Feature/search after before on (#9219)

* initial implementation of after, before, on search flags allowing to restrict the search to a specific day or a date range

* missed setting beforeDate in SearchParams in one place

* fixed condition when only flags are used for search without any plain terms

* changed date format used for after/before/on flags to be in ISO8601 format as suggested in PR comments, added a helper function to pad month and day with zeroes allowing the user user either format, with or without leading zeroes

* corrected expected compare to date setting for the TestParseDateFilterToTimeISO8601 test

* fixed a bug for the scenario when you only have the date flags without any terms, added a couple of tests for that scenario

* updated the date filter logic to use parameters to construct the query instead of simply appending strings together, as suggested in the pull request comments

* added search unit test using date flags

* added a helper function to create a test post with a createat date manually set, updated the test for search using date flags to create test posts with different createat dates to be able to better test the functionality

* MM-11817 Add support for after/before/on search flags with Elasticsearch

* add support to search posts to perform the search in context of the client's timezone when filtering by createat date using on: after: before: flags

* updated tests to match the new signature

3 files changed, 100 insertions, 3 deletions

diff --git a/api4/apitestlib.go b/api4/apitestlib.go
index 652a8f882..6a717faf1 100644
--- a/api4/apitestlib.go
+++ b/api4/apitestlib.go
@@ -444,6 +444,17 @@ func (me *TestHelper) CreateMessagePostWithClient(client *model.Client4, channel
 	return rpost
 }
 
+func (me *TestHelper) CreateMessagePostNoClient(channel *model.Channel, message string, createAtTime int64) *model.Post {
+	post := store.Must(me.App.Srv.Store.Post().Save(&model.Post{
+		UserId:    me.BasicUser.Id,
+		ChannelId: channel.Id,
+		Message:   message,
+		CreateAt:  createAtTime,
+	})).(*model.Post)
+
+	return post
+}
+
 func (me *TestHelper) LoginBasic() {
 	me.LoginBasicWithClient(me.Client)
 }
diff --git a/api4/post.go b/api4/post.go
index b4edc5124..014174b37 100644
--- a/api4/post.go
+++ b/api4/post.go
@@ -333,17 +333,23 @@ func searchPosts(c *Context, w http.ResponseWriter, r *http.Request) {
 	includeDeletedChannels := r.URL.Query().Get("include_deleted_channels") == "true"
 
 	props := model.StringInterfaceFromJson(r.Body)
+
 	terms, ok := props["terms"].(string)
 	if !ok || len(terms) == 0 {
 		c.SetInvalidParam("terms")
 		return
 	}
 
+	timeZoneOffset, ok := props["time_zone_offset"].(float64)
+	if !ok {
+		timeZoneOffset = 0
+	}
+
 	isOrSearch, _ := props["is_or_search"].(bool)
 
 	startTime := time.Now()
 
-	results, err := c.App.SearchPostsInTeam(terms, c.Session.UserId, c.Params.TeamId, isOrSearch, includeDeletedChannels)
+	results, err := c.App.SearchPostsInTeam(terms, c.Session.UserId, c.Params.TeamId, isOrSearch, includeDeletedChannels, int(timeZoneOffset))
 
 	elapsedTime := float64(time.Since(startTime)) / float64(time.Second)
 	metrics := c.App.Metrics
diff --git a/api4/post_test.go b/api4/post_test.go
index 910443fef..5f8cb5b31 100644
--- a/api4/post_test.go
+++ b/api4/post_test.go
@@ -17,6 +17,7 @@ import (
 
 	"github.com/mattermost/mattermost-server/app"
 	"github.com/mattermost/mattermost-server/model"
+	"github.com/mattermost/mattermost-server/utils"
 )
 
 func TestCreatePost(t *testing.T) {
@@ -1302,7 +1303,21 @@ func TestSearchPosts(t *testing.T) {
 	_ = th.CreateMessagePostWithClient(th.Client, archivedChannel, "#hashtag for post3")
 	th.Client.DeleteChannel(archivedChannel.Id)
 
