feat(backend): implement gemini quota simulation and rate limiting

- feat: add local quota tracking for gemini tiers (Legacy/Pro/Ultra)
- feat: implement PreCheckUsage in RateLimitService
- feat: align gemini daily reset window with PST
- fix: sticky session fallback logic

backend/cmd/server/wire_gen.go

@@ -87,9 +87,10 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	geminiOAuthClient := repository.NewGeminiOAuthClient(configConfig)
 	geminiCliCodeAssistClient := repository.NewGeminiCliCodeAssistClient()
 	geminiOAuthService := service.NewGeminiOAuthService(proxyRepository, geminiOAuthClient, geminiCliCodeAssistClient, configConfig)
-	rateLimitService := service.NewRateLimitService(accountRepository, configConfig)
+	geminiQuotaService := service.NewGeminiQuotaService(configConfig, settingRepository)
+	rateLimitService := service.NewRateLimitService(accountRepository, usageLogRepository, configConfig, geminiQuotaService)
 	claudeUsageFetcher := repository.NewClaudeUsageFetcher()
-	accountUsageService := service.NewAccountUsageService(accountRepository, usageLogRepository, claudeUsageFetcher)
+	accountUsageService := service.NewAccountUsageService(accountRepository, usageLogRepository, claudeUsageFetcher, geminiQuotaService)
 	geminiTokenCache := repository.NewGeminiTokenCache(redisClient)
 	geminiTokenProvider := service.NewGeminiTokenProvider(accountRepository, geminiTokenCache, geminiOAuthService)
 	gatewayCache := repository.NewGatewayCache(redisClient)

backend/internal/config/config.go

@@ -43,6 +43,7 @@ type Config struct {
 
 type GeminiConfig struct {
 	OAuth GeminiOAuthConfig `mapstructure:"oauth"`
+	Quota GeminiQuotaConfig `mapstructure:"quota"`
 }
 
 type GeminiOAuthConfig struct {
@@ -51,6 +52,17 @@ type GeminiOAuthConfig struct {
 	Scopes       string `mapstructure:"scopes"`
 }
 
+type GeminiQuotaConfig struct {
+	Tiers  map[string]GeminiTierQuotaConfig `mapstructure:"tiers"`
+	Policy string                           `mapstructure:"policy"`
+}
+
+type GeminiTierQuotaConfig struct {
+	ProRPD          *int64 `mapstructure:"pro_rpd" json:"pro_rpd"`
+	FlashRPD        *int64 `mapstructure:"flash_rpd" json:"flash_rpd"`
+	CooldownMinutes *int   `mapstructure:"cooldown_minutes" json:"cooldown_minutes"`
+}
+
 // TokenRefreshConfig OAuth token自动刷新配置
 type TokenRefreshConfig struct {
 	// 是否启用自动刷新
@@ -352,6 +364,7 @@ func setDefaults() {
 	viper.SetDefault("gemini.oauth.client_id", "")
 	viper.SetDefault("gemini.oauth.client_secret", "")
 	viper.SetDefault("gemini.oauth.scopes", "")
+	viper.SetDefault("gemini.quota.policy", "")
 }
 
 func (c *Config) Validate() error {

backend/internal/service/account.go

@@ -3,6 +3,7 @@ package service
 import (
 	"encoding/json"
 	"strconv"
+	"strings"
 	"time"
 )
 
@@ -78,6 +79,36 @@ func (a *Account) IsGemini() bool {
 	return a.Platform == PlatformGemini
 }
 
