feat: implement quota usage tracking and UI enhancements

apps/remix/app/components/general/organisation-usage-panel.tsx

@@ -1,13 +1,38 @@
 import { currentMonthlyPeriod } from '@documenso/lib/universal/monthly-period';
+import {
+  getQuotaUsagePercent,
+  isQuotaExceeded,
+  isQuotaNearing,
+  normalizeCapacityLimit,
+} from '@documenso/lib/universal/quota-usage';
+import { cn } from '@documenso/ui/lib/utils';
+import type { BadgeProps } from '@documenso/ui/primitives/badge';
+import { Badge } from '@documenso/ui/primitives/badge';
 import { Progress } from '@documenso/ui/primitives/progress';
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@documenso/ui/primitives/select';
 
 import { Trans } from '@lingui/react/macro';
 import type { OrganisationClaim, OrganisationMonthlyStat } from '@prisma/client';
-import { useState } from 'react';
-import { match } from 'ts-pattern';
+import type { LucideIcon } from 'lucide-react';
+import { FileIcon, MailIcon, MailOpenIcon, PlugIcon, UsersIcon, UsersRoundIcon } from 'lucide-react';
+import type { ReactNode } from 'react';
+import { useId, useState } from 'react';
+
 import { OrganisationUsageResetButton } from './organisation-usage-reset-button';
 
+type CapacityUsage = {
+  members: number;
+  teams: number;
+};
+
+type UsageRow = {
+  counter: 'document' | 'email' | 'api';
+  label: ReactNode;
+  icon: LucideIcon;
+  used: number;
+  effectiveLimit: number | null;
+};
+
 type OrganisationUsagePanelProps = {
   organisationId: string;
   monthlyStats: Pick<
@@ -15,13 +40,144 @@ type OrganisationUsagePanelProps = {
     'period' | 'documentCount' | 'emailCount' | 'apiCount' | 'emailReports'
   >[];
   organisationClaim: OrganisationClaim;
+  capacityUsage?: CapacityUsage;
+};
+
+type UsageCardState = {
+  status: {
+    label: ReactNode;
+    variant: NonNullable<BadgeProps['variant']>;
+  };
+  percent: number;
+  hasFiniteLimit: boolean;
+  progressClassName: string;
+  subtext: ReactNode;
+};
+
+type UsageCardStateOptions = {
+  used: number;
+  limit: number | null | undefined;
+  footnote?: ReactNode;
+};
+
+const getUsageCardState = ({ used, limit, footnote }: UsageCardStateOptions): UsageCardState => {
+  const percent = getQuotaUsagePercent(used, limit ?? null);
+  const hasFiniteLimit = Boolean(limit && limit > 0);
+
+  if (limit === null || limit === undefined) {
+    return {
+      status: { label: <Trans>Unlimited</Trans>, variant: 'neutral' },
+      percent,
+      hasFiniteLimit,
+      progressClassName: '',
+      subtext: footnote ?? null,
+    };
+  }
+
+  if (limit === 0) {
+    return {
+      status: { label: <Trans>Blocked</Trans>, variant: 'destructive' },
+      percent,
+      hasFiniteLimit,
+      progressClassName: '',
+      subtext: footnote ?? <Trans>Resource blocked</Trans>,
+    };
+  }
+
+  if (isQuotaExceeded(limit, used)) {
+    return {
+      status: {
+        label: used > limit ? <Trans>Exceeded</Trans> : <Trans>Limit reached</Trans>,
+        variant: 'destructive',
+      },
+      percent,
+      hasFiniteLimit,
+      progressClassName: '[&>div]:bg-destructive',
+      subtext: footnote ?? null,
+    };
+  }
+
+  if (isQuotaNearing(limit, used)) {
+    return {
+      status: { label: <Trans>Near limit</Trans>, variant: 'warning' },
+      percent,
+      hasFiniteLimit,
+      progressClassName: '[&>div]:bg-yellow-500 dark:[&>div]:bg-yellow-400',
+      subtext: footnote ?? null,
+    };
+  }
+
+  return {
+    status: { label: <Trans>Within limit</Trans>, variant: 'default' },
+    percent,
+    hasFiniteLimit,
+    progressClassName: '',
+    subtext: footnote ?? null,
+  };
+};
+
+type UsageStatCardProps = {
+  label: ReactNode;
+  icon: LucideIcon;
+  used: number;
+  limit: number | null | undefined;
+  /** When true the card is a plain counter with no limit, status or progress. */
+  countOnly?: boolean;
+  footnote?: ReactNode;
+  action?: ReactNode;
+};
+
+const UsageStatCard = ({ label, icon: Icon, used, limit, countOnly = false, footnote, action }: UsageStatCardProps) => {
+  const { status, percent, hasFiniteLimit, progressClassName, subtext } = getUsageCardState({ used, limit, footnote });
+
+  return (
+    <div className="flex flex-col rounded-lg border bg-background p-5">
+      <div className="flex items-center justify-between gap-3">
+        <div className="flex items-center gap-2 font-medium text-foreground text-sm">
+          <Icon className="h-4 w-4 text-muted-foreground" />
+          <span>{label}</span>
+        </div>
+
+        {!countOnly && (
+          <Badge variant={status.variant} size="small">
+            {status.label}
+          </Badge>
+        )}
+      </div>
+
+      <div className="mt-4 flex flex-1 flex-col">
+        <div className="flex items-baseline justify-between gap-2">
+          <div className="flex items-baseline gap-1.5">
+            <span className="font-semibold text-3xl text-foreground tabular-nums tracking-tight">
+              {used.toLocaleString()}
+            </span>
+            {hasFiniteLimit ? (
+              <span className="text-base text-muted-foreground tabular-nums">/ {limit?.toLocaleString()}</span>
+            ) : null}
+          </div>
+
+          {hasFiniteLimit ? (
+            <span className="font-medium text-muted-foreground text-sm tabular-nums">{percent}%</span>
+          ) : null}
+        </div>
+
+        {hasFiniteLimit ? <Progress className={cn('mt-3 h-2', progressClassName)} value={percent} /> : null}
+
+        {subtext ? <p className="mt-2 text-muted-foreground text-xs">{subtext}</p> : null}
+      </div>
+
+      {action ? <div className="mt-4 flex justify-end border-t pt-4">{action}</div> : null}
+    </div>
+  );
 };
 
