/**
 * @file MoveComp.ts
 * @description 统一移动组件与系统（英雄 + 怪物）
 *
 * 核心规则：
 *   1. 准备阶段：双方原地待命，不推进不索敌。
 *   2. 战斗阶段：双方向最近敌人推进，进入攻击范围（model.dis）后停止移动并攻击。
 *   3. 场上无敌人：停止移动（战斗结束，由 MissionComp 进入结算）。
 *   4. 击退/位移不会把单位推出屏幕：HERO 不越过 BoxSet.LETF_END，MON 不越过 BoxSet.RIGHT_END。
 *   5. 推进方向无上限限制，直到接触敌人或抵达敌方边界。
 */
import { ecs } from "../../../../extensions/oops-plugin-framework/assets/libs/ecs/ECS";
import { HeroViewComp } from "./HeroViewComp";
import { HeroAttrsComp } from "./HeroAttrsComp";
import { smc } from "../common/SingletonModuleComp";
import { BoxSet, FacSet } from "../common/config/GameSet";
import { Node } from "cc";

@ecs.register('MoveComp')
export class MoveComp extends ecs.Comp {
    /** 朝向：1=向右（HERO），-1=向左（MON），由系统根据 fac 自动维护 */
    direction: number = 1;
    /** 当前移动目标 X */
    targetX: number = 0;
    /** 是否允许移动（出生落地前会短暂关闭） */
    moving: boolean = true;
    /** 站位基准 Y，移动时强制贴地 */
    baseY: number = 0;
    /** 出生序，用于同条件渲染排序稳定 */
    spawnOrder: number = 0;

    reset() {
        this.direction = 1;
        this.targetX = 0;
        this.moving = true;
        this.baseY = 0;
        this.spawnOrder = 0;
    }
}

@ecs.register('MoveSystem')
export class MoveSystem extends ecs.ComblockSystem implements ecs.ISystemUpdate {
    /** 渲染层级重排节流，避免每帧排序 */
    private readonly renderSortInterval = 0.05;
    private lastRenderSortAt = 0;
    private heroViewMatcher: ecs.IMatcher | null = null;
    private readonly renderEntries: { node: Node; bossPriority: number; frontScore: number; spawnOrder: number; eid: number; laneScore: number }[] = [];
    private renderEntryCount = 0;

    private getHeroViewMatcher(): ecs.IMatcher {
        if (!this.heroViewMatcher) {
            this.heroViewMatcher = ecs.allOf(HeroAttrsComp, HeroViewComp);
        }
        return this.heroViewMatcher;
    }

    filter(): ecs.IMatcher {
        return ecs.allOf(MoveComp, HeroViewComp, HeroAttrsComp);
    }

    update(e: ecs.Entity) {
        /** 战斗未开始/暂停时不驱动移动 */
        if (!smc.mission.play || smc.mission.pause) return;

        const model = e.get(HeroAttrsComp);
        const move = e.get(MoveComp);
        const view = e.get(HeroViewComp);
        if (!model || !move || !view || !view.node) return;
        if (!move.moving) return;

        /** 关卡阶段性冻结怪物行为 */
        if (smc.mission.stop_mon_action && model.fac === FacSet.MON) {
            this.clearCombatTarget(model);
            view.status_change("idle");
            return;
        }

        /** 死亡/复活/控制状态：停止移动与索敌 */
        if (model.is_stop || model.is_dead || model.is_reviving || model.isFrost() || model.isStun()) {
            this.clearCombatTarget(model);
            if (!model.is_reviving) view.status_change("idle");
            return;
        }

        /** 所有移动都锁定在 baseY，避免出现“漂移” */
        if (view.node.position.y !== move.baseY) {
            view.node.setPosition(view.node.position.x, move.baseY, 0);
        }

        /** 准备阶段：双方原地待命，不推进不索敌 */
        if (!smc.mission.in_fight) {
            this.clearCombatTarget(model);
            model.is_atking = false;
            if (view.status !== "atk") view.status_change("idle");
            return;
        }

