package com.tcm.training.admin.live.service;

import cn.idev.excel.FastExcel;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.tcm.training.admin.common.Jsons;
import com.tcm.training.admin.common.PageResponse;
import com.tcm.training.admin.live.dto.HealthCourseSaveRequest;
import com.tcm.training.admin.live.dto.HealthCourseStatusRequest;
import com.tcm.training.admin.live.dto.HealthCourseVideoSaveRequest;
import com.tcm.training.admin.live.entity.Expert;
import com.tcm.training.admin.live.entity.HealthCourse;
import com.tcm.training.admin.live.entity.HealthCourseVideo;
import com.tcm.training.admin.live.entity.LiveCourseCategory;
import com.tcm.training.admin.live.excel.HealthCourseExportRow;
import com.tcm.training.admin.live.mapper.ExpertMapper;
import com.tcm.training.admin.live.mapper.HealthCourseMapper;
import com.tcm.training.admin.live.mapper.HealthCourseVideoMapper;
import com.tcm.training.admin.live.mapper.LiveCourseCategoryMapper;
import com.tcm.training.admin.live.vo.ExpertVO;
import com.tcm.training.admin.live.vo.HealthCourseDetailRow;
import com.tcm.training.admin.live.vo.HealthCourseDetailVO;
import com.tcm.training.admin.live.vo.HealthCourseListItemVO;
import com.tcm.training.admin.live.vo.HealthCourseListRow;
import com.tcm.training.admin.live.vo.HealthCourseStatusVO;
import com.tcm.training.admin.live.vo.HealthCourseVideoDetailVO;
import com.tcm.training.admin.live.vo.HealthCourseVideoItemVO;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.List;

@Service
public class HealthCourseAppService {

    private final HealthCourseMapper healthCourseMapper;
    private final HealthCourseVideoMapper healthCourseVideoMapper;
    private final LiveCourseCategoryMapper liveCourseCategoryMapper;
    private final ExpertMapper expertMapper;

    public HealthCourseAppService(HealthCourseMapper healthCourseMapper,
                                  HealthCourseVideoMapper healthCourseVideoMapper,
                                  LiveCourseCategoryMapper liveCourseCategoryMapper,
                                  ExpertMapper expertMapper) {
        this.healthCourseMapper = healthCourseMapper;
        this.healthCourseVideoMapper = healthCourseVideoMapper;
        this.liveCourseCategoryMapper = liveCourseCategoryMapper;
        this.expertMapper = expertMapper;
    }

    public PageResponse<HealthCourseListItemVO> page(int page,
                                                     int pageSize,
                                                     String keyword,
                                                     Long levelCategoryId,
                                                     Long difficultyCategoryId,
                                                     Integer status) {
        IPage<HealthCourseListRow> result = healthCourseMapper.selectCoursePage(
                new Page<HealthCourseListRow>(page, pageSize),
                trimToNull(keyword),
                levelCategoryId,
                difficultyCategoryId,
                status
        );
        List<HealthCourseListItemVO> list = new ArrayList<HealthCourseListItemVO>();
        for (HealthCourseListRow row : result.getRecords()) {
            list.add(toCourseListItem(row));
        }
        return PageResponse.of(list, result.getTotal(), result.getCurrent(), result.getSize());
    }

    public HealthCourseDetailVO detail(Long id) {
        HealthCourseDetailRow row = healthCourseMapper.selectCourseDetail(id);
        if (row == null) {
            throw new IllegalArgumentException("课程不存在");
        }
        return toCourseDetail(row);
    }

    @Transactional
    public HealthCourseDetailVO create(HealthCourseSaveRequest req) {
        validateCategories(req.getLevelCategoryId(), req.getDifficultyCategoryId());
        validateExpert(req.getExpertId());

        HealthCourse course = new HealthCourse();
        fillCourse(course, req);
        course.setRealSalesCount(0);
        course.setLearnUserCount(0);
        course.setFavoriteCount(0);
        course.setTotalDurationSeconds(0);
        course.setVideoCount(0);
        course.setSort(0);
        course.setDeleted(0);
        healthCourseMapper.insert(course);
        return detail(course.getId());
    }

