fix(codex): 修复额度窗口过期展示并补齐高覆盖测试

- 后端新增绝对重置时间字段计算（codex_5h_reset_at/codex_7d_reset_at）

- 前端统一窗口解析逻辑：绝对时间优先，updated_at+seconds 回退，过期自动归零

- 新增后端与前端单元测试，覆盖关键边界与异常场景

backend/internal/service/openai_gateway_service.go

@@ -2796,19 +2796,41 @@ func ParseCodexRateLimitHeaders(headers http.Header) *OpenAICodexUsageSnapshot {
 	return snapshot
 }
 
-// updateCodexUsageSnapshot saves the Codex usage snapshot to account's Extra field
+func codexSnapshotBaseTime(snapshot *OpenAICodexUsageSnapshot, fallback time.Time) time.Time {
-func (s *OpenAIGatewayService) updateCodexUsageSnapshot(ctx context.Context, accountID int64, snapshot *OpenAICodexUsageSnapshot) {
 	if snapshot == nil {
-		return
+		return fallback
 	}
-	if s == nil || s.accountRepo == nil {
+	if snapshot.UpdatedAt == "" {
-		return
+		return fallback
+	}
+	base, err := time.Parse(time.RFC3339, snapshot.UpdatedAt)
+	if err != nil {
+		return fallback
+	}
+	return base
+}
+
+func codexResetAtRFC3339(base time.Time, resetAfterSeconds *int) *string {
+	if resetAfterSeconds == nil {
+		return nil
+	}
+	sec := *resetAfterSeconds
+	if sec < 0 {
+		sec = 0
+	}
+	resetAt := base.Add(time.Duration(sec) * time.Second).Format(time.RFC3339)
+	return &resetAt
+}
+
+func buildCodexUsageExtraUpdates(snapshot *OpenAICodexUsageSnapshot, fallbackNow time.Time) map[string]any {
+	if snapshot == nil {
+		return nil
 	}
 
-	// Convert snapshot to map for merging into Extra
+	baseTime := codexSnapshotBaseTime(snapshot, fallbackNow)
 	updates := make(map[string]any)
 
-	// Save raw primary/secondary fields for debugging/tracing
+	// 保存原始 primary/secondary 字段，便于排查问题
 	if snapshot.PrimaryUsedPercent != nil {
 		updates["codex_primary_used_percent"] = *snapshot.PrimaryUsedPercent
 	}
@@ -2830,9 +2852,9 @@ func (s *OpenAIGatewayService) updateCodexUsageSnapshot(ctx context.Context, acc
 	if snapshot.PrimaryOverSecondaryPercent != nil {
 		updates["codex_primary_over_secondary_percent"] = *snapshot.PrimaryOverSecondaryPercent
 	}
-	updates["codex_usage_updated_at"] = snapshot.UpdatedAt
+	updates["codex_usage_updated_at"] = baseTime.Format(time.RFC3339)
 
-	// Normalize to canonical 5h/7d fields
+	// 归一化到 5h/7d 规范字段
 	if normalized := snapshot.Normalize(); normalized != nil {
 		if normalized.Used5hPercent != nil {
 			updates["codex_5h_used_percent"] = *normalized.Used5hPercent
@@ -2852,6 +2874,29 @@ func (s *OpenAIGatewayService) updateCodexUsageSnapshot(ctx context.Context, acc
 		if normalized.Window7dMinutes != nil {
 			updates["codex_7d_window_minutes"] = *normalized.Window7dMinutes
 		}
+		if reset5hAt := codexResetAtRFC3339(baseTime, normalized.Reset5hSeconds); reset5hAt != nil {
+			updates["codex_5h_reset_at"] = *reset5hAt
+		}
+		if reset7dAt := codexResetAtRFC3339(baseTime, normalized.Reset7dSeconds); reset7dAt != nil {
+			updates["codex_7d_reset_at"] = *reset7dAt
+		}
+	}
+
+	return updates
+}
+
+// updateCodexUsageSnapshot saves the Codex usage snapshot to account's Extra field
+func (s *OpenAIGatewayService) updateCodexUsageSnapshot(ctx context.Context, accountID int64, snapshot *OpenAICodexUsageSnapshot) {
+	if snapshot == nil {
+		return
+	}
+	if s == nil || s.accountRepo == nil {
+		return
+	}
+
+	updates := buildCodexUsageExtraUpdates(snapshot, time.Now())
+	if len(updates) == 0 {
+		return
 	}
 
