import type { EntityId } from 'db://assets/mx/module/ecs';
import {
    BattlePhase,
    BattleTeamId,
    BattleEventFactory,
    HealthComp,
    MovementComp,
    TeamComp,
    TransformComp,
    UnitMetaComp,
    isBajiaoBlowRetreating,
    isYanSoulClaimed,
    type BattleSession,
    type Cell,
} from 'db://assets/mx/module/battle';
import { BattleBuffCarryStore } from '../../manager/battleBuff/BattleBuffCarryStore';
import { MonsterType } from '../../manager/MonsterDataManager';
import {
    resolveCarriedBaseThunderConfig,
    type BattleBuffBaseThunderAdjust,
} from '../../manager/battleBuff/BattleBuffPassiveSkillUtil';
import { schedulePresentation } from '../skill/BattlePresentationClock';
import { isMechanismUnit } from '../mechanism/MechanismServices';
import type { ProjectBattleHandle } from '../runtime/BattleRuntime';
import type { BattleGameBaseThunderPresenter } from '../../ui/BattleGame/BattleGameBaseThunderPresenter';
import { AI_PLAYER_ID } from '../ai/runtime/AiCampArea';

/** 御雷珠伤害类型 */
const BASE_THUNDER_DAMAGE_TYPE = 'base_thunder';
/** 无施法者占位 */
const BASE_THUNDER_CASTER = 0 as EntityId;
/** 飘字展示后再击杀（逻辑秒） */
const BASE_THUNDER_KILL_DELAY_SEC = 0.4;
/** 与 Pathfinder 正交一步代价一致，用于距离场→格数 */
const PATH_ORTH_STEP = 1000;

/** 沿进路排序的目标条目 */
type ThunderTargetEntry = {
    /** 受击实体 */
    entityId: EntityId;
    /** 在生效格序列中的索引（越小越靠前） */
    cellOrder: number;
};

/** 单玩家御雷珠状态 */
type PlayerThunderState = {
    /** 防守方 playerId */
    playerId: number;
    /** 汇总配置 */
    config: BattleBuffBaseThunderAdjust;
    /** 本局已触发次数 */
    usedTriggers: number;
};

/**
 * 被动 functiontype=20：进攻各方军营的敌军接近终点时降雷。
 * 本机/AI 各读 CarryStore，次数独立。
 */
export class BattleBuffBaseThunderHost {
    private _battle: ProjectBattleHandle | null = null;
    private _presenter: BattleGameBaseThunderPresenter | null = null;
    private readonly _states: PlayerThunderState[] = [];
    /** 当前一轮落雷进行中 */
    private _striking = false;
    /** 延迟击杀调度世代（unbind 时递增以作废） */
    private _killScheduleGen = 0;

    /** 绑定本局与表现层 */
    bind(battle: ProjectBattleHandle, presenter: BattleGameBaseThunderPresenter | null): void {
        const sameBattle = this._battle === battle;
        if (!sameBattle) {
            this.unbind();
        }
        this._battle = battle;
        this._presenter = presenter;
        this._rebuildStates(sameBattle);
    }

    /**
     * AI 挂载后按 CarryStore 重扫（保留本局已触发次数）。
     * @param battle 可选；开战时 Host 可能尚未 bind，传入则一并绑定
     */
    refreshCarry(battle?: ProjectBattleHandle): void {
        const b = battle ?? this._battle;
        if (!b) {
            console.log('[BaseThunder] refreshCarry 时尚未 bind');
            return;
        }
        this._battle = b;
        this._rebuildStates(true);
    }

    /**
     * 该玩家御雷珠单局次数是否已用尽。
     * @param playerId 防守方
     */
    isTriggersExhausted(playerId: number): boolean {
        for (let i = 0; i < this._states.length; i++) {
            const state = this._states[i];
            if (state.playerId !== playerId) continue;
            return state.usedTriggers >= state.config.maxTriggers;
        }
        return false;
    }

    /** 解除绑定 */
    unbind(): void {
        this._battle = null;
        this._presenter = null;
        this._states.length = 0;
        this._striking = false;
        this._killScheduleGen++;
    }

    /**
     * 重建各方神雷状态。
     * @param keepUsed 是否保留已触发次数
     */
    private _rebuildStates(keepUsed = false): void {
        const prev: PlayerThunderState[] = [];
        if (keepUsed) {
            for (let i = 0; i < this._states.length; i++) {
                prev.push(this._states[i]);
            }
        }
        this._states.length = 0;
        this._tryPush(0, prev);
        this._tryPush(AI_PLAYER_ID, prev);
    }