+func (a *Account) GeminiOAuthType() string {
+	if a.Platform != PlatformGemini || a.Type != AccountTypeOAuth {
+		return ""
+	}
+	oauthType := strings.TrimSpace(a.GetCredential("oauth_type"))
+	if oauthType == "" && strings.TrimSpace(a.GetCredential("project_id")) != "" {
+		return "code_assist"
+	}
+	return oauthType
+}
+
+func (a *Account) GeminiTierID() string {
+	tierID := strings.TrimSpace(a.GetCredential("tier_id"))
+	if tierID == "" {
+		return ""
+	}
+	return strings.ToUpper(tierID)
+}
+
+func (a *Account) IsGeminiCodeAssist() bool {
+	if a.Platform != PlatformGemini || a.Type != AccountTypeOAuth {
+		return false
+	}
+	oauthType := a.GeminiOAuthType()
+	if oauthType == "" {
+		return strings.TrimSpace(a.GetCredential("project_id")) != ""
+	}
+	return oauthType == "code_assist"
+}
+
 func (a *Account) CanGetUsage() bool {
 	return a.Type == AccountTypeOAuth
 }

backend/internal/service/account_usage_service.go

@@ -97,6 +97,8 @@ type UsageInfo struct {
 	FiveHour       *UsageProgress `json:"five_hour"`                  // 5小时窗口
 	SevenDay       *UsageProgress `json:"seven_day,omitempty"`        // 7天窗口
 	SevenDaySonnet *UsageProgress `json:"seven_day_sonnet,omitempty"` // 7天Sonnet窗口
+	GeminiProDaily *UsageProgress `json:"gemini_pro_daily,omitempty"` // Gemini Pro 日配额
+	GeminiFlashDaily *UsageProgress `json:"gemini_flash_daily,omitempty"` // Gemini Flash 日配额
 }
 
 // ClaudeUsageResponse Anthropic API返回的usage结构
@@ -122,17 +124,19 @@ type ClaudeUsageFetcher interface {
 
 // AccountUsageService 账号使用量查询服务
 type AccountUsageService struct {
-	accountRepo  AccountRepository
-	usageLogRepo UsageLogRepository
-	usageFetcher ClaudeUsageFetcher
+	accountRepo         AccountRepository
+	usageLogRepo        UsageLogRepository
+	usageFetcher        ClaudeUsageFetcher
+	geminiQuotaService  *GeminiQuotaService
 }
 
 // NewAccountUsageService 创建AccountUsageService实例
-func NewAccountUsageService(accountRepo AccountRepository, usageLogRepo UsageLogRepository, usageFetcher ClaudeUsageFetcher) *AccountUsageService {
+func NewAccountUsageService(accountRepo AccountRepository, usageLogRepo UsageLogRepository, usageFetcher ClaudeUsageFetcher, geminiQuotaService *GeminiQuotaService) *AccountUsageService {
 	return &AccountUsageService{
-		accountRepo:  accountRepo,
-		usageLogRepo: usageLogRepo,
-		usageFetcher: usageFetcher,
+		accountRepo:        accountRepo,
+		usageLogRepo:       usageLogRepo,
+		usageFetcher:       usageFetcher,
+		geminiQuotaService: geminiQuotaService,
 	}
 }
 
@@ -146,6 +150,10 @@ func (s *AccountUsageService) GetUsage(ctx context.Context, accountID int64) (*U
 		return nil, fmt.Errorf("get account failed: %w", err)
 	}
 
+	if account.Platform == PlatformGemini {
+		return s.getGeminiUsage(ctx, account)
+	}
+
 	// 只有oauth类型账号可以通过API获取usage（有profile scope）
 	if account.CanGetUsage() {
 		var apiResp *ClaudeUsageResponse
@@ -192,6 +200,33 @@ func (s *AccountUsageService) GetUsage(ctx context.Context, accountID int64) (*U
 	return nil, fmt.Errorf("account type %s does not support usage query", account.Type)
 }
 
