package logic

import (
	"context"
	"encoding/json"
	"fmt"
	"github.com/furryboard/spider-scheduler/pkg/conf"
	"github.com/furryboard/spider-scheduler/pkg/dao"
	"github.com/furryboard/spider-scheduler/pkg/dao/model"
	"github.com/furryboard/spider-scheduler/pkg/exception"
	"github.com/furryboard/spider-scheduler/pkg/log"
	"github.com/furryboard/spider-scheduler/rpc"
	"github.com/furryboard/spider-scheduler/rpc/pb"
	"gorm.io/gorm"
	"strconv"
	"sync"
	"time"
)

// GetValidUsers 分页获取用户信息（数据库）
func GetValidUsers(page, pageSize int) ([]*model.Furry, error) {
	// 分页查询
	var furries []*model.Furry
	//tx := dao.DB().Where("status = 0").Offset((page - 1) * pageSize).Limit(pageSize).Find(&furries)
	tx := dao.DB().Offset((page - 1) * pageSize).Limit(pageSize).Find(&furries)
	if tx.Error != nil {
		return nil, exception.ErrFetchFurries("分页获取Furry列表时失败：" + tx.Error.Error())
	}
	return furries, nil
}

// GetUserInfoByUID 获取用户粉丝数 包括名称，性别，签名等
func GetUserInfoByUID(uid uint) (*pb.InfoReply_Data, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()
	info, err := rpc.SpiderCore().GetUserBasicInfo(ctx, &pb.InfoRequest{
		Uid:    uint64(uid),
		Cookie: conf.Conf.SpiderCore.BiliCookie,
	})
	if err != nil {
		return nil, exception.InternalError("获取用户信息失败：" + err.Error())
	}

	if info.Code != 200 {
		if info.Msg == "" {
			info.Msg = "Unknown"
		}
		return nil, exception.ErrFetchUserInfo(
			fmt.Sprintf("用户[%d]基础信息获取失败：%s(Code: %d)", uid, info.Msg, info.Code))
	}
	
	return info.Data, nil
}

// IsUserExistsByUID 通过UID判断用户是否存在数据库
func IsUserExistsByUID(uid uint) (bool, error) {
	var count int64
	tx := dao.DB().Model(&model.Furry{}).Where("uid = ?", uid).Count(&count)
	if tx.Error != nil {
		return false, exception.ErrFetchFurries(fmt.Sprintf("查找用户[%d]时发生错误：%s", uid, tx.Error.Error()))
	}
	if count == 0 {
		return false, nil
	} else {
		return true, nil
	}
}

// BatchGetUserInfo 批量获取用户基础信息
func BatchGetUserInfo(userIds *[]uint) []*pb.InfoReply_Data {
	poolSize := 8
	sem := make(chan struct{}, poolSize)
	defer close(sem)
	wg := sync.WaitGroup{}

	results := make(chan *pb.InfoReply_Data, len(*userIds))
	defer close(results)
	for _, uid := range *userIds {
		sem <- struct{}{}
		wg.Add(1)
		go func(uid uint) {
			<-sem
			defer wg.Done()
			info, err := GetUserInfoByUID(uid)
			if err != nil {
				log.Logger().Warnf("用户[%d]基础信息获取失败：%s。已忽略", uid, err)
				return
			}
			results <- info
			log.Logger().Debugf("获取用户[%d]基础信息成功", uid)
		}(uid)
	}
	wg.Wait()

	s := make([]*pb.InfoReply_Data, 0)
	resultLen := len(results)
	for i := 0; i < resultLen; i++ {
		s = append(s, <-results)
	}
	return s
}

func UpdateUserInfo(users []*model.Furry, infos []*pb.InfoReply_Data) (int, error) {
	// 以UID为索引转换为map
	infoMap := make(map[uint]*pb.InfoReply_Data)
	for _, info := range infos {
		infoMap[uint(info.Mid)] = info
	}
	// 检测变化
	changelogs, changes, err := createChangelogs(users, infos)
	if err != nil {
		return 0, err
	}
	if len(changelogs) == 0 { // 无变化
		return 0, nil
	}
	// 数据库事务
	err = dao.DB().Transaction(func(tx *gorm.DB) error {
		for _, changed := range changes {
			// 更新furries表
			if err = tx.Model(&model.Furry{ID: changed.ID}).Updates(changed).Error; err != nil {
				return err
			}
		}
		for _, changelog := range changelogs {
			// 插入changelogs表
			if err = tx.Create(changelog).Error; err != nil {
				return err
			}
		}
		return nil
	})
	if err != nil {
		return 0, err
	}
	return len(changelogs), nil
}

