package com.guo.learningprogresstracker.service.impl;

import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.google.protobuf.ServiceException;
import com.guo.learningprogresstracker.dto.StudySessionsDto;
import com.guo.learningprogresstracker.dto.response.StudySessionResponse;
import com.guo.learningprogresstracker.entity.StudyReportFragmentsEntity;
import com.guo.learningprogresstracker.entity.StudyReportsEntity;
import com.guo.learningprogresstracker.entity.StudySessionsEntity;
import com.guo.learningprogresstracker.entity.TaskEntity;
import com.guo.learningprogresstracker.enums.StudySessionStateEnum;
import com.guo.learningprogresstracker.exception.ErrorParameterException;
import com.guo.learningprogresstracker.exception.NotFindEntitiesException;
import com.guo.learningprogresstracker.mapStruct.StudySessionConvert;
import com.guo.learningprogresstracker.mapper.StudyReportFragmentsMapper;
import com.guo.learningprogresstracker.mapper.StudyReportsMapper;
import com.guo.learningprogresstracker.mapper.StudySessionsMapper;
import com.guo.learningprogresstracker.service.StudySessionsService;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Optional;
import java.util.stream.Collectors;

/**
 * 针对表【study_sessions(记录每次学习会话的具体数据)】的数据库操作Service实现
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class StudySessionsServiceImpl extends ServiceImpl<StudySessionsMapper, StudySessionsEntity>
        implements StudySessionsService {

    public static final int WORK_DURATION = 25;

    private final TasksServiceImpl tasksServiceImpl;
    private final StudyReportFragmentsServiceImpl studyReportFragmentsServiceImpl;
    private final StudyReportFragmentsMapper studyReportFragmentsMapper;
    private final StudyReportsMapper studyReportsMapper;

    public StudySessionResponse startOrContinueStudySession(String taskNum) throws NotFindEntitiesException, ServiceException {
        TaskEntity taskEntity = tasksServiceImpl.getOneOpt(
                        Wrappers.lambdaQuery(TaskEntity.class).eq(TaskEntity::getTaskNum, taskNum))
                .orElseThrow(() -> new NotFindEntitiesException(String.format("[%s]不存在", taskNum)));

        StudySessionsEntity session = this.getOneOpt(Wrappers.<StudySessionsEntity>lambdaQuery()
                        .eq(StudySessionsEntity::getTaskNum, taskNum)
                        .ne(StudySessionsEntity::getSessionState, StudySessionStateEnum.ENDED.name()))
                .orElseGet(() -> {
                    // 如果没有则创建新会话
                    StudySessionsEntity newSession = StudySessionsEntity.initNewSession();
                    newSession.setTaskNum(taskNum);
                    newSession.setLastStartTime(LocalDateTime.now());
                    this.save(newSession);
                    return newSession;
                });

        session.calculatePointerPosition();

        if (session.isOverTime()) {
            session.pausedStudySession(session.getLastStartTime().plusMinutes(WORK_DURATION));
            this.updateById(session);
        }

        StudySessionResponse response = StudySessionConvert.MAPPER.toStudySessionResponse(session);
        response.setTaskName(taskEntity.getTaskName());

        if (session.isOverTime()) {
            response.setSystemMessage("上段学习任务已经超时25分钟，将仅计算为25分钟的有效学习时间，请注意休息！");
        }

        return response;
    }


    @Override
    public void pauseStudySession(String sessionNum, LocalDateTime endTime) throws ErrorParameterException, ServiceException {
        StudySessionsEntity studySessionsEntity = this.getOneOpt(Wrappers.lambdaQuery(StudySessionsEntity.class)
                        .eq(StudySessionsEntity::getSessionNum, sessionNum))
                .orElseThrow(() -> new ErrorParameterException("会话[" + sessionNum + "]不存在"));
        if (StudySessionStateEnum.PAUSED.name().equals(studySessionsEntity.getSessionState())) {
            log.error("会话[" + studySessionsEntity.getSessionNum() + "]重复暂停");
            throw new ErrorParameterException("会话[" + sessionNum + "]已经暂停，请勿重复暂停！");
        }
        studySessionsEntity.calculatePointerPosition();
        studySessionsEntity.pausedStudySession(endTime);
        this.updateById(studySessionsEntity);
    }