        /** 战斗阶段：索敌并推进 */
        const nearestEnemy = this.findNearestEnemy(e);
        if (nearestEnemy) {
            this.processCombatLogic(e, move, view, model, nearestEnemy);
            this.syncCombatTarget(model, view, nearestEnemy);
        } else {
            /** 无敌人：停止移动，等待战斗结束结算 */
            this.clearCombatTarget(model);
            model.is_atking = false;
            if (view.status !== "atk") view.status_change("idle");
        }

        /** 渲染层级重排（双阵营统一处理） */
        this.updateRenderOrder();
    }

    private clearCombatTarget(model: HeroAttrsComp): void {
        model.combat_target_eid = -1;
        model.enemy_in_cast_range = false;
    }

    private syncCombatTarget(model: HeroAttrsComp, selfView: HeroViewComp, enemyView: HeroViewComp): void {
        if (!enemyView || !enemyView.node || !enemyView.ent) {
            this.clearCombatTarget(model);
            return;
        }
        const enemyAttrs = enemyView.ent.get(HeroAttrsComp);
        if (!enemyAttrs || enemyAttrs.is_dead || enemyAttrs.is_reviving || enemyAttrs.fac === model.fac) {
            this.clearCombatTarget(model);
            return;
        }
        model.combat_target_eid = enemyView.ent.eid;
        model.enemy_in_cast_range = this.isEnemyInAttackRange(model, selfView.node.position.x, enemyView.node.position.x);
    }

    private isEnemyInAttackRange(model: HeroAttrsComp, selfX: number, enemyX: number): boolean {
        const dist = Math.abs(selfX - enemyX);
        const attackRange = model.dis;
        return dist <= attackRange;
    }

    /**
     * 战斗位移：向最近敌人推进，进入攻击范围后停止。
     * 推进无上限限制，但击退/位移受阵营后退边界保护。
     */
    private processCombatLogic(_e: ecs.Entity, move: MoveComp, view: HeroViewComp, model: HeroAttrsComp, enemy: HeroViewComp) {
        const selfX = view.node.position.x;
        const enemyX = enemy.node.position.x;
        const dist = Math.abs(selfX - enemyX);
        const attackRange = model.dis;
        /** 近战贴身作战：攻击距离 dis(100) 大于技能范围(60)，推进到与敌人相隔 60 才停下，保证技能可命中且不过度贴身 */
        const stopRange = model.type === 0 ? 60 : attackRange;
        const inRange = dist <= stopRange;

        if (inRange) {
            /** 进入攻击范围：停止移动，进入攻击状态，由 SCastSystem 负责技能释放 */
            model.is_atking = true;
            const dir = enemyX > selfX ? 1 : -1;
            view.scale = dir;
            if (view.status === "move") {
                view.status_change("idle");
            }
        } else {
            /** 未接触：向敌人方向推进 */
            model.is_atking = false;
            const dir = enemyX > selfX ? 1 : -1;
            move.direction = dir;
            const speed = model.speed / 3;
            const delta = speed * this.dt * dir;
            let newX = selfX + delta;

            /** 后退边界钳制：防止被击退/位移推出屏幕 */
            newX = this.clampByFacBoundary(newX, model.fac);

            if (Math.abs(newX - selfX) >= 0.01) {
                view.node.setPosition(newX, view.node.position.y, 0);
                view.status_change("move");
            }
        }
    }

    /**
     * 按阵营裁剪 X 坐标，防止被击退/位移推出屏幕。
     * HERO 后退不越过 BoxSet.LETF_END；MON 后退不越过 BoxSet.RIGHT_END。
     */
    private clampByFacBoundary(x: number, fac: number): number {
        if (fac === FacSet.HERO) {
            return Math.max(BoxSet.LETF_END, x);
        }
        return Math.min(BoxSet.RIGHT_END, x);
    }

    private findNearestEnemy(entity: ecs.Entity): HeroViewComp | null {
        const currentView = entity.get(HeroViewComp);
        if (!currentView?.node) return null;

        const currentPos = currentView.node.position;
        const myFac = entity.get(HeroAttrsComp).fac;

        let nearest: HeroViewComp | null = null;
        let minDis = Infinity;

