Step 00 — Squelette + intégration naïve

3 Bounded Contexts (Sales, Invoicing, LegacyFulfillment) avec :
- Domaines complets (agrégats, VOs, événements, invariants)
- Couche application (commands, queries, ports)
- Infrastructure in-memory (repos, gateway fake)
- Controllers HTTP Symfony
- Couplage naïf synchrone entre BC via NaiveSalesEventPublisher
- 20 tests unitaires et d'intégration passants

src/Invoicing/Domain/Event/InvoiceIssued.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MiniShop\Invoicing\Domain\Event;
+
+use MiniShop\Invoicing\Domain\Model\InvoiceId;
+
+final readonly class InvoiceIssued
+{
+    public function __construct(
+        public InvoiceId $invoiceId,
+        public string $invoiceNumber,
+        public string $externalOrderId,
+        public int $totalInclTaxInCents,
+        public \DateTimeImmutable $issuedAt,
+    ) {}
+}

src/Invoicing/Domain/Model/BillingParty.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MiniShop\Invoicing\Domain\Model;
+
+final readonly class BillingParty
+{
+    public function __construct(
+        public string $name,
+        public string $address,
+    ) {}
+}

src/Invoicing/Domain/Model/Invoice.php

@@ -0,0 +1,111 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MiniShop\Invoicing\Domain\Model;
+
+use MiniShop\Invoicing\Domain\Event\InvoiceIssued;
+
+final class Invoice
+{
+    private InvoiceStatus $status;
+    /** @var list<object> */
+    private array $domainEvents = [];
+
+    /**
+     * @param list<InvoiceLine> $lines
+     */
+    private function __construct(
+        public readonly InvoiceId $id,
+        public readonly string $invoiceNumber,
+        public readonly string $externalOrderId,
+        public readonly BillingParty $billingParty,
+        private readonly array $lines,
+        private readonly \DateTimeImmutable $issuedAt,
+    ) {
+        $this->status = InvoiceStatus::Issued;
+    }
+
+    /**
+     * @param list<InvoiceLine> $lines
+     */
+    public static function issueForExternalOrder(
+        InvoiceId $id,
+        string $invoiceNumber,
+        string $externalOrderId,
+        BillingParty $billingParty,
+        array $lines,
+        \DateTimeImmutable $issuedAt,
+    ): self {
+        if ($lines === []) {
+            throw new \DomainException('An invoice must have at least one line.');
+        }
+
+        $invoice = new self($id, $invoiceNumber, $externalOrderId, $billingParty, $lines, $issuedAt);
+
+        $invoice->recordEvent(new InvoiceIssued(
+            $id,
+            $invoiceNumber,
+            $externalOrderId,
+            $invoice->totalInclTax(),
+            $issuedAt,
+        ));
+
+        return $invoice;
+    }
+
+    public function markAsSent(): void
+    {
+        if ($this->status === InvoiceStatus::Sent) {
+            throw new \DomainException('Invoice is already sent.');
+        }
+
+        $this->status = InvoiceStatus::Sent;
+    }
+
+    public function totalExclTax(): int
+    {
+        return array_sum(array_map(
+            static fn (InvoiceLine $line): int => $line->lineTotalExclTax(),
+            $this->lines,
+        ));
+    }
+
+    public function totalInclTax(): int
+    {
+        return array_sum(array_map(
+            static fn (InvoiceLine $line): int => $line->lineTotalInclTax(),
+            $this->lines,
+        ));
+    }
+
+    public function status(): InvoiceStatus
+    {
+        return $this->status;
+    }
+
+    /** @return list<InvoiceLine> */
+    public function lines(): array
+    {
+        return $this->lines;
+    }
+
+    public function issuedAt(): \DateTimeImmutable
+    {
+        return $this->issuedAt;
+    }
+
+    /** @return list<object> */
+    public function releaseEvents(): array
+    {
+        $events = $this->domainEvents;
+        $this->domainEvents = [];
+
+        return $events;
+    }
+
+    private function recordEvent(object $event): void
+    {
+        $this->domainEvents[] = $event;
+    }
+}

src/Invoicing/Domain/Model/InvoiceId.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MiniShop\Invoicing\Domain\Model;
+
+final readonly class InvoiceId
+{
+    private function __construct(public string $value) {}
+
+    public static function fromString(string $value): self
+    {
+        return new self($value);
+    }
+
+    public function toString(): string
+    {
+        return $this->value;
+    }
+
+    public function equals(self $other): bool
+    {
+        return $this->value === $other->value;
+    }
+}

src/Invoicing/Domain/Model/InvoiceLine.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MiniShop\Invoicing\Domain\Model;
+
+final readonly class InvoiceLine
+{
+    public function __construct(
+        public string $description,
+        public int $quantity,
+        public int $unitPriceInCents,
+        public string $currency,
+        public TaxRate $taxRate,
+    ) {
+        if ($quantity <= 0) {
+            throw new \InvalidArgumentException('Quantity must be positive.');
+        }
+    }
+
+    public function lineTotalExclTax(): int
+    {
+        return $this->quantity * $this->unitPriceInCents;
+    }
+
+    public function lineTotalInclTax(): int
+    {
+        return (int) round($this->lineTotalExclTax() * (1 + $this->taxRate->rate));
+    }
+}

src/Invoicing/Domain/Model/InvoiceStatus.php

@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MiniShop\Invoicing\Domain\Model;
+
+enum InvoiceStatus: string
+{
+    case Issued = 'issued';
+    case Sent = 'sent';
+}

src/Invoicing/Domain/Model/TaxRate.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MiniShop\Invoicing\Domain\Model;
+
+final readonly class TaxRate
+{
+    public function __construct(
+        public float $rate,
+        public string $label,
+    ) {
+        if ($rate < 0 || $rate > 1) {
+            throw new \InvalidArgumentException('Tax rate must be between 0 and 1.');
+        }
+    }
+
+    public static function standard(): self
+    {
+        return new self(0.20, 'TVA 20%');
+    }
+
+    public static function zero(): self
+    {
+        return new self(0.0, 'Exonere');
+    }
+}