    @Transactional
    public HealthCourseDetailVO update(Long id, HealthCourseSaveRequest req) {
        validateCategories(req.getLevelCategoryId(), req.getDifficultyCategoryId());
        validateExpert(req.getExpertId());
        HealthCourse course = requireCourse(id);
        fillCourse(course, req);
        healthCourseMapper.updateById(course);
        return detail(id);
    }

    @Transactional
    public HealthCourseStatusVO patchStatus(Long id, HealthCourseStatusRequest req) {
        HealthCourse course = requireCourse(id);
        course.setStatus(req.getStatus());
        healthCourseMapper.updateById(course);
        return new HealthCourseStatusVO(id, req.getStatus());
    }

    @Transactional
    public void delete(Long id) {
        requireCourse(id);
        List<HealthCourseVideo> videos = healthCourseVideoMapper.selectList(new LambdaQueryWrapper<HealthCourseVideo>()
                .eq(HealthCourseVideo::getCourseId, id)
                .eq(HealthCourseVideo::getDeleted, 0));
        for (HealthCourseVideo video : videos) {
            healthCourseVideoMapper.deleteById(video.getId());
        }
        healthCourseMapper.deleteById(id);
    }

    public void export(HttpServletResponse response,
                       String keyword,
                       Long levelCategoryId,
                       Long difficultyCategoryId,
                       Integer status) throws IOException {
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        response.setCharacterEncoding("utf-8");
        String filename = URLEncoder.encode("养身课程", "UTF-8").replace("+", "%20");
        response.setHeader("Content-Disposition", "attachment;filename*=utf-8''" + filename + ".xlsx");

        List<HealthCourseListRow> rows = healthCourseMapper.selectCourseList(
                trimToNull(keyword),
                levelCategoryId,
                difficultyCategoryId,
                status
        );
        List<HealthCourseExportRow> exports = new ArrayList<HealthCourseExportRow>();
        for (int i = 0; i < rows.size(); i++) {
            HealthCourseListRow row = rows.get(i);
            HealthCourseExportRow export = new HealthCourseExportRow();
            export.setSerialNo(i + 1);
            export.setTitle(defaultText(row.getTitle()));
            export.setLevelName(defaultText(row.getLevelName()));
            export.setDifficultyName(defaultText(row.getDifficultyName()));
            export.setSalePrice(row.getSalePrice() == null ? BigDecimal.ZERO : row.getSalePrice());
            export.setSalesCount(resolveSalesCount(row.getBaseSalesCount(), row.getRealSalesCount()));
            export.setLearnUserCount(defaultNumber(row.getLearnUserCount()));
            export.setTotalDuration(formatDuration(defaultNumber(row.getTotalDurationSeconds())));
            export.setFavoriteCount(defaultNumber(row.getFavoriteCount()));
            export.setExpertName(defaultText(row.getExpertName()));
            export.setStatusText(statusText(row.getStatus()));
            exports.add(export);
        }
        FastExcel.write(response.getOutputStream(), HealthCourseExportRow.class)
                .sheet("养身课程")
                .doWrite(exports);
    }

    public PageResponse<HealthCourseVideoItemVO> pageVideos(Long courseId,
                                                            int page,
                                                            int pageSize,
                                                            String chapterName,
                                                            Integer saleType) {
        requireCourse(courseId);
        LambdaQueryWrapper<HealthCourseVideo> qw = new LambdaQueryWrapper<HealthCourseVideo>()
                .eq(HealthCourseVideo::getCourseId, courseId)
                .eq(HealthCourseVideo::getDeleted, 0)
                .orderByAsc(HealthCourseVideo::getSort)
                .orderByAsc(HealthCourseVideo::getId);
        if (chapterName != null && !chapterName.trim().isEmpty()) {
            qw.like(HealthCourseVideo::getChapterName, chapterName.trim());
        }
        if (saleType != null) {
            qw.eq(HealthCourseVideo::getSaleType, saleType);
        }
        IPage<HealthCourseVideo> result = healthCourseVideoMapper.selectPage(new Page<HealthCourseVideo>(page, pageSize), qw);
        List<HealthCourseVideoItemVO> list = new ArrayList<HealthCourseVideoItemVO>();
        for (HealthCourseVideo item : result.getRecords()) {
            list.add(toVideoItem(item));
        }
        return PageResponse.of(list, result.getTotal(), result.getCurrent(), result.getSize());
    }

    public HealthCourseVideoDetailVO detailVideo(Long courseId, Long videoId) {
        return toVideoDetail(requireVideo(courseId, videoId));
    }

