import type { BattleSession } from 'db://assets/mx/module/battle';
import { BattleTeamId } from 'db://assets/mx/module/battle';
import { createAbilityContext } from 'db://assets/mx/module/battle/combat/AbilityContext';
import {
    HealthComp,
    MovementComp,
    TeamComp,
    isBajiaoBlowRetreating,
    isYanSoulClaimed,
} from 'db://assets/mx/module/battle/ecs/Components';
import type { EntityId } from 'db://assets/mx/module/ecs';
import { SkillPresentationEnv } from '../skill/SkillPresentationEnv';

/** 弓箭飞行像素/秒（逻辑与表现共用） */
export const BOW_ATK_ARROW_SPEED = 1280;
/** 散射箭飞行距离 = 初始射程 × 此倍数 */
export const SCATTER_RANGE_MUL = 2;

/** 散射直线穿透箭 */
export interface ScatterRay {
    /** 施法者 */
    caster: EntityId;
    /** Ability id */
    abilityId: string;
    /** 当前 Cocos 世界 X（与表现箭同空间） */
    x: number;
    /** 当前 Cocos 世界 Y（与表现箭同空间） */
    y: number;
    /** 方向单位 X（Cocos） */
    ux: number;
    /** 方向单位 Y（Cocos） */
    uy: number;
    /** 速度像素/秒 */
    speed: number;
    /** 剩余飞行秒 */
    left: number;
    /** 伤害倍率 */
    scale: number;
    /** 体盒半长 */
    halfLen: number;
    /** 体盒半宽 */
    halfWid: number;
    /** atk_buff1 */
    buff1: string;
    /** atk_buff2 */
    buff2: string;
    /** 已命中（每箭每敌一次） */
    hitIds: EntityId[];
}

/** 连发箭：落地伤锁定目标 */
export interface VolleyShot {
    /** 施法者 */
    caster: EntityId;
    /** 锁定目标 */
    target: EntityId;
    /** Ability id */
    abilityId: string;
    /** 剩余飞行秒 */
    wait: number;
    /** 伤害倍率 */
    scale: number;
    /** atk_buff1 */
    buff1: string;
    /** atk_buff2 */
    buff2: string;
    /** 落地回收表现（已死不结算也会调用） */
    onLand?: () => void;
}

/**
 * atk_type 12/13 弓箭逻辑弹道。
 * 伤害在此结算；表现只跟轨迹。
 */
export class BowAtkHost {
    private readonly _rays: ScatterRay[] = [];
    private readonly _volleys: VolleyShot[] = [];
    private _session: BattleSession | null = null;

    /**
     * 绑定本局会话。
     * @param session 战斗会话
     */
    bind(session: BattleSession): void {
        if (this._session === session) return;
        this._session = session;
    }

    /** 清空弹道 */
    clear(): void {
        for (let i = this._volleys.length - 1; i >= 0; i--) {
            this._invokeVolleyLand(this._volleys[i]);
        }
        this._rays.length = 0;
        this._volleys.length = 0;
        this._session = null;
    }

    /**
     * 卸下施法者在飞箭。
     * @param caster 塔实体
     */
    cancelCaster(caster: EntityId): void {
        for (let i = this._rays.length - 1; i >= 0; i--) {
            if (this._rays[i].caster === caster) this._rays.splice(i, 1);
        }
        for (let i = this._volleys.length - 1; i >= 0; i--) {
            if (this._volleys[i].caster !== caster) continue;
            this._invokeVolleyLand(this._volleys[i]);
            this._volleys.splice(i, 1);
        }
    }

    /**
     * 散射角：中线对准目标，左右各步进；偶数十位优先往世界 +Y 一侧补。
     * @param aimDeg 目标连线角
     * @param count 箭数
     * @param stepDeg 邻箭夹角
     * @param out 写出的朝向（度）
     */
    fillScatterDegs(aimDeg: number, count: number, stepDeg: number, out: number[]): void {
        out.length = 0;
        const n = Math.floor(count);
        if (!(n > 0) || !(stepDeg > 0)) return;
        out.push(aimDeg);
        const pairs = Math.floor((n - 1) / 2);
        for (let k = 1; k <= pairs; k++) {
            out.push(aimDeg + k * stepDeg);
            out.push(aimDeg - k * stepDeg);
        }
        if (out.length >= n) return;
        const extraK = pairs + 1;
        const rad = Math.PI / 180;
        const upSin = Math.sin((aimDeg + stepDeg) * rad);
        const dnSin = Math.sin((aimDeg - stepDeg) * rad);
        const upSign = upSin >= dnSin ? 1 : -1;
        out.push(aimDeg + upSign * extraK * stepDeg);
    }

    /**
     * 生成一支散射穿透箭。
     * @param ray 弹道
     */
    spawnRay(ray: ScatterRay): void {
        this._rays.push(ray);
        const session = this._session;
        if (session) this._hitRay(session, ray, 0);
    }

    /**
     * 生成一发落地结算的连发箭。
     * @param shot 弹道
     */
    spawnVolley(shot: VolleyShot): void {
        this._volleys.push(shot);
    }

