import type { BattleSession } from 'db://assets/mx/module/battle';
import { AttributeComp, CombatComp } from 'db://assets/mx/module/battle/ecs/Components';
import type { ComposedUnit } from 'db://assets/mx/module/merge';
import type { EntityId } from 'db://assets/mx/module/ecs';
import { GEvent } from 'db://assets/mx/module/event/GEvent';
import type { Player } from '../../game/Player';
import { WeaponComposeConfigProvider } from '../bag/WeaponComposeConfigProvider';
import type { MapManager } from '../map/legacy/MapManager';
import { composeKey } from '../runtime/ComposeUnitKey';
import { findEntityIdByGridIndex } from '../runtime/DeployEntityQuery';

/** 攻速符落点（背包槽 / 地图格） */
export type BattleGameAttackSpeedDropTarget =
    | { kind: 'map'; gridIndex: number }
    | { kind: 'bag'; slotIndex: number };

/** 已绑定到具体攻击单位的攻速层 */
type AttackSpeedLayer = {
    /** modifier source（buffId + skill 槽 + 落点唯一） */
    source: string;
    /** 万分比加成 */
    bonusWan: number;
    /** 受益 ECS 实体 */
    entityId: EntityId;
    /** buff 配置 ID，用于叠加判定 */
    buffId: number;
};

/** 背包落点待绑定（字块上场后再挂到对应单位） */
type PendingBagAttackSpeed = {
    /** 背包槽索引 */
    bagSlot: number;
    source: string;
    bonusWan: number;
    buffId: number;
    /** 是否已绑定到实体 */
    applied: boolean;
};

/** 背包→地图落点后待重试绑定（DeploySync 晚于 drop 一帧时） */
type DeferredBagPlaceBind = {
    bagSlot: number;
    gridIndex: number;
    buffId: number;
    source: string;
    bonusWan: number;
};

/** 攻速 buff modifier source 前缀 */
const ASPD_SOURCE_PREFIX = 'battle_buff_aspd_';

/**
 * 局内主动攻速符（functiontype=17）宿主。
 * 落点字块类型与封神榜/授仙箓一致（多格组合字已合成武将 / type1 普通单字；type2 未合成散字不可）；
 * 攻速仅作用于落点对应的已上场攻击单位（背包可预绑定，上场后生效）；
 * 每个 buffId 对同一单位仅可成功施放一次（背包预绑与上场后为同一实例；同 buffId 不叠加，不同 buffId 可叠加）。
 */
export class BattleGameGlobalAttackSpeedHost {
    private static _inst: BattleGameGlobalAttackSpeedHost | null = null;

    /** 已绑定单位的攻速层 */
    private _layers: AttackSpeedLayer[] = [];
    /** 背包落点待绑定 */
    private _pendingBag: PendingBagAttackSpeed[] = [];
    /** 落点待重试绑定 */
    private _deferredBagPlace: DeferredBagPlaceBind[] = [];
    /** 已施放单位：buffId + 单位 usageKey（同 buffId 同单位仅一次） */
    private _usedTargets: { buffId: number; targetKey: string }[] = [];
    /** 背包槽 → 上场实体（同一字块实例 bag / map 共用去重） */
    private _bagSlotEntityLinks: { bagSlot: number; entityId: EntityId }[] = [];

    /** 单例 */
    static get(): BattleGameGlobalAttackSpeedHost {
        if (!BattleGameGlobalAttackSpeedHost._inst) {
            BattleGameGlobalAttackSpeedHost._inst = new BattleGameGlobalAttackSpeedHost();
        }
        return BattleGameGlobalAttackSpeedHost._inst;
    }

    /** 重置局内状态（战斗结束） */
    reset(): void {
        this._layers.length = 0;
        this._pendingBag.length = 0;
        this._deferredBagPlace.length = 0;
        this._usedTargets.length = 0;
        this._bagSlotEntityLinks.length = 0;
    }

    /**
     * 快照实体已绑定的攻速符。
     * @param entityId 塔实体
     */
    snapshot(entityId: EntityId): { buffId: number; source: string; value: number }[] {
        const out: { buffId: number; source: string; value: number }[] = [];
        for (let i = 0; i < this._layers.length; i++) {
            const layer = this._layers[i];
            if (layer.entityId !== entityId) continue;
            out.push({ buffId: layer.buffId, source: layer.source, value: layer.bonusWan });
        }
        return out;
    }