 export const OrganisationUsagePanel = ({
   organisationId,
   monthlyStats,
   organisationClaim,
+  capacityUsage,
 }: OrganisationUsagePanelProps) => {
+  const monthlyUsagePeriodId = useId();
   const [selectedPeriod, setSelectedPeriod] = useState<string | undefined>(() => monthlyStats[0]?.period);
 
   const selectedStat = monthlyStats.find((stat) => stat.period === selectedPeriod) ?? monthlyStats[0];
@@ -30,86 +186,105 @@ export const OrganisationUsagePanel = ({
   // current period), so only offer the reset action when viewing the current month.
   const isCurrentPeriod = selectedStat?.period === currentMonthlyPeriod();
 
-  const rows = [
+  const capacityRows = capacityUsage
+    ? [
+        {
+          key: 'members',
+          label: <Trans>Members</Trans>,
+          icon: UsersIcon,
+          used: capacityUsage.members,
+          limit: normalizeCapacityLimit(organisationClaim.memberCount),
+        },
+        {
+          key: 'teams',
+          label: <Trans>Teams</Trans>,
+          icon: UsersRoundIcon,
+          used: capacityUsage.teams,
+          limit: normalizeCapacityLimit(organisationClaim.teamCount),
+        },
+      ]
+    : [];
+
+  const monthlyRows: UsageRow[] = [
     {
-      counter: 'document' as const,
+      counter: 'document',
       label: <Trans>Documents</Trans>,
+      icon: FileIcon,
       used: selectedStat?.documentCount ?? 0,
       effectiveLimit: organisationClaim.documentQuota,
     },
     {
-      counter: 'email' as const,
+      counter: 'email',
       label: <Trans>Emails</Trans>,
+      icon: MailIcon,
       used: selectedStat?.emailCount ?? 0,
       effectiveLimit: organisationClaim.emailQuota,
     },
     {
-      counter: 'api' as const,
+      counter: 'api',
       label: <Trans>API requests</Trans>,
+      icon: PlugIcon,
       used: selectedStat?.apiCount ?? 0,
       effectiveLimit: organisationClaim.apiQuota,
     },
   ];
 
