环信 聊天 插入时间显示

func formatMessage(_ messages: [EMMessage]) -> [LXChatMsgModel] {
        var results = [LXChatMsgModel]()
        
        for msg in messages {
            let time = TimeInterval(msg.timestamp)
            
            let diff = (lastMsgTimeTag - time) / 1000
            if diff > 300 ||
                diff < -300 {
                let timeModel = LXChatMsgModel()
                timeModel.timeStr = LXDateHelper.messageTimeToNowFormat(timestamp: Double(msg.timestamp))
                timeModel.modelType = .time
                
                results.append(timeModel)
                
                self.lastMsgTimeTag = TimeInterval(msg.timestamp)
            }
            
            let model = LXChatMsgModel(message: msg)
            results.append(model)
        }
        return results
    }

class func messageTimeToNowFormat(timestamp: Double) -> String {
        let currentTime = Date().timeIntervalSince1970
        
        let timeSta:TimeInterval = TimeInterval(timestamp / 1000)
        
        //时间差
        let reduceTime : TimeInterval = currentTime - timeSta
        
        var format: String = "HH:mm"
        
        let hours = Int(reduceTime / 3600)
       if hours < 48 {
            let timeDate = Date(timeIntervalSince1970: timeSta)
            if timeDate.isToday {
                format = "HH:mm"
            }else if timeDate.isYesterday {
                format = "昨天 HH:mm"
            } else {
                format = "EEEE HH:mm"
            }
        } else {
            let days = Int(reduceTime / 3600 / 24)
            if days < 7 {
                format = "EEEE HH:mm"
            } else {
                format = "yyyy年MM月dd日 HH:mm"
            }
        }
        
        let date = Date(timeIntervalSince1970: timeSta)
        let dfmatter = DateFormatter()
        dfmatter.dateFormat = format
        return dfmatter.string(from: date)
    }