 	// Update account's Extra field asynchronously

backend/internal/service/openai_gateway_service_codex_snapshot_test.go

@@ -0,0 +1,192 @@
+package service
+
+import (
+	"testing"
+	"time"
+)
+
+func TestCodexSnapshotBaseTime(t *testing.T) {
+	fallback := time.Date(2026, 2, 20, 9, 0, 0, 0, time.UTC)
+
+	t.Run("nil snapshot uses fallback", func(t *testing.T) {
+		got := codexSnapshotBaseTime(nil, fallback)
+		if !got.Equal(fallback) {
+			t.Fatalf("got %v, want fallback %v", got, fallback)
+		}
+	})
+
+	t.Run("empty updatedAt uses fallback", func(t *testing.T) {
+		got := codexSnapshotBaseTime(&OpenAICodexUsageSnapshot{}, fallback)
+		if !got.Equal(fallback) {
+			t.Fatalf("got %v, want fallback %v", got, fallback)
+		}
+	})
+
+	t.Run("valid updatedAt wins", func(t *testing.T) {
+		got := codexSnapshotBaseTime(&OpenAICodexUsageSnapshot{UpdatedAt: "2026-02-16T10:00:00Z"}, fallback)
+		want := time.Date(2026, 2, 16, 10, 0, 0, 0, time.UTC)
+		if !got.Equal(want) {
+			t.Fatalf("got %v, want %v", got, want)
+		}
+	})
+
+	t.Run("invalid updatedAt uses fallback", func(t *testing.T) {
+		got := codexSnapshotBaseTime(&OpenAICodexUsageSnapshot{UpdatedAt: "invalid"}, fallback)
+		if !got.Equal(fallback) {
+			t.Fatalf("got %v, want fallback %v", got, fallback)
+		}
+	})
+}
+
+func TestCodexResetAtRFC3339(t *testing.T) {
+	base := time.Date(2026, 2, 16, 10, 0, 0, 0, time.UTC)
+
+	t.Run("nil reset returns nil", func(t *testing.T) {
+		if got := codexResetAtRFC3339(base, nil); got != nil {
+			t.Fatalf("expected nil, got %v", *got)
+		}
+	})
+
+	t.Run("positive seconds", func(t *testing.T) {
+		sec := 90
+		got := codexResetAtRFC3339(base, &sec)
+		if got == nil {
+			t.Fatal("expected non-nil")
+		}
+		if *got != "2026-02-16T10:01:30Z" {
+			t.Fatalf("got %s, want %s", *got, "2026-02-16T10:01:30Z")
+		}
+	})
+
+	t.Run("negative seconds clamp to base", func(t *testing.T) {
+		sec := -3
+		got := codexResetAtRFC3339(base, &sec)
+		if got == nil {
+			t.Fatal("expected non-nil")
+		}
+		if *got != "2026-02-16T10:00:00Z" {
+			t.Fatalf("got %s, want %s", *got, "2026-02-16T10:00:00Z")
+		}
+	})
+}
+
+func TestBuildCodexUsageExtraUpdates_UsesSnapshotUpdatedAt(t *testing.T) {
+	primaryUsed := 88.0
+	primaryReset := 86400
+	primaryWindow := 10080
+	secondaryUsed := 12.0
+	secondaryReset := 3600
+	secondaryWindow := 300
+
+	snapshot := &OpenAICodexUsageSnapshot{
+		PrimaryUsedPercent:         &primaryUsed,
+		PrimaryResetAfterSeconds:   &primaryReset,
+		PrimaryWindowMinutes:       &primaryWindow,
+		SecondaryUsedPercent:       &secondaryUsed,
+		SecondaryResetAfterSeconds: &secondaryReset,
+		SecondaryWindowMinutes:     &secondaryWindow,
+		UpdatedAt:                  "2026-02-16T10:00:00Z",
+	}
+
+	updates := buildCodexUsageExtraUpdates(snapshot, time.Date(2026, 2, 20, 8, 0, 0, 0, time.UTC))
+	if updates == nil {
+		t.Fatal("expected non-nil updates")
+	}
+
+	if got := updates["codex_usage_updated_at"]; got != "2026-02-16T10:00:00Z" {
+		t.Fatalf("codex_usage_updated_at = %v, want %s", got, "2026-02-16T10:00:00Z")
+	}
+	if got := updates["codex_5h_reset_at"]; got != "2026-02-16T11:00:00Z" {
+		t.Fatalf("codex_5h_reset_at = %v, want %s", got, "2026-02-16T11:00:00Z")
