package service

import (
	"encoding/json"
	"errors"
	"strings"
	"time"

	"github.com/google/uuid"
	"github.com/mhsanaei/3x-ui/v3/database"
	"github.com/mhsanaei/3x-ui/v3/database/model"
	"github.com/mhsanaei/3x-ui/v3/util/common"
	"github.com/mhsanaei/3x-ui/v3/xray"

	"gorm.io/gorm"
)

type ClientWithAttachments struct {
	model.ClientRecord
	InboundIds []int               `json:"inboundIds"`
	Traffic    *xray.ClientTraffic `json:"traffic,omitempty"`
}

func clientKeyForProtocol(p model.Protocol, rec *model.ClientRecord) string {
	if rec == nil {
		return ""
	}
	switch p {
	case model.Trojan:
		return rec.Password
	case model.Shadowsocks:
		return rec.Email
	case model.Hysteria, model.Hysteria2:
		return rec.Auth
	default:
		return rec.UUID
	}
}

type ClientService struct{}

func (s *ClientService) SyncInbound(tx *gorm.DB, inboundId int, clients []model.Client) error {
	if tx == nil {
		tx = database.GetDB()
	}

	if err := tx.Where("inbound_id = ?", inboundId).Delete(&model.ClientInbound{}).Error; err != nil {
		return err
	}

	for i := range clients {
		c := clients[i]
		email := strings.TrimSpace(c.Email)
		if email == "" {
			continue
		}

		incoming := c.ToRecord()
		row := &model.ClientRecord{}
		err := tx.Where("email = ?", email).First(row).Error
		if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
			return err
		}
		if errors.Is(err, gorm.ErrRecordNotFound) {
			if err := tx.Create(incoming).Error; err != nil {
				return err
			}
			row = incoming
		} else {
			row.UUID = incoming.UUID
			row.Password = incoming.Password
			row.Auth = incoming.Auth
			row.Flow = incoming.Flow
			row.Security = incoming.Security
			row.Reverse = incoming.Reverse
			row.SubID = incoming.SubID
			row.LimitIP = incoming.LimitIP
			row.TotalGB = incoming.TotalGB
			row.ExpiryTime = incoming.ExpiryTime
			row.Enable = incoming.Enable
			row.TgID = incoming.TgID
			row.Comment = incoming.Comment
			row.Reset = incoming.Reset
			if incoming.CreatedAt > 0 && (row.CreatedAt == 0 || incoming.CreatedAt < row.CreatedAt) {
				row.CreatedAt = incoming.CreatedAt
			}
			if incoming.UpdatedAt > row.UpdatedAt {
				row.UpdatedAt = incoming.UpdatedAt
			}
			if err := tx.Save(row).Error; err != nil {
				return err
			}
		}

		link := model.ClientInbound{
			ClientId:     row.Id,
			InboundId:    inboundId,
			FlowOverride: c.Flow,
		}
		if err := tx.Create(&link).Error; err != nil {
			return err
		}
	}
	return nil
}

func (s *ClientService) DetachInbound(tx *gorm.DB, inboundId int) error {
	if tx == nil {
		tx = database.GetDB()
	}
	return tx.Where("inbound_id = ?", inboundId).Delete(&model.ClientInbound{}).Error
}

func (s *ClientService) ListForInbound(tx *gorm.DB, inboundId int) ([]model.Client, error) {
	if tx == nil {
		tx = database.GetDB()
	}
	type joinedRow struct {
		model.ClientRecord
		FlowOverride string
	}
	var rows []joinedRow
	err := tx.Table("clients").
		Select("clients.*, client_inbounds.flow_override AS flow_override").
		Joins("JOIN client_inbounds ON client_inbounds.client_id = clients.id").
		Where("client_inbounds.inbound_id = ?", inboundId).
		Order("clients.id ASC").
		Find(&rows).Error
	if err != nil {
		return nil, err
	}

	out := make([]model.Client, 0, len(rows))
	for i := range rows {
		c := rows[i].ToClient()
		if rows[i].FlowOverride != "" {
			c.Flow = rows[i].FlowOverride
		}
		out = append(out, *c)
	}
	return out, nil
}

func (s *ClientService) GetRecordByEmail(tx *gorm.DB, email string) (*model.ClientRecord, error) {
	if tx == nil {
		tx = database.GetDB()
	}
	row := &model.ClientRecord{}
	err := tx.Where("email = ?", email).First(row).Error
	if err != nil {
		return nil, err
	}
	return row, nil
}

func (s *ClientService) GetInboundIdsForEmail(tx *gorm.DB, email string) ([]int, error) {
	if tx == nil {
		tx = database.GetDB()
	}
	var ids []int
	err := tx.Table("client_inbounds").
		Select("client_inbounds.inbound_id").
		Joins("JOIN clients ON clients.id = client_inbounds.client_id").
		Where("clients.email = ?", email).
		Scan(&ids).Error
	if err != nil {
		return nil, err
	}
	return ids, nil
}