+func (s *AccountUsageService) getGeminiUsage(ctx context.Context, account *Account) (*UsageInfo, error) {
+	now := time.Now()
+	start := geminiDailyWindowStart(now)
+
+	stats, err := s.usageLogRepo.GetModelStatsWithFilters(ctx, start, now, 0, 0, account.ID)
+	if err != nil {
+		return nil, fmt.Errorf("get gemini usage stats failed: %w", err)
+	}
+
+	usage := &UsageInfo{
+		UpdatedAt: &now,
+	}
+
+	quota, ok := s.geminiQuotaService.QuotaForAccount(ctx, account)
+	if !ok {
+		return usage, nil
+	}
+
+	totals := geminiAggregateUsage(stats)
+	resetAt := geminiDailyResetTime(now)
+
+	usage.GeminiProDaily = buildGeminiUsageProgress(totals.ProRequests, quota.ProRPD, resetAt, totals.ProTokens, totals.ProCost, now)
+	usage.GeminiFlashDaily = buildGeminiUsageProgress(totals.FlashRequests, quota.FlashRPD, resetAt, totals.FlashTokens, totals.FlashCost, now)
+
+	return usage, nil
+}
+
 // addWindowStats 为 usage 数据添加窗口期统计
 // 使用独立缓存（1 分钟），与 API 缓存分离
 func (s *AccountUsageService) addWindowStats(ctx context.Context, account *Account, usage *UsageInfo) {
@@ -388,3 +423,25 @@ func (s *AccountUsageService) estimateSetupTokenUsage(account *Account) *UsageIn
 	// Setup Token无法获取7d数据
 	return info
 }
+
+func buildGeminiUsageProgress(used, limit int64, resetAt time.Time, tokens int64, cost float64, now time.Time) *UsageProgress {
+	if limit <= 0 {
+		return nil
+	}
+	utilization := (float64(used) / float64(limit)) * 100
+	remainingSeconds := int(resetAt.Sub(now).Seconds())
+	if remainingSeconds < 0 {
+		remainingSeconds = 0
+	}
+	resetCopy := resetAt
+	return &UsageProgress{
+		Utilization:      utilization,
+		ResetsAt:         &resetCopy,
+		RemainingSeconds: remainingSeconds,
+		WindowStats: &WindowStats{
+			Requests: used,
+			Tokens:   tokens,
+			Cost:     cost,
+		},
+	}
+}

backend/internal/service/domain_constants.go

@@ -91,6 +91,9 @@ const (
 
 	// 管理员 API Key
 	SettingKeyAdminApiKey = "admin_api_key" // 全局管理员 API Key（用于外部系统集成）
+
+	// Gemini 配额策略（JSON）
+	SettingKeyGeminiQuotaPolicy = "gemini_quota_policy"
 )
 
 // Admin API Key prefix (distinct from user "sk-" keys)

backend/internal/service/gemini_messages_compat_service.go

@@ -116,8 +116,20 @@ func (s *GeminiMessagesCompatService) SelectAccountForModelWithExclusions(ctx co
 						valid = true
 					}
 					if valid {
-						_ = s.cache.RefreshSessionTTL(ctx, cacheKey, geminiStickySessionTTL)
-						return account, nil
+						usable := true
+						if s.rateLimitService != nil && requestedModel != "" {
+							ok, err := s.rateLimitService.PreCheckUsage(ctx, account, requestedModel)
+							if err != nil {
+								log.Printf("[Gemini PreCheck] Account %d precheck error: %v", account.ID, err)
+							}
+							if !ok {
+								usable = false
+							}
+						}
+						if usable {
+							_ = s.cache.RefreshSessionTTL(ctx, cacheKey, geminiStickySessionTTL)
+							return account, nil
+						}
 					}
 				}
 			}
@@ -157,6 +169,15 @@ func (s *GeminiMessagesCompatService) SelectAccountForModelWithExclusions(ctx co
 		if requestedModel != "" && !s.isModelSupportedByAccount(acc, requestedModel) {
 			continue
 		}
+		if s.rateLimitService != nil && requestedModel != "" {
+			ok, err := s.rateLimitService.PreCheckUsage(ctx, acc, requestedModel)
+			if err != nil {
+				log.Printf("[Gemini PreCheck] Account %d precheck error: %v", acc.ID, err)
+			}
+			if !ok {
+				continue
+			}
+		}
 		if selected == nil {
 			selected = acc
 			continue
@@ -1887,26 +1908,23 @@ func (s *GeminiMessagesCompatService) handleGeminiUpstreamError(ctx context.Cont
 		return
 	}
 