+	}
+	if got := updates["codex_7d_reset_at"]; got != "2026-02-17T10:00:00Z" {
+		t.Fatalf("codex_7d_reset_at = %v, want %s", got, "2026-02-17T10:00:00Z")
+	}
+}
+
+func TestBuildCodexUsageExtraUpdates_FallbackToNowWhenUpdatedAtInvalid(t *testing.T) {
+	primaryUsed := 15.0
+	primaryReset := 30
+	primaryWindow := 300
+
+	fallbackNow := time.Date(2026, 2, 20, 8, 30, 0, 0, time.UTC)
+	snapshot := &OpenAICodexUsageSnapshot{
+		PrimaryUsedPercent:       &primaryUsed,
+		PrimaryResetAfterSeconds: &primaryReset,
+		PrimaryWindowMinutes:     &primaryWindow,
+		UpdatedAt:                "invalid-time",
+	}
+
+	updates := buildCodexUsageExtraUpdates(snapshot, fallbackNow)
+	if updates == nil {
+		t.Fatal("expected non-nil updates")
+	}
+
+	if got := updates["codex_usage_updated_at"]; got != "2026-02-20T08:30:00Z" {
+		t.Fatalf("codex_usage_updated_at = %v, want %s", got, "2026-02-20T08:30:00Z")
+	}
+	if got := updates["codex_5h_reset_at"]; got != "2026-02-20T08:30:30Z" {
+		t.Fatalf("codex_5h_reset_at = %v, want %s", got, "2026-02-20T08:30:30Z")
+	}
+}
+
+func TestBuildCodexUsageExtraUpdates_ClampNegativeResetSeconds(t *testing.T) {
+	primaryUsed := 90.0
+	primaryReset := 7200
+	primaryWindow := 10080
+	secondaryUsed := 100.0
+	secondaryReset := -15
+	secondaryWindow := 300
+
+	snapshot := &OpenAICodexUsageSnapshot{
+		PrimaryUsedPercent:         &primaryUsed,
+		PrimaryResetAfterSeconds:   &primaryReset,
+		PrimaryWindowMinutes:       &primaryWindow,
+		SecondaryUsedPercent:       &secondaryUsed,
+		SecondaryResetAfterSeconds: &secondaryReset,
+		SecondaryWindowMinutes:     &secondaryWindow,
+		UpdatedAt:                  "2026-02-16T10:00:00Z",
+	}
+
+	updates := buildCodexUsageExtraUpdates(snapshot, time.Time{})
+	if updates == nil {
+		t.Fatal("expected non-nil updates")
+	}
+
+	if got := updates["codex_5h_reset_after_seconds"]; got != -15 {
+		t.Fatalf("codex_5h_reset_after_seconds = %v, want %d", got, -15)
+	}
+	if got := updates["codex_5h_reset_at"]; got != "2026-02-16T10:00:00Z" {
+		t.Fatalf("codex_5h_reset_at = %v, want %s", got, "2026-02-16T10:00:00Z")
+	}
+}
+
+func TestBuildCodexUsageExtraUpdates_NilSnapshot(t *testing.T) {
+	if got := buildCodexUsageExtraUpdates(nil, time.Now()); got != nil {
+		t.Fatalf("expected nil updates, got %v", got)
+	}
+}
+
+func TestBuildCodexUsageExtraUpdates_WithoutNormalizedWindowFields(t *testing.T) {
+	primaryUsed := 42.0
+	fallbackNow := time.Date(2026, 2, 20, 9, 15, 0, 0, time.UTC)
+	snapshot := &OpenAICodexUsageSnapshot{
+		PrimaryUsedPercent: &primaryUsed,
+		UpdatedAt:          "",
+	}
+
+	updates := buildCodexUsageExtraUpdates(snapshot, fallbackNow)
+	if updates == nil {
+		t.Fatal("expected non-nil updates")
+	}
+
+	if got := updates["codex_usage_updated_at"]; got != "2026-02-20T09:15:00Z" {
+		t.Fatalf("codex_usage_updated_at = %v, want %s", got, "2026-02-20T09:15:00Z")
+	}
+	if _, ok := updates["codex_5h_reset_at"]; ok {
+		t.Fatalf("did not expect codex_5h_reset_at in updates: %v", updates["codex_5h_reset_at"])
+	}
+	if _, ok := updates["codex_7d_reset_at"]; ok {
+		t.Fatalf("did not expect codex_7d_reset_at in updates: %v", updates["codex_7d_reset_at"])
+	}
+}

