feat: 实现固定时间重置模式的 SQL 表达式，并添加相关单元测试

backend/internal/repository/account_repo.go

@@ -1747,21 +1747,70 @@ const weeklyExpiredExpr = `(
 )`
 
 // nextDailyResetAtExpr is a SQL expression to compute the next daily reset_at when a reset occurs.
-// For fixed mode: advances current reset_at by 1 day. For rolling mode: not used (NULL).
+// For fixed mode: computes the next future reset time based on NOW(), timezone, and configured hour.
+// This correctly handles long-inactive accounts by jumping directly to the next valid reset point.
 const nextDailyResetAtExpr = `(
 	CASE WHEN COALESCE(extra->>'quota_daily_reset_mode', 'rolling') = 'fixed'
-	THEN to_char(
-		COALESCE((extra->>'quota_daily_reset_at')::timestamptz, NOW()) + '1 day'::interval
-		AT TIME ZONE 'UTC', 'YYYY-MM-DD"T"HH24:MI:SS"Z"')
+	THEN to_char((
+		-- Compute today's reset point in the configured timezone, then pick next future one
+		CASE WHEN NOW() >= (
+			date_trunc('day', NOW() AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC'))
+			+ (COALESCE((extra->>'quota_daily_reset_hour')::int, 0) || ' hours')::interval
+		) AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC')
+		-- NOW() is at or past today's reset point → next reset is tomorrow
+		THEN (
+			date_trunc('day', NOW() AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC'))
+			+ (COALESCE((extra->>'quota_daily_reset_hour')::int, 0) || ' hours')::interval
+			+ '1 day'::interval
+		) AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC')
+		-- NOW() is before today's reset point → next reset is today
+		ELSE (
+			date_trunc('day', NOW() AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC'))
+			+ (COALESCE((extra->>'quota_daily_reset_hour')::int, 0) || ' hours')::interval
+		) AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC')
+		END
+	) AT TIME ZONE 'UTC', 'YYYY-MM-DD"T"HH24:MI:SS"Z"')
 	ELSE NULL END
 )`
 
 // nextWeeklyResetAtExpr is a SQL expression to compute the next weekly reset_at when a reset occurs.
+// For fixed mode: computes the next future reset time based on NOW(), timezone, configured day and hour.
+// This correctly handles long-inactive accounts by jumping directly to the next valid reset point.
 const nextWeeklyResetAtExpr = `(
 	CASE WHEN COALESCE(extra->>'quota_weekly_reset_mode', 'rolling') = 'fixed'
-	THEN to_char(
-		COALESCE((extra->>'quota_weekly_reset_at')::timestamptz, NOW()) + '7 days'::interval
-		AT TIME ZONE 'UTC', 'YYYY-MM-DD"T"HH24:MI:SS"Z"')
+	THEN to_char((
+		-- Compute this week's reset point in the configured timezone
+		-- Step 1: get today's date at reset hour in configured tz
+		-- Step 2: compute days forward to target weekday
+		-- Step 3: if same day but past reset hour, advance 7 days
+		CASE
+		WHEN (
+			-- days_forward = (target_day - current_day + 7) % 7
+			(COALESCE((extra->>'quota_weekly_reset_day')::int, 1)
+			 - EXTRACT(DOW FROM NOW() AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC'))::int
+			 + 7) % 7
+		) = 0 AND NOW() >= (
+			date_trunc('day', NOW() AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC'))
+			+ (COALESCE((extra->>'quota_weekly_reset_hour')::int, 0) || ' hours')::interval
+		) AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC')
+		-- Same weekday and past reset hour → next week
+		THEN (
+			date_trunc('day', NOW() AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC'))
+			+ (COALESCE((extra->>'quota_weekly_reset_hour')::int, 0) || ' hours')::interval
+			+ '7 days'::interval
+		) AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC')
+		ELSE (
+			-- Advance to target weekday this week (or next if days_forward > 0)