    /**
     * 拆塔后把攻速符绑回新实体。
     * @param session 战斗会话
     * @param entityId 新实体
     * @param buffs 快照
     */
    restore(session: BattleSession, entityId: EntityId, buffs: readonly { buffId: number; source: string; value: number }[]): void {
        for (let i = 0; i < buffs.length; i++) {
            const b = buffs[i];
            if (this._hasEntityBuffLayer(b.buffId, entityId)) continue;
            this._bindLayer(session, entityId, b.source, b.value, b.buffId);
            this._markTargetUsed(b.buffId, `entity:${entityId}`);
        }
    }

    /**
     * 实体卖掉后清层（字上的绑定快照仍保留）。
     * @param entityId 塔实体
     */
    forgetEntity(entityId: EntityId): void {
        if (!(entityId > 0)) return;
        for (let i = this._layers.length - 1; i >= 0; i--) {
            if (this._layers[i].entityId === entityId) this._layers.splice(i, 1);
        }
        for (let i = this._bagSlotEntityLinks.length - 1; i >= 0; i--) {
            if (this._bagSlotEntityLinks[i].entityId === entityId) this._bagSlotEntityLinks.splice(i, 1);
        }
    }

    /**
     * 指定 buffId 是否已对目标单位施放过。
     * @param buffId Battlebuff.id（functiontype=17）
     */
    isTargetUsed(
        buffId: number,
        target: BattleGameAttackSpeedDropTarget,
        session: BattleSession,
        player: Player | null,
        map: MapManager | null,
    ): boolean {
        if (buffId <= 0) return false;
        if (target.kind === 'map') {
            const entityId = this.resolveMapTargetEntityId(session, player, map, target.gridIndex);
            if (entityId != null && this._hasEntityBuffLayer(buffId, entityId)) return true;
        }
        const keys = this._collectUsageKeys(buffId, session, player, map, target);
        for (let i = 0; i < keys.length; i++) {
            if (this._hasUsedTarget(buffId, keys[i])) return true;
        }
        return false;
    }

    /**
     * 解析攻速符去重键：已上场 → entity；多格未上场 → compose；单字未上场 → map 格；背包 → bag 槽。
     */
    static resolveUsageKey(
        session: BattleSession,
        player: Player | null,
        map: MapManager | null,
        target: BattleGameAttackSpeedDropTarget,
    ): string {
        if (target.kind === 'bag') {
            return `bag:${target.slotIndex}`;
        }

        const gridIndex = target.gridIndex;
        const host = BattleGameGlobalAttackSpeedHost.get();
        const entityId = host.resolveMapTargetEntityId(session, player, map, gridIndex);
        if (entityId != null) {
            return `entity:${entityId}`;
        }

        const compose = BattleGameGlobalAttackSpeedHost._findCompositionAt(player, gridIndex);
        if (compose && BattleGameGlobalAttackSpeedHost._isMultiCellComposition(compose)) {
            return `compose:${composeKey(compose)}`;
        }

        return `map:${gridIndex}`;
    }

    /**
     * 解析地图落点对应的已部署攻击单位。
     * @returns 实体 ID；无单位时 null
     */
    resolveMapTargetEntityId(
        session: BattleSession,
        player: Player | null,
        map: MapManager | null,
        gridIndex: number,
    ): EntityId | null {
        if (!player || !map) return null;
        const entityId = findEntityIdByGridIndex(gridIndex, session, map, player);
        if (entityId == null) return null;
        if (!session.world.isAlive(entityId)) return null;
        if (!session.world.getComponent(entityId, CombatComp)) return null;
        return entityId;
    }

