jakciehan
90 lines
3.2 KiB
TypeScript
90 lines
3.2 KiB
TypeScript
import { EnemyType, ItemType } from '../data/Interfaces';
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/**
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* Drop system (req 7.1-7.6).
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*
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* Rules encoded here:
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*
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* 1. **水晶玉 (crystal jade)** — deterministic: every 12th kill on forest
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* stages spawns one above the player (req 7.1). Lifetime 13-20s (req 7.2,
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* handled by caller).
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* 2. **点丸 / 术丸** — after 3 consecutive 赤忍 kills, 50% chance of one or
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* the other (req 7.3).
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* 3. **魔笛** — dropped by 黑忍 on death (implemented in `HeiRenAI`). Picking
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* it up triggers a screen-wipe (req 7.4), applied by the level manager.
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* 4. **增丸** — fixed spawn point per level config, no probability (req 7.5).
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*
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* All probabilistic decisions funnel through an injectable `random()` so
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* deterministic tests stay stable.
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*/
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export interface IDropSystemCfg {
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/** Kills required before a crystal jade is guaranteed. Default 12 (req 7.1). */
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crystalJadeEveryN?: number;
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/** Kills of Chi Ren required before point/spell ball eligible. Default 3. */
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dianShuWanThresholdKills?: number;
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/** Probability for dian_wan or shu_wan drop once threshold reached. Default 0.5. */
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dianShuWanProbability?: number;
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/** Injectable RNG. Default `Math.random`. */
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random?: () => number;
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}
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export interface IDropEvent {
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item: ItemType;
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x: number;
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y: number;
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}
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export class DropSystem {
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private globalKills = 0;
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private chiRenConsecutiveKills = 0;
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private readonly crystalJadeEveryN: number;
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private readonly dianShuWanThresholdKills: number;
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private readonly dianShuWanProbability: number;
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private readonly random: () => number;
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constructor(cfg: IDropSystemCfg = {}) {
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this.crystalJadeEveryN = cfg.crystalJadeEveryN ?? 12;
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this.dianShuWanThresholdKills = cfg.dianShuWanThresholdKills ?? 3;
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this.dianShuWanProbability = cfg.dianShuWanProbability ?? 0.5;
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this.random = cfg.random ?? Math.random;
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}
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/** Register an enemy kill and return any drops produced. */
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public onEnemyKilled(enemy: EnemyType, at: { x: number; y: number }): IDropEvent[] {
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this.globalKills++;
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const drops: IDropEvent[] = [];
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// Crystal-jade rule (deterministic, req 7.1).
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if (this.globalKills % this.crystalJadeEveryN === 0) {
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drops.push({ item: ItemType.CrystalJade, x: at.x, y: at.y + 180 });
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}
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// Chi Ren consecutive rule (req 7.3).
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if (enemy === EnemyType.ChiRen) {
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this.chiRenConsecutiveKills++;
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if (this.chiRenConsecutiveKills >= this.dianShuWanThresholdKills) {
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this.chiRenConsecutiveKills = 0;
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if (this.random() < this.dianShuWanProbability) {
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const pickDian = this.random() < 0.5;
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drops.push({
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item: pickDian ? ItemType.DianWan : ItemType.ShuWan,
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x: at.x,
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y: at.y,
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});
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}
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}
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} else {
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this.chiRenConsecutiveKills = 0;
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}
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return drops;
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}
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public reset(): void {
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this.globalKills = 0;
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this.chiRenConsecutiveKills = 0;
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}
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public get kills(): number {
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return this.globalKills;
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}
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}
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