-	// 获取账号的 oauth_type、tier_id 和 project_id
-	oauthType := strings.TrimSpace(account.GetCredential("oauth_type"))
-	tierID := strings.TrimSpace(account.GetCredential("tier_id"))
+	oauthType := account.GeminiOAuthType()
+	tierID := account.GeminiTierID()
 	projectID := strings.TrimSpace(account.GetCredential("project_id"))
-
-	// 判断是否为 Code Assist：以 project_id 是否存在为准（更可靠）
-	isCodeAssist := projectID != ""
-	// Legacy 兼容：oauth_type 为空但 project_id 存在时视为 code_assist
-	if oauthType == "" && isCodeAssist {
-		oauthType = "code_assist"
-	}
+	isCodeAssist := account.IsGeminiCodeAssist()
 
 	resetAt := ParseGeminiRateLimitResetTime(body)
 	if resetAt == nil {
 		// 根据账号类型使用不同的默认重置时间
 		var ra time.Time
 		if isCodeAssist {
-			// Code Assist: 5 分钟滚动窗口
-			ra = time.Now().Add(5 * time.Minute)
-			log.Printf("[Gemini 429] Account %d (Code Assist, tier=%s, project=%s) rate limited, reset in 5min", account.ID, tierID, projectID)
+			// Code Assist: fallback cooldown by tier
+				cooldown := geminiCooldownForTier(tierID)
+				if s.rateLimitService != nil {
+					cooldown = s.rateLimitService.GeminiCooldown(ctx, account)
+				}
+			ra = time.Now().Add(cooldown)
+			log.Printf("[Gemini 429] Account %d (Code Assist, tier=%s, project=%s) rate limited, cooldown=%v", account.ID, tierID, projectID, ra.Sub(time.Now()).Truncate(time.Second))
 		} else {
 			// API Key / AI Studio OAuth: PST 午夜
 			if ts := nextGeminiDailyResetUnix(); ts != nil {
@@ -1982,16 +2000,7 @@ func looksLikeGeminiDailyQuota(message string) bool {
 }
 
 func nextGeminiDailyResetUnix() *int64 {
-	loc, err := time.LoadLocation("America/Los_Angeles")
-	if err != nil {
-		// Fallback: PST without DST.
-		loc = time.FixedZone("PST", -8*3600)
-	}
-	now := time.Now().In(loc)
-	reset := time.Date(now.Year(), now.Month(), now.Day(), 0, 5, 0, 0, loc)
-	if !reset.After(now) {
-		reset = reset.Add(24 * time.Hour)
-	}
+	reset := geminiDailyResetTime(time.Now())
 	ts := reset.Unix()
 	return &ts
 }

