From 4a28db044bb812a7e60e55a860b92521369bf856 Mon Sep 17 00:00:00 2001
From: Mo Kweon <kkweon@google.com>
Date: Tue, 22 Jun 2021 21:03:51 -0700
Subject: [PATCH] feat: add VideosResponseFromDB :: Database ->
 GetVideosResponse

---
 server/go.mod                        |  1 +
 server/pkg/handlers/handlers.go      | 58 ++++++++++++++++++
 server/pkg/handlers/handlers_test.go | 88 ++++++++++++++++++++++++++++
 3 files changed, 147 insertions(+)
 create mode 100644 server/pkg/handlers/handlers.go
 create mode 100644 server/pkg/handlers/handlers_test.go

diff --git a/server/go.mod b/server/go.mod
index ffebfd1b..8a6c85e9 100644
--- a/server/go.mod
+++ b/server/go.mod
@@ -6,6 +6,7 @@ require (
 	cloud.google.com/go v0.84.0 // indirect
 	github.com/daixiang0/gci v0.2.8
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
+	github.com/google/go-cmp v0.5.6
 	github.com/grpc-ecosystem/go-grpc-middleware v1.3.0
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
 	github.com/prometheus/client_golang v1.10.0
diff --git a/server/pkg/handlers/handlers.go b/server/pkg/handlers/handlers.go
new file mode 100644
index 00000000..c03a22c6
--- /dev/null
+++ b/server/pkg/handlers/handlers.go
@@ -0,0 +1,58 @@
+package handlers
+
+import (
+	"sort"
+
+	"github.com/codingpot/pr12er/server/pkg/pr12er"
+)
+
+// VideosResponseFromDB converts DB proto to GetVideosResponse.
+func VideosResponseFromDB(db *pr12er.Database) *pr12er.GetVideosResponse {
+	videos := make([]*pr12er.Video, len(db.GetPrIdToVideo()))
+	i := 0
+
+	for prID, data := range db.GetPrIdToVideo() {
+		dataVideo := data.GetVideo()
+		videos[i] = &pr12er.Video{
+			PrId:          prID,
+			Title:         dataVideo.GetVideoTitle(),
+			Link:          getYouTubeLinkFromID(dataVideo.GetVideoId()),
+			Presenter:     dataVideo.GetUploader(),
+			Category:      getCategory(data),
+			NumberOfLike:  dataVideo.GetNumberOfLikes(),
+			Keywords:      getKeywords(data),
+			NumberOfViews: dataVideo.GetNumberOfViews(),
+			PublishedDate: dataVideo.GetPublishedDate(),
+		}
+		i++
+	}
+
+	sort.Slice(videos, func(i, j int) bool {
+		return videos[i].GetPrId() < videos[j].GetPrId()
+	})
+
+	return &pr12er.GetVideosResponse{
+		Videos: videos,
+	}
+}
+
+// getKeywords returns all keywords by merging each paper's methods.
+func getKeywords(prVideo *pr12er.PrVideo) []string {
+	var ret []string
+	for _, p := range prVideo.GetPapers() {
+		for _, m := range p.GetMethods() {
+			ret = append(ret, m.GetName())
+		}
+	}
+	return ret
+}
+
+// TODO: Implement getCategory based on papers.
+func getCategory(prVideo *pr12er.PrVideo) pr12er.Category {
+	return pr12er.Category_CATEGORY_UNSPECIFIED
+}
+
+// getYouTubeLinkFromID returns the full URL.
+func getYouTubeLinkFromID(videoID string) string {
+	return "https://youtu.be/" + videoID
+}
diff --git a/server/pkg/handlers/handlers_test.go b/server/pkg/handlers/handlers_test.go
new file mode 100644
index 00000000..aa791a10
--- /dev/null
+++ b/server/pkg/handlers/handlers_test.go
@@ -0,0 +1,88 @@
+package handlers
+
+import (
+	"testing"
+
+	"github.com/codingpot/pr12er/server/pkg/pr12er"
+	"github.com/google/go-cmp/cmp"
+	"google.golang.org/protobuf/testing/protocmp"
+)
+
+// nolint:funlen
+func TestConvertToGet(t *testing.T) {
+	type args struct {
+		db *pr12er.Database
+	}
+	tests := []struct {
+		name string
+		args args
+		want *pr12er.GetVideosResponse
+	}{
+		{
+			name: "convert pr12er.Database to GetVideosResponse in sorted order",
+			args: args{
+				db: &pr12er.Database{
+					PrIdToVideo: map[int32]*pr12er.PrVideo{
+						199: {
+							PrId: 199,
+							Video: &pr12er.YouTubeVideo{
+								VideoId:       "video-id-199",
+								VideoTitle:    "Video Title",
+								NumberOfLikes: 3,
+								NumberOfViews: 4,
+							},
+						},
+						2: {
+							PrId: 2,
+							Video: &pr12er.YouTubeVideo{
+								VideoId:       "video-id-1",
+								VideoTitle:    "Video Title",
+								NumberOfLikes: 1,
+								NumberOfViews: 2,
+							},
+							Papers: []*pr12er.Paper{
+								{
+									PaperId: "paper-id-2",
+									Title:   "paper-title-2",
+									Methods: []*pr12er.Method{
+										{
+											Name: "Method 1",
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+			want: &pr12er.GetVideosResponse{
+				Videos: []*pr12er.Video{
+					{
+						PrId:          2,
+						Title:         "Video Title",
+						Link:          "https://youtu.be/video-id-1",
+						NumberOfLike:  1,
+						NumberOfViews: 2,
+						Keywords:      []string{"Method 1"},
+					},
+					{
+						PrId:          199,
+						Title:         "Video Title",
+						Link:          "https://youtu.be/video-id-199",
+						NumberOfLike:  3,
+						NumberOfViews: 4,
+					},
+				},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := VideosResponseFromDB(tt.args.db)
+			if got := cmp.Diff(tt.want, got, protocmp.Transform()); got != "" {
+				t.Error(got)
+			}
+		})
+	}
+}