Add charges and the billing limit for trusted apps

src/Id/Concerns/ManagesBalance.php

@@ -1,60 +1,66 @@
-<?php
-
-namespace Anikeen\Id\Concerns;
-
-use Anikeen\Id\Resources\Transaction;
-use Throwable;
-
-trait ManagesBalance
-{
-    use HasBillable;
-
-    /**
-     * Get balance from the current user.
-     *
-     * @throws Throwable
-     */
-    public function balance(): float
-    {
-        return $this->getUserData()->current_balance;
-    }
-
-    /**
-     * Get charges from the current user.
-     *
-     * @throws Throwable
-     */
-    public function charges(): float
-    {
-        return $this->getUserData()->current_charges;
-    }
-
-    /**
-     * Billing overview of the current user: current_balance, current_charges, vat_rate,
-     * has_billing_address, has_default_payment_method, open_orders.
-     *
-     * @throws Throwable
-     */
-    public function billingOverview(): object
-    {
-        return $this->anikeenId()->request('GET', 'v1/billing')->data;
-    }
-
-    /**
-     * Charge given amount (deposit) from one of the current user's payment methods.
-     *
-     * @param float|string $amount Amount in euros (0.50 to 10,000, at most 2 decimals).
-     * @param string $paymentMethodId Stripe payment method ID (pm_…).
-     * @param array $options Ignored; Stripe options can no longer be passed through.
-     * @throws Throwable
-     */
-    public function charge(float|string $amount, string $paymentMethodId, array $options = []): Transaction
-    {
-        return (new Transaction(fn() => $this->anikeenId()
-            ->request('POST', 'v1/billing/charge', [
-                'amount' => $amount,
-                'payment_method_id' => $paymentMethodId,
-            ])))
-            ->setBillable($this);
-    }
-}␍
+<?php
+
+namespace Anikeen\Id\Concerns;
+
+use Anikeen\Id\Resources\Transaction;
+use Throwable;
+
+trait ManagesBalance
+{
+    use HasBillable;
+
+    /**
+     * Get balance from the current user.
+     *
+     * @throws Throwable
+     */
+    public function balance(): float
+    {
+        return $this->getUserData()->current_balance;
+    }
+
+    /**
+     * Get charges from the current user.
+     *
+     * @throws Throwable
+     */
+    public function charges(): float
+    {
+        return $this->getUserData()->current_charges;
+    }
+
+    /**
+     * Billing overview of the current user: current_balance, current_charges, vat_rate,
+     * has_billing_address, has_default_payment_method, open_orders and billing_limit.
+     *
+     * billing_limit is the user's monthly billing limit {object: "billing_limit", user_id,
+     * currency, basis, limit, used, remaining, remaining_net, vat_rate, reached, resets_at,
+     * version} (`limit`, `remaining` and `remaining_net` null without a limit; wrap it in
+     * `new \Anikeen\Id\Resources\BillingLimit(…)` for its helpers), or null while the user has no
+     * limit and can't set one yet. Older Anikeen ID releases don't send the key.
+     *
+     * @throws Throwable
+     */
+    public function billingOverview(): object
+    {
+        return $this->anikeenId()->request('GET', 'v1/billing')->data;
+    }
+
+    /**
+     * Charge given amount (deposit) from one of the current user's payment methods.
+     *
+     * @param float|string $amount Amount in euros (0.50 to 10,000, at most 2 decimals).
+     * @param string $paymentMethodId Stripe payment method ID (pm_…).
+     * @param array $options Ignored; Stripe options can no longer be passed through.
+     * @throws Throwable
+     */
+    public function charge(float|string $amount, string $paymentMethodId, array $options = []): Transaction
+    {
+        return (new Transaction(fn() => $this->anikeenId()
+            ->request('POST', 'v1/billing/charge', [
+                'amount' => $amount,
+                'payment_method_id' => $paymentMethodId,
+            ])))
+            ->setBillable($this);
+    }
+}

