package com.ard.tianyu.service.control;

import com.ard.common.exception.NoPermissionException;
import com.ard.common.utils.SecurityUtils;
import com.ard.tianyu.websocket.domain.UavControlType;
import com.ard.tianyu.websocket.handler.UavControlManager;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
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。
 */
@Service
public class UavControlService {

    @Resource
    private UavControlManager uavControlManager;

    /**
     * 记录当前获得飞行控制权限的用户
     */
    private final ConcurrentHashMap<String, Long> uavFlyControlMap = new ConcurrentHashMap<>();
    /**
     * 记录当前获得载荷控制权限的用户
     */
    private final ConcurrentHashMap<String, Long> uavPayloadControlMap = new ConcurrentHashMap<>();

    /**
     * 记录飞行控制请求
     */
    private final ConcurrentHashMap<String, Long> flyControlRequests = new ConcurrentHashMap<>();
    /**
     * 记录载荷控制请求
     */
    private final ConcurrentHashMap<String, Long> payloadControlRequests = new ConcurrentHashMap<>();

    /**
     * 请求获取 UAV 控制权限
     *
     * @param boxSn 设备序列号
     * @param type  控制类型（"fly"、"payload"）
     * @return 是否立即获得控制权限
     */
    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
     */
    private boolean requestSingleControl(String boxSn, UavControlType controlType, Long requester) {

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

        Long controller = controlMap.get(boxSn);
        if (controller == null) {
            controlMap.put(boxSn, requester);
            return true;
        }
        if (!controller.equals(requester)) {
            requestMap.put(boxSn, requester);
            uavControlManager.sendControlRequest(controller, boxSn, controlType.getType(), requester);
        } else {
            throw new NoPermissionException("当前已拥有控制权");
        }
        return false;
    }

    /**
     * 处理 UAV 控制请求的响应（同意或拒绝）
     *
     * @param boxSn   设备序列号
     * @param approve 是否同意
     * @param type    控制类型
     * @return 是否成功处理
     */
    public boolean handleControlResponse(String boxSn, boolean approve, String type) {
        UavControlType controlType = UavControlType.fromString(type);
        Long controller = SecurityUtils.getUserId();
        return handleSingleControlResponse(boxSn, approve, controlType, controller);
    }

    /**
     * 处理单个控制类型的请求响应
     */
    private boolean handleSingleControlResponse(String boxSn, boolean approve, UavControlType controlType,
                                                Long controller) {
        ConcurrentHashMap<String, Long> requestMap = getRequestMap(controlType);
        Long requester = requestMap.get(boxSn);

        if (requester == null || requester.equals(controller)) {
            throw new NoPermissionException("无控制请求");
        }

        if (approve) {
            getControlMap(controlType).put(boxSn, requester);
            uavControlManager.sendControlApproval(requester, boxSn, controlType.getType());
        } else {
            uavControlManager.sendControlRejection(requester, boxSn, controlType.getType());
        }

        requestMap.remove(boxSn);
        return true;
    }

    /**
     * 释放 UAV 控制权限
     *
     * @param boxSn 设备序列号
     * @param type  控制类型
     * @return 是否成功释放控制
     */
    public boolean releaseControl(String boxSn, String type) {
        UavControlType controlType = UavControlType.fromString(type);
        Long controller = SecurityUtils.getUserId();
        return releaseSingleControl(boxSn, controlType, controller);
    }

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

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

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

    /**
     * 释放用户所有 UAV 控制权
     */
    public void releaseAllControls(Long userId) {
        // 释放飞行控制
        uavFlyControlMap.entrySet().removeIf(entry -> entry.getValue().equals(userId));

        // 释放载荷控制
        uavPayloadControlMap.entrySet().removeIf(entry -> entry.getValue().equals(userId));
    }

    /**
     * 获取当前某设备的控制用户
     *
     * @param boxSn 设备序列号
     * @param type  控制类型
     * @return 当前控制该设备的用户 ID
     */
    public Long getCurrentController(String boxSn, String type) {
        UavControlType controlType = UavControlType.fromString(type);
        return getControlMap(controlType).get(boxSn);
    }

    /**
     * 根据控制类型获取对应的控制 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的请求 Map
     */
    private ConcurrentHashMap<String, 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");
        }
    }
}