-	posts, resp := Client.SearchPosts(th.BasicTeam.Id, "search", false)
+	terms := "search"
+	isOrSearch := false
+	timezoneOffset := 5
+	searchParams := model.SearchParameter{
+		Terms:          &terms,
+		IsOrSearch:     &isOrSearch,
+		TimeZoneOffset: &timezoneOffset,
+	}
+	posts, resp := Client.SearchPostsWithParams(th.BasicTeam.Id, &searchParams)
+	CheckNoError(t, resp)
+	if len(posts.Order) != 3 {
+		t.Fatal("wrong search")
+	}
+
+	posts, resp = Client.SearchPosts(th.BasicTeam.Id, "search", false)
 	CheckNoError(t, resp)
 	if len(posts.Order) != 3 {
 		t.Fatal("wrong search")
@@ -1329,7 +1344,7 @@ func TestSearchPosts(t *testing.T) {
 	th.App.UpdateConfig(func(cfg *model.Config) {
 		*cfg.TeamSettings.ExperimentalViewArchivedChannels = false
 	})
-	
+
 	posts, resp = Client.SearchPostsIncludeDeletedChannels(th.BasicTeam.Id, "#hashtag", false)
 	CheckNoError(t, resp)
 	if len(posts.Order) != 1 {
@@ -1516,6 +1531,71 @@ func TestSearchPostsFromUser(t *testing.T) {
 	}
 }
 
+func TestSearchPostsWithDateFlags(t *testing.T) {
+	th := Setup().InitBasic()
+	defer th.TearDown()
+	th.LoginBasic()
+	Client := th.Client
+
+	message := "sgtitlereview\n with return"
+	createDate := time.Date(2018, 8, 1, 5, 0, 0, 0, time.UTC)
+	_ = th.CreateMessagePostNoClient(th.BasicChannel, message, utils.MillisFromTime(createDate))
+
+	message = "other message with no return"
+	createDate = time.Date(2018, 8, 2, 5, 0, 0, 0, time.UTC)
+	_ = th.CreateMessagePostNoClient(th.BasicChannel, message, utils.MillisFromTime(createDate))
+
+	message = "other message with no return"
+	createDate = time.Date(2018, 8, 3, 5, 0, 0, 0, time.UTC)
+	_ = th.CreateMessagePostNoClient(th.BasicChannel, message, utils.MillisFromTime(createDate))
+
+	posts, _ := Client.SearchPosts(th.BasicTeam.Id, "return", false)
+	if len(posts.Order) != 3 {
+		t.Fatalf("wrong number of posts returned %v", len(posts.Order))
+	}
+
+	posts, _ = Client.SearchPosts(th.BasicTeam.Id, "on:", false)
+	if len(posts.Order) != 0 {
+		t.Fatalf("wrong number of posts returned %v", len(posts.Order))
+	}
+
+	posts, _ = Client.SearchPosts(th.BasicTeam.Id, "after:", false)
+	if len(posts.Order) != 0 {
+		t.Fatalf("wrong number of posts returned %v", len(posts.Order))
+	}
+
+	posts, _ = Client.SearchPosts(th.BasicTeam.Id, "before:", false)
+	if len(posts.Order) != 0 {
+		t.Fatalf("wrong number of posts returned %v", len(posts.Order))
+	}
+
+	posts, _ = Client.SearchPosts(th.BasicTeam.Id, "on:2018-08-01", false)
+	if len(posts.Order) != 1 {
+		t.Fatalf("wrong number of posts returned %v", len(posts.Order))
+	}
+
+	posts, _ = Client.SearchPosts(th.BasicTeam.Id, "after:2018-08-01", false)
+	resultCount := 0
+	for _, post := range posts.Posts {
+		if post.UserId == th.BasicUser.Id {
+			resultCount = resultCount + 1
+		}
+	}
+	if resultCount != 3 {
+		t.Fatalf("wrong number of posts returned %v", len(posts.Order))
+	}
+
+	posts, _ = Client.SearchPosts(th.BasicTeam.Id, "before:2018-08-02", false)
+	if len(posts.Order) != 2 {
+		t.Fatalf("wrong number of posts returned %v", len(posts.Order))
+	}
+
+	posts, _ = Client.SearchPosts(th.BasicTeam.Id, "before:2018-08-03 after:2018-08-02", false)
+	if len(posts.Order) != 2 {
+		t.Fatalf("wrong number of posts returned %v", len(posts.Order))
+	}
+}
+
 func TestGetFileInfosForPost(t *testing.T) {
 	th := Setup().InitBasic().InitSystemAdmin()
 	defer th.TearDown()