src/Id/Concerns/ManagesUserBilling.php

@@ -3,8 +3,10 @@
 namespace Anikeen\Id\Concerns;
 
 use Anikeen\Id\Exceptions\ApiException;
+use Anikeen\Id\Resources\AppCharge;
 use Anikeen\Id\Resources\AppCheckoutSessions;
 use Anikeen\Id\Resources\AppOrders;
+use Anikeen\Id\Resources\BillingLimit;
 use Anikeen\Id\Result;
 use Anikeen\Id\Support\AppRequest;
 use Throwable;
@@ -123,4 +125,101 @@ trait ManagesUserBilling
     {
         return $this->asApp()->request('POST', 'v1/admin/transactions', [...$attributes, 'user_id' => $userId]);
     }
+
+    /**
+     * Book a charge onto a user's open monthly bill of the app, e.g. a shipped item: one line,
+     * no subscription, charged with the bill on the 1st. Trusted apps that Anikeen allowed to
+     * charge (with a maximum per charge), for users connected to the app (they authorised it or
+     * the app bills them). The user's billing limit is checked when it is booked.
+     *
+     * Retrying with the same idempotency key and the same fields returns the existing charge
+     * (also after the limit was reached); other fields with that key: 409
+     * "idempotency_key_conflict" (`charge_id` in body()).
+     *
+     * @param string $userId The user's Anikeen ID.
+     * @param array{
+     *     idempotency_key: string,
+     *     name: string,
+     *     description?: null|string,
+     *     type?: string,
+     *     quantity: int,
+     *     unit_price: float|int|string,
+     *     currency_iso?: string,
+     *     group?: null|string,
+     *     occurred_at?: string,
+     *     reference?: null|string,
+     *     metadata?: null|array<string, string>,
+     *     image_url?: null|string
+     * } $attributes idempotency_key: unique per app and user, ≤ 255 (e.g. "shipment-123").
+     *               name: the line on the bill, ≤ 255. description: ≤ 255.
+     *               type: digital (default), physical or physical-reduced (the VAT treatment).
+     *               quantity: 1–10000 pieces. unit_price: net per piece, > 0, ≤ 100000, up to 6
+     *               decimals; quantity × unit_price rounded to cents must be at least 0.01.
+     *               currency_iso: EUR only (default).
+     *               group: null, or a group in which the app already bills the user (a running
+     *               subscription or an open monthly bill of the app).
+     *               occurred_at: the service date, not in the future, at most 31 days ago
+     *               (default now).
+     *               reference: the app's own id (≤ 255). metadata: ≤ 20 keys (≤ 40 characters),
+     *               string values ≤ 500. Both are not on the bill; put nothing sensitive there.
+     *               image_url: http(s) URL of an image for the line.
+     *
+     * @throws ApiException 403 "client_not_allowed" (not a trusted app), "charges_not_enabled";
+     *     404 "user_not_found" (unknown, deleted or not connected); 409 "billing_limit_reached"
+     *     (isBillingLimitReached(); body() has limit, used, remaining, remaining_net, required,
+     *     currency, resets_at), "charge_exceeds_maximum" (+ max_charge_net),
+     *     "group_not_allowed", "idempotency_key_conflict" (+ charge_id),
+     *     "billing_address_missing"; 422 validation; 429 "too_many_requests"
+     */
+    public function createChargeForUser(string $userId, array $attributes): AppCharge
+    {
+        return new AppCharge(AppRequest::send('POST', $this->chargesPath($userId), $attributes)->data);
+    }
+
+    /**
+     * A charge of the app (or of a client delegated to the same app) for a user.
+     *
+     * @throws ApiException 403 "client_not_allowed", "charges_not_enabled"; 404 "user_not_found",
+     *     "charge_not_found"; 429 "too_many_requests"
+     */
+    public function findChargeForUser(string $userId, string $chargeId): AppCharge
+    {
+        return new AppCharge(AppRequest::send('GET', $this->chargesPath($userId, $chargeId))->data);
+    }
+
+    /**
+     * Void a charge while its bill is open: the line is removed and the bill's total drops. An
+     * already voided charge is returned as it is. Once the bill is closed only a refund of the
+     * order by Anikeen credits it.
+     *
+     * @param string|null $reason why (≤ 255), stored with the charge
+     * @throws ApiException 409 "charge_already_billed" (+ charge_id); 404 "charge_not_found",
+     *     "user_not_found"; 403 "client_not_allowed", "charges_not_enabled"; 429 "too_many_requests"
+     */
+    public function voidChargeForUser(string $userId, string $chargeId, ?string $reason = null): AppCharge
+    {
+        $payload = $reason === null ? null : ['reason' => $reason];
+
+        return new AppCharge(AppRequest::send('POST', $this->chargesPath($userId, $chargeId) . '/void', $payload)->data);
+    }
+
+    /**
+     * A user's monthly billing limit as the app sees it, e.g. to pause paid features while it is
+     * reached. Advisory only: it reserves nothing; a charge is checked when it is booked. Trusted
+     * apps that may charge or that Anikeen allowed to read limits, for users connected to the app.
+     *
+     * @throws ApiException 403 "client_not_allowed", "billing_limit_not_enabled"; 404
+     *     "user_not_found"; 429 "too_many_requests"
+     */
+    public function billingLimitForUser(string $userId): BillingLimit
+    {
+        return new BillingLimit(AppRequest::send('GET', sprintf('v1/client/users/%s/billing-limit', rawurlencode($userId)))->data);
+    }
+
+    private function chargesPath(string $userId, ?string $chargeId = null): string
+    {
+        $path = sprintf('v1/client/users/%s/charges', rawurlencode($userId));
+
+        return $chargeId === null ? $path : $path . '/' . rawurlencode($chargeId);
+    }
 }