backend/internal/service/gemini_quota.go

+package service
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"log"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/usagestats"
+)
+
+type geminiModelClass string
+
+const (
+	geminiModelPro   geminiModelClass = "pro"
+	geminiModelFlash geminiModelClass = "flash"
+)
+
+type GeminiDailyQuota struct {
+	ProRPD   int64
+	FlashRPD int64
+}
+
+type GeminiTierPolicy struct {
+	Quota    GeminiDailyQuota
+	Cooldown time.Duration
+}
+
+type GeminiQuotaPolicy struct {
+	tiers map[string]GeminiTierPolicy
+}
+
+type GeminiUsageTotals struct {
+	ProRequests   int64
+	FlashRequests int64
+	ProTokens     int64
+	FlashTokens   int64
+	ProCost       float64
+	FlashCost     float64
+}
+
+const geminiQuotaCacheTTL = time.Minute
+
+type geminiQuotaOverrides struct {
+	Tiers map[string]config.GeminiTierQuotaConfig `json:"tiers"`
+}
+
+type GeminiQuotaService struct {
+	cfg         *config.Config
+	settingRepo SettingRepository
+	mu          sync.Mutex
+	cachedAt    time.Time
+	policy      *GeminiQuotaPolicy
+}
+
+func NewGeminiQuotaService(cfg *config.Config, settingRepo SettingRepository) *GeminiQuotaService {
+	return &GeminiQuotaService{
+		cfg:         cfg,
+		settingRepo: settingRepo,
+	}
+}
+
+func (s *GeminiQuotaService) Policy(ctx context.Context) *GeminiQuotaPolicy {
+	if s == nil {
+		return newGeminiQuotaPolicy()
+	}
+
+	now := time.Now()
+	s.mu.Lock()
+	if s.policy != nil && now.Sub(s.cachedAt) < geminiQuotaCacheTTL {
+		policy := s.policy
+		s.mu.Unlock()
+		return policy
+	}
+	s.mu.Unlock()
+
+	policy := newGeminiQuotaPolicy()
+	if s.cfg != nil {
+		policy.ApplyOverrides(s.cfg.Gemini.Quota.Tiers)
+		if strings.TrimSpace(s.cfg.Gemini.Quota.Policy) != "" {
+			var overrides geminiQuotaOverrides
+			if err := json.Unmarshal([]byte(s.cfg.Gemini.Quota.Policy), &overrides); err != nil {
+				log.Printf("gemini quota: parse config policy failed: %v", err)
+			} else {
+				policy.ApplyOverrides(overrides.Tiers)
+			}
+		}
+	}
+
+	if s.settingRepo != nil {
+		value, err := s.settingRepo.GetValue(ctx, SettingKeyGeminiQuotaPolicy)
+		if err != nil && !errors.Is(err, ErrSettingNotFound) {
+			log.Printf("gemini quota: load setting failed: %v", err)
+		} else if strings.TrimSpace(value) != "" {
+			var overrides geminiQuotaOverrides
+			if err := json.Unmarshal([]byte(value), &overrides); err != nil {
+				log.Printf("gemini quota: parse setting failed: %v", err)
+			} else {
+				policy.ApplyOverrides(overrides.Tiers)
+			}
+		}
+	}
+
+	s.mu.Lock()
+	s.policy = policy
+	s.cachedAt = now
+	s.mu.Unlock()
+
+	return policy
+}
+
+func (s *GeminiQuotaService) QuotaForAccount(ctx context.Context, account *Account) (GeminiDailyQuota, bool) {
+	if account == nil || !account.IsGeminiCodeAssist() {
+		return GeminiDailyQuota{}, false
+	}
+	policy := s.Policy(ctx)
+	return policy.QuotaForTier(account.GeminiTierID())
+}
+
+func (s *GeminiQuotaService) CooldownForTier(ctx context.Context, tierID string) time.Duration {
+	policy := s.Policy(ctx)
+	return policy.CooldownForTier(tierID)
+}
+
+func newGeminiQuotaPolicy() *GeminiQuotaPolicy {
+	return &GeminiQuotaPolicy{
+		tiers: map[string]GeminiTierPolicy{
+			"LEGACY": {Quota: GeminiDailyQuota{ProRPD: 50, FlashRPD: 1500}, Cooldown: 30 * time.Minute},
+			"PRO":    {Quota: GeminiDailyQuota{ProRPD: 1500, FlashRPD: 4000}, Cooldown: 5 * time.Minute},
+			"ULTRA":  {Quota: GeminiDailyQuota{ProRPD: 2000, FlashRPD: 0}, Cooldown: 5 * time.Minute},
+		},
+	}
