[MM-414] Code refactoring

Author: raghavaggarwal2308

server/welcomebot.go

@@ -10,6 +10,11 @@ import (
 	"github.com/mattermost/mattermost-server/v6/model"
 )
 
+const (
+	defaultPerPage = 100
+	defaultPage    = 0
+)
+
 func (p *Plugin) constructMessageTemplate(userID, teamID string) *MessageTemplate {
 	data := &MessageTemplate{}
 	var err *model.AppError
@@ -229,13 +234,12 @@ func (p *Plugin) processActionMessage(messageTemplate MessageTemplate, action *A
 
 func (p *Plugin) joinChannel(action *Action, channelName string) {
 	if channelName == "*" {
-		perPage := 100
-		page := 0
+		page := defaultPage
 		for {
-			// Adding user to all the public channels only in case of all i.e. *
-			channels, appErr := p.API.GetPublicChannelsForTeam(action.Context.TeamID, page, perPage)
-			if appErr != nil {
-				p.API.LogError("Failed to get all the public channels for the team", "team_id", action.Context.TeamID)
+			// Adding user to all the public channels when channel name in '*' (i.e. all)
+			channels, err := p.client.Channel.ListPublicChannelsForTeam(action.Context.TeamID, page, defaultPerPage)
+			if err != nil {
+				p.client.Log.Error("Failed to get all the public channels for the team", "team_id", action.Context.TeamID, "error", err.Error())
 				return
 			}
 
@@ -244,21 +248,21 @@ func (p *Plugin) joinChannel(action *Action, channelName string) {
 			}
 
 			for _, channel := range channels {
-				if _, err := p.API.AddChannelMember(channel.Id, action.Context.UserID); err != nil {
-					p.API.LogError("Couldn't add user to the channel", "user_id", action.Context.UserID, "channel_id", channel.Id)
+				if _, err := p.client.Channel.AddMember(channel.Id, action.Context.UserID); err != nil {
+					p.client.Log.Error("Couldn't add user to the channel", "user_id", action.Context.UserID, "channel_id", channel.Id, "error", err.Error())
 					return
 				}
 			}
 			page++
 		}
 	} else {
-		if channel, err := p.API.GetChannelByName(action.Context.TeamID, channelName, false); err == nil {
-			if _, err := p.API.AddChannelMember(channel.Id, action.Context.UserID); err != nil {
-				p.API.LogError("Couldn't add user to the channel, continuing to next channel", "user_id", action.Context.UserID, "channel_id", channel.Id)
+		if channel, err := p.client.Channel.GetByName(action.Context.TeamID, channelName, false); err == nil {
+			if _, err = p.client.Channel.AddMember(channel.Id, action.Context.UserID); err != nil {
+				p.client.Log.Error("Couldn't add user to the channel, continuing to next channel", "user_id", action.Context.UserID, "channel_id", channel.Id, "error", err.Error())
 				return
 			}
 		} else {
-			p.API.LogError("failed to get channel, continuing to the next channel", "channel_name", channelName, "user_id", action.Context.UserID)
+			p.client.Log.Error("failed to get channel, continuing to the next channel", "channel_name", channelName, "user_id", action.Context.UserID, "error", err.Error())
 		}
 	}
 }