+			date_trunc('day', NOW() AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC'))
+			+ (COALESCE((extra->>'quota_weekly_reset_hour')::int, 0) || ' hours')::interval
+			+ ((
+				(COALESCE((extra->>'quota_weekly_reset_day')::int, 1)
+				 - EXTRACT(DOW FROM NOW() AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC'))::int
+				 + 7) % 7
+			) || ' days')::interval
+		) AT TIME ZONE COALESCE(extra->>'quota_reset_timezone', 'UTC')
+		END
+	) AT TIME ZONE 'UTC', 'YYYY-MM-DD"T"HH24:MI:SS"Z"')
 	ELSE NULL END
 )`
 

backend/internal/service/account_quota_reset_test.go

+//go:build unit
+
+package service
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// ---------------------------------------------------------------------------
+// nextFixedDailyReset
+// ---------------------------------------------------------------------------
+
+func TestNextFixedDailyReset_BeforeResetHour(t *testing.T) {
+	tz := time.UTC
+	// 2026-03-14 06:00 UTC, reset hour = 9
+	after := time.Date(2026, 3, 14, 6, 0, 0, 0, tz)
+	got := nextFixedDailyReset(9, tz, after)
+	want := time.Date(2026, 3, 14, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestNextFixedDailyReset_AtResetHour(t *testing.T) {
+	tz := time.UTC
+	// Exactly at reset hour → should return tomorrow
+	after := time.Date(2026, 3, 14, 9, 0, 0, 0, tz)
+	got := nextFixedDailyReset(9, tz, after)
+	want := time.Date(2026, 3, 15, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestNextFixedDailyReset_AfterResetHour(t *testing.T) {
+	tz := time.UTC
+	// After reset hour → should return tomorrow
+	after := time.Date(2026, 3, 14, 15, 30, 0, 0, tz)
+	got := nextFixedDailyReset(9, tz, after)
+	want := time.Date(2026, 3, 15, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestNextFixedDailyReset_MidnightReset(t *testing.T) {
+	tz := time.UTC
+	// Reset at hour 0 (midnight), currently 23:59
+	after := time.Date(2026, 3, 14, 23, 59, 0, 0, tz)
+	got := nextFixedDailyReset(0, tz, after)
+	want := time.Date(2026, 3, 15, 0, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestNextFixedDailyReset_NonUTCTimezone(t *testing.T) {
+	tz, err := time.LoadLocation("Asia/Shanghai")
+	require.NoError(t, err)
+
+	// 2026-03-14 07:00 UTC = 2026-03-14 15:00 CST, reset hour = 9 (CST)
+	after := time.Date(2026, 3, 14, 7, 0, 0, 0, time.UTC)
+	got := nextFixedDailyReset(9, tz, after)
+	// Already past 9:00 CST today → tomorrow 9:00 CST = 2026-03-15 01:00 UTC
+	want := time.Date(2026, 3, 15, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+// ---------------------------------------------------------------------------
+// lastFixedDailyReset
+// ---------------------------------------------------------------------------
+
+func TestLastFixedDailyReset_BeforeResetHour(t *testing.T) {
+	tz := time.UTC
+	now := time.Date(2026, 3, 14, 6, 0, 0, 0, tz)
+	got := lastFixedDailyReset(9, tz, now)
+	// Before today's 9:00 → yesterday 9:00
+	want := time.Date(2026, 3, 13, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestLastFixedDailyReset_AtResetHour(t *testing.T) {
+	tz := time.UTC
+	now := time.Date(2026, 3, 14, 9, 0, 0, 0, tz)
+	got := lastFixedDailyReset(9, tz, now)
+	// At exactly 9:00 → today 9:00
+	want := time.Date(2026, 3, 14, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestLastFixedDailyReset_AfterResetHour(t *testing.T) {
+	tz := time.UTC
+	now := time.Date(2026, 3, 14, 15, 0, 0, 0, tz)
+	got := lastFixedDailyReset(9, tz, now)
+	// After 9:00 → today 9:00
+	want := time.Date(2026, 3, 14, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+// ---------------------------------------------------------------------------
+// nextFixedWeeklyReset