+}
+
+func (p *GeminiQuotaPolicy) ApplyOverrides(tiers map[string]config.GeminiTierQuotaConfig) {
+	if p == nil || len(tiers) == 0 {
+		return
+	}
+	for rawID, override := range tiers {
+		tierID := normalizeGeminiTierID(rawID)
+		if tierID == "" {
+			continue
+		}
+		policy, ok := p.tiers[tierID]
+		if !ok {
+			policy = GeminiTierPolicy{Cooldown: 5 * time.Minute}
+		}
+		if override.ProRPD != nil {
+			policy.Quota.ProRPD = clampGeminiQuotaInt64(*override.ProRPD)
+		}
+		if override.FlashRPD != nil {
+			policy.Quota.FlashRPD = clampGeminiQuotaInt64(*override.FlashRPD)
+		}
+		if override.CooldownMinutes != nil {
+			minutes := clampGeminiQuotaInt(*override.CooldownMinutes)
+			policy.Cooldown = time.Duration(minutes) * time.Minute
+		}
+		p.tiers[tierID] = policy
+	}
+}
+
+func (p *GeminiQuotaPolicy) QuotaForTier(tierID string) (GeminiDailyQuota, bool) {
+	policy, ok := p.policyForTier(tierID)
+	if !ok {
+		return GeminiDailyQuota{}, false
+	}
+	return policy.Quota, true
+}
+
+func (p *GeminiQuotaPolicy) CooldownForTier(tierID string) time.Duration {
+	policy, ok := p.policyForTier(tierID)
+	if ok && policy.Cooldown > 0 {
+		return policy.Cooldown
+	}
+	return 5 * time.Minute
+}
+
+func (p *GeminiQuotaPolicy) policyForTier(tierID string) (GeminiTierPolicy, bool) {
+	if p == nil {
+		return GeminiTierPolicy{}, false
+	}
+	normalized := normalizeGeminiTierID(tierID)
+	if normalized == "" {
+		normalized = "LEGACY"
+	}
+	if policy, ok := p.tiers[normalized]; ok {
+		return policy, true
+	}
+	policy, ok := p.tiers["LEGACY"]
+	return policy, ok
+}
+
+func normalizeGeminiTierID(tierID string) string {
+	return strings.ToUpper(strings.TrimSpace(tierID))
+}
+
+func clampGeminiQuotaInt64(value int64) int64 {
+	if value < 0 {
+		return 0
+	}
+	return value
+}
+
+func clampGeminiQuotaInt(value int) int {
+	if value < 0 {
+		return 0
+	}
+	return value
+}
+
+func geminiCooldownForTier(tierID string) time.Duration {
+	policy := newGeminiQuotaPolicy()
+	return policy.CooldownForTier(tierID)
+}
+
+func geminiModelClassFromName(model string) geminiModelClass {
+	name := strings.ToLower(strings.TrimSpace(model))
+	if strings.Contains(name, "flash") || strings.Contains(name, "lite") {
+		return geminiModelFlash
+	}
+	return geminiModelPro
+}
+
+func geminiAggregateUsage(stats []usagestats.ModelStat) GeminiUsageTotals {
+	var totals GeminiUsageTotals
+	for _, stat := range stats {
+		switch geminiModelClassFromName(stat.Model) {
+		case geminiModelFlash:
+			totals.FlashRequests += stat.Requests
+			totals.FlashTokens += stat.TotalTokens
+			totals.FlashCost += stat.ActualCost
+		default:
+			totals.ProRequests += stat.Requests
+			totals.ProTokens += stat.TotalTokens
+			totals.ProCost += stat.ActualCost
+		}
+	}
+	return totals
+}
+
+func geminiQuotaLocation() *time.Location {
+	loc, err := time.LoadLocation("America/Los_Angeles")
+	if err != nil {
+		return time.FixedZone("PST", -8*3600)
+	}
+	return loc
+}
+
+func geminiDailyWindowStart(now time.Time) time.Time {
+	loc := geminiQuotaLocation()
+	localNow := now.In(loc)
+	return time.Date(localNow.Year(), localNow.Month(), localNow.Day(), 0, 0, 0, 0, loc)
+}
+
+func geminiDailyResetTime(now time.Time) time.Time {
+	loc := geminiQuotaLocation()
+	localNow := now.In(loc)
+	start := time.Date(localNow.Year(), localNow.Month(), localNow.Day(), 0, 0, 0, 0, loc)
+	reset := start.Add(24 * time.Hour)
+	if !reset.After(localNow) {
+		reset = reset.Add(24 * time.Hour)
+	}
+	return reset
+}