func (s *ClientService) GetByID(id int) (*model.ClientRecord, error) {
	row := &model.ClientRecord{}
	if err := database.GetDB().Where("id = ?", id).First(row).Error; err != nil {
		return nil, err
	}
	return row, nil
}

func (s *ClientService) GetInboundIdsForRecord(id int) ([]int, error) {
	var ids []int
	err := database.GetDB().Table("client_inbounds").
		Where("client_id = ?", id).
		Order("inbound_id ASC").
		Pluck("inbound_id", &ids).Error
	if err != nil {
		return nil, err
	}
	return ids, nil
}

func (s *ClientService) List() ([]ClientWithAttachments, error) {
	db := database.GetDB()
	var rows []model.ClientRecord
	if err := db.Order("id ASC").Find(&rows).Error; err != nil {
		return nil, err
	}
	if len(rows) == 0 {
		return []ClientWithAttachments{}, nil
	}

	clientIds := make([]int, 0, len(rows))
	emails := make([]string, 0, len(rows))
	for i := range rows {
		clientIds = append(clientIds, rows[i].Id)
		if rows[i].Email != "" {
			emails = append(emails, rows[i].Email)
		}
	}

	var links []model.ClientInbound
	if err := db.Where("client_id IN ?", clientIds).Find(&links).Error; err != nil {
		return nil, err
	}
	attachments := make(map[int][]int, len(rows))
	for _, l := range links {
		attachments[l.ClientId] = append(attachments[l.ClientId], l.InboundId)
	}

	trafficByEmail := make(map[string]*xray.ClientTraffic, len(emails))
	if len(emails) > 0 {
		var stats []xray.ClientTraffic
		if err := db.Where("email IN ?", emails).Find(&stats).Error; err != nil {
			return nil, err
		}
		for i := range stats {
			trafficByEmail[stats[i].Email] = &stats[i]
		}
	}

	out := make([]ClientWithAttachments, 0, len(rows))
	for i := range rows {
		out = append(out, ClientWithAttachments{
			ClientRecord: rows[i],
			InboundIds:   attachments[rows[i].Id],
			Traffic:      trafficByEmail[rows[i].Email],
		})
	}
	return out, nil
}

type ClientCreatePayload struct {
	Client     model.Client `json:"client"`
	InboundIds []int        `json:"inboundIds"`
}

func (s *ClientService) Create(inboundSvc *InboundService, payload *ClientCreatePayload) (bool, error) {
	if payload == nil {
		return false, common.NewError("empty payload")
	}
	client := payload.Client
	if strings.TrimSpace(client.Email) == "" {
		return false, common.NewError("client email is required")
	}
	if len(payload.InboundIds) == 0 {
		return false, common.NewError("at least one inbound is required")
	}

	if client.SubID == "" {
		client.SubID = uuid.NewString()
	}
	if !client.Enable {
		client.Enable = true
	}
	now := time.Now().UnixMilli()
	if client.CreatedAt == 0 {
		client.CreatedAt = now
	}
	client.UpdatedAt = now

	existing := &model.ClientRecord{}
	err := database.GetDB().Where("email = ?", client.Email).First(existing).Error
	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
		return false, err
	}
	emailTaken := !errors.Is(err, gorm.ErrRecordNotFound)
	if emailTaken {
		if existing.SubID == "" || existing.SubID != client.SubID {
			return false, common.NewError("email already in use:", client.Email)
		}
	}

	needRestart := false
	for _, ibId := range payload.InboundIds {
		inbound, getErr := inboundSvc.GetInbound(ibId)
		if getErr != nil {
			return needRestart, getErr
		}
		if err := s.fillProtocolDefaults(&client, inbound.Protocol); err != nil {
			return needRestart, err
		}
		settingsPayload, mErr := json.Marshal(map[string][]model.Client{"clients": {client}})
		if mErr != nil {
			return needRestart, mErr
		}
		nr, addErr := inboundSvc.AddInboundClient(&model.Inbound{
			Id:       ibId,
			Settings: string(settingsPayload),
		})
		if addErr != nil {
			return needRestart, addErr
		}
		if nr {
			needRestart = true
		}
	}
	return needRestart, nil
}

func (s *ClientService) fillProtocolDefaults(c *model.Client, p model.Protocol) error {
	switch p {
	case model.VMESS, model.VLESS:
		if c.ID == "" {
			c.ID = uuid.NewString()
		}
	case model.Trojan, model.Shadowsocks:
		if c.Password == "" {
			c.Password = strings.ReplaceAll(uuid.NewString(), "-", "")
		}
	case model.Hysteria, model.Hysteria2:
		if c.Auth == "" {
			c.Auth = strings.ReplaceAll(uuid.NewString(), "-", "")
		}
	}
	return nil
}

func (s *ClientService) Update(inboundSvc *InboundService, id int, updated model.Client) (bool, error) {
	existing, err := s.GetByID(id)
	if err != nil {
		return false, err
	}
	inboundIds, err := s.GetInboundIdsForRecord(id)
	if err != nil {
		return false, err
	}