    /**
     * 推进穿透与落地。
     * @param dt 逻辑秒
     */
    tick(dt: number): void {
        const session = this._session;
        if (!session) return;
        for (let i = this._rays.length - 1; i >= 0; i--) {
            const d = this._rays[i];
            const step = d.speed * dt;
            d.x += d.ux * step;
            d.y += d.uy * step;
            d.left -= dt;
            this._hitRay(session, d, step * 0.5);
            if (d.left <= 0) this._rays.splice(i, 1);
        }
        for (let i = this._volleys.length - 1; i >= 0; i--) {
            const d = this._volleys[i];
            d.wait -= dt;
            if (d.wait > 0) continue;
            this._landVolley(session, d);
            this._volleys.splice(i, 1);
        }
    }

    /**
     * 连发落地：可伤则结算；无论是否结算都回收表现箭。
     * @param session 战斗会话
     * @param d 在飞箭
     */
    private _landVolley(session: BattleSession, d: VolleyShot): void {
        if (session.world.isAlive(d.caster) && this._canHurt(session, d.target)) {
            this._deal(session, d.caster, d.target, d.abilityId, d.scale, d.buff1, d.buff2);
        }
        this._invokeVolleyLand(d);
    }

    /**
     * 触发并清空连发落地回收。
     * @param d 弹道
     */
    private _invokeVolleyLand(d: VolleyShot): void {
        const onLand = d.onLand;
        d.onLand = undefined;
        onLand?.();
    }

    /**
     * 散射体盒内敌方各伤一次（Cocos 空间，与画面箭一致）。
     * @param session 战斗会话
     * @param d 在飞箭
     * @param extraLen 本帧步进半长，防穿透漏检
     */
    private _hitRay(session: BattleSession, d: ScatterRay, extraLen: number): void {
        if (!session.world.isAlive(d.caster)) return;
        const casterTeam = session.world.getComponent(d.caster, TeamComp);
        const logical = SkillPresentationEnv.toLogical(d.caster, d.x, d.y);
        if (!logical) {
            console.log('[BowAtkHost] 散射箭无法映射逻辑格', d.caster);
            return;
        }
        const cellSize = Math.max(1, session.grid.cellSize);
        const halfBody = cellSize * 0.5;
        const cell = session.grid.worldToCell(logical.x, logical.y);
        const radiusCells = (d.halfLen + extraLen + halfBody) / cellSize + 2;
        const ids = session.spatial.queryRadius(cell, radiusCells);
        for (let i = 0; i < ids.length; i++) {
            const id = ids[i];
            if (id === d.caster) continue;
            if (this._hasHit(d.hitIds, id)) continue;
            if (!this._canHurt(session, id)) continue;
            if (!BattleTeamId.isHostile(casterTeam, session.world.getComponent(id, TeamComp))) continue;
            const pos = SkillPresentationEnv.getTargetWorldPos(id);
            if (!pos) continue;
            const rx = pos.x - d.x;
            const ry = pos.y - d.y;
            const lx = rx * d.ux + ry * d.uy;
            const ly = rx * d.uy - ry * d.ux;
            if (Math.abs(lx) > d.halfLen + extraLen + halfBody) continue;
            if (Math.abs(ly) > d.halfWid + halfBody) continue;
            d.hitIds.push(id);
            this._deal(session, d.caster, id, d.abilityId, d.scale, d.buff1, d.buff2);
        }
    }

    /**
     * 造成普攻伤害（可暴击、走 atk_buff）。
     * @param session 战斗会话
     * @param caster 施法者
     * @param target 目标
     * @param abilityId Ability id
     * @param scale 伤害倍率
     * @param buff1 atk_buff1
     * @param buff2 atk_buff2
     */
    private _deal(session: BattleSession, caster: EntityId, target: EntityId, abilityId: string, scale: number, buff1: string, buff2: string): void {
        const ctx = createAbilityContext(session, caster, abilityId, [target]);
        session.damage.dealToTarget(caster, target, {
            scale,
            allowCrit: true,
            skillAtkBuff1: buff1,
            skillAtkBuff2: buff2,
        }, ctx);
    }

    /**
     * 目标是否可受伤。
     * @param session 战斗会话
     * @param id 实体
     */
    private _canHurt(session: BattleSession, id: EntityId): boolean {
        if (!session.world.isAlive(id)) return false;
        const hp = session.world.getComponent(id, HealthComp);
        if (!hp || !(hp.hp > 0)) return false;
        const move = session.world.getComponent(id, MovementComp);
        if (move?.spawnProtected || isYanSoulClaimed(move) || isBajiaoBlowRetreating(move)) return false;
        return true;
    }

    /**
     * 是否已命中。
     * @param ids 已命中列表
     * @param id 实体
     */
    private _hasHit(ids: EntityId[], id: EntityId): boolean {
        for (let i = 0; i < ids.length; i++) {
            if (ids[i] === id) return true;
        }
        return false;
    }
}

let _host: BowAtkHost | null = null;

/** 全局弓箭弹道宿主 */
export function getBowAtkHost(): BowAtkHost {
    if (!_host) _host = new BowAtkHost();
    return _host;
}

/** 测试用重置 */
export function resetBowAtkHostForTests(): void {
    _host = null;
}