+// ---------------------------------------------------------------------------
+
+func TestNextFixedWeeklyReset_TargetDayAhead(t *testing.T) {
+	tz := time.UTC
+	// 2026-03-14 is Saturday (day=6), target = Monday (day=1), hour = 9
+	after := time.Date(2026, 3, 14, 10, 0, 0, 0, tz)
+	got := nextFixedWeeklyReset(1, 9, tz, after)
+	// Next Monday = 2026-03-16
+	want := time.Date(2026, 3, 16, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestNextFixedWeeklyReset_TargetDayToday_BeforeHour(t *testing.T) {
+	tz := time.UTC
+	// 2026-03-16 is Monday (day=1), target = Monday, hour = 9, before 9:00
+	after := time.Date(2026, 3, 16, 6, 0, 0, 0, tz)
+	got := nextFixedWeeklyReset(1, 9, tz, after)
+	// Today at 9:00
+	want := time.Date(2026, 3, 16, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestNextFixedWeeklyReset_TargetDayToday_AtHour(t *testing.T) {
+	tz := time.UTC
+	// 2026-03-16 is Monday, target = Monday, hour = 9, exactly at 9:00
+	after := time.Date(2026, 3, 16, 9, 0, 0, 0, tz)
+	got := nextFixedWeeklyReset(1, 9, tz, after)
+	// Next Monday at 9:00
+	want := time.Date(2026, 3, 23, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestNextFixedWeeklyReset_TargetDayToday_AfterHour(t *testing.T) {
+	tz := time.UTC
+	// 2026-03-16 is Monday, target = Monday, hour = 9, after 9:00
+	after := time.Date(2026, 3, 16, 15, 0, 0, 0, tz)
+	got := nextFixedWeeklyReset(1, 9, tz, after)
+	// Next Monday at 9:00
+	want := time.Date(2026, 3, 23, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestNextFixedWeeklyReset_TargetDayPast(t *testing.T) {
+	tz := time.UTC
+	// 2026-03-18 is Wednesday (day=3), target = Monday (day=1)
+	after := time.Date(2026, 3, 18, 10, 0, 0, 0, tz)
+	got := nextFixedWeeklyReset(1, 9, tz, after)
+	// Next Monday = 2026-03-23
+	want := time.Date(2026, 3, 23, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestNextFixedWeeklyReset_Sunday(t *testing.T) {
+	tz := time.UTC
+	// 2026-03-14 is Saturday (day=6), target = Sunday (day=0)
+	after := time.Date(2026, 3, 14, 10, 0, 0, 0, tz)
+	got := nextFixedWeeklyReset(0, 0, tz, after)
+	// Next Sunday = 2026-03-15
+	want := time.Date(2026, 3, 15, 0, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+// ---------------------------------------------------------------------------
+// lastFixedWeeklyReset
+// ---------------------------------------------------------------------------
+
+func TestLastFixedWeeklyReset_SameDay_AfterHour(t *testing.T) {
+	tz := time.UTC
+	// 2026-03-16 is Monday (day=1), target = Monday, hour = 9, now = 15:00
+	now := time.Date(2026, 3, 16, 15, 0, 0, 0, tz)
+	got := lastFixedWeeklyReset(1, 9, tz, now)
+	// Today at 9:00
+	want := time.Date(2026, 3, 16, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestLastFixedWeeklyReset_SameDay_BeforeHour(t *testing.T) {
+	tz := time.UTC
+	// 2026-03-16 is Monday, target = Monday, hour = 9, now = 06:00
+	now := time.Date(2026, 3, 16, 6, 0, 0, 0, tz)
+	got := lastFixedWeeklyReset(1, 9, tz, now)
+	// Last Monday at 9:00 = 2026-03-09
+	want := time.Date(2026, 3, 9, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+func TestLastFixedWeeklyReset_DifferentDay(t *testing.T) {
+	tz := time.UTC
+	// 2026-03-18 is Wednesday (day=3), target = Monday (day=1)
+	now := time.Date(2026, 3, 18, 10, 0, 0, 0, tz)
+	got := lastFixedWeeklyReset(1, 9, tz, now)
+	// Last Monday = 2026-03-16
+	want := time.Date(2026, 3, 16, 9, 0, 0, 0, tz)
+	assert.Equal(t, want, got)
+}
+
+// ---------------------------------------------------------------------------
+// isFixedDailyPeriodExpired
+// ---------------------------------------------------------------------------
+
