Allow printing match statistics

cmd/bgammon-server/database.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"log"
+	"time"
 
 	"code.rocket9labs.com/tslocum/bgammon"
 	"github.com/jackc/pgx/v5"
@@ -82,3 +83,71 @@ func recordGameResult(conn *pgx.Conn, g bgammon.Game) error {
 	_, err = tx.Exec(context.Background(), "INSERT INTO game (started, ended, winner, player1, player2) VALUES ($1, $2, $3, $4, $5)", g.Started.Unix(), g.Ended.Unix(), g.Winner, g.Player1.Name, g.Player2.Name)
 	return err
 }
+
+type serverStatsEntry struct {
+	Date  string
+	Games int
+}
+
+type serverStatsResult struct {
+	History []*serverStatsEntry
+}
+
+func serverStats(conn *pgx.Conn, tz *time.Location) (*serverStatsResult, error) {
+	tx, err := begin(conn)
+	if err != nil {
+		return nil, err
+	}
+	defer tx.Commit(context.Background())
+
+	var earliestGame int64
+	rows, err := tx.Query(context.Background(), "SELECT started FROM game ORDER BY started ASC LIMIT 1")
+	if err != nil {
+		return nil, err
+	}
+	for rows.Next() {
+		if err != nil {
+			continue
+		}
+		err = rows.Scan(&earliestGame)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	result := &serverStatsResult{}
+	earliest := midnight(time.Unix(earliestGame, 0).In(tz))
+	rangeStart, rangeEnd := earliest.Unix(), earliest.AddDate(0, 0, 1).Unix()
+	var count int
+	for {
+		rows, err := tx.Query(context.Background(), "SELECT COUNT(*) FROM game WHERE started >= $1 AND started < $2", rangeStart, rangeEnd)
+		if err != nil {
+			return nil, err
+		}
+		for rows.Next() {
+			if err != nil {
+				continue
+			}
+			err = rows.Scan(&count)
+		}
+		if err != nil {
+			return nil, err
+		}
+
+		result.History = append(result.History, &serverStatsEntry{
+			Date:  earliest.Format("2006-01-02"),
+			Games: count,
+		})
+
+		earliest = earliest.AddDate(0, 0, 1)
+		rangeStart, rangeEnd = rangeEnd, earliest.AddDate(0, 0, 1).Unix()
+		if rangeStart >= time.Now().Unix() {
+			break
+		}
+	}
+	return result, nil
+}
+
+func midnight(t time.Time) time.Time {
+	return time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, t.Location())
+}

cmd/bgammon-server/main.go

@@ -13,6 +13,7 @@ func main() {
 	var (
 		tcpAddress     string
 		wsAddress      string
+		tz             string
 		dataSource     string
 		debug          int
 		debugCommands  bool
@@ -20,6 +21,7 @@ func main() {
 	)
 	flag.StringVar(&tcpAddress, "tcp", "localhost:1337", "TCP listen address")
 	flag.StringVar(&wsAddress, "ws", "localhost:1338", "WebSocket listen address")
+	flag.StringVar(&tz, "tz", "", "Time zone used when calculating statistics")
 	flag.StringVar(&dataSource, "db", "", "Database data source (postgres://username:password@localhost:5432/database_name")
 	flag.IntVar(&debug, "debug", 0, "print debug information and serve pprof on specified port")
 	flag.BoolVar(&debugCommands, "debug-commands", false, "allow players to use restricted commands")
@@ -49,7 +51,7 @@ func main() {
 		allowDebugCommands = debugCommands
 	}
 
-	s := newServer(dataSource)
+	s := newServer(tz, dataSource)
 	if tcpAddress != "" {
 		s.listen("tcp", tcpAddress)
 	}

cmd/bgammon-server/server.go

@@ -49,10 +49,12 @@ type server struct {
 	gamesCacheTime time.Time
 	gamesCacheLock sync.Mutex
 
+	tz *time.Location
+
 	db *pgx.Conn
 }
 
-func newServer(dataSource string) *server {
+func newServer(tz string, dataSource string) *server {
 	const bufferSize = 10
 	s := &server{
 		newGameIDs:   make(chan int),
@@ -61,6 +63,16 @@ func newServer(dataSource string) *server {
 		welcome:      []byte("hello Welcome to bgammon.org! Please log in by sending the 'login' command. You may specify a username, otherwise you will be assigned a random username. If you specify a username, you may also specify a password. Have fun!"),
 	}
 
+	if tz != "" {
+		var err error
+		s.tz, err = time.LoadLocation(tz)
+		if err != nil {
+			log.Fatalf("failed to parse timezone %s: %s", tz, err)
+		}
+	} else {
+		s.tz = time.UTC
+	}
+
 	if dataSource != "" {
 		var err error
 		s.db, err = connectDB(dataSource)
@@ -123,6 +135,23 @@ func (s *server) handleListMatches(w http.ResponseWriter, r *http.Request) {
 	w.Write(s.cachedMatches())
 }
 
+func (s *server) handlePrintStats(w http.ResponseWriter, r *http.Request) {
+	if s.db == nil {
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+
+	stats, err := serverStats(s.db, s.tz)
+	if err != nil {
+		log.Fatalf("failed to fetch server statistics: %s", err)
+	}
+	buf, err := json.Marshal(stats)
+	if err != nil {
+		log.Fatalf("failed to fetch serialize statistics: %s", err)
+	}
+	w.Write(buf)
+}
+
 func (s *server) handleWebSocket(w http.ResponseWriter, r *http.Request) {
 	const bufferSize = 8
 	commands := make(chan []byte, bufferSize)
@@ -151,6 +180,7 @@ func (s *server) listenWebSocket(address string) {
 
 	mux := http.NewServeMux()
 	mux.HandleFunc("/matches", s.handleListMatches)
+	mux.HandleFunc("/stats", s.handlePrintStats)
 	mux.HandleFunc("/", s.handleWebSocket)
 
 	err := http.ListenAndServe(address, mux)