src/Id/Exceptions/ApiException.php

@@ -79,6 +79,16 @@ class ApiException extends ResourceException
         return $this->status === 409;
     }
 
+    /**
+     * A charge was refused because it would take the user's open monthly bill above their billing
+     * limit (409 "billing_limit_reached"). body() has limit, used, remaining, remaining_net,
+     * required, currency and resets_at.
+     */
+    public function isBillingLimitReached(): bool
+    {
+        return $this->status === 409 && $this->error === 'billing_limit_reached';
+    }
+
     /**
      * The ID service could not be reached (network error, timeout) or failed (5xx): retry later.
      */

src/Id/Resources/AppCharge.php

@@ -0,0 +1,139 @@
+<?php
+
+namespace Anikeen\Id\Resources;
+
+use DateTimeImmutable;
+use JsonSerializable;
+
+/**
+ * A charge a trusted app booked onto a user's open monthly bill, see
+ * AnikeenId::createChargeForUser(). Amounts are decimal strings (`unit_price` with six decimals,
+ * the others with two).
+ *
+ * @property string $object "charge"
+ * @property string $id
+ * @property string $user_id
+ * @property string $status open (its bill is open), billed (the bill was closed) or voided
+ * @property string $idempotency_key
+ * @property string $name the line on the bill
+ * @property ?string $description
+ * @property string $type digital, physical or physical-reduced (the VAT treatment)
+ * @property int $quantity
+ * @property string $unit "piece"
+ * @property string $unit_price net per piece
+ * @property string $net_amount
+ * @property string $gross_amount what the charge added to the bill, VAT included
+ * @property string $currency_iso
+ * @property ?string $group
+ * @property string $occurred_at the line's service date (ISO 8601)
+ * @property ?string $reference the app's own id
+ * @property object $metadata the app's own data (string values)
+ * @property ?string $order_id the monthly bill (order) the line is on; follows the line when a rollover moves it
+ * @property ?string $voided_at
+ * @property ?string $void_reason
+ * @property string $created_at
+ */
+class AppCharge implements JsonSerializable
+{
+    public const STATUS_OPEN = 'open';
+
+    public const STATUS_BILLED = 'billed';
+
+    public const STATUS_VOIDED = 'voided';
+
+    public function __construct(protected object $data)
+    {
+    }
+
+    public function __get(string $name): mixed
+    {
+        return $this->data->{$name} ?? null;
+    }
+
+    public function __isset(string $name): bool
+    {
+        return isset($this->data->{$name});
+    }
+
+    public function id(): string
+    {
+        return $this->data->id;
+    }
+
+    /**
+     * open, billed or voided (the STATUS_* constants).
+     */
+    public function status(): string
+    {
+        return $this->data->status;
+    }
+
+    /**
+     * Its bill is still open: the charge can be voided.
+     */
+    public function isOpen(): bool
+    {
+        return $this->status() === self::STATUS_OPEN;
+    }
+
+    /**
+     * Its bill was closed (paid, waiting for payment or cancelled): only a refund of the order by
+     * Anikeen credits it.
+     */
+    public function isBilled(): bool
+    {
+        return $this->status() === self::STATUS_BILLED;
+    }
+
+    public function isVoided(): bool
+    {
+        return $this->status() === self::STATUS_VOIDED;
+    }
+
+    /**
+     * Net, e.g. "8.00".
+     */
+    public function netAmount(): string
+    {
+        return $this->data->net_amount;
+    }
+
+    /**
+     * Gross, what the charge added to the bill, e.g. "9.52".
+     */
+    public function grossAmount(): string
+    {
+        return $this->data->gross_amount;
+    }
+
+    /**
+     * The monthly bill (order) the charge is on, null once its line is gone (voided).
+     */
+    public function orderId(): ?string
+    {
+        return $this->data->order_id ?? null;
+    }
+
+    /**
+     * @return array<string, string>
+     */
+    public function metadata(): array
+    {
+        return (array) ($this->data->metadata ?? []);
+    }
+
+    public function occurredAt(): ?DateTimeImmutable
+    {
+        return isset($this->data->occurred_at) ? new DateTimeImmutable($this->data->occurred_at) : null;
+    }
+
+    public function toArray(): array
+    {
+        return (array) $this->data;
+    }
+
+    public function jsonSerialize(): array
+    {
+        return $this->toArray();
+    }
+}

