import type { EntityId } from 'db://assets/mx/module/ecs';
import {
    BattleEventType,
    type BattleEvent,
} from 'db://assets/mx/module/battle';
import { BattleBuffCarryStore } from '../../manager/battleBuff/BattleBuffCarryStore';
import { resolveMarchOwnerPlayerId } from '../../manager/battleBuff/BattleBuffSideResolve';
import { resolveCarriedUnitHpBonusWan } from '../../manager/battleBuff/BattleBuffPassiveSkillUtil';
import type { ProjectBattleHandle } from '../runtime/BattleRuntime';
import { SkillAtkBuffExecutor } from './SkillAtkBuffExecutor';
import { AI_PLAYER_ID } from '../ai/runtime/AiCampArea';

/** 单玩家血量加成 */
type PlayerHpBonus = {
    /** playerId（出征方） */
    playerId: number;
    /** 万分比 */
    bonusWan: number;
};

/**
 * 被动 functiontype=15 补元丹：携带方「出征兵」maxHp/hp ×(1+万分比/10000)。
 * 出征兵 = 进攻对面基地的行军怪（本机视角常在对面半场），不是己侧场上单位。
 */
export class BattleBuffUnitHpHost {
    private _battle: ProjectBattleHandle | null = null;
    private readonly _bonuses: PlayerHpBonus[] = [];
    private _onUnitSpawnedBound = false;

    /** 绑定本局并监听出怪 */
    bind(battle: ProjectBattleHandle): void {
        this.unbind();
        this._battle = battle;
        this._bonuses.length = 0;
        this._pushBonus(battle.localPlayerId);
        this._pushBonus(AI_PLAYER_ID);
        if (this._bonuses.length <= 0) return;

        battle.session.events.on(BattleEventType.UnitSpawned, this._onUnitSpawned);
        this._onUnitSpawnedBound = true;
        battle.session.world.forEachAlive((entityId) => {
            this._tryApply(entityId);
        });
    }

    /** 解除绑定 */
    unbind(): void {
        const battle = this._battle;
        if (battle && this._onUnitSpawnedBound) {
            battle.session.events.off(BattleEventType.UnitSpawned, this._onUnitSpawned);
        }
        this._onUnitSpawnedBound = false;
        this._battle = null;
        this._bonuses.length = 0;
    }

    private _pushBonus(playerId: number): void {
        const adjust = resolveCarriedUnitHpBonusWan(BattleBuffCarryStore.getPassives(playerId));
        if (!adjust.active || adjust.bonusWan <= 0) return;
        this._bonuses.push({ playerId, bonusWan: adjust.bonusWan });
    }

    private _onUnitSpawned = (event: BattleEvent): void => {
        if (event.type !== BattleEventType.UnitSpawned) return;
        this._tryApply(event.entity);
    };

    private _tryApply(entityId: EntityId): void {
        const battle = this._battle;
        if (!battle || this._bonuses.length <= 0) return;
        const ownerId = resolveMarchOwnerPlayerId(battle.session, entityId);
        if (ownerId < 0) return;
        for (let i = 0; i < this._bonuses.length; i++) {
            if (this._bonuses[i].playerId !== ownerId) continue;
            SkillAtkBuffExecutor.applyMaxHpCoeff(battle.session.world, entityId, this._bonuses[i].bonusWan, battle);
            return;
        }
    }
}

let _host: BattleBuffUnitHpHost | null = null;

/** 全局出征兵血量被动 Host（单局复用） */
export function getBattleBuffUnitHpHost(): BattleBuffUnitHpHost {
    if (!_host) _host = new BattleBuffUnitHpHost();
    return _host;
}