MM-21357: Use typed constant for channel types (#17928)

* MM-21357: Use typed constant for channel types

https://mattermost.atlassian.net/browse/MM-21357

```release-note
- Introduced a new type ChannelType for all channel types.
- Updated the Client4.UpdateChannelPrivacy method to ChannelType.
```

* Address review comments

```release-note
NONE
```

* telemetry fix

```release-note
NONE
```

app/channel.go

@@ -725,7 +725,7 @@ func (a *App) postChannelPrivacyMessage(c *request.Context, user *model.User, ch
 		authorUsername = systemBot.Username
 	}
 
-	message := (map[string]string{
+	message := (map[model.ChannelType]string{
 		model.ChannelTypeOpen:    i18n.T("api.channel.change_channel_privacy.private_to_public"),
 		model.ChannelTypePrivate: i18n.T("api.channel.change_channel_privacy.public_to_private"),
 	})[channel.Type]
@@ -1080,7 +1080,7 @@ func (a *App) PatchChannelModerationsForChannel(channel *model.Channel, channelM
 	return buildChannelModerations(channel.Type, memberRole, guestRole, higherScopedMemberRole, higherScopedGuestRole), nil
 }
 
-func buildChannelModerations(channelType string, memberRole *model.Role, guestRole *model.Role, higherScopedMemberRole *model.Role, higherScopedGuestRole *model.Role) []*model.ChannelModeration {
+func buildChannelModerations(channelType model.ChannelType, memberRole *model.Role, guestRole *model.Role, higherScopedMemberRole *model.Role, higherScopedGuestRole *model.Role) []*model.ChannelModeration {
 	var memberPermissions, guestPermissions, higherScopedMemberPermissions, higherScopedGuestPermissions map[string]bool
 	if memberRole != nil {
 		memberPermissions = memberRole.GetChannelModeratedPermissions(channelType)

app/helper_test.go

@@ -316,7 +316,7 @@ func (th *TestHelper) CreatePrivateChannel(team *model.Team) *model.Channel {
 	return th.createChannel(team, model.ChannelTypePrivate)
 }
 
-func (th *TestHelper) createChannel(team *model.Team, channelType string, options ...ChannelOption) *model.Channel {
+func (th *TestHelper) createChannel(team *model.Team, channelType model.ChannelType, options ...ChannelOption) *model.Channel {
 	id := model.NewId()
 
 	channel := &model.Channel{

app/import_functions_test.go

@@ -610,10 +610,11 @@ func TestImportImportChannel(t *testing.T) {
 	require.NoError(t, nErr, "Failed to get team count.")
 
 	// Do an invalid channel in dry-run mode.
+	chanOpen := model.ChannelTypeOpen
 	data := ChannelImportData{
 		Team:        &teamName,
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanOpen,
 		Header:      ptrStr("Channe Header"),
 		Purpose:     ptrStr("Channel Purpose"),
 		Scheme:      &scheme1.Name,
@@ -678,8 +679,9 @@ func TestImportImportChannel(t *testing.T) {
 	assert.Equal(t, scheme1.Id, *channel.SchemeId)
 
 	// Alter all the fields of that channel.
+	cTypePr := model.ChannelTypePrivate
 	data.DisplayName = ptrStr("Chaned Disp Name")
-	data.Type = ptrStr(model.ChannelTypePrivate)
+	data.Type = &cTypePr
 	data.Header = ptrStr("New Header")
 	data.Purpose = ptrStr("New Purpose")
 	data.Scheme = &scheme2.Name
@@ -874,11 +876,12 @@ func TestImportImportUser(t *testing.T) {
 	require.Nil(t, appErr, "Failed to get team from database.")
 
 	channelName := model.NewId()
+	chanTypeOpen := model.ChannelTypeOpen
 	th.App.importChannel(th.Context, &ChannelImportData{
 		Team:        &teamName,
 		Name:        &channelName,
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanTypeOpen,
 	}, false)
 	channel, appErr := th.App.GetChannelByName(channelName, team.Id, false)
 	require.Nil(t, appErr, "Failed to get channel from database.")
@@ -1396,7 +1399,7 @@ func TestImportImportUser(t *testing.T) {
 		Team:        &teamName,
 		Name:        ptrStr(model.NewId()),
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanTypeOpen,
 		Header:      ptrStr("Channe Header"),
 		Purpose:     ptrStr("Channel Purpose"),
 	}
@@ -1939,11 +1942,12 @@ func TestImportimportMultiplePostLines(t *testing.T) {
 