	if strings.TrimSpace(updated.Email) == "" {
		return false, common.NewError("client email is required")
	}
	if updated.SubID == "" {
		updated.SubID = existing.SubID
	}
	if updated.SubID == "" {
		updated.SubID = uuid.NewString()
	}
	updated.UpdatedAt = time.Now().UnixMilli()
	if updated.CreatedAt == 0 {
		updated.CreatedAt = existing.CreatedAt
	}

	needRestart := false
	for _, ibId := range inboundIds {
		inbound, getErr := inboundSvc.GetInbound(ibId)
		if getErr != nil {
			return needRestart, getErr
		}
		oldKey := clientKeyForProtocol(inbound.Protocol, existing)
		if oldKey == "" {
			continue
		}
		if err := s.fillProtocolDefaults(&updated, inbound.Protocol); err != nil {
			return needRestart, err
		}
		settingsPayload, mErr := json.Marshal(map[string][]model.Client{"clients": {updated}})
		if mErr != nil {
			return needRestart, mErr
		}
		nr, upErr := inboundSvc.UpdateInboundClient(&model.Inbound{
			Id:       ibId,
			Settings: string(settingsPayload),
		}, oldKey)
		if upErr != nil {
			return needRestart, upErr
		}
		if nr {
			needRestart = true
		}
	}
	return needRestart, nil
}

func (s *ClientService) Delete(inboundSvc *InboundService, id int, keepTraffic bool) (bool, error) {
	existing, err := s.GetByID(id)
	if err != nil {
		return false, err
	}
	inboundIds, err := s.GetInboundIdsForRecord(id)
	if err != nil {
		return false, err
	}

	needRestart := false
	for _, ibId := range inboundIds {
		inbound, getErr := inboundSvc.GetInbound(ibId)
		if getErr != nil {
			return needRestart, getErr
		}
		key := clientKeyForProtocol(inbound.Protocol, existing)
		if key == "" {
			continue
		}
		nr, delErr := inboundSvc.DelInboundClient(ibId, key)
		if delErr != nil {
			return needRestart, delErr
		}
		if nr {
			needRestart = true
		}
	}

	db := database.GetDB()
	if err := db.Where("client_id = ?", id).Delete(&model.ClientInbound{}).Error; err != nil {
		return needRestart, err
	}
	if !keepTraffic && existing.Email != "" {
		if err := db.Where("email = ?", existing.Email).Delete(&xray.ClientTraffic{}).Error; err != nil {
			return needRestart, err
		}
		if err := db.Where("client_email = ?", existing.Email).Delete(&model.InboundClientIps{}).Error; err != nil {
			return needRestart, err
		}
	}
	if err := db.Delete(&model.ClientRecord{}, id).Error; err != nil {
		return needRestart, err
	}
	return needRestart, nil
}

func (s *ClientService) Attach(inboundSvc *InboundService, id int, inboundIds []int) (bool, error) {
	existing, err := s.GetByID(id)
	if err != nil {
		return false, err
	}
	currentIds, err := s.GetInboundIdsForRecord(id)
	if err != nil {
		return false, err
	}
	have := make(map[int]struct{}, len(currentIds))
	for _, x := range currentIds {
		have[x] = struct{}{}
	}

	clientWire := existing.ToClient()
	clientWire.UpdatedAt = time.Now().UnixMilli()

	needRestart := false
	for _, ibId := range inboundIds {
		if _, attached := have[ibId]; attached {
			continue
		}
		inbound, getErr := inboundSvc.GetInbound(ibId)
		if getErr != nil {
			return needRestart, getErr
		}
		copyClient := *clientWire
		if err := s.fillProtocolDefaults(&copyClient, inbound.Protocol); err != nil {
			return needRestart, err
		}
		settingsPayload, mErr := json.Marshal(map[string][]model.Client{"clients": {copyClient}})
		if mErr != nil {
			return needRestart, mErr
		}
		nr, addErr := inboundSvc.AddInboundClient(&model.Inbound{
			Id:       ibId,
			Settings: string(settingsPayload),
		})
		if addErr != nil {
			return needRestart, addErr
		}
		if nr {
			needRestart = true
		}
	}
	return needRestart, nil
}

func (s *ClientService) Detach(inboundSvc *InboundService, id int, inboundIds []int) (bool, error) {
	existing, err := s.GetByID(id)
	if err != nil {
		return false, err
	}
	currentIds, err := s.GetInboundIdsForRecord(id)
	if err != nil {
		return false, err
	}
	have := make(map[int]struct{}, len(currentIds))
	for _, x := range currentIds {
		have[x] = struct{}{}
	}

	needRestart := false
	for _, ibId := range inboundIds {
		if _, attached := have[ibId]; !attached {
			continue
		}
		inbound, getErr := inboundSvc.GetInbound(ibId)
		if getErr != nil {
			return needRestart, getErr
		}
		key := clientKeyForProtocol(inbound.Protocol, existing)
		if key == "" {
			continue
		}
		nr, delErr := inboundSvc.DelInboundClient(ibId, key)
		if delErr != nil {
			return needRestart, delErr
		}
		if nr {
			needRestart = true
		}
	}
	return needRestart, nil
}