func userInfoDiff(user *model.Furry, info *pb.InfoReply_Data) (*model.Changelog, *model.Furry, error) {
	if uint64(user.UID) != info.Mid {
		return nil, nil, exception.ErrUserMismatch(fmt.Sprintf("对比用户ID不匹配：%d和%d", user.UID, info.Mid))
	}
	changelog := model.Changelog{
		Operation: "",
		Target:    strconv.FormatUint(uint64(user.UID), 10),
		Result:    "",
	}
	updated := model.Furry{
		ID: user.ID,
	}
	if user.Name != info.Name {
		result, _ := json.Marshal(map[string]string{"previous_name": user.Name, "new_name": info.Name})
		changelog.Operation = "UpdateName"
		changelog.Result = string(result)
		updated.Name = info.Name
		return &changelog, &updated, nil
	} else if info.LiveRoom != nil && user.LiveRoomID != uint(info.LiveRoom.Roomid) {
		updated.LiveRoomID = uint(info.LiveRoom.Roomid)
		changelog.Operation = "AddLiveRoom"
		changelog.Result = strconv.FormatUint(info.LiveRoom.Roomid, 10)
		return &changelog, &updated, nil
	} else {
		return nil, nil, nil
	}
}

func createChangelogs(users []*model.Furry, infos []*pb.InfoReply_Data) ([]*model.Changelog, []*model.Furry, error) {
	// 以UID为索引转换为map
	infoMap := make(map[uint]*pb.InfoReply_Data)
	for _, i := range infos {
		infoMap[uint(i.Mid)] = i
	}
	// 检测变化
	changelogs := make([]*model.Changelog, 0)
	changes := make([]*model.Furry, 0)
	for _, u := range users {
		if info, ok := infoMap[u.UID]; ok {
			changelog, changed, err := userInfoDiff(u, info)
			if err != nil {
				return nil, nil, err
			}
			if changed == nil { // 无变化
				continue
			}
			changes = append(changes, changed)
			changelogs = append(changelogs, changelog)
		}
	}
	return changelogs, changes, nil
}

// GetStatByUID 获取用户粉丝数
func GetStatByUID(uid uint) (*pb.StatReply_Data, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()
	info, err := rpc.SpiderCore().GetUserStat(ctx, &pb.StatRequest{Uid: uint64(uid)})
	if err != nil {
		return nil, exception.InternalError("获取用户信息失败：" + err.Error())
	}
	if info.Code != 200 {
		if info.Msg == "" {
			info.Msg = "Unknown"
		}
		return nil, exception.ErrFetchStat(
			fmt.Sprintf("用户[%d]粉丝数获取失败：%s(Code: %d)", uid, info.Msg, info.Code))
	}
	return info.Data, nil
}

// BatchGetUserStat 批量获取用户粉丝数
func BatchGetUserStat(uids *[]uint) []*pb.StatReply_Data {
	poolSize := 8
	sem := make(chan struct{}, poolSize)
	defer close(sem)
	wg := sync.WaitGroup{}

	results := make(chan *pb.StatReply_Data, len(*uids))
	defer close(results)
	for _, uid := range *uids {
		sem <- struct{}{}
		wg.Add(1)
		go func(uid uint) {
			<-sem
			defer wg.Done()
			stat, err := GetStatByUID(uid)
			if err != nil {
				log.Logger().Warnf("用户[%d]粉丝数获取失败：%s。已忽略", uid, err)
				return
			}
			results <- stat
			log.Logger().Debugf("获取用户[%d]粉丝数成功", uid)
		}(uid)
	}
	wg.Wait()

	s := make([]*pb.StatReply_Data, 0)
	resultLen := len(results)
	for i := 0; i < resultLen; i++ {
		s = append(s, <-results)
	}
	return s
}

func UpdateFansToDB(stats []*pb.StatReply_Data) (int, error) {
	var err error
	// 抽取必要字段转为数据库模型
	var models []*model.Fans
	for _, stat := range stats {
		models = append(models, &model.Fans{
			UID:  uint(stat.Mid),
			Fans: uint(stat.Follower),
		})
	}

	// 数据库事务
	err = dao.DB().Transaction(func(tx *gorm.DB) error {
		for _, m := range models {
			if err = tx.Create(m).Error; err != nil {
				return err
			}
		}
		return nil
	})
	if err != nil {
		return 0, err
	}
	return len(stats), nil
}

func AddUser(user *model.Furry) error {
	tx := dao.DB().Create(user)
	return tx.Error
}