    /**
     * 拖拽落点施放：提升落点对应攻击单位攻速。
     * @param buffId buff 配置 ID（去重 + source 标识）
     * @param skillSlot skill 槽（仅用于 source 标识不同槽位的同一 buffId）
     * @param target 落点字块
     * @param bonusWan functionpar 第二段万分比
     * @returns 是否成功
     */
    tryActivate(
        session: BattleSession,
        player: Player | null,
        map: MapManager | null,
        buffId: number,
        skillSlot: number,
        target: BattleGameAttackSpeedDropTarget,
        bonusWan: number,
    ): boolean {
        if (!player) {
            console.log('[BattleGameAttackSpeed] 无 player');
            return false;
        }
        if (buffId <= 0) {
            console.log('[BattleGameAttackSpeed] 非法 buffId', buffId);
            return false;
        }
        if (this.isTargetUsed(buffId, target, session, player, map)) {
            return false;
        }
        const wan = Math.floor(Number(bonusWan) || 0);
        if (wan <= 0) {
            console.log('[BattleGameAttackSpeed] bonusWan 无效', bonusWan);
            return false;
        }

        const usageKey = BattleGameGlobalAttackSpeedHost.resolveUsageKey(session, player, map, target);
        const source = BattleGameGlobalAttackSpeedHost._sourceFor(buffId, skillSlot, usageKey);

        if (target.kind === 'map') {
            const entityId = this.resolveMapTargetEntityId(session, player, map, target.gridIndex);
            if (entityId == null) return false;
            this._markTargetUsed(buffId, usageKey);
            this._bindLayer(session, entityId, source, wan, buffId);
            this._syncHeroBindAspd(player, target.gridIndex, entityId);
            return true;
        }

        this._markTargetUsed(buffId, usageKey);
        this._pendingBag.push({
            bagSlot: target.slotIndex,
            source,
            bonusWan: wan,
            buffId,
            applied: false,
        });
        return true;
    }

    /**
     * 背包字块落到地图后，将待绑定攻速挂到对应单位。
     * @param bagSlot 来源背包槽
     * @param gridIndex 落点地图格
     */
    onBagPlacedOnMap(
        session: BattleSession,
        player: Player | null,
        map: MapManager | null,
        bagSlot: number,
        gridIndex: number,
    ): void {
        if (!player || !map) return;
        const entityId = this.resolveMapTargetEntityId(session, player, map, gridIndex);
        if (entityId != null) {
            this._linkBagSlotEntity(bagSlot, entityId);
            this._bindPendingBagSlot(session, entityId, bagSlot);
            this._syncHeroBindAspd(player, gridIndex, entityId);
            return;
        }
        const pending = this._findPendingBag(bagSlot);
        if (!pending || pending.applied) return;
        this._deferredBagPlace.push({
            bagSlot,
            gridIndex,
            buffId: pending.buffId,
            source: pending.source,
            bonusWan: pending.bonusWan,
        });
    }

    /** 塔部署/升级后补施加已绑定的攻速 buff（仅该实体） */
    refreshEntity(session: BattleSession, entityId: EntityId, player?: Player | null, map?: MapManager | null): void {
        if (player && map) {
            this._retryDeferredBagBind(session, player, map, entityId);
        }
        for (let i = 0; i < this._layers.length; i++) {
            const layer = this._layers[i];
            if (layer.entityId !== entityId) continue;
            this._applyModifier(session, entityId, layer.source, layer.bonusWan);
        }
    }

    private _findPendingBag(bagSlot: number): PendingBagAttackSpeed | null {
        for (let i = 0; i < this._pendingBag.length; i++) {
            const pending = this._pendingBag[i];
            if (pending.bagSlot === bagSlot && !pending.applied) return pending;
        }
        return null;
    }

    private _bindPendingBagSlot(session: BattleSession, entityId: EntityId, bagSlot: number): void {
        for (let i = 0; i < this._pendingBag.length; i++) {
            const pending = this._pendingBag[i];
            if (pending.applied || pending.bagSlot !== bagSlot) continue;
            this._linkBagSlotEntity(bagSlot, entityId);
            this._markTargetUsed(pending.buffId, `entity:${entityId}`);
            this._bindLayer(session, entityId, pending.source, pending.bonusWan, pending.buffId);
            pending.applied = true;
            return;
        }
    }

