OpenFrontIO/src/core/execution/DefensePostExecution.ts

import { consolex } from "../Consolex";
import {
  Execution,
  Game,
  Player,
  PlayerID,
  Unit,
  UnitType,
} from "../game/Game";
import { TileRef } from "../game/GameMap";
import { ShellExecution } from "./ShellExecution";

export class DefensePostExecution implements Execution {
  private player: Player;
  private mg: Game;
  private post: Unit;
  private active: boolean = true;

  private target: Unit = null;
  private lastShellAttack = 0;

  private alreadySentShell = new Set<Unit>();

  constructor(
    private ownerId: PlayerID,
    private tile: TileRef,
  ) {}

  init(mg: Game, ticks: number): void {
    this.mg = mg;
    if (!mg.hasPlayer(this.ownerId)) {
      console.warn(`DefensePostExectuion: owner ${this.ownerId} not found`);
      this.active = false;
      return;
    }
    this.player = mg.player(this.ownerId);
  }

  private shoot() {
    const shellAttackRate = this.mg.config().defensePostShellAttackRate();
    if (this.mg.ticks() - this.lastShellAttack > shellAttackRate) {
      this.lastShellAttack = this.mg.ticks();
      this.mg.addExecution(
        new ShellExecution(
          this.post.tile(),
          this.post.owner(),
          this.post,
          this.target,
        ),
      );
      if (!this.target.hasHealth()) {
        // Don't send multiple shells to target that can be oneshotted
        this.alreadySentShell.add(this.target);
        this.target = null;
        return;
      }
    }
  }

  tick(ticks: number): void {
    if (this.post == null) {
      const spawnTile = this.player.canBuild(UnitType.DefensePost, this.tile);
      if (spawnTile == false) {
        consolex.warn("cannot build Defense Post");
        this.active = false;
        return;
      }
      this.post = this.player.buildUnit(UnitType.DefensePost, spawnTile, {});
    }
    if (!this.post.isActive()) {
      this.active = false;
      return;
    }

    if (this.player != this.post.owner()) {
      this.player = this.post.owner();
    }

    if (this.target != null && !this.target.isActive()) {
      this.target = null;
    }

    // TODO: Reconsider how/if defense posts target ships.
    return;

    const ships = this.mg
      .nearbyUnits(
        this.post.tile(),
        this.mg.config().defensePostTargettingRange(),
        [UnitType.TransportShip, UnitType.Warship],
      )
      .filter(
        ({ unit }) =>
          unit.owner() !== this.post.owner() &&
          !unit.owner().isFriendly(this.post.owner()) &&
          !this.alreadySentShell.has(unit),
      );

    this.target =
      ships.sort((a, b) => {
        const { unit: unitA, distSquared: distA } = a;
        const { unit: unitB, distSquared: distB } = b;

        // Prioritize TransportShip
        if (
          unitA.type() === UnitType.TransportShip &&
          unitB.type() !== UnitType.TransportShip
        )
          return -1;
        if (
          unitA.type() !== UnitType.TransportShip &&
          unitB.type() === UnitType.TransportShip
        )
          return 1;

        // If both are the same type, sort by distance (lower `distSquared` means closer)
        return distA - distB;
      })[0]?.unit ?? null;

    if (this.target == null || !this.target.isActive()) {
      this.target = null;
      return;
    } else {
      this.shoot();
      return;
    }
  }

  isActive(): boolean {
    return this.active;
  }

  activeDuringSpawnPhase(): boolean {
    return false;
  }
}