import type { EntityId } from 'db://assets/mx/module/ecs';
import {
    AttributeComp,
    BattleEventType,
    BattleTeamId,
    TeamComp,
    type BattleEvent,
} from 'db://assets/mx/module/battle';
import { BattleBuffCarryStore } from '../../manager/battleBuff/BattleBuffCarryStore';
import { resolveCarriedEnemySlowWan } from '../../manager/battleBuff/BattleBuffPassiveSkillUtil';
import type { ProjectBattleHandle } from '../runtime/BattleRuntime';
import { AI_PLAYER_ID } from '../ai/runtime/AiCampArea';

/** 被动敌军减速 modifier 分组 */
const ENEMY_SLOW_MOD_GROUP = 'battle_buff_enemy_slow';

/** 单玩家减速 */
type PlayerSlow = {
    /** 被进攻方 playerId（WaveSpawner ownerId） */
    playerId: number;
    /** 万分比 */
    slowWan: number;
};

/**
 * 被动 functiontype=23 弱水：进攻「携带者基地」的敌军移速 ×(1-万分比/10000)。
 * Team.ownerId = 被进攻方（基地所属）；减速的是往该基地冲的出征兵（敌方出征）。
 */
export class BattleBuffEnemySlowHost {
    private _battle: ProjectBattleHandle | null = null;
    private readonly _slows: PlayerSlow[] = [];
    private _onUnitSpawnedBound = false;

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

    private _pushSlow(playerId: number): void {
        const adjust = resolveCarriedEnemySlowWan(BattleBuffCarryStore.getPassives(playerId));
        if (!adjust.active || adjust.slowWan <= 0) return;
        this._slows.push({ playerId, slowWan: adjust.slowWan });
    }

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

    /** 是否已挂载弱水减速 */
    isActive(): boolean {
        return this._slows.length > 0;
    }

    /**
     * 该出征怪是否受弱水减速。
     * @param entityId 怪物实体
     * @returns 减速万分比；不受减则 null
     */
    resolveSlowWanForEntity(entityId: EntityId): number | null {
        const battle = this._battle;
        if (!battle || this._slows.length <= 0) return null;
        const world = battle.session.world;
        if (!world.isAlive(entityId)) return null;
        const team = world.getComponent(entityId, TeamComp);
        if (!team || !BattleTeamId.isEnemyTeam(team.team)) return null;
        for (let i = 0; i < this._slows.length; i++) {
            if (this._slows[i].playerId !== team.ownerId) continue;
            return this._slows[i].slowWan;
        }
        return null;
    }

    private _tryApply(entityId: EntityId): void {
        const battle = this._battle;
        if (!battle || this._slows.length <= 0) return;
        const world = battle.session.world;
        if (!world.isAlive(entityId)) return;
        const team = world.getComponent(entityId, TeamComp);
        if (!team || !BattleTeamId.isEnemyTeam(team.team)) return;
        for (let i = 0; i < this._slows.length; i++) {
            if (this._slows[i].playerId !== team.ownerId) continue;
            this._applySlow(battle, entityId, this._slows[i].slowWan);
            return;
        }
    }

    private _applySlow(battle: ProjectBattleHandle, entityId: EntityId, slowWan: number): void {
        const world = battle.session.world;
        if (!world.getComponent(entityId, AttributeComp)) {
            world.addComponent(entityId, new AttributeComp());
        }
        const speedMul = Math.max(0, 1 - slowWan / 10000);
        battle.session.attributes.addModifier(entityId, {
            attr: 'move_speed_mul',
            op: 'Mul',
            value: speedMul,
            source: `${ENEMY_SLOW_MOD_GROUP}_${slowWan}`,
            group: ENEMY_SLOW_MOD_GROUP,
        });
    }
}

let _host: BattleBuffEnemySlowHost | null = null;

/** 全局敌军减速被动 Host（单局复用） */
export function getBattleBuffEnemySlowHost(): BattleBuffEnemySlowHost {
    if (!_host) _host = new BattleBuffEnemySlowHost();
    return _host;
}