package com.iailab.module.bpm.framework.flowable.core.candidate.strategy;

import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.lang.Assert;
import com.iailab.module.bpm.framework.flowable.core.candidate.BpmTaskCandidateStrategy;
import com.iailab.module.bpm.framework.flowable.core.enums.BpmTaskCandidateStrategyEnum;
import com.iailab.module.bpm.framework.flowable.core.util.BpmnModelUtils;
import com.iailab.module.bpm.framework.flowable.core.util.FlowableUtils;
import com.iailab.module.bpm.service.task.BpmProcessInstanceService;
import org.flowable.bpmn.model.BpmnModel;
import org.flowable.bpmn.model.UserTask;
import org.flowable.engine.delegate.DelegateExecution;
import org.flowable.engine.runtime.ProcessInstance;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.util.*;

/**
 * 发起人自选 {@link BpmTaskCandidateUserStrategy} 实现类
 *
 * @author iailab
 */
@Component
public class BpmTaskCandidateStartUserSelectStrategy implements BpmTaskCandidateStrategy {

    @Resource
    @Lazy // 延迟加载，避免循环依赖
    private BpmProcessInstanceService processInstanceService;

    @Override
    public BpmTaskCandidateStrategyEnum getStrategy() {
        return BpmTaskCandidateStrategyEnum.START_USER_SELECT;
    }

    @Override
    public void validateParam(String param) {}

    @Override
    public Set<Long> calculateUsers(DelegateExecution execution, String param) {
        ProcessInstance processInstance = processInstanceService.getProcessInstance(execution.getProcessInstanceId());
        Assert.notNull(processInstance, "流程实例({})不能为空", execution.getProcessInstanceId());
        Map<String, List<Long>> startUserSelectAssignees = FlowableUtils.getStartUserSelectAssignees(processInstance);
        Assert.notNull(startUserSelectAssignees, "流程实例({}) 的发起人自选审批人不能为空",
                execution.getProcessInstanceId());
        // 获得审批人
        List<Long> assignees = startUserSelectAssignees.get(execution.getCurrentActivityId());
        return new LinkedHashSet<>(assignees);
    }

    @Override
    public boolean isParamRequired() {
        return false;
    }

    /**
     * 获得发起人自选审批人的 UserTask 列表
     *
     * @param bpmnModel BPMN 模型
     * @return UserTask 列表
     */
    public static List<UserTask> getStartUserSelectUserTaskList(BpmnModel bpmnModel) {
        if (bpmnModel == null) {
            return null;
        }
        List<UserTask> userTaskList = BpmnModelUtils.getBpmnModelElements(bpmnModel, UserTask.class);
        if (CollUtil.isEmpty(userTaskList)) {
            return null;
        }
        userTaskList.removeIf(userTask -> !Objects.equals(BpmnModelUtils.parseCandidateStrategy(userTask),
                BpmTaskCandidateStrategyEnum.START_USER_SELECT.getStrategy()));
        return userTaskList;
    }

}