import { ecs } from "../../../../extensions/oops-plugin-framework/assets/libs/ecs/ECS";
import { Vec3 } from "cc";
import { HeroAttrsComp } from "./HeroAttrsComp";
import { HeroViewComp } from "./HeroViewComp";
import { BuffsList, SkillConfig, SkillKind, SkillSet, TGroup, TType } from "../common/config/SkillSet";
import { Skill } from "../skill/Skill";
import { smc } from "../common/SingletonModuleComp";
import { GameConst } from "../common/config/GameConst";

/**
 * ==================== 自动施法系统 ====================
 * 
 * 职责：
 * 1. 检测可施放的技能
 * 2. 根据策略自动施法（AI）
 * 3. 选择目标
 * 4. 添加施法请求标记
 * 
 * 设计理念：
 * - 负责"何时施法"的决策
 * - 通过添加 CSRequestComp 触发施法
 * - 可被玩家输入系统或AI系统复用
 * - 支持多种AI策略
 */
@ecs.register('SCastSystem')
export class SCastSystem extends ecs.ComblockSystem implements ecs.ISystemUpdate {
    debugMode: boolean = false;  // 是否启用调试模式
    private readonly emptyCastPlan = { skillId: 0, targets: [] as HeroViewComp[] };
    private readonly emptyCandidates: { view: HeroViewComp; attrs: HeroAttrsComp; dis: number; lane: number; isSameFac: boolean }[] = [];
    
    filter(): ecs.IMatcher {
        return ecs.allOf(HeroAttrsComp, HeroViewComp);
    }

    update(e: ecs.Entity): void {
        if(!smc.mission.play ) return;
        if(smc.mission.pause) return
        const heroAttrs = e.get(HeroAttrsComp);
        const heroView = e.get(HeroViewComp);
        if (!heroAttrs || !heroView || !heroView.node) return;
        if (heroAttrs.is_dead || heroAttrs.is_reviving || heroAttrs.isStun() || heroAttrs.isFrost()) return;
        heroAttrs.updateCD(this.dt);
        if (!heroAttrs.is_atking) return;
        const castPlan = this.pickCastSkill(heroAttrs, heroView);
        if (castPlan.skillId === 0 || castPlan.targets.length === 0) return;
        this.castSkill(e, castPlan, heroAttrs, heroView);
    }

    private pickCastSkill(heroAttrs: HeroAttrsComp, heroView: HeroViewComp): { skillId: number; targets: HeroViewComp[] } {
        const range = heroAttrs.getCachedMaxSkillDistance() || GameConst.Battle.DEFAULT_SEARCH_RANGE;
        const candidates = this.collectCandidates(heroView, heroAttrs, range);
        const skillCandidates = [heroAttrs.skill_id, heroAttrs.atk_id];
        for (const s_uuid of skillCandidates) {
            if (!s_uuid) continue;
            const config = SkillSet[s_uuid];
            if (!config) continue;
            const isMainSkill = s_uuid === heroAttrs.skill_id;
            if (isMainSkill && !heroAttrs.can_skill) continue;
            if (!isMainSkill && !heroAttrs.can_atk) continue;
            const targets = this.findTargetsByCandidates(heroView, config, candidates);
            if (targets.length === 0) continue;
            return { skillId: s_uuid, targets };
        }
        return this.emptyCastPlan;
    }

    private castSkill(entity: ecs.Entity, castPlan: { skillId: number; targets: HeroViewComp[] }, heroAttrs: HeroAttrsComp, heroView: HeroViewComp) {
        const s_uuid = castPlan.skillId;
        const config = SkillSet[s_uuid];
        if (!config) return;
        heroView.playSkillEffect(s_uuid);
        const isMainSkill = s_uuid === heroAttrs.skill_id;
        
        // 优先使用技能配置的前摇时间，否则使用全局默认值
        // 注意：这里仍然是基于时间的延迟，受帧率波动影响。
        // 若需精确同步，建议在动画中添加帧事件并在 HeroViewComp 中监听。
        const delay = config.ready > 0 ? config.ready : GameConst.Battle.SKILL_CAST_DELAY;
        
        heroView.scheduleOnce(() => {
            if (!heroView.node || !heroView.node.isValid || heroAttrs.is_dead) return;
            const validTargets = this.filterValidTargets(castPlan.targets);
            if (validTargets.length === 0) return;
            this.applyPrimaryEffect(entity, s_uuid, config, heroView, validTargets);
            this.applyExtraEffects(config, validTargets);
        }, delay);
        if (isMainSkill) {
            heroAttrs.triggerSkillCD();
        } else {
            heroAttrs.triggerAtkCD();
        }
    }

    private createSkillEntity(s_uuid: number, caster: HeroViewComp, targetPos: Vec3) {
        if (!caster.node || !caster.node.isValid) return;
        const parent = caster.node.parent;
        if (!parent) return;
        const skill = ecs.getEntity<Skill>(Skill);
        skill.load(caster.node.position.clone(), parent, s_uuid, targetPos.clone(), caster, 0);
    }