   return (
-    <div className="space-y-4 rounded-md border p-4">
-      <div className="flex items-center justify-between gap-2">
-        <h3 className="font-medium text-sm">
-          <Trans>Usage for period: {selectedStat?.period || 'N/A'}</Trans>
-        </h3>
+    <div className="mt-4 space-y-6">
+      {capacityRows.length > 0 ? (
+        <div className="grid grid-cols-1 gap-4 sm:grid-cols-2 xl:grid-cols-3">
+          {capacityRows.map((row) => (
+            <UsageStatCard key={row.key} label={row.label} icon={row.icon} used={row.used} limit={row.limit} />
+          ))}
+        </div>
+      ) : null}
 
-        {monthlyStats.length > 0 && (
-          <Select value={selectedStat?.period} onValueChange={setSelectedPeriod}>
-            <SelectTrigger className="w-40">
-              <SelectValue />
-            </SelectTrigger>
-            <SelectContent>
-              {monthlyStats.map((stat) => (
-                <SelectItem key={stat.period} value={stat.period}>
-                  {stat.period}
-                </SelectItem>
-              ))}
-            </SelectContent>
-          </Select>
-        )}
-      </div>
+      <div className="space-y-3">
+        <div className="flex flex-col gap-3 sm:flex-row sm:items-center sm:justify-between">
+          <h3 id={monthlyUsagePeriodId} className="font-semibold text-base">
+            <Trans>Monthly usage</Trans>
+          </h3>
 
-      {rows.map((row) => {
-        const percent =
-          row.effectiveLimit && row.effectiveLimit > 0
-            ? Math.min(100, Math.round((row.used / row.effectiveLimit) * 100))
-            : 0;
+          {monthlyStats.length > 0 ? (
+            <Select value={selectedStat?.period} onValueChange={setSelectedPeriod}>
+              <SelectTrigger className="h-9 w-full sm:w-44" aria-labelledby={monthlyUsagePeriodId}>
+                <SelectValue />
+              </SelectTrigger>
+              <SelectContent>
+                {monthlyStats.map((stat) => (
+                  <SelectItem key={stat.period} value={stat.period}>
+                    {stat.period}
+                  </SelectItem>
+                ))}
+              </SelectContent>
+            </Select>
+          ) : null}
+        </div>
 
-        return (
-          <div key={row.counter} className="space-y-1">
-            <div className="flex items-center justify-between text-sm">
-              <span>{row.label}</span>
-              <span className="text-muted-foreground">
-                {row.used} /{' '}
-                {match(row.effectiveLimit)
-                  .with(null, () => <Trans>Unlimited</Trans>)
-                  .with(0, () => <Trans>Blocked</Trans>)
-                  .otherwise(String)}
-              </span>
-            </div>
+        <div className="grid grid-cols-1 gap-4 sm:grid-cols-2 xl:grid-cols-3">
+          {monthlyRows.map((row) => (
+            <UsageStatCard
+              key={row.counter}
+              label={row.label}
+              icon={row.icon}
+              used={row.used}
+              limit={row.effectiveLimit}
+              action={
+                selectedStat && isCurrentPeriod ? (
+                  <OrganisationUsageResetButton organisationId={organisationId} counter={row.counter} />
+                ) : undefined
+              }
+            />
+          ))}
 
