// ❌ WRONG - domain polluted with infrastructure
class Delivery {
  async dispatch() {
    this.logger.info('Dispatching delivery', { id: this.id })  // Infrastructure!
    await this.db.beginTransaction()                           // Infrastructure!
    if (this.status !== 'ready') throw new Error('Not ready')
    this.status = 'dispatched'
    await this.db.save(this)                                   // Infrastructure!
    await this.db.commit()                                     // Infrastructure!
    await this.pushNotification.notifyDriver()                 // Infrastructure!
  }
}

// ✅ RIGHT - isolated domain logic
class Delivery {
  dispatch(): void {
    if (this.status !== DeliveryStatus.Ready) {
      throw new DeliveryNotReadyError(this.id)
    }
    this.status = DeliveryStatus.Dispatched
    this.dispatchedAt = new Date()
  }
}

// ❌ WRONG - programmer jargon
class ClaimHandler {
  processClaimData(claimData: ClaimDTO): ProcessingResult {
    return this.claimProcessor.handle(claimData)
  }
}

// ✅ RIGHT - domain language
class ClaimAssessor {
  assessClaim(claim: InsuranceClaim): AssessmentDecision {
    if (claim.exceedsCoverageLimit()) {
      return AssessmentDecision.deny(DenialReason.ExceedsCoverage)
    }
    return AssessmentDecision.approve()
  }
}

DELIVERY APP MENU:
├── Request Delivery     ← Use case: user goal
├── Track Delivery       ← Use case: user goal
├── Cancel Delivery      ← Use case: user goal
├── Calculate ETA        ← NOT a use case: internal machinery
└── Check Delivery Radius ← NOT a use case: domain rule

// ❌ WRONG - not a user goal, this is internal machinery
// use-cases/calculate-eta.use-case.ts
async function calculateETA(deliveryId: DeliveryId) {
  const delivery = await deliveryRepository.find(deliveryId)
  const driver = await driverRepository.find(delivery.driverId)
  return routeService.estimateArrival(driver.location, delivery.destination)
}

// ✅ RIGHT - actual user goal (appears in menu)
// use-cases/cancel-delivery.use-case.ts
async function cancelDelivery(deliveryId: DeliveryId, reason: CancellationReason) {
  const delivery = await deliveryRepository.find(deliveryId)
  delivery.cancel(reason)
  await deliveryRepository.save(delivery)
}

// ❌ WRONG - business logic in use case (anemic domain)
async function confirmDropoff(deliveryId: DeliveryId, photo: ProofPhoto) {
  const delivery = await deliveryRepository.find(deliveryId)

  // Business rules leaked into use case!
  if (delivery.status !== 'in_transit') {
    throw new Error('Delivery not in transit')
  }
  if (!photo && delivery.requiresSignature) {
    throw new Error('Proof of delivery required')
  }

  delivery.status = 'delivered'
  delivery.proofPhoto = photo
  delivery.deliveredAt = new Date()
  await deliveryRepository.save(delivery)
}

// ✅ RIGHT - use case orchestrates, domain decides
async function confirmDropoff(deliveryId: DeliveryId, photo: ProofPhoto) {
  const delivery = await deliveryRepository.find(deliveryId)

  delivery.confirmDropoff(photo)  // Domain enforces the rules

  await deliveryRepository.save(delivery)
}

// ❌ WRONG - generic retry logic mixed with domain
// domain/driver-locator.ts
class DriverLocator {
  // Generic retry logic does not belong in domain!
  private async withRetry<T>(fn: () => Promise<T>, attempts: number): Promise<T> {
    for (let i = 0; i < attempts; i++) {
      try { return await fn() }
      catch (e) { if (i === attempts - 1) throw e }
    }
    throw new Error('Retry failed')
  }

  async findAvailableDriver(zone: Zone): Promise<Driver> {
    return this.withRetry(() => this.searchDriversInZone(zone), 3)
  }

  private async searchDriversInZone(zone: Zone): Promise<Driver> {
    // domain logic to find nearest available driver
  }
}