    @Transactional
    public HealthCourseVideoDetailVO createVideo(Long courseId, HealthCourseVideoSaveRequest req) {
        requireCourse(courseId);
        validateVideoSale(req);
        HealthCourseVideo next = new HealthCourseVideo();
        next.setCourseId(courseId);
        fillVideo(next, req);
        next.setSort(resolveNextVideoSort(courseId));
        next.setDeleted(0);
        healthCourseVideoMapper.insert(next);
        refreshCourseStats(courseId);
        return detailVideo(courseId, next.getId());
    }

    @Transactional
    public HealthCourseVideoDetailVO updateVideo(Long courseId, Long videoId, HealthCourseVideoSaveRequest req) {
        validateVideoSale(req);
        HealthCourseVideo video = requireVideo(courseId, videoId);
        fillVideo(video, req);
        healthCourseVideoMapper.updateById(video);
        refreshCourseStats(courseId);
        return detailVideo(courseId, videoId);
    }

    @Transactional
    public void deleteVideo(Long courseId, Long videoId) {
        requireVideo(courseId, videoId);
        healthCourseVideoMapper.deleteById(videoId);
        refreshCourseStats(courseId);
    }

    private void fillCourse(HealthCourse course, HealthCourseSaveRequest req) {
        course.setTitle(req.getTitle().trim());
        course.setLevelCategoryId(req.getLevelCategoryId());
        course.setDifficultyCategoryId(req.getDifficultyCategoryId());
        course.setExpertId(req.getExpertId());
        course.setSalePrice(req.getSalePrice());
        course.setSummary(trimToNull(req.getSummary()));
        course.setTargetUsers(trimToNull(req.getTargetUsers()));
        course.setCoverImg(req.getCoverImg().trim());
        course.setBannerImgs(req.getBannerImgs());
        course.setContent(req.getContent().trim());
        course.setBaseSalesCount(req.getBaseSalesCount() == null ? 0 : req.getBaseSalesCount());
        course.setStatus(req.getStatus());
        course.setIsHomeRecommend(req.getIsHomeRecommend());
    }

    private void fillVideo(HealthCourseVideo video, HealthCourseVideoSaveRequest req) {
        video.setChapterName(req.getChapterName().trim());
        video.setChapterRemark(trimToNull(req.getChapterRemark()));
        video.setVideoUrl(req.getVideoUrl().trim());
        video.setDurationSeconds(req.getDurationSeconds());
        video.setSaleType(req.getSaleType());
        video.setSalePrice(req.getSaleType() != null && req.getSaleType() == 0 ? BigDecimal.ZERO : req.getSalePrice());
        video.setPlayCount(req.getPlayCount());
        video.setStatus(req.getStatus());
    }

    private void validateCategories(Long levelCategoryId, Long difficultyCategoryId) {
        LiveCourseCategory level = requireCategory(levelCategoryId, LiveCourseCategoryAppService.TYPE_LEVEL, "养身等级");
        LiveCourseCategory difficulty = requireCategory(difficultyCategoryId, LiveCourseCategoryAppService.TYPE_DIFFICULTY, "难度");
        if (level == null || difficulty == null) {
            throw new IllegalArgumentException("分类不存在");
        }
    }

    private LiveCourseCategory requireCategory(Long id, String type, String label) {
        LiveCourseCategory category = liveCourseCategoryMapper.selectOne(new LambdaQueryWrapper<LiveCourseCategory>()
                .eq(LiveCourseCategory::getId, id)
                .eq(LiveCourseCategory::getType, type)
                .eq(LiveCourseCategory::getDeleted, 0)
                .last("limit 1"));
        if (category == null) {
            throw new IllegalArgumentException(label + "不存在");
        }
        return category;
    }

