not an invader any more.
    for (const unit of this.units) {
      if (unit.invader && !this._hasHostileOn(unit.coords, unit.civ)) unit.invader = false;
    }
    this._emitChanged();
  }
}

// Compose the behaviour mixins onto the prototype. Each module owns one concern
// and may call methods from any other through `this`.
Object.assign(
  GameState.prototype,
  worldMethods,
  territoryMethods,
  economyMethods,
  movementMethods,
  combatMethods,
  statusMethods,
  diplomacyMethods,
  orderMethods,
  visibilityMethods,
  serializationMethods
);