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

/** 被动行军速度 modifier 分组 */
const MOVE_SPEED_MOD_GROUP = 'battle_buff_enemy_march_slow';

/** 单玩家：减速攻向其基地的敌军 */
type PlayerApproachSlow = {
    /** 防守方 playerId（基地被攻方） */
    defenderPlayerId: number;
    /** 减速万分比 */
    slowWan: number;
};

/**
 * 被动 functiontype=13 滞行牌：减速攻向携带方基地的敌方怪物。
 */
export class BattleBuffMoveSpeedHost {
    private _battle: ProjectBattleHandle | null = null;
    private readonly _slows: PlayerApproachSlow[] = [];
    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;
    }

    /**
     * 携带方滞行牌 → 减速攻向该方基地的敌军。
     * @param carrierPlayerId 携带方
     */
    private _pushSlow(carrierPlayerId: number): void {
        const adjust = resolveCarriedEnemyMarchSlowWan(BattleBuffCarryStore.getPassives(carrierPlayerId));
        if (!adjust.active || adjust.slowWan <= 0) return;
        for (let i = 0; i < this._slows.length; i++) {
            if (this._slows[i].defenderPlayerId !== carrierPlayerId) continue;
            this._slows[i].slowWan += adjust.slowWan;
            return;
        }
        this._slows.push({ defenderPlayerId: carrierPlayerId, slowWan: adjust.slowWan });
    }

    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._slows.length <= 0) return;
        const team = battle.session.world.getComponent(entityId, TeamComp);
        if (!team || !BattleTeamId.isEnemyTeam(team.team)) return;
        const defenderId = Math.max(0, Math.floor(Number(team.ownerId) || 0));
        for (let i = 0; i < this._slows.length; i++) {
            if (this._slows[i].defenderPlayerId !== defenderId) continue;
            this._applyMarchSlow(battle, entityId, this._slows[i].slowWan);
            return;
        }
    }

    private _applyMarchSlow(battle: ProjectBattleHandle, entityId: EntityId, slowWan: number): void {
        const clamped = Math.min(10000, Math.max(0, slowWan));
        const mul = 1 - clamped / 10000;
        const world = battle.session.world;
        if (!world.getComponent(entityId, AttributeComp)) {
            world.addComponent(entityId, new AttributeComp());
        }
        battle.session.attributes.addModifier(entityId, {
            attr: 'move_speed_mul',
            op: 'Mul',
            value: mul,
            source: `${MOVE_SPEED_MOD_GROUP}_${clamped}`,
            group: MOVE_SPEED_MOD_GROUP,
        });
        const move = world.getComponent(entityId, MovementComp);
        if (move) {
            move.speed = Math.max(0, (move.baseSpeed || move.speed) * mul);
        }
    }
}

let _host: BattleBuffMoveSpeedHost | null = null;

/** 全局敌军来攻移速被动 Host（单局复用） */
export function getBattleBuffMoveSpeedHost(): BattleBuffMoveSpeedHost {
    if (!_host) _host = new BattleBuffMoveSpeedHost();
    return _host;
}