+func TestIsFixedDailyPeriodExpired_ZeroPeriodStart(t *testing.T) {
+	a := &Account{Extra: map[string]any{
+		"quota_daily_reset_mode": "fixed",
+		"quota_daily_reset_hour": float64(9),
+		"quota_reset_timezone":   "UTC",
+	}}
+	assert.True(t, a.isFixedDailyPeriodExpired(time.Time{}))
+}
+
+func TestIsFixedDailyPeriodExpired_NotExpired(t *testing.T) {
+	a := &Account{Extra: map[string]any{
+		"quota_daily_reset_mode": "fixed",
+		"quota_daily_reset_hour": float64(9),
+		"quota_reset_timezone":   "UTC",
+	}}
+	// Period started after the most recent reset → not expired
+	// (This test uses a time very close to "now", which is after the last reset)
+	periodStart := time.Now().Add(-1 * time.Minute)
+	assert.False(t, a.isFixedDailyPeriodExpired(periodStart))
+}
+
+func TestIsFixedDailyPeriodExpired_Expired(t *testing.T) {
+	a := &Account{Extra: map[string]any{
+		"quota_daily_reset_mode": "fixed",
+		"quota_daily_reset_hour": float64(9),
+		"quota_reset_timezone":   "UTC",
+	}}
+	// Period started 3 days ago → definitely expired
+	periodStart := time.Now().Add(-72 * time.Hour)
+	assert.True(t, a.isFixedDailyPeriodExpired(periodStart))
+}
+
+func TestIsFixedDailyPeriodExpired_InvalidTimezone(t *testing.T) {
+	a := &Account{Extra: map[string]any{
+		"quota_daily_reset_mode": "fixed",
+		"quota_daily_reset_hour": float64(9),
+		"quota_reset_timezone":   "Invalid/Timezone",
+	}}
+	// Invalid timezone falls back to UTC
+	periodStart := time.Now().Add(-72 * time.Hour)
+	assert.True(t, a.isFixedDailyPeriodExpired(periodStart))
+}
+
+// ---------------------------------------------------------------------------
+// isFixedWeeklyPeriodExpired
+// ---------------------------------------------------------------------------
+
+func TestIsFixedWeeklyPeriodExpired_ZeroPeriodStart(t *testing.T) {
+	a := &Account{Extra: map[string]any{
+		"quota_weekly_reset_mode": "fixed",
+		"quota_weekly_reset_day":  float64(1),
+		"quota_weekly_reset_hour": float64(9),
+		"quota_reset_timezone":    "UTC",
+	}}
+	assert.True(t, a.isFixedWeeklyPeriodExpired(time.Time{}))
+}
+
+func TestIsFixedWeeklyPeriodExpired_NotExpired(t *testing.T) {
+	a := &Account{Extra: map[string]any{
+		"quota_weekly_reset_mode": "fixed",
+		"quota_weekly_reset_day":  float64(1),
+		"quota_weekly_reset_hour": float64(9),
+		"quota_reset_timezone":    "UTC",
+	}}
+	// Period started 1 minute ago → not expired
+	periodStart := time.Now().Add(-1 * time.Minute)
+	assert.False(t, a.isFixedWeeklyPeriodExpired(periodStart))
+}
+
+func TestIsFixedWeeklyPeriodExpired_Expired(t *testing.T) {
+	a := &Account{Extra: map[string]any{
+		"quota_weekly_reset_mode": "fixed",
+		"quota_weekly_reset_day":  float64(1),
+		"quota_weekly_reset_hour": float64(9),
+		"quota_reset_timezone":    "UTC",
+	}}
+	// Period started 10 days ago → definitely expired
+	periodStart := time.Now().Add(-240 * time.Hour)
+	assert.True(t, a.isFixedWeeklyPeriodExpired(periodStart))
+}
+
+// ---------------------------------------------------------------------------
+// ValidateQuotaResetConfig
+// ---------------------------------------------------------------------------
+
+func TestValidateQuotaResetConfig_NilExtra(t *testing.T) {
+	assert.NoError(t, ValidateQuotaResetConfig(nil))
+}
+
+func TestValidateQuotaResetConfig_EmptyExtra(t *testing.T) {
+	assert.NoError(t, ValidateQuotaResetConfig(map[string]any{}))
+}
+
+func TestValidateQuotaResetConfig_ValidFixed(t *testing.T) {
+	extra := map[string]any{
+		"quota_daily_reset_mode":  "fixed",
+		"quota_daily_reset_hour":  float64(9),
+		"quota_weekly_reset_mode": "fixed",
+		"quota_weekly_reset_day":  float64(1),
+		"quota_weekly_reset_hour": float64(0),