    /**
     * 若该玩家携带有效御雷珠则记入。
     * @param playerId 槽位
     * @param prev 重建前状态（用于保留次数）
     */
    private _tryPush(playerId: number, prev: readonly PlayerThunderState[] = []): void {
        const passives = BattleBuffCarryStore.getPassives(playerId);
        const adjust = resolveCarriedBaseThunderConfig(passives);
        if (!adjust.active || adjust.maxTriggers <= 0 || adjust.triggerCells <= 0 || adjust.effectCells <= 0) {
            if (adjust.active) {
                console.log('[BaseThunder] 御雷珠配置无效，未启用', playerId, adjust);
            }
            return;
        }
        if (adjust.smallDmgWan <= 0 || adjust.bossDmgWan <= 0) {
            console.log('[BaseThunder] 御雷珠伤害比例无效', playerId, adjust);
            return;
        }
        let usedTriggers = 0;
        for (let i = 0; i < prev.length; i++) {
            if (prev[i].playerId === playerId) {
                usedTriggers = prev[i].usedTriggers;
                break;
            }
        }
        this._states.push({ playerId, config: adjust, usedTriggers });
    }

    /** 帧更新：扫描触发条件 */
    tick(_dt: number): void {
        if (this._striking || !this._battle || this._states.length <= 0) return;
        if (this._battle.session.phase !== BattlePhase.COMBAT) return;

        for (let i = 0; i < this._states.length; i++) {
            const state = this._states[i];
            if (state.usedTriggers >= state.config.maxTriggers) continue;
            const anchor = this._findTriggerAnchor(state.playerId, state.config.triggerCells);
            if (anchor == null) continue;

            const effectCells = this._collectEffectCells(anchor, state.config.effectCells);
            if (effectCells.length <= 0) continue;

            const targets = this._collectTargets(state.playerId, effectCells);
            if (targets.length <= 0) continue;

            state.usedTriggers++;
            this._striking = true;
            const config = state.config;
            const presenter = this._presenter;
            if (presenter) {
                presenter.playStrike(
                    targets,
                    (entityId) => this._applyDamage(state.playerId, config, entityId),
                    () => {
                        this._striking = false;
                    },
                );
                return;
            }
            for (let t = 0; t < targets.length; t++) {
                this._applyDamage(state.playerId, config, targets[t]);
            }
            this._striking = false;
            return;
        }
    }

    /**
     * 找最靠近终点、且处于触发距离内的进攻指定玩家的小怪/Boss/召唤怪。
     * @param ownerPlayerId 防守方
     * @param triggerCells 触发距离
     */
    private _findTriggerAnchor(ownerPlayerId: number, triggerCells: number): EntityId | null {
        const battle = this._battle;
        if (!battle) return null;
        const session = battle.session;
        const thresholdCells = Math.max(1, Math.floor(triggerCells));
        let bestId: EntityId | null = null;
        let bestRemaining = Number.POSITIVE_INFINITY;

        session.world.forEachAlive((entityId) => {
            if (!this._isThunderCandidate(battle, ownerPlayerId, entityId)) return;
            const move = session.world.getComponent(entityId, MovementComp);
            if (!move || move.spawnProtected || move.presentLocked || isYanSoulClaimed(move) || isBajiaoBlowRetreating(move)) return;
            const remainingCells = this._getRemainingCellsToAttackTarget(session, entityId);
            if (!Number.isFinite(remainingCells) || remainingCells > thresholdCells) return;
            if (remainingCells < bestRemaining) {
                bestRemaining = remainingCells;
                bestId = entityId;
            }
        });
        return bestId;
    }

    /**
     * 实体沿进路至攻击终点的剩余格数。
     * 取「未走完路径步数」与「距离场格数」的较小值，避免 path 过长或重寻路导致漏触发。
     */
    private _getRemainingCellsToAttackTarget(session: BattleSession, entityId: EntityId): number {
        const world = session.world;
        const move = world.getComponent(entityId, MovementComp);
        const tf = world.getComponent(entityId, TransformComp);
        if (!move || !tf) return Number.POSITIVE_INFINITY;
        if (move.reachedGoal) return 0;

        let best = Number.POSITIVE_INFINITY;
        const pathSteps = move.path.length - move.pathIndex;
        if (pathSteps > 0) best = pathSteps;

        const campAreaId = this._resolveEntityCampAreaId(session, entityId);
        const cost = session.pathfinder.getPathCost({ row: tf.row, col: tf.col }, campAreaId);
        if (Number.isFinite(cost) && cost >= 0) {
            const costCells = Math.max(0, Math.ceil(cost / PATH_ORTH_STEP));
            if (costCells < best) best = costCells;
        }

        if (Number.isFinite(best)) return best;

        const forward = this._buildPathToAttackTarget(session, entityId);
        if (forward.length <= 0) return 0;
        return forward.length;
    }

