package com.ard.work.service.control;

import com.ard.common.exception.ControlException;
import com.ard.common.utils.SecurityUtils;
import com.ard.system.service.ISysUserService;
import com.ard.work.component.websocket.handler.UavControlManager;
import com.ard.work.domain.message.UavControlType;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

/**
 * UAV控制服务类，负责管理对飞行和载荷的控制请求、释放和权限管理
 * 支持优先级抢占
 */
@Service
public class UavControlService {

    @Resource
    private UavControlManager uavControlManager;

    @Resource
    private ISysUserService sysUserService;

    /**
     * 当前飞行控制权限用户
     */
    private final ConcurrentHashMap<String, Long> uavFlyControlMap = new ConcurrentHashMap<>();

    /**
     * 当前载荷控制权限用户
     */
    private final ConcurrentHashMap<String, Long> uavPayloadControlMap = new ConcurrentHashMap<>();

    /**
     * 飞行控制请求：boxSn -> 多个请求者
     */
    private final ConcurrentHashMap<String, Set<Long>> flyControlRequests = new ConcurrentHashMap<>();

    /**
     * 载荷控制请求
     */
    private final ConcurrentHashMap<String, Set<Long>> payloadControlRequests = new ConcurrentHashMap<>();


    /**
     * 请求获取 UAV 控制权限
     */
    public boolean requestControl(String boxSn, String type) {
        UavControlType controlType = UavControlType.fromString(type);
        Long requester = SecurityUtils.getUserId();
        return requestSingleControl(boxSn, controlType, requester);
    }

    /**
     * 处理单个控制类型的请求
     */
    /**
     * 处理单个控制类型的请求（支持多请求者）
     */
    private boolean requestSingleControl(String boxSn, UavControlType controlType, Long requester) {

        ConcurrentHashMap<String, Long> controlMap = getControlMap(controlType);
        ConcurrentHashMap<String, Set<Long>> requestMap = getRequestMap(controlType);

        Long controller = controlMap.get(boxSn);

        // 无人控制 → 直接获取
        if (controller == null) {
            controlMap.put(boxSn, requester);
            uavControlManager.sendControlApproval(requester, boxSn, controlType.getType(), requester);
            return true;
        }

        // 已是控制者
        if (controller.equals(requester)) {
            throw new ControlException("当前已拥有控制权");
        }

        int requesterPriority = getUserPriority(requester);
        int controllerPriority = getUserPriority(controller);

        // 优先级高 → 直接接管
        if (requesterPriority > controllerPriority) {
            controlMap.put(boxSn, requester);

            // 通知原控制者被抢占
            uavControlManager.sendControlTakeover(controller, requester, boxSn, controlType.getType());
            return true;
        }

        // ===== 以下是关键改动点 =====

        // 优先级相同或更低 → 加入请求集合（不覆盖）
        Set<Long> requesters = requestMap.computeIfAbsent(boxSn, k -> ConcurrentHashMap.newKeySet());
        requesters.add(requester);

        // 通知当前控制者：有新的请求者
        uavControlManager.sendControlRequest(controller, boxSn, controlType.getType(), requester);

        return false;
    }


    /**
     * 处理 UAV 控制请求的响应
     */
    public boolean handleControlResponse(String boxSn, boolean approve, String type, Long requester) {
        UavControlType controlType = UavControlType.fromString(type);
        Long controller = SecurityUtils.getUserId();
        return handleSingleControlResponse(boxSn, approve, controlType, controller, requester);
    }


    /**
     * 处理单个控制类型请求响应
     */
    private boolean handleSingleControlResponse(String boxSn,
                                                boolean approve,
                                                UavControlType controlType,
                                                Long controller,
                                                Long requester) {

        ConcurrentHashMap<String, Set<Long>> requestMap = getRequestMap(controlType);
        Set<Long> requesters = requestMap.get(boxSn);

        if (requesters == null || !requesters.contains(requester)) {
            throw new ControlException("无控制请求");
        }

        if (approve) {
            getControlMap(controlType).put(boxSn, requester);

            // 通知被批准者
            uavControlManager.sendControlApproval(requester, boxSn, controlType.getType(), controller);

            // 🚨 其他请求者自动拒绝（强烈建议）
            for (Long other : requesters) {
                if (!other.equals(requester)) {
                    uavControlManager.sendControlRejection(other, boxSn, controlType.getType(), controller);
                }
            }
        } else {
            uavControlManager.sendControlRejection(requester, boxSn, controlType.getType(), controller);
        }

        requesters.remove(requester);
        if (requesters.isEmpty()) {
            requestMap.remove(boxSn);
        }

        return true;
    }


    /**
     * 释放 UAV 控制权限
     */
    public boolean releaseControl(String boxSn, String type) {
        UavControlType controlType = UavControlType.fromString(type);
        Long controller = SecurityUtils.getUserId();
        return releaseSingleControl(boxSn, controlType, controller);
    }

    /**
     * 释放单个控制类型权限
     */
    private boolean releaseSingleControl(String boxSn, UavControlType controlType, Long controller) {
        ConcurrentHashMap<String, Long> controlMap = getControlMap(controlType);

        if (!controller.equals(controlMap.get(boxSn))) {
            throw new ControlException("没有该设备的" + controlType.getType().toUpperCase() + "控制权");
        }

        controlMap.remove(boxSn);
        uavControlManager.sendControlRelease(boxSn, controlType.getType(), controller);
        return true;
    }

    /**
     * 释放用户所有控制权限
     */
    public void releaseAllControls(Long userId) {
        uavFlyControlMap.entrySet().removeIf(entry -> entry.getValue().equals(userId));
        uavPayloadControlMap.entrySet().removeIf(entry -> entry.getValue().equals(userId));
    }

    /**
     * 获取当前某设备的控制用户
     */
    public Long getCurrentController(String boxSn, String type) {
        UavControlType controlType = UavControlType.fromString(type);
        return getControlMap(controlType).get(boxSn);
    }

    public Map<String, Long> getCurrentController(String boxSn) {
        Map<String, Long> map = new HashMap<>();
        map.put("flyController", uavFlyControlMap.get(boxSn));
        map.put("payloadController", uavPayloadControlMap.get(boxSn));
        return map;
    }

    /**
     * 根据控制类型获取对应控制 Map
     */
    private ConcurrentHashMap<String, Long> getControlMap(UavControlType controlType) {
        switch (controlType) {
            case FLY:
                return uavFlyControlMap;
            case PAYLOAD:
                return uavPayloadControlMap;
            default:
                throw new IllegalArgumentException("不支持的控制类型");
        }
    }

    /**
     * 根据控制类型获取对应请求 Map
     */
    private ConcurrentHashMap<String, Set<Long>> getRequestMap(UavControlType controlType) {
        switch (controlType) {
            case FLY:
                return flyControlRequests;
            case PAYLOAD:
                return payloadControlRequests;
            default:
                throw new IllegalArgumentException("不支持的控制类型");
        }
    }


    /**
     * 获取用户优先级
     */
    private int getUserPriority(Long userId) {
        return sysUserService.selectUserById(userId).getPriority();
    }
}