+		"quota_reset_timezone":    "Asia/Shanghai",
+	}
+	assert.NoError(t, ValidateQuotaResetConfig(extra))
+}
+
+func TestValidateQuotaResetConfig_ValidRolling(t *testing.T) {
+	extra := map[string]any{
+		"quota_daily_reset_mode":  "rolling",
+		"quota_weekly_reset_mode": "rolling",
+	}
+	assert.NoError(t, ValidateQuotaResetConfig(extra))
+}
+
+func TestValidateQuotaResetConfig_InvalidTimezone(t *testing.T) {
+	extra := map[string]any{
+		"quota_reset_timezone": "Not/A/Timezone",
+	}
+	err := ValidateQuotaResetConfig(extra)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "quota_reset_timezone")
+}
+
+func TestValidateQuotaResetConfig_InvalidDailyMode(t *testing.T) {
+	extra := map[string]any{
+		"quota_daily_reset_mode": "invalid",
+	}
+	err := ValidateQuotaResetConfig(extra)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "quota_daily_reset_mode")
+}
+
+func TestValidateQuotaResetConfig_InvalidDailyHour_TooHigh(t *testing.T) {
+	extra := map[string]any{
+		"quota_daily_reset_hour": float64(24),
+	}
+	err := ValidateQuotaResetConfig(extra)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "quota_daily_reset_hour")
+}
+
+func TestValidateQuotaResetConfig_InvalidDailyHour_Negative(t *testing.T) {
+	extra := map[string]any{
+		"quota_daily_reset_hour": float64(-1),
+	}
+	err := ValidateQuotaResetConfig(extra)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "quota_daily_reset_hour")
+}
+
+func TestValidateQuotaResetConfig_InvalidWeeklyMode(t *testing.T) {
+	extra := map[string]any{
+		"quota_weekly_reset_mode": "unknown",
+	}
+	err := ValidateQuotaResetConfig(extra)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "quota_weekly_reset_mode")
+}
+
+func TestValidateQuotaResetConfig_InvalidWeeklyDay_TooHigh(t *testing.T) {
+	extra := map[string]any{
+		"quota_weekly_reset_day": float64(7),
+	}
+	err := ValidateQuotaResetConfig(extra)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "quota_weekly_reset_day")
+}
+
+func TestValidateQuotaResetConfig_InvalidWeeklyDay_Negative(t *testing.T) {
+	extra := map[string]any{
+		"quota_weekly_reset_day": float64(-1),
+	}
+	err := ValidateQuotaResetConfig(extra)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "quota_weekly_reset_day")
+}
+
+func TestValidateQuotaResetConfig_InvalidWeeklyHour(t *testing.T) {
+	extra := map[string]any{
+		"quota_weekly_reset_hour": float64(25),
+	}
+	err := ValidateQuotaResetConfig(extra)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "quota_weekly_reset_hour")
+}
+
+func TestValidateQuotaResetConfig_BoundaryValues(t *testing.T) {
+	// All boundary values should be valid
+	extra := map[string]any{
+		"quota_daily_reset_hour":  float64(23),
+		"quota_weekly_reset_day":  float64(0), // Sunday
+		"quota_weekly_reset_hour": float64(0),
+		"quota_reset_timezone":    "UTC",
+	}
+	assert.NoError(t, ValidateQuotaResetConfig(extra))
+
+	extra2 := map[string]any{
+		"quota_daily_reset_hour":  float64(0),
+		"quota_weekly_reset_day":  float64(6), // Saturday
+		"quota_weekly_reset_hour": float64(23),
+	}
+	assert.NoError(t, ValidateQuotaResetConfig(extra2))
+}
+
+// ---------------------------------------------------------------------------
+// ComputeQuotaResetAt
+// ---------------------------------------------------------------------------
+
+func TestComputeQuotaResetAt_RollingMode_NoResetAt(t *testing.T) {
+	extra := map[string]any{
+		"quota_daily_reset_mode":  "rolling",
+		"quota_weekly_reset_mode": "rolling",
+	}
+	ComputeQuotaResetAt(extra)
+	_, hasDailyResetAt := extra["quota_daily_reset_at"]
+	_, hasWeeklyResetAt := extra["quota_weekly_reset_at"]