    private void validateExpert(Long expertId) {
        Expert expert = expertMapper.selectOne(new LambdaQueryWrapper<Expert>()
                .eq(Expert::getId, expertId)
                .eq(Expert::getDeleted, 0)
                .last("limit 1"));
        if (expert == null) {
            throw new IllegalArgumentException("授课专家不存在");
        }
        if (expert.getStatus() == null || expert.getStatus() != 1) {
            throw new IllegalArgumentException("授课专家已禁用");
        }
    }

    private void validateVideoSale(HealthCourseVideoSaveRequest req) {
        if (req.getSaleType() == null || (req.getSaleType() != 0 && req.getSaleType() != 1)) {
            throw new IllegalArgumentException("售价类型不合法");
        }
        if (req.getSaleType() == 0 && req.getSalePrice() != null && req.getSalePrice().compareTo(BigDecimal.ZERO) != 0) {
            throw new IllegalArgumentException("免费课程售价必须为0");
        }
    }

    private int resolveNextVideoSort(Long courseId) {
        HealthCourseVideo latest = healthCourseVideoMapper.selectOne(new LambdaQueryWrapper<HealthCourseVideo>()
                .eq(HealthCourseVideo::getCourseId, courseId)
                .eq(HealthCourseVideo::getDeleted, 0)
                .orderByDesc(HealthCourseVideo::getSort)
                .last("limit 1"));
        if (latest == null || latest.getSort() == null) {
            return 10;
        }
        return latest.getSort() + 10;
    }

    private void refreshCourseStats(Long courseId) {
        HealthCourse course = requireCourse(courseId);
        List<HealthCourseVideo> videos = healthCourseVideoMapper.selectList(new LambdaQueryWrapper<HealthCourseVideo>()
                .eq(HealthCourseVideo::getCourseId, courseId)
                .eq(HealthCourseVideo::getDeleted, 0));
        int totalDurationSeconds = 0;
        for (HealthCourseVideo video : videos) {
            totalDurationSeconds += video.getDurationSeconds() == null ? 0 : video.getDurationSeconds();
        }
        course.setVideoCount(videos.size());
        course.setTotalDurationSeconds(totalDurationSeconds);
        healthCourseMapper.updateById(course);
    }

    private HealthCourse requireCourse(Long id) {
        HealthCourse course = healthCourseMapper.selectById(id);
        if (course == null) {
            throw new IllegalArgumentException("课程不存在");
        }
        return course;
    }

    private HealthCourseVideo requireVideo(Long courseId, Long videoId) {
        requireCourse(courseId);
        HealthCourseVideo video = healthCourseVideoMapper.selectById(videoId);
        if (video == null) {
            throw new IllegalArgumentException("视频课程不存在");
        }
        if (!courseId.equals(video.getCourseId())) {
            throw new IllegalArgumentException("视频课程不属于当前课程");
        }
        return video;
    }

    private HealthCourseListItemVO toCourseListItem(HealthCourseListRow row) {
        HealthCourseListItemVO vo = new HealthCourseListItemVO();
        vo.setId(row.getId());
        vo.setTitle(row.getTitle());
        vo.setLevelName(row.getLevelName());
        vo.setDifficultyName(row.getDifficultyName());
        vo.setSalePrice(row.getSalePrice() == null ? BigDecimal.ZERO : row.getSalePrice());
        vo.setSalesCount(resolveSalesCount(row.getBaseSalesCount(), row.getRealSalesCount()));
        vo.setLearnUserCount(defaultNumber(row.getLearnUserCount()));
        vo.setTotalDurationSeconds(defaultNumber(row.getTotalDurationSeconds()));
        vo.setFavoriteCount(defaultNumber(row.getFavoriteCount()));
        vo.setExpert(new ExpertVO(row.getExpertId(), row.getExpertName(), row.getExpertAvatar()));
        vo.setCoverImg(row.getCoverImg());
        vo.setStatus(row.getStatus());
        vo.setIsHomeRecommend(row.getIsHomeRecommend());
        vo.setCreatedAt(row.getCreatedAt());
        return vo;
    }