frontend/src/components/account/AccountUsageCell.vue

@@ -282,6 +282,7 @@ import { ref, computed, onMounted } from 'vue'
 import { useI18n } from 'vue-i18n'
 import { adminAPI } from '@/api/admin'
 import type { Account, AccountUsageInfo, GeminiCredentials, WindowStats } from '@/types'
+import { resolveCodexUsageWindow } from '@/utils/codexUsage'
 import UsageProgressBar from './UsageProgressBar.vue'
 import AccountQuotaInfo from './AccountQuotaInfo.vue'
 
@@ -326,153 +327,18 @@ const geminiUsageAvailable = computed(() => {
   )
 })
 
+const codex5hWindow = computed(() => resolveCodexUsageWindow(props.account.extra, '5h'))
+const codex7dWindow = computed(() => resolveCodexUsageWindow(props.account.extra, '7d'))
+
 // OpenAI Codex usage computed properties
 const hasCodexUsage = computed(() => {
-  const extra = props.account.extra
+  return codex5hWindow.value.usedPercent !== null || codex7dWindow.value.usedPercent !== null
-  return (
-    extra &&
-    // Check for new canonical fields first
-    (extra.codex_5h_used_percent !== undefined ||
-      extra.codex_7d_used_percent !== undefined ||
-      // Fallback to legacy fields
-      extra.codex_primary_used_percent !== undefined ||
-      extra.codex_secondary_used_percent !== undefined)
-  )
 })
 