-            {row.effectiveLimit && row.effectiveLimit > 0 ? <Progress className="h-2 w-full" value={percent} /> : null}
-
-            {selectedStat && isCurrentPeriod && (
-              <div className="flex w-full justify-end pt-1">
-                <OrganisationUsageResetButton organisationId={organisationId} counter={row.counter} />
-              </div>
-            )}
-          </div>
-        );
-      })}
-
-      <div className="space-y-1">
-        <div className="flex items-center justify-between text-sm">
-          <span>
-            <Trans>Reports</Trans>
-          </span>
-          <span className="text-muted-foreground">{selectedStat?.emailReports ?? 0}</span>
+          <UsageStatCard
+            label={<Trans>Reports</Trans>}
+            icon={MailOpenIcon}
+            used={selectedStat?.emailReports ?? 0}
+            limit={null}
+            countOnly
+            footnote={<Trans>Sent this period</Trans>}
+          />
         </div>
       </div>
     </div>

apps/remix/app/components/general/rate-limit-array-input.tsx

@@ -1,7 +1,9 @@
+import { RATE_LIMIT_WINDOW_REGEX } from '@documenso/lib/types/subscription';
 import { Button } from '@documenso/ui/primitives/button';
 import { Input } from '@documenso/ui/primitives/input';
-import { Trans } from '@lingui/react/macro';
+import { Trans, useLingui } from '@lingui/react/macro';
 import { PlusIcon, Trash2Icon } from 'lucide-react';
+import { useState } from 'react';
 
 type RateLimitEntryValue = { window: string; max: number };
 
@@ -11,50 +13,153 @@ type RateLimitArrayInputProps = {
   disabled?: boolean;
 };
 
+const EMPTY_ENTRY: RateLimitEntryValue = { window: '', max: 0 };
+
+/** Keep in-progress rows; drop rows that are completely empty. */
+const persistEntries = (entries: RateLimitEntryValue[]) => {
+  return entries
+    .map((entry) => ({ ...entry, window: entry.window.trim() }))
+    .filter((entry) => entry.window !== '' || entry.max > 0);
+};
+
 export const RateLimitArrayInput = ({ value, onChange, disabled }: RateLimitArrayInputProps) => {
-  const entries = value ?? [];
+  const { t } = useLingui();
+  const [draftEntry, setDraftEntry] = useState<RateLimitEntryValue | null>(null);
+
+  const entries = draftEntry ? [...value, draftEntry] : value.length ? value : [EMPTY_ENTRY];
+
+  const getWindowError = (entry: RateLimitEntryValue, index: number) => {
+    const window = entry.window.trim();
+
+    if (window === '' && entry.max <= 0) {
+      return null;
+    }
+
+    if (window === '') {
+      return t`Enter a window, e.g. 5m`;
+    }
+
+    if (!RATE_LIMIT_WINDOW_REGEX.test(window)) {
+      return t`Use a duration with a unit, e.g. 5m, 1h, or 24h`;
+    }
+
+    const isDuplicateWindow = entries.some((otherEntry, otherIndex) => {
+      return otherIndex !== index && otherEntry.window.trim() === window;
+    });
+
+    return isDuplicateWindow ? t`Use a unique window for each rate limit` : null;
+  };
+
+  const getMaxError = (entry: RateLimitEntryValue) => {
+    if (entry.window.trim() === '' && entry.max <= 0) {
+      return null;
+    }
+
+    return entry.max > 0 ? null : t`Enter a max request count greater than 0`;
+  };
 
   const updateEntry = (index: number, patch: Partial<RateLimitEntryValue>) => {
-    const next = entries.map((entry, i) => (i === index ? { ...entry, ...patch } : entry));
-    onChange(next);
+    if (index >= value.length) {
+      const nextDraftEntry = { ...(draftEntry ?? EMPTY_ENTRY), ...patch };
+      const shouldPersistDraft = nextDraftEntry.window.trim() !== '' || nextDraftEntry.max > 0;
+
+      if (shouldPersistDraft) {
+        onChange(persistEntries([...value, nextDraftEntry]));
+        setDraftEntry(null);
+        return;
+      }
+
+      setDraftEntry(nextDraftEntry);
+      return;
+    }
+
+    const next = value.map((entry, i) => (i === index ? { ...entry, ...patch } : entry));
+    onChange(persistEntries(next));
   };
 
