MM-38132: Improve Auto Responder logic (#18264)

We properly truncate the date part from the createAt time.

The SQL query is improved now to directly return the bool.

Fixed the test to properly test the feature.

https://mattermost.atlassian.net/browse/MM-38132

```release-note
NONE
```

app/auto_responder.go

@@ -13,7 +13,7 @@ import (
 
 // check if there is any auto_response type post in channel by the user in a calender day
 func (a *App) checkIfRespondedToday(createdAt int64, channelId, userId string) (bool, error) {
-	y, m, d := time.Unix(int64(model.GetTimeForMillis(createdAt).Second()), 0).Date()
+	y, m, d := model.GetTimeForMillis(createdAt).Date()
 	since := model.GetMillisForTime(time.Date(y, m, d, 0, 0, 0, 0, time.UTC))
 	return a.Srv().Store.Post().HasAutoResponsePostByUserSince(
 		model.GetPostsSinceOptions{ChannelId: channelId, Time: since},

app/auto_responder_test.go

@@ -5,6 +5,7 @@ package app
 
 import (
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -100,7 +101,7 @@ func TestSendAutoResponseIfNecessary(t *testing.T) {
 
 		savedPost, _ := th.App.CreatePost(th.Context, &model.Post{
 			ChannelId: channel.Id,
-			Message:   "zz" + model.NewId() + "a",
+			Message:   NewTestId(),
 			UserId:    th.BasicUser.Id},
 			th.BasicChannel,
 			false, true)
@@ -130,7 +131,7 @@ func TestSendAutoResponseIfNecessary(t *testing.T) {
 
 		savedPost, _ := th.App.CreatePost(th.Context, &model.Post{
 			ChannelId: channel.Id,
-			Message:   "zz" + model.NewId() + "a",
+			Message:   NewTestId(),
 			UserId:    th.BasicUser.Id},
 			th.BasicChannel,
 			false, true)
@@ -147,7 +148,7 @@ func TestSendAutoResponseIfNecessary(t *testing.T) {
 
 		savedPost, _ := th.App.CreatePost(th.Context, &model.Post{
 			ChannelId: th.BasicChannel.Id,
-			Message:   "zz" + model.NewId() + "a",
+			Message:   NewTestId(),
 			UserId:    th.BasicUser.Id},
 			th.BasicChannel,
 			false, true)
@@ -187,7 +188,7 @@ func TestSendAutoResponseIfNecessary(t *testing.T) {
 
 		savedPost, _ := th.App.CreatePost(th.Context, &model.Post{
 			ChannelId: channel.Id,
-			Message:   "zz" + model.NewId() + "a",
+			Message:   NewTestId(),
 			UserId:    botUser.Id},
 			th.BasicChannel,
 			false, true)
@@ -215,24 +216,27 @@ func TestSendAutoResponseIfNecessary(t *testing.T) {
 
 		channel := th.CreateDmChannel(receiver)
 
+		// Clean up all posts from this user.
+		// There are some dummy messages like "user joined team" etc.
+		// which needs to be cleaned up.
+		require.NoError(t, th.GetSqlStore().Post().PermanentDeleteByUser(th.BasicUser.Id))
+
 		savedPost, err := th.App.CreatePost(th.Context, &model.Post{
 			ChannelId: channel.Id,
-			Message:   NewTestId(),
-			UserId:    th.BasicUser.Id},
+			Message:   patch.NotifyProps["auto_responder_message"],
+			UserId:    receiver.Id,
+			CreateAt:  model.GetMillisForTime(time.Now().Add(-48 * time.Hour)),
+			Type:      model.PostTypeAutoResponder,
+		},
 			th.BasicChannel,
 			false, true)
-
-		assert.Nil(t, err)
+		require.Nil(t, err)
+		savedPost.CreateAt = model.GetMillisForTime(time.Now())
 
 		sent, err := th.App.SendAutoResponseIfNecessary(th.Context, channel, th.BasicUser, savedPost)
 
 		require.Nil(t, err)
 		assert.True(t, sent)
-
-		sent, err = th.App.SendAutoResponseIfNecessary(th.Context, channel, th.BasicUser, savedPost)
-
-		require.Nil(t, err)
-		assert.False(t, sent)
 	})
 }