-// 5h window usage (prefer canonical field)
+const codex5hUsedPercent = computed(() => codex5hWindow.value.usedPercent)
-const codex5hUsedPercent = computed(() => {
+const codex5hResetAt = computed(() => codex5hWindow.value.resetAt)
-  const extra = props.account.extra
+const codex7dUsedPercent = computed(() => codex7dWindow.value.usedPercent)
-  if (!extra) return null
+const codex7dResetAt = computed(() => codex7dWindow.value.resetAt)
-
-  // Prefer canonical field
-  if (extra.codex_5h_used_percent !== undefined) {
-    return extra.codex_5h_used_percent
-  }
-
-  // Fallback: detect from legacy fields using window_minutes
-  if (
-    extra.codex_primary_window_minutes !== undefined &&
-    extra.codex_primary_window_minutes <= 360
-  ) {
-    return extra.codex_primary_used_percent ?? null
-  }
-  if (
-    extra.codex_secondary_window_minutes !== undefined &&
-    extra.codex_secondary_window_minutes <= 360
-  ) {
-    return extra.codex_secondary_used_percent ?? null
-  }
-
-  // Legacy assumption: secondary = 5h (may be incorrect)
-  return extra.codex_secondary_used_percent ?? null
-})
-
-const codex5hResetAt = computed(() => {
-  const extra = props.account.extra
-  if (!extra) return null
-
-  // Prefer canonical field
-  if (extra.codex_5h_reset_after_seconds !== undefined) {
-    const resetTime = new Date(Date.now() + extra.codex_5h_reset_after_seconds * 1000)
-    return resetTime.toISOString()
-  }
-
-  // Fallback: detect from legacy fields using window_minutes
-  if (
-    extra.codex_primary_window_minutes !== undefined &&
-    extra.codex_primary_window_minutes <= 360
-  ) {
-    if (extra.codex_primary_reset_after_seconds !== undefined) {
-      const resetTime = new Date(Date.now() + extra.codex_primary_reset_after_seconds * 1000)
-      return resetTime.toISOString()
-    }
-  }
-  if (
-    extra.codex_secondary_window_minutes !== undefined &&
-    extra.codex_secondary_window_minutes <= 360
-  ) {
-    if (extra.codex_secondary_reset_after_seconds !== undefined) {
-      const resetTime = new Date(Date.now() + extra.codex_secondary_reset_after_seconds * 1000)
-      return resetTime.toISOString()
-    }
-  }
-
-  // Legacy assumption: secondary = 5h
-  if (extra.codex_secondary_reset_after_seconds !== undefined) {
-    const resetTime = new Date(Date.now() + extra.codex_secondary_reset_after_seconds * 1000)
-    return resetTime.toISOString()
-  }
-
-  return null
-})
-
-// 7d window usage (prefer canonical field)
-const codex7dUsedPercent = computed(() => {
-  const extra = props.account.extra
-  if (!extra) return null
-
-  // Prefer canonical field
-  if (extra.codex_7d_used_percent !== undefined) {
-    return extra.codex_7d_used_percent
-  }
-
-  // Fallback: detect from legacy fields using window_minutes
-  if (
-    extra.codex_primary_window_minutes !== undefined &&
-    extra.codex_primary_window_minutes >= 10000
-  ) {
-    return extra.codex_primary_used_percent ?? null
-  }
-  if (
-    extra.codex_secondary_window_minutes !== undefined &&
-    extra.codex_secondary_window_minutes >= 10000
-  ) {
-    return extra.codex_secondary_used_percent ?? null
-  }
-
-  // Legacy assumption: primary = 7d (may be incorrect)
-  return extra.codex_primary_used_percent ?? null
-})
-
-const codex7dResetAt = computed(() => {
-  const extra = props.account.extra
-  if (!extra) return null
-
-  // Prefer canonical field
-  if (extra.codex_7d_reset_after_seconds !== undefined) {
-    const resetTime = new Date(Date.now() + extra.codex_7d_reset_after_seconds * 1000)
-    return resetTime.toISOString()
-  }
-
-  // Fallback: detect from legacy fields using window_minutes
-  if (
-    extra.codex_primary_window_minutes !== undefined &&
-    extra.codex_primary_window_minutes >= 10000
-  ) {
-    if (extra.codex_primary_reset_after_seconds !== undefined) {
-      const resetTime = new Date(Date.now() + extra.codex_primary_reset_after_seconds * 1000)
-      return resetTime.toISOString()
-    }
-  }
-  if (
-    extra.codex_secondary_window_minutes !== undefined &&
-    extra.codex_secondary_window_minutes >= 10000
-  ) {
-    if (extra.codex_secondary_reset_after_seconds !== undefined) {
-      const resetTime = new Date(Date.now() + extra.codex_secondary_reset_after_seconds * 1000)
-      return resetTime.toISOString()
-    }
-  }
-
-  // Legacy assumption: primary = 7d
-  if (extra.codex_primary_reset_after_seconds !== undefined) {
-    const resetTime = new Date(Date.now() + extra.codex_primary_reset_after_seconds * 1000)
-    return resetTime.toISOString()
-  }
-
-  return null
-})
 
