package service

import (
	"errors"
	"time"

	"gorm.io/gorm"

	"laic-backend/cache"
	"laic-backend/common"
	"laic-backend/logger"
	"laic-backend/model"
	"laic-backend/tool"
	"laic-backend/vo"
)

type AlarmService struct{}

var DefaultAlarmService = &AlarmService{}

// GetPage 告警分页列表（按所属机巢过滤）
func (s *AlarmService) GetPage(userID int64, isAdmin bool, req *vo.AlarmPageReq) (*common.PageResponse[model.Alarm], *common.BusiError) {
	db := common.DB.Model(&model.Alarm{}).Scopes(withDockFilter(userID, isAdmin))
	if req.Status != "" {
		db = db.Where("status = ?", req.Status)
	}
	if req.Level != "" {
		db = db.Where("level = ?", req.Level)
	}
	if req.DeviceType != "" {
		db = db.Where("device_type = ?", req.DeviceType)
	}
	if req.DockID != "" {
		db = db.Where("dock_id = ?", req.DockID)
	}
	if req.Keyword != "" {
		kw := "%" + req.Keyword + "%"
		db = db.Where("code LIKE ? OR message_cn LIKE ?", kw, kw)
	}

	var total int64
	if err := db.Count(&total).Error; err != nil {
		logger.ERROR("统计告警失败", err)
		return nil, common.ErrInternal
	}
	var list []model.Alarm
	if err := db.Scopes(req.Paginate).Order("id DESC").Find(&list).Error; err != nil {
		logger.ERROR("查询告警列表失败", err)
		return nil, common.ErrInternal
	}
	return common.Page(req.Pagination, total, list), nil
}

// Acknowledge 确认告警（active → acknowledged）
func (s *AlarmService) Acknowledge(userID int64, isAdmin bool, id int64) *common.BusiError {
	var alarm model.Alarm
	if err := common.DB.Scopes(withDockFilter(userID, isAdmin)).First(&alarm, id).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return common.ErrAlarmNotFound
		}
		return common.ErrInternal
	}
	if alarm.Status == "active" {
		if err := common.DB.Model(&model.Alarm{}).Where("id = ?", id).Update("status", "acknowledged").Error; err != nil {
			logger.ERROR("确认告警失败", err)
			return common.ErrInternal
		}
		broadcast("alarm.acknowledged", map[string]any{
			"id":     id,
			"dockId": alarm.DockID,
			"code":   alarm.Code,
		})
	}
	return nil
}

// Resolve 关闭告警（active/acknowledged → resolved）
func (s *AlarmService) Resolve(userID int64, isAdmin bool, id int64) *common.BusiError {
	var alarm model.Alarm
	if err := common.DB.Scopes(withDockFilter(userID, isAdmin)).First(&alarm, id).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return common.ErrAlarmNotFound
		}
		return common.ErrInternal
	}
	if alarm.Status != "resolved" {
		now := time.Now()
		if err := common.DB.Model(&model.Alarm{}).Where("id = ?", id).
			Updates(map[string]any{"status": "resolved", "resolved_at": now}).Error; err != nil {
			logger.ERROR("关闭告警失败", err)
			return common.ErrInternal
		}
		broadcast("alarm.resolved", map[string]any{
			"id":         id,
			"dockId":     alarm.DockID,
			"code":       alarm.Code,
			"resolvedAt": now,
		})
	}
	return nil
}

// SyncByState 根据设备最新 alarmCodes 做 diff，生成/关闭告警
// deviceType: dock / drone
func (s *AlarmService) SyncByState(dockID, deviceType string, codes []string) {
	key := s.alarmKey(dockID, deviceType)

	last, err := common.SetMembers(key)
	if err != nil {
		last = []string{}
	}
	lastSet := toSet(last)
	newSet := toSet(codes)

	// 新增告警 → active
	for code := range newSet {
		if !lastSet[code] {
			s.createAlarm(dockID, deviceType, code)
		}
	}
	// 移除告警 → resolved
	for code := range lastSet {
		if !newSet[code] {
			s.resolveAlarm(dockID, code)
		}
	}

	// 更新当前告警码集合
	_ = common.Delete(key)
	for _, code := range codes {
		_ = common.SetAdd(key, code)
	}
}

func (s *AlarmService) createAlarm(dockID, deviceType, code string) {
	messageCn, level := code, "critical"
	var ac model.AlarmCode
	if err := common.DB.Where("code = ?", code).First(&ac).Error; err == nil {
		messageCn, level = ac.MessageCn, ac.Level
	}

	id, err := tool.NextID()
	if err != nil {
		logger.ERROR("生成告警 ID 失败", err)
		return
	}
	now := time.Now()
	alarm := model.Alarm{
		ID:          id,
		DockID:      dockID,
		Code:        code,
		DeviceType:  deviceType,
		MessageCn:   messageCn,
		Level:       level,
		Status:      "active",
		TriggeredAt: &now,
		CreatedAt:   now,
	}
	if err := common.DB.Create(&alarm).Error; err != nil {
		logger.ERROR("写入告警失败", err)
		return
	}

	broadcast("alarm.created", map[string]any{
		"dockId": dockID,
		"alarm":  alarm,
	})
}

func (s *AlarmService) resolveAlarm(dockID, code string) {
	now := time.Now()
	res := common.DB.Model(&model.Alarm{}).Where("dock_id = ? AND code = ? AND status = 'active'", dockID, code).
		Updates(map[string]any{"status": "resolved", "resolved_at": now})
	if res.Error != nil {
		logger.ERROR("关闭告警失败", res.Error)
		return
	}
	if res.RowsAffected > 0 {
		broadcast("alarm.resolved", map[string]any{
			"dockId":     dockID,
			"code":       code,
			"resolvedAt": now,
		})
	}
}

func (s *AlarmService) alarmKey(dockID, deviceType string) string {
	if deviceType == "drone" {
		return cache.DroneAlarmKeyOf(dockID)
	}
	return cache.DockAlarmKeyOf(dockID)
}

func toSet(items []string) map[string]bool {
	set := make(map[string]bool, len(items))
	for _, it := range items {
		set[it] = true
	}
	return set
}