   const removeEntry = (index: number) => {
-    onChange(entries.filter((_, i) => i !== index));
+    if (index >= value.length) {
+      setDraftEntry(null);
+      return;
+    }
+
+    const next = value.filter((_, i) => i !== index);
+    onChange(persistEntries(next));
   };
 
   const addEntry = () => {
-    onChange([...entries, { window: '5m', max: 100 }]);
+    setDraftEntry(EMPTY_ENTRY);
   };
 
+  const hasErrors = entries.some((entry, index) => getWindowError(entry, index) || getMaxError(entry));
+  const isAddDisabled = disabled || value.length === 0 || Boolean(draftEntry) || hasErrors;
+
   return (
     <div className="space-y-2">
-      {entries.map((entry, index) => (
-        <div key={index} className="flex items-center gap-2">
-          <Input
-            className="w-24"
-            placeholder="5m"
-            value={entry.window}
-            disabled={disabled}
-            onChange={(e) => updateEntry(index, { window: e.target.value })}
-          />
-          <Input
-            className="w-32"
-            type="number"
-            min={1}
-            value={entry.max}
-            disabled={disabled}
-            onChange={(e) => updateEntry(index, { max: parseInt(e.target.value, 10) || 0 })}
-          />
-          <Button type="button" variant="ghost" size="sm" disabled={disabled} onClick={() => removeEntry(index)}>
-            <Trash2Icon className="h-4 w-4" />
-          </Button>
-        </div>
-      ))}
+      <div className="flex items-center gap-2 text-muted-foreground text-xs">
+        <span className="w-20 shrink-0">
+          <Trans>Window</Trans>
+        </span>
+        <span className="flex-1">
+          <Trans>Max requests</Trans>
+        </span>
+        <span className="w-9 shrink-0" aria-hidden="true" />
+      </div>
 
-      <Button type="button" variant="secondary" size="sm" disabled={disabled} onClick={addEntry}>
+      {entries.map((entry, index) => {
+        const windowError = getWindowError(entry, index);
+        const maxError = getMaxError(entry);
+
+        return (
+          <div key={index} className="space-y-1">
+            <div className="flex items-center gap-2">
+              <Input
+                className="w-20 shrink-0"
+                placeholder="5m"
+                value={entry.window}
+                disabled={disabled}
+                aria-invalid={Boolean(windowError)}
+                onChange={(e) => updateEntry(index, { window: e.target.value })}
+              />
+              <Input
+                className="flex-1"
+                type="number"
+                min={1}
+                placeholder="100"
+                value={entry.max || ''}
+                disabled={disabled}
+                aria-invalid={Boolean(maxError)}
+                onChange={(e) => updateEntry(index, { max: parseInt(e.target.value, 10) || 0 })}
+              />
+              <Button
+                type="button"
+                variant="ghost"
+                size="sm"
+                className="h-9 w-9 shrink-0 p-0 text-muted-foreground hover:text-foreground"
+                disabled={disabled}
+                aria-label={t`Remove rate limit`}
+                onClick={() => removeEntry(index)}
+              >
+                <Trash2Icon className="h-4 w-4" />
+              </Button>
+            </div>
+
+            {windowError ? <p className="text-destructive text-xs">{windowError}</p> : null}
+            {maxError ? <p className="text-destructive text-xs">{maxError}</p> : null}
+          </div>
+        );
+      })}
+
+      <Button
+        type="button"
+        variant="outline"
+        size="sm"
+        className="w-full border-dashed"
+        disabled={isAddDisabled}
+        onClick={addEntry}
+      >
         <PlusIcon className="mr-2 h-4 w-4" />
-        <Trans>Add rate limit</Trans>
+        <Trans>Add rate limit window</Trans>
       </Button>
     </div>
   );

packages/lib/types/subscription.ts

@@ -8,8 +8,11 @@ import { z } from 'zod';
  */
 export const RATE_LIMIT_WINDOW_REGEX = /^\d+[smhd]$/;
 