 // Antigravity quota types (用于 API 返回的数据)
 interface AntigravityUsageResult {

frontend/src/utils/__tests__/codexUsage.spec.ts

@@ -0,0 +1,206 @@
+import { describe, expect, it } from 'vitest'
+import { resolveCodexUsageWindow } from '@/utils/codexUsage'
+
+describe('resolveCodexUsageWindow', () => {
+  it('快照为空时返回空窗口', () => {
+    const result = resolveCodexUsageWindow(null, '5h', new Date('2026-02-20T08:00:00Z'))
+    expect(result).toEqual({ usedPercent: null, resetAt: null })
+  })
+
+  it('优先使用后端提供的绝对重置时间', () => {
+    const now = new Date('2026-02-20T08:00:00Z')
+    const result = resolveCodexUsageWindow(
+      {
+        codex_5h_used_percent: 55,
+        codex_5h_reset_at: '2026-02-20T10:00:00Z',
+        codex_5h_reset_after_seconds: 1
+      },
+      '5h',
+      now
+    )
+
+    expect(result.usedPercent).toBe(55)
+    expect(result.resetAt).toBe('2026-02-20T10:00:00.000Z')
+  })
+
+  it('窗口已过期时自动归零', () => {
+    const now = new Date('2026-02-20T08:00:00Z')
+    const result = resolveCodexUsageWindow(
+      {
+        codex_7d_used_percent: 100,
+        codex_7d_reset_at: '2026-02-20T07:00:00Z'
+      },
+      '7d',
+      now
+    )
+
+    expect(result.usedPercent).toBe(0)
+    expect(result.resetAt).toBe('2026-02-20T07:00:00.000Z')
+  })
+
+  it('无绝对时间时使用 updated_at + seconds 回退计算', () => {
+    const now = new Date('2026-02-20T07:00:00Z')
+    const result = resolveCodexUsageWindow(
+      {
+        codex_5h_used_percent: 20,
+        codex_5h_reset_after_seconds: 3600,
+        codex_usage_updated_at: '2026-02-20T06:30:00Z'
+      },
+      '5h',
+      now
+    )
+
+    expect(result.usedPercent).toBe(20)
+    expect(result.resetAt).toBe('2026-02-20T07:30:00.000Z')
+  })
+
+  it('支持 legacy primary/secondary 字段映射', () => {
+    const now = new Date('2026-02-20T07:05:00Z')
+    const result5h = resolveCodexUsageWindow(
+      {
+        codex_primary_window_minutes: 10080,
+        codex_primary_used_percent: 70,
+        codex_primary_reset_after_seconds: 86400,
+        codex_secondary_window_minutes: 300,
+        codex_secondary_used_percent: 15,
+        codex_secondary_reset_after_seconds: 1200,
+        codex_usage_updated_at: '2026-02-20T07:00:00Z'
+      },
+      '5h',
+      now
+    )
+    const result7d = resolveCodexUsageWindow(
+      {
+        codex_primary_window_minutes: 10080,
+        codex_primary_used_percent: 70,
+        codex_primary_reset_after_seconds: 86400,
+        codex_secondary_window_minutes: 300,
+        codex_secondary_used_percent: 15,
+        codex_secondary_reset_after_seconds: 1200,
+        codex_usage_updated_at: '2026-02-20T07:00:00Z'
+      },
+      '7d',
+      now
+    )
+
+    expect(result5h.usedPercent).toBe(15)
+    expect(result5h.resetAt).toBe('2026-02-20T07:20:00.000Z')
+    expect(result7d.usedPercent).toBe(70)
+    expect(result7d.resetAt).toBe('2026-02-21T07:00:00.000Z')
+  })
+
+  it('legacy 5h 在 primary<=360 时优先 primary 并支持字符串数字', () => {
+    const result = resolveCodexUsageWindow(
+      {
+        codex_primary_window_minutes: '300',
+        codex_primary_used_percent: '21',
+        codex_primary_reset_after_seconds: '1800',