    private HealthCourseDetailVO toCourseDetail(HealthCourseDetailRow row) {
        HealthCourseDetailVO vo = new HealthCourseDetailVO();
        vo.setId(row.getId());
        vo.setTitle(row.getTitle());
        vo.setLevelCategoryId(row.getLevelCategoryId());
        vo.setLevelName(row.getLevelName());
        vo.setDifficultyCategoryId(row.getDifficultyCategoryId());
        vo.setDifficultyName(row.getDifficultyName());
        vo.setExpert(new ExpertVO(row.getExpertId(), row.getExpertName(), row.getExpertAvatar()));
        vo.setSalePrice(row.getSalePrice() == null ? BigDecimal.ZERO : row.getSalePrice());
        vo.setSummary(row.getSummary());
        vo.setTargetUsers(row.getTargetUsers());
        vo.setCoverImg(row.getCoverImg());
        vo.setBannerImgs(Jsons.parseStringList(row.getBannerImgs()));
        vo.setContent(row.getContent());
        vo.setBaseSalesCount(defaultNumber(row.getBaseSalesCount()));
        vo.setRealSalesCount(defaultNumber(row.getRealSalesCount()));
        vo.setSalesCount(resolveSalesCount(row.getBaseSalesCount(), row.getRealSalesCount()));
        vo.setLearnUserCount(defaultNumber(row.getLearnUserCount()));
        vo.setFavoriteCount(defaultNumber(row.getFavoriteCount()));
        vo.setTotalDurationSeconds(defaultNumber(row.getTotalDurationSeconds()));
        vo.setVideoCount(defaultNumber(row.getVideoCount()));
        vo.setStatus(row.getStatus());
        vo.setIsHomeRecommend(row.getIsHomeRecommend());
        vo.setSort(row.getSort());
        vo.setCreatedAt(row.getCreatedAt());
        vo.setUpdatedAt(row.getUpdatedAt());
        return vo;
    }

    private HealthCourseVideoItemVO toVideoItem(HealthCourseVideo item) {
        HealthCourseVideoItemVO vo = new HealthCourseVideoItemVO();
        vo.setId(item.getId());
        vo.setCourseId(item.getCourseId());
        vo.setChapterName(item.getChapterName());
        vo.setChapterRemark(item.getChapterRemark());
        vo.setVideoUrl(item.getVideoUrl());
        vo.setDurationSeconds(item.getDurationSeconds());
        vo.setSaleType(item.getSaleType());
        vo.setSalePrice(item.getSalePrice());
        vo.setPlayCount(item.getPlayCount());
        vo.setSort(item.getSort());
        vo.setStatus(item.getStatus());
        vo.setCreatedAt(item.getCreatedAt());
        return vo;
    }

    private HealthCourseVideoDetailVO toVideoDetail(HealthCourseVideo item) {
        HealthCourseVideoDetailVO vo = new HealthCourseVideoDetailVO();
        vo.setId(item.getId());
        vo.setCourseId(item.getCourseId());
        vo.setChapterName(item.getChapterName());
        vo.setChapterRemark(item.getChapterRemark());
        vo.setVideoUrl(item.getVideoUrl());
        vo.setDurationSeconds(item.getDurationSeconds());
        vo.setSaleType(item.getSaleType());
        vo.setSalePrice(item.getSalePrice());
        vo.setPlayCount(item.getPlayCount());
        vo.setSort(item.getSort());
        vo.setStatus(item.getStatus());
        vo.setCreatedAt(item.getCreatedAt());
        vo.setUpdatedAt(item.getUpdatedAt());
        return vo;
    }

    private Integer resolveSalesCount(Integer baseSalesCount, Integer realSalesCount) {
        return defaultNumber(baseSalesCount) + defaultNumber(realSalesCount);
    }

    private Integer defaultNumber(Integer value) {
        return value == null ? 0 : value;
    }

    private String formatDuration(Integer seconds) {
        int totalSeconds = seconds == null ? 0 : seconds;
        int minutes = totalSeconds / 60;
        int remainSeconds = totalSeconds % 60;
        return minutes + ":" + String.format("%02d", remainSeconds);
    }

    private String statusText(Integer status) {
        return status != null && status == 1 ? "启用" : "禁用";
    }

    private String defaultText(String text) {
        return text == null || text.trim().isEmpty() ? "-" : text;
    }

    private String trimToNull(String text) {
        if (text == null) {
            return null;
        }
        String trimmed = text.trim();
        return trimmed.isEmpty() ? null : trimmed;
    }
}