    /** 从实体当前格起，沿进路至攻击目标的路径格（不含起点） */
    private _buildPathToAttackTarget(session: BattleSession, entityId: EntityId): Cell[] {
        const world = session.world;
        const tf = world.getComponent(entityId, TransformComp);
        if (!tf) return [];

        const move = world.getComponent(entityId, MovementComp);
        const out: Cell[] = [];
        if (move && move.pathIndex < move.path.length) {
            for (let i = move.pathIndex; i < move.path.length; i++) {
                const c = move.path[i];
                const last = out.length > 0 ? out[out.length - 1] : tf;
                if (last.row === c.row && last.col === c.col) continue;
                out.push({ row: c.row, col: c.col });
            }
        }
        if (out.length > 0) return out;

        const campAreaId = this._resolveEntityCampAreaId(session, entityId);
        const from = { row: tf.row, col: tf.col };
        const target = session.pathfinder.shortestTargetCell(from, campAreaId);
        if (!target) return [];
        const fullPath = session.pathfinder.buildPathToTarget(from, target, campAreaId);
        if (fullPath.length <= 1) return [];
        for (let i = 1; i < fullPath.length; i++) {
            const c = fullPath[i];
            const last = out.length > 0 ? out[out.length - 1] : from;
            if (last.row === c.row && last.col === c.col) continue;
            out.push({ row: c.row, col: c.col });
        }
        return out;
    }

    /** 实体出怪口所属阵营区域（与 MovementSystem.assignPath 一致） */
    private _resolveEntityCampAreaId(session: BattleSession, entityId: EntityId): number | undefined {
        const meta = session.world.getComponent(entityId, UnitMetaComp);
        const port = meta?.spawnPoint ?? 0;
        if (port < 1) {
            console.log('[BaseThunder] 实体缺少有效 spawnPoint', entityId);
            return undefined;
        }
        const area = session.topology.getSpawnPortCampArea(port);
        if (area === undefined) {
            console.log('[BaseThunder] 出怪口缺少阵营区域', port, entityId);
        }
        return area;
    }

    /** 实体出怪口格（与 MovementSystem 一致） */
    private _resolveEntitySpawnCell(session: BattleSession, entityId: EntityId): Cell | null {
        const meta = session.world.getComponent(entityId, UnitMetaComp);
        const port = meta?.spawnPoint ?? 0;
        if (port < 1) {
            console.log('[BaseThunder] 实体缺少有效 spawnPoint', entityId);
            return null;
        }
        const spawn = session.topology.getSpawnCell(port);
        if (!spawn) {
            console.log('[BaseThunder] 出怪口格缺失', port, entityId);
        }
        return spawn ?? null;
    }

    /**
     * 从锚点格起沿进路向出怪口后退收集生效格（含锚点格，共 effectCells 格）。
     * @param anchorId 锚点
     * @param effectCells 生效格数
     */
    private _collectEffectCells(anchorId: EntityId, effectCells: number): Cell[] {
        const battle = this._battle;
        const count = Math.max(1, Math.floor(effectCells));
        if (!battle) return [];
        const session = battle.session;
        const world = session.world;
        const tf = world.getComponent(anchorId, TransformComp);
        if (!tf) return [];

        const from = { row: tf.row, col: tf.col };
        const meta = world.getComponent(anchorId, UnitMetaComp);
        const port = meta?.spawnPoint ?? 0;
        const spawn = this._resolveEntitySpawnCell(session, anchorId);
        if (!spawn || port < 1) return [{ ...from }];

        const retreatSteps = count - 1;
        const path = session.pathfinder.buildRetreatPath(from, retreatSteps, spawn, port);
        if (path.length <= 0) return [{ ...from }];
        if (path.length <= count) return path;
        return path.slice(0, count);
    }

    /**
     * 收集生效格上的小怪/Boss；排序为锚点格（近终点）优先，再沿后退方向。
     * @param ownerPlayerId 防守方
     * @param effectCells 生效格
     */
    private _collectTargets(ownerPlayerId: number, effectCells: Cell[]): EntityId[] {
        const battle = this._battle;
        if (!battle) return [];
        const session = battle.session;
        const entries: ThunderTargetEntry[] = [];

        session.world.forEachAlive((entityId) => {
            if (!this._isThunderCandidate(battle, ownerPlayerId, entityId)) return;
            const tf = session.world.getComponent(entityId, TransformComp);
            const move = session.world.getComponent(entityId, MovementComp);
            let cellOrder = -1;
            if (move) {
                const cell = session.grid.worldToCell(move.worldX, move.worldY);
                cellOrder = this._indexOfCell(effectCells, cell.row, cell.col);
            }
            if (cellOrder < 0 && tf) {
                cellOrder = this._indexOfCell(effectCells, tf.row, tf.col);
            }
            if (cellOrder < 0) return;
            entries.push({ entityId, cellOrder });
        });

        entries.sort((a, b) => {
            if (a.cellOrder !== b.cellOrder) return a.cellOrder - b.cellOrder;
            return a.entityId - b.entityId;
        });

        const out: EntityId[] = [];
        for (let i = 0; i < entries.length; i++) {
            out.push(entries[i].entityId);
        }
        return out;
    }