+        codex_secondary_window_minutes: '10080',
+        codex_secondary_used_percent: '99',
+        codex_secondary_reset_after_seconds: '99999',
+        codex_usage_updated_at: '2026-02-20T08:00:00Z'
+      },
+      '5h',
+      new Date('2026-02-20T08:10:00Z')
+    )
+
+    expect(result.usedPercent).toBe(21)
+    expect(result.resetAt).toBe('2026-02-20T08:30:00.000Z')
+  })
+
+  it('legacy 5h 在无窗口信息时回退 secondary', () => {
+    const result = resolveCodexUsageWindow(
+      {
+        codex_secondary_used_percent: 19,
+        codex_secondary_reset_after_seconds: 120,
+        codex_usage_updated_at: '2026-02-20T08:00:00Z'
+      },
+      '5h',
+      new Date('2026-02-20T08:00:01Z')
+    )
+
+    expect(result.usedPercent).toBe(19)
+    expect(result.resetAt).toBe('2026-02-20T08:02:00.000Z')
+  })
+
+  it('legacy 场景下 secondary 为 7d 时能正确识别', () => {
+    const now = new Date('2026-02-20T07:30:00Z')
+    const result = resolveCodexUsageWindow(
+      {
+        codex_primary_window_minutes: 300,
+        codex_primary_used_percent: 5,
+        codex_primary_reset_after_seconds: 600,
+        codex_secondary_window_minutes: 10080,
+        codex_secondary_used_percent: 66,
+        codex_secondary_reset_after_seconds: 7200,
+        codex_usage_updated_at: '2026-02-20T07:00:00Z'
+      },
+      '7d',
+      now
+    )
+
+    expect(result.usedPercent).toBe(66)
+    expect(result.resetAt).toBe('2026-02-20T09:00:00.000Z')
+  })
+
+  it('绝对时间非法时回退到 updated_at + seconds', () => {
+    const now = new Date('2026-02-20T07:40:00Z')
+    const result = resolveCodexUsageWindow(
+      {
+        codex_5h_used_percent: 33,
+        codex_5h_reset_at: 'not-a-date',
+        codex_5h_reset_after_seconds: 900,
+        codex_usage_updated_at: '2026-02-20T07:30:00Z'
+      },
+      '5h',
+      now
+    )
+
+    expect(result.usedPercent).toBe(33)
+    expect(result.resetAt).toBe('2026-02-20T07:45:00.000Z')
+  })
+
+  it('updated_at 非法且无绝对时间时 resetAt 返回 null', () => {
+    const result = resolveCodexUsageWindow(
+      {
+        codex_5h_used_percent: 10,
+        codex_5h_reset_after_seconds: 123,
+        codex_usage_updated_at: 'invalid-time'
+      },
+      '5h',
+      new Date('2026-02-20T08:00:00Z')
+    )
+
+    expect(result.usedPercent).toBe(10)
+    expect(result.resetAt).toBeNull()
+  })
+
+  it('reset_after_seconds 为负数时按 0 秒处理', () => {
+    const result = resolveCodexUsageWindow(
+      {
+        codex_5h_used_percent: 80,
+        codex_5h_reset_after_seconds: -30,
+        codex_usage_updated_at: '2026-02-20T08:00:00Z'
+      },
+      '5h',
+      new Date('2026-02-20T07:59:00Z')
+    )
+
+    expect(result.usedPercent).toBe(80)
+    expect(result.resetAt).toBe('2026-02-20T08:00:00.000Z')
+  })
+
+  it('百分比缺失时仍可计算 resetAt 供倒计时展示', () => {
+    const result = resolveCodexUsageWindow(
+      {
+        codex_7d_reset_after_seconds: 60,
+        codex_usage_updated_at: '2026-02-20T08:00:00Z'
+      },
+      '7d',
+      new Date('2026-02-20T08:00:01Z')
+    )
+
+    expect(result.usedPercent).toBeNull()
+    expect(result.resetAt).toBe('2026-02-20T08:01:00.000Z')
+  })
+})