    /** 收集同一字块实例在 bag / map 上的全部去重键 */
    private _collectUsageKeys(
        buffId: number,
        session: BattleSession,
        player: Player | null,
        map: MapManager | null,
        target: BattleGameAttackSpeedDropTarget,
    ): string[] {
        const keys: string[] = [];
        const pushKey = (key: string): void => {
            if (keys.indexOf(key) >= 0) return;
            keys.push(key);
        };

        pushKey(BattleGameGlobalAttackSpeedHost.resolveUsageKey(session, player, map, target));

        if (target.kind === 'bag') {
            const linkedEntity = this._findEntityForBagSlot(target.slotIndex);
            if (linkedEntity != null) {
                pushKey(`entity:${linkedEntity}`);
            }
            return keys;
        }

        const entityId = this.resolveMapTargetEntityId(session, player, map, target.gridIndex);
        if (entityId != null) {
            pushKey(`entity:${entityId}`);
            const linkedBagSlot = this._findBagSlotForEntity(entityId);
            if (linkedBagSlot != null) {
                pushKey(`bag:${linkedBagSlot}`);
            }
        }

        for (let i = 0; i < this._deferredBagPlace.length; i++) {
            const row = this._deferredBagPlace[i];
            if (row.buffId !== buffId) continue;
            if (!BattleGameGlobalAttackSpeedHost._isSameMapTileUnit(player, row.gridIndex, target.gridIndex)) continue;
            if (!this._hasUsedTarget(row.buffId, `bag:${row.bagSlot}`)) continue;
            pushKey(`bag:${row.bagSlot}`);
        }

        for (let i = 0; i < this._usedTargets.length; i++) {
            const row = this._usedTargets[i];
            if (row.buffId !== buffId) continue;
            const bagPrefix = 'bag:';
            if (!row.targetKey.startsWith(bagPrefix)) continue;
            const bagSlot = Number(row.targetKey.slice(bagPrefix.length));
            if (!Number.isFinite(bagSlot)) continue;

            const linkedEntity = this._findEntityForBagSlot(bagSlot);
            if (entityId != null && linkedEntity === entityId) {
                pushKey(row.targetKey);
                continue;
            }

            for (let j = 0; j < this._deferredBagPlace.length; j++) {
                const def = this._deferredBagPlace[j];
                if (def.bagSlot !== bagSlot || def.buffId !== buffId) continue;
                if (BattleGameGlobalAttackSpeedHost._isSameMapTileUnit(player, def.gridIndex, target.gridIndex)) {
                    pushKey(row.targetKey);
                    break;
                }
            }
        }

        return keys;
    }

    /** 实体是否已绑定指定 buffId 的攻速层 */
    private _hasEntityBuffLayer(buffId: number, entityId: EntityId): boolean {
        for (let i = 0; i < this._layers.length; i++) {
            const layer = this._layers[i];
            if (layer.buffId === buffId && layer.entityId === entityId) return true;
        }
        return false;
    }

    /** 两地图格是否同一字块实例（同格或多格组合占格） */
    private static _isSameMapTileUnit(player: Player | null, gridA: number, gridB: number): boolean {
        if (gridA === gridB) return true;
        if (!player) return false;
        const compose = player.compositions.find(c => c.gridIndices.includes(gridA)) ?? null;
        if (!compose) return false;
        return compose.gridIndices.includes(gridB);
    }

    private _linkBagSlotEntity(bagSlot: number, entityId: EntityId): void {
        for (let i = 0; i < this._bagSlotEntityLinks.length; i++) {
            if (this._bagSlotEntityLinks[i].bagSlot === bagSlot) {
                this._bagSlotEntityLinks[i].entityId = entityId;
                return;
            }
        }
        this._bagSlotEntityLinks.push({ bagSlot, entityId });
    }

    private _findBagSlotForEntity(entityId: EntityId): number | null {
        for (let i = 0; i < this._bagSlotEntityLinks.length; i++) {
            if (this._bagSlotEntityLinks[i].entityId === entityId) {
                return this._bagSlotEntityLinks[i].bagSlot;
            }
        }
        return null;
    }

    private _findEntityForBagSlot(bagSlot: number): EntityId | null {
        for (let i = 0; i < this._bagSlotEntityLinks.length; i++) {
            if (this._bagSlotEntityLinks[i].bagSlot === bagSlot) {
                return this._bagSlotEntityLinks[i].entityId;
            }
        }
        return null;
    }