        /** 遍历筛出最近敌人：以 X 轴距离为主，Y 轴距离作为同排的决胜权重，使角色优先攻击同路的敌人 */
        ecs.query(this.getHeroViewMatcher()).forEach(e => {
            const m = e.get(HeroAttrsComp);
            if (m.fac !== myFac && !m.is_dead) {
                const v = e.get(HeroViewComp);
                if (v?.node) {
                    const dx = Math.abs(currentPos.x - v.node.position.x);
                    const dy = Math.abs(currentPos.y - v.node.position.y);
                    const d = dx + dy * 0.1; // Y轴权重较小，仅在 X 相近时起决定作用
                    if (d < minDis) {
                        minDis = d;
                        nearest = v;
                    }
                }
            }
        });
        return nearest;
    }

    private updateRenderOrder() {
        const scene = smc.map?.MapView?.scene;
        const layerNode = scene?.entityLayer?.node;
        if (!layerNode) return;

        const now = Date.now() / 1000;
        if (now - this.lastRenderSortAt < this.renderSortInterval) return;
        this.lastRenderSortAt = now;

        const heroRoot = layerNode.getChildByName("HERO");
        const monRoot = layerNode.getChildByName("MON");
        const bossRoot = layerNode.getChildByName("BOSS");

        /** 分层重排同层节点：各阵营层内按 Y 轴路次 -> 前后位置 -> 出生序 -> eid 排序
         * （Boss 已有独立 BOSS 层固定在最底，无需 bossPriority 参与排序） */
        this.renderEntryCount = 0;
        ecs.query(this.getHeroViewMatcher()).forEach(e => {
            const attrs = e.get(HeroAttrsComp);
            const actorView = e.get(HeroViewComp);
            if (!attrs || !actorView?.node || attrs.is_dead) return;
            if (attrs.fac !== FacSet.HERO && attrs.fac !== FacSet.MON) return;

            /** 按阵营/身份归位到对应显示层 */
            let targetRoot: Node | null | undefined;
            if (attrs.fac === FacSet.HERO) {
                targetRoot = heroRoot;
            } else {
                targetRoot = attrs.is_boss ? (bossRoot ?? monRoot ?? heroRoot) : (monRoot ?? heroRoot);
            }
            if (!targetRoot) return;
            if (actorView.node.parent !== targetRoot) {
                actorView.node.parent = targetRoot;
            }

            /** 统一从 MoveComp 获取 spawnOrder */
            const move = e.get(MoveComp);
            const spawnOrder = move?.spawnOrder ?? 0;

            // 按 Y 轴计算渲染层级权重（Y 越小，说明越靠近屏幕下方，应该渲染在越前面）
            const laneScore = -actorView.node.position.y;
            // X 轴权重：站在前排的（交战处）优先渲染
            const frontScore = attrs.fac === FacSet.HERO ? actorView.node.position.x : -actorView.node.position.x;

            const entryIndex = this.renderEntryCount;
            let entry = this.renderEntries[entryIndex];
            if (!entry) {
                entry = { node: actorView.node, bossPriority: 0, frontScore: 0, spawnOrder: 0, eid: 0, laneScore: 0 };
                this.renderEntries.push(entry);
            }
            entry.node = actorView.node;
            entry.laneScore = laneScore;
            entry.frontScore = frontScore;
            entry.spawnOrder = spawnOrder;
            entry.eid = e.eid;
            this.renderEntryCount += 1;
        });
        this.renderEntries.length = this.renderEntryCount;

        this.renderEntries.sort((a, b) => {
            // Y轴靠下的（laneScore 较大）应该在后面，从而渲染在上面
            if (Math.abs(a.laneScore - b.laneScore) > 10) return a.laneScore - b.laneScore;
            if (a.frontScore !== b.frontScore) return a.frontScore - b.frontScore;
            if (a.spawnOrder !== b.spawnOrder) return a.spawnOrder - b.spawnOrder;
            return a.eid - b.eid;
        });

        /** 分层应用 siblingIndex：各层内部从 0 递增 */
        const layerCounters = new Map<Node, number>();
        this.renderEntries.forEach((item) => {
            const parent = item.node.parent;
            if (!parent) return;
            const index = layerCounters.get(parent) ?? 0;
            item.node.setSiblingIndex(index);
            layerCounters.set(parent, index + 1);
        });
    }
}