frontend/src/utils/codexUsage.ts

@@ -0,0 +1,130 @@
+import type { CodexUsageSnapshot } from '@/types'
+
+export interface ResolvedCodexUsageWindow {
+  usedPercent: number | null
+  resetAt: string | null
+}
+
+type WindowKind = '5h' | '7d'
+
+function asNumber(value: unknown): number | null {
+  if (typeof value === 'number' && Number.isFinite(value)) return value
+  if (typeof value === 'string' && value.trim() !== '') {
+    const n = Number(value)
+    if (Number.isFinite(n)) return n
+  }
+  return null
+}
+
+function asString(value: unknown): string | null {
+  if (typeof value !== 'string') return null
+  const trimmed = value.trim()
+  return trimmed === '' ? null : trimmed
+}
+
+function asISOTime(value: unknown): string | null {
+  const raw = asString(value)
+  if (!raw) return null
+  const date = new Date(raw)
+  if (Number.isNaN(date.getTime())) return null
+  return date.toISOString()
+}
+
+function resolveLegacy5h(snapshot: Record<string, unknown>): { used: number | null; resetAfterSeconds: number | null } {
+  const primaryWindow = asNumber(snapshot.codex_primary_window_minutes)
+  const secondaryWindow = asNumber(snapshot.codex_secondary_window_minutes)
+  const primaryUsed = asNumber(snapshot.codex_primary_used_percent)
+  const secondaryUsed = asNumber(snapshot.codex_secondary_used_percent)
+  const primaryReset = asNumber(snapshot.codex_primary_reset_after_seconds)
+  const secondaryReset = asNumber(snapshot.codex_secondary_reset_after_seconds)
+
+  if (primaryWindow != null && primaryWindow <= 360) {
+    return { used: primaryUsed, resetAfterSeconds: primaryReset }
+  }
+  if (secondaryWindow != null && secondaryWindow <= 360) {
+    return { used: secondaryUsed, resetAfterSeconds: secondaryReset }
+  }
+  return { used: secondaryUsed, resetAfterSeconds: secondaryReset }
+}
+
+function resolveLegacy7d(snapshot: Record<string, unknown>): { used: number | null; resetAfterSeconds: number | null } {
+  const primaryWindow = asNumber(snapshot.codex_primary_window_minutes)
+  const secondaryWindow = asNumber(snapshot.codex_secondary_window_minutes)
+  const primaryUsed = asNumber(snapshot.codex_primary_used_percent)
+  const secondaryUsed = asNumber(snapshot.codex_secondary_used_percent)
+  const primaryReset = asNumber(snapshot.codex_primary_reset_after_seconds)
+  const secondaryReset = asNumber(snapshot.codex_secondary_reset_after_seconds)
+
+  if (primaryWindow != null && primaryWindow >= 10000) {
+    return { used: primaryUsed, resetAfterSeconds: primaryReset }
+  }
+  if (secondaryWindow != null && secondaryWindow >= 10000) {
+    return { used: secondaryUsed, resetAfterSeconds: secondaryReset }
+  }
+  return { used: primaryUsed, resetAfterSeconds: primaryReset }
+}
+
+function resolveFromSeconds(snapshot: Record<string, unknown>, resetAfterSeconds: number | null): string | null {
+  if (resetAfterSeconds == null) return null
+
+  const baseRaw = asString(snapshot.codex_usage_updated_at)
+  const base = baseRaw ? new Date(baseRaw) : new Date()
+  if (Number.isNaN(base.getTime())) {
+    return null
+  }
+
+  const sec = Math.max(0, resetAfterSeconds)
+  const resetAt = new Date(base.getTime() + sec * 1000)
+  return resetAt.toISOString()
+}
+
+function applyExpiredRule(window: ResolvedCodexUsageWindow, now: Date): ResolvedCodexUsageWindow {
+  if (window.usedPercent == null || !window.resetAt) return window
+  const resetDate = new Date(window.resetAt)
+  if (Number.isNaN(resetDate.getTime())) return window
+  if (resetDate.getTime() <= now.getTime()) {
+    return { usedPercent: 0, resetAt: resetDate.toISOString() }
+  }
+  return window
+}
+
+export function resolveCodexUsageWindow(
+  snapshot: (CodexUsageSnapshot & Record<string, unknown>) | null | undefined,
+  window: WindowKind,
+  now: Date = new Date()
+): ResolvedCodexUsageWindow {
+  if (!snapshot) {
+    return { usedPercent: null, resetAt: null }
+  }
+
+  const typedSnapshot = snapshot as Record<string, unknown>
+  let usedPercent: number | null
+  let resetAfterSeconds: number | null
+  let resetAt: string | null
+
+  if (window === '5h') {
+    usedPercent = asNumber(typedSnapshot.codex_5h_used_percent)
+    resetAfterSeconds = asNumber(typedSnapshot.codex_5h_reset_after_seconds)
+    resetAt = asISOTime(typedSnapshot.codex_5h_reset_at)
+    if (usedPercent == null || (resetAfterSeconds == null && !resetAt)) {
+      const legacy = resolveLegacy5h(typedSnapshot)
+      if (usedPercent == null) usedPercent = legacy.used
+      if (resetAfterSeconds == null) resetAfterSeconds = legacy.resetAfterSeconds
+    }
+  } else {
+    usedPercent = asNumber(typedSnapshot.codex_7d_used_percent)
+    resetAfterSeconds = asNumber(typedSnapshot.codex_7d_reset_after_seconds)
+    resetAt = asISOTime(typedSnapshot.codex_7d_reset_at)
+    if (usedPercent == null || (resetAfterSeconds == null && !resetAt)) {
+      const legacy = resolveLegacy7d(typedSnapshot)
+      if (usedPercent == null) usedPercent = legacy.used
+      if (resetAfterSeconds == null) resetAfterSeconds = legacy.resetAfterSeconds
+    }
+  }
+
+  if (!resetAt) {
+    resetAt = resolveFromSeconds(typedSnapshot, resetAfterSeconds)
+  }
+
+  return applyExpiredRule({ usedPercent, resetAt }, now)
+}