src/Id/Resources/BillingLimit.php

@@ -0,0 +1,186 @@
+<?php
+
+namespace Anikeen\Id\Resources;
+
+use DateTimeImmutable;
+use JsonSerializable;
+
+/**
+ * A user's monthly billing limit: one gross limit for their whole open monthly bill across all
+ * Anikeen services, see AnikeenId::billingLimitForUser() and the `billing_limit` key of
+ * billingOverview(). Amounts are decimal strings with two decimals.
+ *
+ * Without a limit `limit`, `remaining` and `remaining_net` are null; for an app `used` is null
+ * too (an app sees the user's whole open bill only while they have set a limit). `used_by_app`
+ * (the open bills of your app) is there only when an app reads the limit.
+ *
+ * @property string $object "billing_limit"
+ * @property string $user_id
+ * @property string $currency "EUR"
+ * @property string $basis "gross"
+ * @property ?string $limit
+ * @property ?string $used the user's open monthly bills across all Anikeen services
+ * @property ?string $used_by_app the open monthly bills of your app (app reads only)
+ * @property ?string $remaining max(0, limit − used)
+ * @property ?string $remaining_net remaining at the user's VAT rate, rounded down (a hint)
+ * @property int|float|null $vat_rate null without a billing address
+ * @property bool $reached used >= limit: start no new paid service
+ * @property string $resets_at when this month's bills are closed (ISO 8601)
+ * @property int $version only goes up; keep the highest seen (also in the billing_limit.* webhooks)
+ */
+class BillingLimit implements JsonSerializable
+{
+    public function __construct(protected object $data)
+    {
+    }
+
+    public function __get(string $name): mixed
+    {
+        return $this->data->{$name} ?? null;
+    }
+
+    public function __isset(string $name): bool
+    {
+        return isset($this->data->{$name});
+    }
+
+    /**
+     * The user has set a limit (`0.00` is one too: no new charges at all).
+     */
+    public function hasLimit(): bool
+    {
+        return $this->limit() !== null;
+    }
+
+    /**
+     * Gross, null without a limit.
+     */
+    public function limit(): ?string
+    {
+        return $this->data->limit ?? null;
+    }
+
+    /**
+     * The user's open monthly bills across all Anikeen services (gross). Null for an app while the
+     * user has no limit.
+     */
+    public function used(): ?string
+    {
+        return $this->data->used ?? null;
+    }
+
+    /**
+     * The open monthly bills of your app (gross); null outside an app read (billingOverview()).
+     * `used − used_by_app` is what the user spends on their other Anikeen services.
+     */
+    public function usedByApp(): ?string
+    {
+        return $this->data->used_by_app ?? null;
+    }
+
+    /**
+     * Gross room left (never negative), null without a limit.
+     */
+    public function remaining(): ?string
+    {
+        return $this->data->remaining ?? null;
+    }
+
+    /**