    private applyPrimaryEffect(casterEntity: ecs.Entity, s_uuid: number, config: SkillConfig, heroView: HeroViewComp, targets: HeroViewComp[]) {
        const kind = config.kind ?? SkillKind.Damage;
        if (kind === SkillKind.Damage) {
            if (config.ap > 0) {
                this.createSkillEntity(s_uuid, heroView, targets[0].node.position);
            }
            return;
        }
        for (const target of targets) {
            if (!target.ent) continue;
            const model = target.ent.get(HeroAttrsComp);
            if (!model || model.is_dead) continue;
            if (kind === SkillKind.Heal && config.ap !== 0) {
                model.add_hp(config.ap, false);
            } else if (kind === SkillKind.Shield && config.ap !== 0) {
                model.add_shield(config.ap, false);
            }
        }
    }

    private applyExtraEffects(config: SkillConfig, targets: HeroViewComp[]) {
        for (const target of targets) {
            if (!target.ent) continue;
            const model = target.ent.get(HeroAttrsComp);
            if (!model || model.is_dead) continue;
            if (config.buffs) {
                for (const buffId of config.buffs) {
                    const buffConf = BuffsList[buffId];
                    if (buffConf) {
                        model.addBuff(buffConf);
                    }
                }
            }

            if (config.debuffs) {
                for (const buffId of config.debuffs) {
                    const buffConf = BuffsList[buffId];
                    if (buffConf) {
                        model.addBuff(buffConf);
                    }
                }
            }
        }
    }

    private filterValidTargets(targets: HeroViewComp[]): HeroViewComp[] {
        return targets.filter(target => {
            if (!target || !target.node || !target.node.isValid) return false;
            if (!target.ent) return false;
            const model = target.ent.get(HeroAttrsComp);
            if (!model || model.is_dead || model.is_reviving) return false;
            return true;
        });
    }

    private collectCandidates(caster: HeroViewComp, casterAttrs: HeroAttrsComp, range: number): { view: HeroViewComp; attrs: HeroAttrsComp; dis: number; lane: number; isSameFac: boolean }[] {
        if (!caster || !caster.node || !caster.node.isValid) return this.emptyCandidates;
        const currentPos = caster.node.position;
        const list: { view: HeroViewComp; attrs: HeroAttrsComp; dis: number; lane: number; isSameFac: boolean }[] = [];
        ecs.query(ecs.allOf(HeroAttrsComp, HeroViewComp)).forEach(ent => {
            const targetAttrs = ent.get(HeroAttrsComp);
            const targetView = ent.get(HeroViewComp);
            if (!targetAttrs || !targetView || !targetView.node || targetAttrs.is_dead) return;
            if (targetView === caster) return;
            const dis = Math.abs(currentPos.x - targetView.node.position.x);
            if (dis > range) return;
            const lane = Math.abs(currentPos.y - targetView.node.position.y);
            const isSameFac = targetAttrs.fac === casterAttrs.fac;
            list.push({ view: targetView, attrs: targetAttrs, dis, lane, isSameFac });
        });
        return list;
    }

    private findTargetsByCandidates(caster: HeroViewComp, config: SkillConfig, candidates: { view: HeroViewComp; attrs: HeroAttrsComp; dis: number; lane: number; isSameFac: boolean }[]): HeroViewComp[] {
        const isEnemy = config.TGroup === TGroup.Enemy;
        const isSelf = config.TGroup === TGroup.Self;
        const isTeam = config.TGroup === TGroup.Team || config.TGroup === TGroup.Ally;
        const isAll = config.TGroup === TGroup.All;
        if (isSelf) return [caster];
        if (!isEnemy && !isTeam && !isAll) return this.emptyCastPlan.targets;
        const list = candidates.filter(item => {
            if (isEnemy && item.isSameFac) return false;
            if (isTeam && !item.isSameFac) return false;
            return true;
        });
        list.sort((a, b) => {
            const type = config.TType ?? TType.Frontline;
            switch (type) {
                case TType.Backline:
                    if (a.lane !== b.lane) return a.lane - b.lane;
                    return b.dis - a.dis;
                case TType.LowestHP:
                    if (a.attrs.hp !== b.attrs.hp) return a.attrs.hp - b.attrs.hp;
                    return a.dis - b.dis;
                case TType.HighestHP:
                    if (a.attrs.hp !== b.attrs.hp) return b.attrs.hp - a.attrs.hp;
                    return a.dis - b.dis;
                case TType.HighestAP:
                    if (a.attrs.ap !== b.attrs.ap) return b.attrs.ap - a.attrs.ap;
                    return a.dis - b.dis;
                case TType.Frontline:
                default:
                    if (a.lane !== b.lane) return a.lane - b.lane;
                    return a.dis - b.dis;
            }
        });

        const maxTargets = Math.max(GameConst.Skill.MIN_TARGET_COUNT, 1);
        return list.slice(0, maxTargets).map(item => item.view);
    }
}