    @Override
    public String endedStudySession(String sessionNum, String content) throws ErrorParameterException {
        StudySessionsEntity studySessionsEntity = this.getOneOpt(Wrappers.lambdaQuery(StudySessionsEntity.class)
                        .eq(StudySessionsEntity::getSessionNum, sessionNum))
                .orElseThrow(() -> new ErrorParameterException("会话[" + sessionNum + "]不存在"));
        boolean wasOngoing = StudySessionStateEnum.ONGOING.name().equals(studySessionsEntity.getSessionState());
        studySessionsEntity.endedStudySession();
        this.updateById(studySessionsEntity);
        StudyReportsEntity studyReportsEntity = new StudyReportsEntity();
        studyReportsEntity.setSessionNum(sessionNum);
        studyReportsEntity.setContent(content);
        studyReportsMapper.insert(studyReportsEntity);
        if (wasOngoing && studySessionsEntity.getEffectiveTime() == 0) {
            return "本次有效学习时间不足10分钟，不计入总学习时间";
        }
        return null;
    }

    @Override
    public StudySessionResponse getNotEndedStudySessionByTaskNum(String taskNum) throws ErrorParameterException {
        TaskEntity task = tasksServiceImpl.getOneOpt(Wrappers.lambdaQuery(TaskEntity.class)
                        .eq(TaskEntity::getTaskNum, taskNum))
                .orElseThrow(() -> new ErrorParameterException("任务[" + taskNum + "]不存在"));
        StudySessionsDto dto = Optional.ofNullable(studyReportsMapper.getNotEndedStudySessionDtoByTaskNum(taskNum))
                .orElseThrow(() -> new ErrorParameterException("任务[" + taskNum + "]不存在进行中或暂停中的会话"));
        return StudySessionConvert.MAPPER.toStudySessionResponse(dto);
    }

    @Override
    public ArrayList<String> getAllFragments(String sessionNum) throws ErrorParameterException {
        if (this.exists(Wrappers.lambdaQuery(StudySessionsEntity.class)
                .eq(StudySessionsEntity::getSessionNum, sessionNum))) {
            return studyReportFragmentsMapper.selectList(Wrappers.lambdaQuery(StudyReportFragmentsEntity.class)
                            .eq(StudyReportFragmentsEntity::getSessionNum, sessionNum))
                    .stream().map(StudyReportFragmentsEntity::getContent).collect(Collectors.toCollection(ArrayList::new));
        } else {
            throw new ErrorParameterException("会话[" + sessionNum + "]不存在");
        }
    }

    @Override
    public void continueStudySession(String sessionNum) throws ErrorParameterException, ServiceException {
        StudySessionsEntity studySessionsEntity = this.getOneOpt(Wrappers.lambdaQuery(StudySessionsEntity.class)
                        .eq(StudySessionsEntity::getSessionNum, sessionNum))
                .orElseThrow(() -> new ErrorParameterException("会话[" + sessionNum + "]不存在"));
        if (StudySessionStateEnum.ONGOING.name().equals(studySessionsEntity.getSessionState())) {
            log.error("会话[" + studySessionsEntity.getSessionNum() + "]重复开始");
            throw new ErrorParameterException("会话[" + sessionNum + "]已经开始，请勿重复开始！");
        } else if (StudySessionStateEnum.ENDED.name().equals(studySessionsEntity.getSessionState())) {
            log.error("会话[" + studySessionsEntity.getSessionNum() + "]处于结束状态，不可开始该会话！");
            throw new ErrorParameterException("会话[" + sessionNum + "]处于结束状态，不可开始该会话！");
        }
        studySessionsEntity.continueStudySession();
        this.updateById(studySessionsEntity);
    }

    /**
     * 通过 sessionNum 获取学习会话
     */
    public StudySessionResponse getStudySessionBySessionNum(String sessionNum) throws ErrorParameterException {
        StudySessionsEntity session = this.getOneOpt(Wrappers.lambdaQuery(StudySessionsEntity.class)
                        .eq(StudySessionsEntity::getSessionNum, sessionNum))
                .orElseThrow(() -> new ErrorParameterException("会话[" + sessionNum + "]不存在"));
        return StudySessionConvert.MAPPER.toStudySessionResponse(session);
    }

}