+     * The room left as a net amount at the user's VAT rate, rounded down: a hint only (the VAT of
+     * a charge depends on its type). Null without a limit or a billing address.
+     */
+    public function remainingNet(): ?string
+    {
+        return $this->data->remaining_net ?? null;
+    }
+
+    /**
+     * The user's VAT rate in percent (e.g. 19.0), null without a billing address.
+     */
+    public function vatRate(): ?float
+    {
+        return isset($this->data->vat_rate) ? (float) $this->data->vat_rate : null;
+    }
+
+    public function currency(): string
+    {
+        return $this->data->currency ?? 'EUR';
+    }
+
+    /**
+     * The limit is reached (used >= limit): start no new paid service for the user.
+     */
+    public function isReached(): bool
+    {
+        return (bool) ($this->data->reached ?? false);
+    }
+
+    /**
+     * When this month's bills are closed and `used` drops.
+     */
+    public function resetsAt(): ?DateTimeImmutable
+    {
+        return isset($this->data->resets_at) ? new DateTimeImmutable($this->data->resets_at) : null;
+    }
+
+    /**
+     * Only goes up: keep the highest one seen and ignore webhooks with a lower or equal one.
+     */
+    public function version(): int
+    {
+        return (int) ($this->data->version ?? 0);
+    }
+
+    /**
+     * Whether a charge of $gross (gross, e.g. "4.76") would fit as of this read: always without a
+     * limit, else at most `remaining`. Advisory only: it reserves nothing, the binding check is
+     * the booking (409 "billing_limit_reached").
+     */
+    public function allows(string|int|float $gross): bool
+    {
+        if (!$this->hasLimit()) {
+            return true;
+        }
+
+        $remaining = $this->remaining();
+
+        return $remaining !== null && self::compare($gross, $remaining) <= 0;
+    }
+
+    public function toArray(): array
+    {
+        return (array) $this->data;
+    }
+
+    public function jsonSerialize(): array
+    {
+        return $this->toArray();
+    }
+
+    /**
+     * Compares two non-negative decimal amounts exactly (as digit strings, no float rounding);
+     * negative amounts count as zero.
+     */
+    private static function compare(string|int|float $a, string|int|float $b): int
+    {
+        return strcmp(self::micros($a), self::micros($b)) <=> 0;
+    }
+
+    /**
+     * The amount in millionths as a zero-padded digit string of a fixed width.
+     */
+    private static function micros(string|int|float $amount): string
+    {
+        $amount = is_float($amount) ? number_format($amount, 6, '.', '') : trim((string) $amount);
+
+        if (str_starts_with($amount, '-')) {
+            return str_repeat('0', 40);
+        }
+
+        [$whole, $fraction] = array_pad(explode('.', ltrim($amount, '+'), 2), 2, '');
+        $digits = preg_replace('/\D/', '', $whole) . substr(str_pad(preg_replace('/\D/', '', $fraction), 6, '0'), 0, 6);
+
+        return str_pad(ltrim($digits, '0'), 40, '0', STR_PAD_LEFT);
+    }
+}