 	// Create a Channel.
 	channelName := model.NewId()
+	chanTypeOpen := model.ChannelTypeOpen
 	th.App.importChannel(th.Context, &ChannelImportData{
 		Team:        &teamName,
 		Name:        &channelName,
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanTypeOpen,
 	}, false)
 	channel, err := th.App.GetChannelByName(channelName, team.Id, false)
 	require.Nil(t, err, "Failed to get channel from database.")
@@ -2418,7 +2422,7 @@ func TestImportimportMultiplePostLines(t *testing.T) {
 		Team:        &teamName2,
 		Name:        &channelName,
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanTypeOpen,
 	}, false)
 	_, err = th.App.GetChannelByName(channelName, team2.Id, false)
 	require.Nil(t, err, "Failed to get channel from database.")
@@ -2477,11 +2481,12 @@ func TestImportImportPost(t *testing.T) {
 
 	// Create a Channel.
 	channelName := model.NewId()
+	chanTypeOpen := model.ChannelTypeOpen
 	th.App.importChannel(th.Context, &ChannelImportData{
 		Team:        &teamName,
 		Name:        &channelName,
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanTypeOpen,
 	}, false)
 	channel, appErr := th.App.GetChannelByName(channelName, team.Id, false)
 	require.Nil(t, appErr, "Failed to get channel from database.")
@@ -3920,11 +3925,12 @@ func TestImportPostAndRepliesWithAttachments(t *testing.T) {
 
 	// Create a Channel.
 	channelName := model.NewId()
+	chanTypeOpen := model.ChannelTypeOpen
 	th.App.importChannel(th.Context, &ChannelImportData{
 		Team:        &teamName,
 		Name:        &channelName,
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanTypeOpen,
 	}, false)
 	_, appErr = th.App.GetChannelByName(channelName, team.Id, false)
 	require.Nil(t, appErr, "Failed to get channel from database.")
@@ -4195,11 +4201,12 @@ func TestZippedImportPostAndRepliesWithAttachments(t *testing.T) {
 
 	// Create a Channel.
 	channelName := model.NewId()
+	chanTypeOpen := model.ChannelTypeOpen
 	th.App.importChannel(th.Context, &ChannelImportData{
 		Team:        &teamName,
 		Name:        &channelName,
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanTypeOpen,
 	}, false)
 	_, appErr = th.App.GetChannelByName(channelName, team.Id, false)
 	require.Nil(t, appErr, "Failed to get channel from database.")

app/import_test.go

@@ -70,7 +70,7 @@ func AssertAllPostsCount(t *testing.T, a *App, initialCount int64, change int64,
 	require.Equal(t, initialCount+change, result, "Did not find the expected number of posts.")
 }
 
-func AssertChannelCount(t *testing.T, a *App, channelType string, expectedCount int64) {
+func AssertChannelCount(t *testing.T, a *App, channelType model.ChannelType, expectedCount int64) {
 	count, err := a.Srv().Store.Channel().AnalyticsTypeCount("", channelType)
 	require.Equalf(t, expectedCount, count, "Channel count of type: %v. Expected: %v, Got: %v", channelType, expectedCount, count)
 	require.NoError(t, err, "Failed to get channel count.")

app/import_types.go

@@ -34,13 +34,13 @@ type TeamImportData struct {
 }
 
 type ChannelImportData struct {
-	Team        *string `json:"team"`
-	Name        *string `json:"name"`
-	DisplayName *string `json:"display_name"`
-	Type        *string `json:"type"`
-	Header      *string `json:"header,omitempty"`
-	Purpose     *string `json:"purpose,omitempty"`
-	Scheme      *string `json:"scheme,omitempty"`
+	Team        *string            `json:"team"`
+	Name        *string            `json:"name"`
+	DisplayName *string            `json:"display_name"`
+	Type        *model.ChannelType `json:"type"`
+	Header      *string            `json:"header,omitempty"`
+	Purpose     *string            `json:"purpose,omitempty"`
+	Scheme      *string            `json:"scheme,omitempty"`
 }
 
 type UserImportData struct {

app/import_validators_test.go

@@ -357,11 +357,12 @@ func TestImportValidateTeamImportData(t *testing.T) {
 func TestImportValidateChannelImportData(t *testing.T) {
 