+	assert.False(t, hasDailyResetAt, "rolling mode should not set quota_daily_reset_at")
+	assert.False(t, hasWeeklyResetAt, "rolling mode should not set quota_weekly_reset_at")
+}
+
+func TestComputeQuotaResetAt_RollingMode_ClearsExistingResetAt(t *testing.T) {
+	extra := map[string]any{
+		"quota_daily_reset_mode":  "rolling",
+		"quota_weekly_reset_mode": "rolling",
+		"quota_daily_reset_at":    "2026-03-14T09:00:00Z",
+		"quota_weekly_reset_at":   "2026-03-16T09:00:00Z",
+	}
+	ComputeQuotaResetAt(extra)
+	_, hasDailyResetAt := extra["quota_daily_reset_at"]
+	_, hasWeeklyResetAt := extra["quota_weekly_reset_at"]
+	assert.False(t, hasDailyResetAt, "rolling mode should remove quota_daily_reset_at")
+	assert.False(t, hasWeeklyResetAt, "rolling mode should remove quota_weekly_reset_at")
+}
+
+func TestComputeQuotaResetAt_FixedDaily_SetsResetAt(t *testing.T) {
+	extra := map[string]any{
+		"quota_daily_reset_mode": "fixed",
+		"quota_daily_reset_hour": float64(9),
+		"quota_reset_timezone":   "UTC",
+	}
+	ComputeQuotaResetAt(extra)
+	resetAtStr, ok := extra["quota_daily_reset_at"].(string)
+	require.True(t, ok, "quota_daily_reset_at should be set")
+
+	resetAt, err := time.Parse(time.RFC3339, resetAtStr)
+	require.NoError(t, err)
+	// Reset time should be in the future
+	assert.True(t, resetAt.After(time.Now()), "reset_at should be in the future")
+	// Reset hour should be 9 UTC
+	assert.Equal(t, 9, resetAt.UTC().Hour())
+}
+
+func TestComputeQuotaResetAt_FixedWeekly_SetsResetAt(t *testing.T) {
+	extra := map[string]any{
+		"quota_weekly_reset_mode": "fixed",
+		"quota_weekly_reset_day":  float64(1), // Monday
+		"quota_weekly_reset_hour": float64(0),
+		"quota_reset_timezone":    "UTC",
+	}
+	ComputeQuotaResetAt(extra)
+	resetAtStr, ok := extra["quota_weekly_reset_at"].(string)
+	require.True(t, ok, "quota_weekly_reset_at should be set")
+
+	resetAt, err := time.Parse(time.RFC3339, resetAtStr)
+	require.NoError(t, err)
+	// Reset time should be in the future
+	assert.True(t, resetAt.After(time.Now()), "reset_at should be in the future")
+	// Reset day should be Monday
+	assert.Equal(t, time.Monday, resetAt.UTC().Weekday())
+}
+
+func TestComputeQuotaResetAt_FixedDaily_WithTimezone(t *testing.T) {
+	tz, err := time.LoadLocation("Asia/Shanghai")
+	require.NoError(t, err)
+
+	extra := map[string]any{
+		"quota_daily_reset_mode": "fixed",
+		"quota_daily_reset_hour": float64(9),
+		"quota_reset_timezone":   "Asia/Shanghai",
+	}
+	ComputeQuotaResetAt(extra)
+	resetAtStr, ok := extra["quota_daily_reset_at"].(string)
+	require.True(t, ok)
+
+	resetAt, err := time.Parse(time.RFC3339, resetAtStr)
+	require.NoError(t, err)
+	// In Shanghai timezone, the hour should be 9
+	assert.Equal(t, 9, resetAt.In(tz).Hour())
+}
+
+func TestComputeQuotaResetAt_DefaultTimezone(t *testing.T) {
+	extra := map[string]any{
+		"quota_daily_reset_mode": "fixed",
+		"quota_daily_reset_hour": float64(12),
+	}
+	ComputeQuotaResetAt(extra)
+	resetAtStr, ok := extra["quota_daily_reset_at"].(string)
+	require.True(t, ok)
+
+	resetAt, err := time.Parse(time.RFC3339, resetAtStr)
+	require.NoError(t, err)
+	// Default timezone is UTC
+	assert.Equal(t, 12, resetAt.UTC().Hour())
+}
+
+func TestComputeQuotaResetAt_InvalidHour_ClampedToZero(t *testing.T) {
+	extra := map[string]any{
+		"quota_daily_reset_mode": "fixed",
+		"quota_daily_reset_hour": float64(99),
+		"quota_reset_timezone":   "UTC",
+	}
+	ComputeQuotaResetAt(extra)
+	resetAtStr, ok := extra["quota_daily_reset_at"].(string)
+	require.True(t, ok)
+
+	resetAt, err := time.Parse(time.RFC3339, resetAtStr)
+	require.NoError(t, err)
+	// Invalid hour → clamped to 0
+	assert.Equal(t, 0, resetAt.UTC().Hour())
+}