    private _retryDeferredBagBind(
        session: BattleSession,
        player: Player,
        map: MapManager,
        entityId: EntityId,
    ): void {
        for (let i = this._deferredBagPlace.length - 1; i >= 0; i--) {
            const row = this._deferredBagPlace[i];
            const atGrid = this.resolveMapTargetEntityId(session, player, map, row.gridIndex);
            if (atGrid !== entityId) continue;
            this._linkBagSlotEntity(row.bagSlot, entityId);
            this._markTargetUsed(row.buffId, `entity:${entityId}`);
            this._bindLayer(session, entityId, row.source, row.bonusWan, row.buffId);
            const pending = this._findPendingBag(row.bagSlot);
            if (pending) pending.applied = true;
            this._deferredBagPlace.splice(i, 1);
            this._syncHeroBindAspd(player, row.gridIndex, entityId);
        }
    }

    /**
     * 攻速变化后写回组合内每个字的绑定。
     * @param player 玩家
     * @param gridIndex 落点格
     * @param entityId 塔实体
     */
    private _syncHeroBindAspd(player: Player, gridIndex: number, entityId: EntityId): void {
        const compose = BattleGameGlobalAttackSpeedHost._findCompositionAt(player, gridIndex);
        if (!compose) return;
        const merge = player.bagSession?.merge;
        if (!merge) return;
        const prev = merge.readCompositionHeroBind(compose);
        merge.writeCompositionHeroBind(compose, {
            weapon1Id: prev?.weapon1Id ?? compose.weapon1Id,
            level: prev?.level ?? compose.level,
            exp: prev?.exp ?? 0,
            aspd: this.snapshot(entityId),
            range: prev?.range ?? [],
        });
    }

    private _bindLayer(session: BattleSession, entityId: EntityId, source: string, bonusWan: number, buffId: number): void {
        this._layers.push({ source, bonusWan, entityId, buffId });
        this._applyModifier(session, entityId, source, bonusWan);
        GEvent.Ins.emit(GEvent.UpdateBestPlace);
    }

    private _hasUsedTarget(buffId: number, targetKey: string): boolean {
        for (let i = 0; i < this._usedTargets.length; i++) {
            const row = this._usedTargets[i];
            if (row.buffId === buffId && row.targetKey === targetKey) return true;
        }
        return false;
    }

    private _markTargetUsed(buffId: number, targetKey: string): void {
        if (this._hasUsedTarget(buffId, targetKey)) return;
        this._usedTargets.push({ buffId, targetKey });
    }

    private static _sourceFor(buffId: number, skillSlot: number, usageKey: string): string {
        return `${ASPD_SOURCE_PREFIX}b${buffId}_s${skillSlot}_${usageKey}`;
    }

    private static _findCompositionAt(player: Player | null, gridIndex: number): ComposedUnit | null {
        if (!player) return null;
        return player.compositions.find(c => c.gridIndices.includes(gridIndex)) ?? null;
    }

    private static _isMultiCellComposition(compose: ComposedUnit): boolean {
        WeaponComposeConfigProvider.instance.load();
        const provider = WeaponComposeConfigProvider.instance;
        return !provider.isSingleCellWeapon1(compose.weapon1Id) && compose.gridIndices.length >= 2;
    }

    private _applyModifier(session: BattleSession, entityId: EntityId, source: string, bonusWan: number): void {
        const world = session.world;
        if (!world.isAlive(entityId)) return;
        if (!world.getComponent(entityId, CombatComp)) return;

        if (!world.getComponent(entityId, AttributeComp)) {
            world.addComponent(entityId, new AttributeComp());
        }

        const attr = world.getComponent(entityId, AttributeComp);
        if (attr?.modifiers.some(m => m.source === source)) return;

        session.attributes.addModifier(entityId, {
            attr: 'aspd_add',
            op: 'Add',
            value: bonusWan,
            source,
            group: source,
        });
    }
}

/** 获取局内攻速符宿主 */
export function getBattleGameGlobalAttackSpeedHost(): BattleGameGlobalAttackSpeedHost {
    return BattleGameGlobalAttackSpeedHost.get();
}