 	// Test with minimum required valid properties.
+	chanTypeOpen := model.ChannelTypeOpen
 	data := ChannelImportData{
 		Team:        ptrStr("teamname"),
 		Name:        ptrStr("channelname"),
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanTypeOpen,
 	}
 	err := validateChannelImportData(&data)
 	require.Nil(t, err, "Validation failed but should have been valid.")
@@ -370,7 +371,7 @@ func TestImportValidateChannelImportData(t *testing.T) {
 	data = ChannelImportData{
 		Name:        ptrStr("channelname"),
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanTypeOpen,
 	}
 	err = validateChannelImportData(&data)
 	require.NotNil(t, err, "Should have failed due to missing team.")
@@ -379,7 +380,7 @@ func TestImportValidateChannelImportData(t *testing.T) {
 	data = ChannelImportData{
 		Team:        ptrStr("teamname"),
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanTypeOpen,
 	}
 	err = validateChannelImportData(&data)
 	require.NotNil(t, err, "Should have failed due to missing name.")
@@ -400,7 +401,7 @@ func TestImportValidateChannelImportData(t *testing.T) {
 	data = ChannelImportData{
 		Team: ptrStr("teamname"),
 		Name: ptrStr("channelname"),
-		Type: ptrStr("O"),
+		Type: &chanTypeOpen,
 	}
 	err = validateChannelImportData(&data)
 	require.NotNil(t, err, "Should have failed due to missing display_name.")
@@ -422,11 +423,13 @@ func TestImportValidateChannelImportData(t *testing.T) {
 	err = validateChannelImportData(&data)
 	require.NotNil(t, err, "Should have failed due to missing type.")
 
-	data.Type = ptrStr("A")
+	invalidType := model.ChannelType("A")
+	data.Type = &invalidType
 	err = validateChannelImportData(&data)
 	require.NotNil(t, err, "Should have failed due to invalid type.")
 
-	data.Type = ptrStr("P")
+	chanTypePr := model.ChannelTypePrivate
+	data.Type = &chanTypePr
 	err = validateChannelImportData(&data)
 	require.Nil(t, err, "Should have succeeded with valid type.")
 
@@ -435,7 +438,7 @@ func TestImportValidateChannelImportData(t *testing.T) {
 		Team:        ptrStr("teamname"),
 		Name:        ptrStr("channelname"),
 		DisplayName: ptrStr("Display Name"),
-		Type:        ptrStr("O"),
+		Type:        &chanTypeOpen,
 		Header:      ptrStr("Channel Header Here"),
 		Purpose:     ptrStr("Channel Purpose Here"),
 	}

app/notification_push.go

@@ -161,7 +161,7 @@ func (a *App) sendPushNotification(notification *PostNotification, user *model.U
 }
 
 func (a *App) getPushNotificationMessage(contentsConfig, postMessage string, explicitMention, channelWideMention,
-	hasFiles bool, senderName, channelType, replyToThreadType string, userLocale i18n.TranslateFunc) string {
+	hasFiles bool, senderName string, channelType model.ChannelType, replyToThreadType string, userLocale i18n.TranslateFunc) string {
 
 	// If the post only has images then push an appropriate message
 	if postMessage == "" && hasFiles {

app/notification_push_test.go

@@ -573,7 +573,7 @@ func TestGetPushNotificationMessage(t *testing.T) {
 		replyToThreadType        string
 		Locale                   string
 		PushNotificationContents string
-		ChannelType              string
+		ChannelType              model.ChannelType
 
 		ExpectedMessage string
 	}{

app/slashcommands/auto_channels.go

@@ -19,7 +19,7 @@ type AutoChannelCreator struct {
 	DisplayNameCharset string
 	NameLen            utils.Range
 	NameCharset        string
-	ChannelType        string
+	ChannelType        model.ChannelType
 }
 
 func NewAutoChannelCreator(a *app.App, team *model.Team, userID string) *AutoChannelCreator {

app/slashcommands/helper_test.go

@@ -247,7 +247,7 @@ func (th *TestHelper) createPrivateChannel(team *model.Team) *model.Channel {
 	return th.createChannel(team, model.ChannelTypePrivate)
 }
 
-func (th *TestHelper) createChannel(team *model.Team, channelType string, options ...ChannelOption) *model.Channel {
+func (th *TestHelper) createChannel(team *model.Team, channelType model.ChannelType, options ...ChannelOption) *model.Channel {
 	id := model.NewId()
 
 	channel := &model.Channel{
@@ -288,7 +288,7 @@ func (th *TestHelper) createChannel(team *model.Team, channelType string, option
 	return channel
 }
 
-func (th *TestHelper) createChannelWithAnotherUser(team *model.Team, channelType, userID string) *model.Channel {
+func (th *TestHelper) createChannelWithAnotherUser(team *model.Team, channelType model.ChannelType, userID string) *model.Channel {
 	id := model.NewId()
 
 	channel := &model.Channel{