+const RATE_LIMIT_WINDOW_ERROR_MESSAGE = 'Use a duration with a unit, e.g. 5m, 1h, or 24h';
+const RATE_LIMIT_DUPLICATE_WINDOW_ERROR_MESSAGE = 'Use a unique window for each rate limit';
+
 export const ZRateLimitWindowSchema = z.string().trim().regex(RATE_LIMIT_WINDOW_REGEX, {
-  message: 'Use a duration with a unit, e.g. 5m, 1h, or 24h',
+  message: RATE_LIMIT_WINDOW_ERROR_MESSAGE,
 });
 
 export const ZRateLimitArraySchema = z
@@ -20,21 +23,20 @@ export const ZRateLimitArraySchema = z
     }),
   )
   .superRefine((entries, ctx) => {
-    const windows = new Map<string, number>();
+    const windows = new Set<string>();
 
     entries.forEach((entry, index) => {
       const window = entry.window.trim();
-      const duplicateIndex = windows.get(window);
 
-      if (duplicateIndex !== undefined) {
+      if (windows.has(window)) {
         ctx.addIssue({
           code: z.ZodIssueCode.custom,
-          message: 'Use a unique window for each rate limit',
+          message: RATE_LIMIT_DUPLICATE_WINDOW_ERROR_MESSAGE,
           path: [index, 'window'],
         });
       }
 
-      windows.set(window, index);
+      windows.add(window);
     });
   });
 

