refactor: Use Firestore struct tags for pairings

database.go

@@ -177,8 +177,13 @@ func (f *FirestoreAPIAuthDB) GetToken(ctx context.Context, path string) (string,
 	return token.Value, nil
 }
 
+type Pairing struct {
+	Value     int   `firestore:"value"`
+	Timestamp int64 `firestore:"timestamp"`
+}
+
 type PairingsDB interface {
-	SetNumPairings(ctx context.Context, timestamp int, numPairings int) error
+	SetNumPairings(ctx context.Context, pairing Pairing) error
 	GetTotalPairingsDuringLastWeek(ctx context.Context) (int, error)
 }
 
@@ -187,13 +192,10 @@ type FirestorePairingsDB struct {
 	client *firestore.Client
 }
 
-func (f *FirestorePairingsDB) SetNumPairings(ctx context.Context, timestamp int, numPairings int) error {
-	timestampAsString := strconv.Itoa(timestamp)
+func (f *FirestorePairingsDB) SetNumPairings(ctx context.Context, pairing Pairing) error {
+	timestampAsString := strconv.FormatInt(pairing.Timestamp, 10)
 
-	_, err := f.client.Collection("pairings").Doc(timestampAsString).Set(ctx, map[string]interface{}{
-		"value":     numPairings,
-		"timestamp": timestamp,
-	})
+	_, err := f.client.Collection("pairings").Doc(timestampAsString).Set(ctx, pairing)
 	return err
 }
 
@@ -213,11 +215,15 @@ func (f *FirestorePairingsDB) GetTotalPairingsDuringLastWeek(ctx context.Context
 			return 0, err
 		}
 
-		dailyPairings := int(doc.Data()["value"].(int64))
+		var pairing Pairing
+		if err = doc.DataTo(&pairing); err != nil {
+			log.Printf("Skipping %q: %s", doc.Ref.Path, err)
+			continue
+		}
 
-		log.Println("The timestamp is: ", doc.Data()["timestamp"])
+		log.Println("The timestamp is: ", pairing.Timestamp)
 
-		totalPairings += dailyPairings
+		totalPairings += pairing.Value
 	}
 
 	return totalPairings, nil

database_test.go

@@ -8,8 +8,10 @@ import (
 	"math/big"
 	"strconv"
 	"testing"
+	"time"
 
 	"cloud.google.com/go/firestore"
+	"github.com/recursecenter/pairing-bot/internal/assert"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 )
@@ -206,3 +208,33 @@ func TestFirestoreAuthDB(t *testing.T) {
 		}
 	})
 }
+
+func TestFirestorePairingsDB(t *testing.T) {
+	t.Run("round trip weekly pairings", func(t *testing.T) {
+		ctx := context.Background()
+		projectID := fakeProjectID(t)
+
+		client := testFirestoreClient(t, ctx, projectID)
+		pairings := &FirestorePairingsDB{client}
+
+		// Entries representing pairings for each day of the week
+		for i := 6; i >= 0; i-- {
+			err := pairings.SetNumPairings(ctx, Pairing{
+				Value:     5,
+				Timestamp: time.Now().Add(-time.Duration(i) * 24 * time.Hour).Unix(),
+			})
+			if err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		expected := 35
+
+		actual, err := pairings.GetTotalPairingsDuringLastWeek(ctx)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		assert.Equal(t, actual, expected)
+	})
+}

pairing_bot.go

@@ -219,10 +219,12 @@ func (pl *PairingLogic) match(w http.ResponseWriter, r *http.Request) {
 
 	log.Printf("Pairing Bot paired up %d recursers today", numRecursersPairedUp)
 
-	numPairings := numRecursersPairedUp / 2
+	pairing := Pairing{
+		Value:     numRecursersPairedUp / 2,
+		Timestamp: time.Now().Unix(),
+	}
 
-	timestamp := time.Now().Unix()
-	if err := pl.pdb.SetNumPairings(ctx, int(timestamp), numPairings); err != nil {
+	if err := pl.pdb.SetNumPairings(ctx, pairing); err != nil {
 		log.Printf("Failed to record today's pairings: %s", err)
 	}
 }