feat(stats): add usage stats and quota reset

internal/service/stats.go

@@ -0,0 +1,79 @@
+package service
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/redis/go-redis/v9"
+)
+
+type StatsService struct {
+	rdb *redis.Client
+}
+
+type RealtimeStats struct {
+	Requests       int64
+	Tokens         int64
+	LastAccessedAt *time.Time
+}
+
+func NewStatsService(rdb *redis.Client) *StatsService {
+	return &StatsService{rdb: rdb}
+}
+
+func (s *StatsService) GetKeyRealtimeStats(ctx context.Context, tokenHash string) (RealtimeStats, error) {
+	if s == nil || s.rdb == nil {
+		return RealtimeStats{}, fmt.Errorf("redis client is required")
+	}
+	tokenHash = strings.TrimSpace(tokenHash)
+	if tokenHash == "" {
+		return RealtimeStats{}, fmt.Errorf("token hash required")
+	}
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	reqs, err := s.rdb.Get(ctx, fmt.Sprintf("key:stats:%s:requests", tokenHash)).Int64()
+	if err != nil && err != redis.Nil {
+		return RealtimeStats{}, fmt.Errorf("read key requests: %w", err)
+	}
+	tokens, err := s.rdb.Get(ctx, fmt.Sprintf("key:stats:%s:tokens", tokenHash)).Int64()
+	if err != nil && err != redis.Nil {
+		return RealtimeStats{}, fmt.Errorf("read key tokens: %w", err)
+	}
+	lastRaw, err := s.rdb.Get(ctx, fmt.Sprintf("key:stats:%s:last_access", tokenHash)).Result()
+	if err != nil && err != redis.Nil {
+		return RealtimeStats{}, fmt.Errorf("read key last access: %w", err)
+	}
+	var lastAt *time.Time
+	if lastRaw != "" {
+		if sec, err := strconv.ParseInt(lastRaw, 10, 64); err == nil && sec > 0 {
+			t := time.Unix(sec, 0).UTC()
+			lastAt = &t
+		}
+	}
+	return RealtimeStats{Requests: reqs, Tokens: tokens, LastAccessedAt: lastAt}, nil
+}
+
+func (s *StatsService) GetMasterRealtimeStats(ctx context.Context, masterID uint) (RealtimeStats, error) {
+	if s == nil || s.rdb == nil {
+		return RealtimeStats{}, fmt.Errorf("redis client is required")
+	}
+	if masterID == 0 {
+		return RealtimeStats{}, fmt.Errorf("master id required")
+	}
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	reqs, err := s.rdb.Get(ctx, fmt.Sprintf("master:stats:%d:requests", masterID)).Int64()
+	if err != nil && err != redis.Nil {
+		return RealtimeStats{}, fmt.Errorf("read master requests: %w", err)
+	}
+	tokens, err := s.rdb.Get(ctx, fmt.Sprintf("master:stats:%d:tokens", masterID)).Int64()
+	if err != nil && err != redis.Nil {
+		return RealtimeStats{}, fmt.Errorf("read master tokens: %w", err)
+	}
+	return RealtimeStats{Requests: reqs, Tokens: tokens}, nil
+}