packages/lib/universal/quota-usage.test.ts

@@ -0,0 +1,99 @@
+import { describe, expect, it } from 'vitest';
+
+import {
+  getQuotaUsagePercent,
+  getQuotaWarningCount,
+  isQuotaExceeded,
+  isQuotaNearing,
+  normalizeCapacityLimit,
+} from './quota-usage';
+
+describe('isQuotaExceeded', () => {
+  it('treats null quota as unlimited (never exceeded)', () => {
+    expect(isQuotaExceeded(null, 0)).toBe(false);
+    expect(isQuotaExceeded(null, 1_000_000)).toBe(false);
+  });
+
+  it('treats a zero quota as blocked (always exceeded)', () => {
+    expect(isQuotaExceeded(0, 0)).toBe(true);
+    expect(isQuotaExceeded(0, 5)).toBe(true);
+  });
+
+  it('is exceeded once usage reaches the quota (>= boundary)', () => {
+    expect(isQuotaExceeded(10, 9)).toBe(false);
+    expect(isQuotaExceeded(10, 10)).toBe(true);
+    expect(isQuotaExceeded(10, 11)).toBe(true);
+  });
+});
+
+describe('getQuotaWarningCount', () => {
+  it('rounds the 80% threshold up', () => {
+    expect(getQuotaWarningCount(10)).toBe(8);
+    expect(getQuotaWarningCount(100)).toBe(80);
+    // 5 * 0.8 = 4 exactly.
+    expect(getQuotaWarningCount(5)).toBe(4);
+    // 3 * 0.8 = 2.4 -> 3, so the warning count equals the quota itself.
+    expect(getQuotaWarningCount(3)).toBe(3);
+  });
+});
+
+describe('isQuotaNearing', () => {
+  it('is never nearing for unlimited or blocked quotas', () => {
+    expect(isQuotaNearing(null, 5)).toBe(false);
+    expect(isQuotaNearing(0, 5)).toBe(false);
+  });
+
+  it('is nearing from the warning threshold up to (but not including) the quota', () => {
+    expect(isQuotaNearing(10, 7)).toBe(false);
+    expect(isQuotaNearing(10, 8)).toBe(true);
+    expect(isQuotaNearing(10, 9)).toBe(true);
+  });
+
+  it('is not nearing once exceeded (nearing and exceeded are mutually exclusive)', () => {
+    expect(isQuotaNearing(10, 10)).toBe(false);
+    expect(isQuotaNearing(10, 11)).toBe(false);
+  });
+
+  it('can never fire for tiny quotas where the warning count equals the quota', () => {
+    // getQuotaWarningCount(3) === 3, so usage >= 3 is already exceeded.
+    expect(isQuotaNearing(3, 2)).toBe(false);
+    expect(isQuotaNearing(3, 3)).toBe(false);
+  });
+
+  it('agrees with the warning-count helper at the boundary', () => {
+    const quota = 250;
+    const warningCount = getQuotaWarningCount(quota);
+
+    expect(isQuotaNearing(quota, warningCount - 1)).toBe(false);
+    expect(isQuotaNearing(quota, warningCount)).toBe(true);
+  });
+});
+
+describe('getQuotaUsagePercent', () => {
+  it('returns 0 for unlimited or non-positive quotas', () => {
+    expect(getQuotaUsagePercent(5, null)).toBe(0);
+    expect(getQuotaUsagePercent(5, 0)).toBe(0);
+    expect(getQuotaUsagePercent(5, -10)).toBe(0);
+  });
+
+  it('rounds the percentage to the nearest integer', () => {
+    expect(getQuotaUsagePercent(1, 3)).toBe(33);
+    expect(getQuotaUsagePercent(2, 3)).toBe(67);
+    expect(getQuotaUsagePercent(50, 100)).toBe(50);
+  });
+
+  it('clamps the percentage to 100 when usage exceeds the quota', () => {
+    expect(getQuotaUsagePercent(150, 100)).toBe(100);
+  });
+});
+
+describe('normalizeCapacityLimit', () => {
+  it('maps 0 (unlimited for capacity limits) to null', () => {
+    expect(normalizeCapacityLimit(0)).toBeNull();
+  });
+
+  it('passes positive limits through unchanged', () => {
+    expect(normalizeCapacityLimit(1)).toBe(1);
+    expect(normalizeCapacityLimit(25)).toBe(25);
+  });
+});

packages/lib/universal/quota-usage.ts

@@ -0,0 +1,57 @@
+export const QUOTA_WARNING_THRESHOLD = 0.8;
+
+/**
+ * Monthly quotas: `null` = unlimited, `0` = blocked. Usage `>=` quota is exceeded.
+ */
+export const isQuotaExceeded = (quota: number | null, usage: number): boolean => {
+  if (quota === null) {
+    return false;
+  }
+
+  if (quota === 0) {
+    return true;
+  }
+
+  return usage >= quota;
+};
+
+/**
+ * The usage count at which a positive quota starts "nearing" (80% rounded up).
+ * The single source for the warning threshold math so the UI panel, quota flags,
+ * and the per-request alert path can't drift apart.
+ */
+export const getQuotaWarningCount = (quota: number): number => {
+  return Math.ceil(quota * QUOTA_WARNING_THRESHOLD);
+};
+
+/**
+ * Nearing once usage reaches the warning threshold (80% rounded up) but is not exceeded.
+ */
+export const isQuotaNearing = (quota: number | null, usage: number): boolean => {
+  if (quota === null || quota === 0) {
+    return false;
+  }
+
+  if (isQuotaExceeded(quota, usage)) {
+    return false;
+  }
+
+  return usage >= getQuotaWarningCount(quota);
+};
+
+export const getQuotaUsagePercent = (usage: number, quota: number | null): number => {
+  if (quota === null || quota <= 0) {
+    return 0;
+  }
+
+  return Math.min(100, Math.round((usage / quota) * 100));
+};
+
+/** Member/team capacity limits use `0` for unlimited. */
+export const normalizeCapacityLimit = (limit: number): number | null => {
+  if (limit === 0) {
+    return null;
+  }
+
+  return limit;
+};