import type { BattleSession } from 'db://assets/mx/module/battle';
import { TransformComp } 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 type { MapManager } from '../map/legacy/MapManager';
import { composeKey } from './ComposeUnitKey';

/** 部署查询只需合成与已部署列表 */
export interface IDeployOwner {
    /** Merge 合成单位 */
    readonly compositions: readonly ComposedUnit[];
    /** 已部署实体 */
    readonly deployedUnits: readonly EntityId[];
}

/** 部署信息 DTO（由 Merge.compositions 查询时现算） */
export interface DeployedTowerInfo {
    /** Hero.id */
    weapon1Id: number;
    /** 合成等级 */
    level: number;
    /** 合成键 */
    composeKey: string;
    /** 占地格 */
    gridIndices: readonly number[];
    /** 朝向 */
    direction: ComposedUnit['direction'];
}

/** ECS 实体 → 地图格 index（TransformComp + MapManager，不读 DeploySync 缓存） */
export function findGridIndexByEntity(
    entityId: EntityId,
    session: BattleSession,
    map: MapManager,
): number | null {
    const world = session.world;
    if (!world.isAlive(entityId)) return null;
    const tf = world.getComponent(entityId, TransformComp);
    if (!tf) return null;
    const mg = map.getMapGrid(tf.row, tf.col);
    return mg?.Index ?? null;
}

/** 地图格 → 与 TransformComp 格坐标精确匹配的已部署实体 */
function findEntityIdAtMapGrid(
    gridIndex: number,
    session: BattleSession,
    map: MapManager,
    player?: IDeployOwner | null,
): EntityId | null {
    const g = map.getMapGridByIndex(gridIndex);
    if (!g) return null;
    const world = session.world;
    const deployed = player?.deployedUnits ?? session.players[0]?.deployedUnits ?? [];
    for (const entityId of deployed) {
        if (!world.isAlive(entityId)) continue;
        const tf = world.getComponent(entityId, TransformComp);
        if (tf && tf.row === g.Row && tf.col === g.Col) return entityId;
    }
    return null;
}

/**
 * 地图格 index → ECS 实体。
 * 多格合成体只在 gridIndices[0] 落 Transform，其余格通过 composition 回查同一实体。
 */
export function findEntityIdByGridIndex(
    gridIndex: number,
    session: BattleSession,
    map: MapManager,
    player?: IDeployOwner | null,
): EntityId | null {
    const direct = findEntityIdAtMapGrid(gridIndex, session, map, player);
    if (direct != null) return direct;

    // 多格合成：实体只挂在一格，其余格经 composition 回查
    const comp = player?.compositions.find(c => c.gridIndices.includes(gridIndex)) ?? null;
    if (!comp) return null;
    for (const idx of comp.gridIndices) {
        if (idx === gridIndex) continue;
        const entityId = findEntityIdAtMapGrid(idx, session, map, player);
        if (entityId != null) return entityId;
    }
    return null;
}

/**
 * 实体 → 地图格 index。
 * 多格合成体 Transform 只落在锚点格；锚点格对不上时，沿 composition 其它格回查。
 */
export function findGridIndexForEntity(
    entityId: EntityId,
    player: IDeployOwner,
    session: BattleSession,
    map: MapManager,
): number | null {
    const direct = findGridIndexByEntity(entityId, session, map);
    if (direct != null) return direct;
    for (const comp of player.compositions) {
        for (const idx of comp.gridIndices) {
            if (findEntityIdByGridIndex(idx, session, map, player) === entityId) {
                return idx;
            }
        }
    }
    return null;
}

/** MergeSession.compositions 中查找实体所属合成单位（唯一合成态来源） */
export function findCompositionForEntity(
    entityId: EntityId,
    player: IDeployOwner,
    session: BattleSession,
    map: MapManager,
): ComposedUnit | null {
    const gridIndex = findGridIndexForEntity(entityId, player, session, map);
    if (gridIndex == null) return null;
    return player.compositions.find(c => c.gridIndices.includes(gridIndex)) ?? null;
}

/** 由 Merge 合成单位构建部署信息 DTO（查询时现算，不缓存） */
export function buildDeployedTowerInfo(comp: ComposedUnit): DeployedTowerInfo {
    return {
        weapon1Id: comp.weapon1Id,
        level: comp.level,
        composeKey: composeKey(comp),
        gridIndices: comp.gridIndices,
        direction: comp.direction,
    };
}