backend/internal/service/ratelimit_service.go

@@ -5,6 +5,7 @@ import (
 	"log"
 	"net/http"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/Wei-Shaw/sub2api/internal/config"
@@ -12,15 +13,19 @@ import (
 
 // RateLimitService 处理限流和过载状态管理
 type RateLimitService struct {
-	accountRepo AccountRepository
-	cfg         *config.Config
+	accountRepo        AccountRepository
+	usageRepo          UsageLogRepository
+	cfg                *config.Config
+	geminiQuotaService *GeminiQuotaService
 }
 
 // NewRateLimitService 创建RateLimitService实例
-func NewRateLimitService(accountRepo AccountRepository, cfg *config.Config) *RateLimitService {
+func NewRateLimitService(accountRepo AccountRepository, usageRepo UsageLogRepository, cfg *config.Config, geminiQuotaService *GeminiQuotaService) *RateLimitService {
 	return &RateLimitService{
-		accountRepo: accountRepo,
-		cfg:         cfg,
+		accountRepo:        accountRepo,
+		usageRepo:          usageRepo,
+		cfg:                cfg,
+		geminiQuotaService: geminiQuotaService,
 	}
 }
 
@@ -62,6 +67,68 @@ func (s *RateLimitService) HandleUpstreamError(ctx context.Context, account *Acc
 	}
 }
 
+// PreCheckUsage proactively checks local quota before dispatching a request.
+// Returns false when the account should be skipped.
+func (s *RateLimitService) PreCheckUsage(ctx context.Context, account *Account, requestedModel string) (bool, error) {
+	if account == nil || !account.IsGeminiCodeAssist() || strings.TrimSpace(requestedModel) == "" {
+		return true, nil
+	}
+	if s.usageRepo == nil {
+		return true, nil
+	}
+
+	quota, ok := s.geminiQuotaService.QuotaForAccount(ctx, account)
+	if !ok {
+		return true, nil
+	}
+
+	var limit int64
+	switch geminiModelClassFromName(requestedModel) {
+	case geminiModelFlash:
+		limit = quota.FlashRPD
+	default:
+		limit = quota.ProRPD
+	}
+	if limit <= 0 {
+		return true, nil
+	}
+
+	now := time.Now()
+	start := geminiDailyWindowStart(now)
+	stats, err := s.usageRepo.GetModelStatsWithFilters(ctx, start, now, 0, 0, account.ID)
+	if err != nil {
+		return true, err
+	}
+	totals := geminiAggregateUsage(stats)
+
+	var used int64
+	switch geminiModelClassFromName(requestedModel) {
+	case geminiModelFlash:
+		used = totals.FlashRequests
+	default:
+		used = totals.ProRequests
+	}
+
+	if used >= limit {
+		resetAt := geminiDailyResetTime(now)
+		if err := s.accountRepo.SetRateLimited(ctx, account.ID, resetAt); err != nil {
+			log.Printf("SetRateLimited failed for account %d: %v", account.ID, err)
+		}
+		log.Printf("[Gemini PreCheck] Account %d reached daily quota (%d/%d), rate limited until %v", account.ID, used, limit, resetAt)
+		return false, nil
+	}
+
+	return true, nil
+}
+
+// GeminiCooldown returns the fallback cooldown duration for Gemini 429s based on tier.
+func (s *RateLimitService) GeminiCooldown(ctx context.Context, account *Account) time.Duration {
+	if account == nil {
+		return 5 * time.Minute
+	}
+	return s.geminiQuotaService.CooldownForTier(ctx, account.GeminiTierID())
+}
+
 // handleAuthError 处理认证类错误(401/403)，停止账号调度
 func (s *RateLimitService) handleAuthError(ctx context.Context, account *Account, errorMsg string) {
 	if err := s.accountRepo.SetError(ctx, account.ID, errorMsg); err != nil {

backend/internal/service/wire.go

@@ -94,6 +94,7 @@ var ProviderSet = wire.NewSet(
 	NewOAuthService,
 	NewOpenAIOAuthService,
 	NewGeminiOAuthService,
+	NewGeminiQuotaService,
 	NewAntigravityOAuthService,
 	NewGeminiTokenProvider,
 	NewGeminiMessagesCompatService,