    /** 格在序列中的索引；-1 表示不在序列内 */
    private _indexOfCell(cells: Cell[], row: number, col: number): number {
        for (let i = 0; i < cells.length; i++) {
            if (cells[i].row === row && cells[i].col === col) return i;
        }
        return -1;
    }

    /**
     * 是否可被御雷珠选中的进攻指定玩家的小怪/Boss/召唤怪。
     * @param battle 战斗
     * @param ownerPlayerId 防守方
     * @param entityId 实体
     */
    private _isThunderCandidate(battle: ProjectBattleHandle, ownerPlayerId: number, entityId: EntityId): boolean {
        const session = battle.session;
        const world = session.world;
        if (!world.isAlive(entityId)) return false;
        if (isMechanismUnit(session, entityId)) return false;
        const team = world.getComponent(entityId, TeamComp);
        if (!team || !BattleTeamId.isEnemyTeam(team.team)) return false;
        if (Math.max(0, Math.floor(Number(team.ownerId) || 0)) !== ownerPlayerId) return false;
        const row = battle.resolveMonsterRow(entityId);
        if (!row) return false;
        const type = Math.floor(Number(row.type));
        return type === MonsterType.SmallMonster
            || type === MonsterType.Boss
            || type === MonsterType.SummonMonster;
    }

    /**
     * 对单目标结算伤害（走正常掉血/击杀流程）。
     * @param ownerPlayerId 防守方
     * @param config 配置
     * @param entityId 目标
     */
    private _applyDamage(ownerPlayerId: number, config: BattleBuffBaseThunderAdjust, entityId: EntityId): void {
        const battle = this._battle;
        if (!battle || !config) return;
        const session = battle.session;
        const world = session.world;
        if (!world.isAlive(entityId)) return;
        if (!this._isThunderCandidate(battle, ownerPlayerId, entityId)) return;

        const hp = world.getComponent(entityId, HealthComp);
        if (!hp || hp.maxHp <= 0) return;
        const move = world.getComponent(entityId, MovementComp);
        if (move?.spawnProtected || move?.presentLocked || isYanSoulClaimed(move) || isBajiaoBlowRetreating(move)) return;

        const monsterRow = battle.resolveMonsterRow(entityId);
        const isBoss = monsterRow != null && Math.floor(Number(monsterRow.type)) === MonsterType.Boss;
        const wan = isBoss ? config.bossDmgWan : config.smallDmgWan;
        const amount = Math.max(1, Math.floor(hp.maxHp * wan / 10000));
        const hpBefore = hp.hp;

        session.damage.apply(BASE_THUNDER_CASTER, entityId, amount, BASE_THUNDER_DAMAGE_TYPE, undefined, false);
        session.events.flush();
        session.events.emit(
            BattleEventFactory.hitAfter(BASE_THUNDER_CASTER, entityId, amount, false, undefined, BASE_THUNDER_DAMAGE_TYPE),
            true,
        );

        if (hp.hp <= 0) {
            this._scheduleKill(entityId, hpBefore);
        }
    }

    /** 飘字后再击杀，避免产桃/死亡特效抢在伤害数字前 */
    private _scheduleKill(entityId: EntityId, hpBefore: number): void {
        const battle = this._battle;
        if (!battle) return;
        const scheduleGen = this._killScheduleGen;
        schedulePresentation(BASE_THUNDER_KILL_DELAY_SEC, () => {
            if (scheduleGen !== this._killScheduleGen || !this._battle) return;
            const session = this._battle.session;
            const world = session.world;
            if (!world.isAlive(entityId)) return;
            const hpNow = world.getComponent(entityId, HealthComp);
            if (!hpNow || hpNow.hp > 0) return;
            session.lifecycle.kill(entityId, BASE_THUNDER_CASTER, hpBefore);
        });
    }
}

let _host: BattleBuffBaseThunderHost | null = null;

/** 全局御雷珠被动 Host（单局复用） */
export function getBattleBuffBaseThunderHost(): BattleBuffBaseThunderHost {
    if (!_host) _host = new BattleBuffBaseThunderHost();
    return _host;
}