deploy/.env.example

@@ -86,3 +86,11 @@ GEMINI_OAUTH_CLIENT_ID=
 GEMINI_OAUTH_CLIENT_SECRET=
 # Optional; leave empty to auto-select scopes based on oauth_type
 GEMINI_OAUTH_SCOPES=
+
+# -----------------------------------------------------------------------------
+# Gemini Quota Policy (OPTIONAL, local simulation)
+# -----------------------------------------------------------------------------
+# JSON overrides for local quota simulation (Code Assist only).
+# Example:
+# GEMINI_QUOTA_POLICY={"tiers":{"LEGACY":{"pro_rpd":50,"flash_rpd":1500,"cooldown_minutes":30},"PRO":{"pro_rpd":1500,"flash_rpd":4000,"cooldown_minutes":5},"ULTRA":{"pro_rpd":2000,"flash_rpd":0,"cooldown_minutes":5}}}
+GEMINI_QUOTA_POLICY=

deploy/README.md

@@ -123,6 +123,7 @@ docker-compose down -v
 | `GEMINI_OAUTH_CLIENT_ID` | No | *(builtin)* | Google OAuth client ID (Gemini OAuth). Leave empty to use the built-in Gemini CLI client. |
 | `GEMINI_OAUTH_CLIENT_SECRET` | No | *(builtin)* | Google OAuth client secret (Gemini OAuth). Leave empty to use the built-in Gemini CLI client. |
 | `GEMINI_OAUTH_SCOPES` | No | *(default)* | OAuth scopes (Gemini OAuth) |
+| `GEMINI_QUOTA_POLICY` | No | *(empty)* | JSON overrides for Gemini local quota simulation (Code Assist only). |
 
 See `.env.example` for all available options.
 

deploy/config.example.yaml

@@ -156,3 +156,19 @@ gemini:
     client_secret: "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"
     # Optional scopes (space-separated). Leave empty to auto-select based on oauth_type.
     scopes: ""
+  quota:
+    # Optional: local quota simulation for Gemini Code Assist (local billing).
+    # These values are used for UI progress + precheck scheduling, not official Google quotas.
+    tiers:
+      LEGACY:
+        pro_rpd: 50
+        flash_rpd: 1500
+        cooldown_minutes: 30
+      PRO:
+        pro_rpd: 1500
+        flash_rpd: 4000
+        cooldown_minutes: 5
+      ULTRA:
+        pro_rpd: 2000
+        flash_rpd: 0
+        cooldown_minutes: 5

deploy/docker-compose-test.yml

@@ -90,6 +90,7 @@ services:
       - GEMINI_OAUTH_CLIENT_ID=${GEMINI_OAUTH_CLIENT_ID:-}
       - GEMINI_OAUTH_CLIENT_SECRET=${GEMINI_OAUTH_CLIENT_SECRET:-}
       - GEMINI_OAUTH_SCOPES=${GEMINI_OAUTH_SCOPES:-}
+      - GEMINI_QUOTA_POLICY=${GEMINI_QUOTA_POLICY:-}
     depends_on:
       postgres:
         condition: service_healthy

deploy/docker-compose.override.yml

+# =============================================================================
+# Docker Compose Override for Local Development
+# =============================================================================
+# This file automatically extends docker-compose-test.yml
+# Usage: docker-compose -f docker-compose-test.yml up -d
+# =============================================================================
+
+services:
+  # ===========================================================================
+  # PostgreSQL - 暴露端口用于本地开发
+  # ===========================================================================
+  postgres:
+    ports:
+      - "127.0.0.1:5432:5432"
+
+  # ===========================================================================
+  # Redis - 暴露端口用于本地开发
+  # ===========================================================================
+  redis:
+    ports:
+      - "127.0.0.1:6379:6379"

deploy/docker-compose.yml

@@ -90,6 +90,7 @@ services:
       - GEMINI_OAUTH_CLIENT_ID=${GEMINI_OAUTH_CLIENT_ID:-}
       - GEMINI_OAUTH_CLIENT_SECRET=${GEMINI_OAUTH_CLIENT_SECRET:-}
       - GEMINI_OAUTH_SCOPES=${GEMINI_OAUTH_SCOPES:-}
+      - GEMINI_QUOTA_POLICY=${GEMINI_QUOTA_POLICY:-}
     depends_on:
       postgres:
         condition: service_healthy