// ✅ RIGHT - same behavior, properly separated
// infra/retry.ts (generic, reusable in any project)
export async function withRetry<T>(fn: () => Promise<T>, attempts: number): Promise<T> {
  for (let i = 0; i < attempts; i++) {
    try { return await fn() }
    catch (e) { if (i === attempts - 1) throw e }
  }
  throw new Error('Retry failed')
}

// domain/driver-locator.ts (pure domain, no infra imports)
class DriverLocator {
  async findAvailableDriver(zone: Zone): Promise<Driver> {
    // domain logic to find nearest available driver
  }
}

// use-cases/dispatch-delivery.ts (orchestrates domain + infra)
async function dispatchDelivery(deliveryId: DeliveryId) {
  const delivery = await deliveryRepository.find(deliveryId)
  const driver = await withRetry(
    () => driverLocator.findAvailableDriver(delivery.zone), 3
  )
  delivery.assignDriver(driver)
  await deliveryRepository.save(delivery)
}

// This code looks fine - isolated, uses domain terms
class Delivery {
  status: DeliveryStatus
  driver: Driver | null
  pickupTime: Date | null
  dropoffTime: Date | null
  proofOfDelivery: Photo | null

  assignDriver(driver: Driver): void {
    if (this.status !== DeliveryStatus.Confirmed) throw new Error('...')
    this.driver = driver
    this.status = DeliveryStatus.Assigned
  }

  recordPickup(): void {
    if (this.status !== DeliveryStatus.Assigned) throw new Error('...')
    this.pickupTime = new Date()
    this.status = DeliveryStatus.InTransit
  }

  recordDropoff(photo: Photo): void {
    if (this.status !== DeliveryStatus.InTransit) throw new Error('...')
    this.proofOfDelivery = photo
    this.dropoffTime = new Date()
    this.status = DeliveryStatus.Delivered
  }
}

// But the TYPES can describe the domain! Each state is a distinct concept.
// Reading the types alone tells you how deliveries work.

type Delivery =
  | RequestedDelivery      // Customer placed request
  | ConfirmedDelivery      // Restaurant accepted
  | AssignedDelivery       // Driver assigned, heading to restaurant
  | InTransitDelivery      // Driver picked up, heading to customer
  | DeliveredDelivery      // Complete with proof

interface RequestedDelivery {
  kind: 'requested'
  customer: Customer
  restaurant: Restaurant
  items: MenuItem[]
}

interface ConfirmedDelivery {
  kind: 'confirmed'
  customer: Customer
  restaurant: Restaurant
  items: MenuItem[]
  estimatedPrepTime: Duration
}

interface AssignedDelivery {
  kind: 'assigned'
  customer: Customer
  restaurant: Restaurant
  items: MenuItem[]
  driver: Driver              // Now guaranteed to exist
  estimatedPickup: Time
}

interface InTransitDelivery {
  kind: 'in_transit'
  customer: Customer
  restaurant: Restaurant
  items: MenuItem[]
  driver: Driver
  pickupTime: Time            // Now guaranteed to exist
  estimatedDropoff: Time
}

interface DeliveredDelivery {
  kind: 'delivered'
  customer: Customer
  restaurant: Restaurant
  items: MenuItem[]
  driver: Driver
  pickupTime: Time
  dropoffTime: Time           // Now guaranteed to exist
  proofOfDelivery: Photo      // Now guaranteed to exist
}

// State transitions are explicit functions
function confirmDelivery(d: RequestedDelivery, prepTime: Duration): ConfirmedDelivery
function assignDriver(d: ConfirmedDelivery, driver: Driver): AssignedDelivery
function recordPickup(d: AssignedDelivery): InTransitDelivery
function recordDropoff(d: InTransitDelivery, photo: Photo): DeliveredDelivery

// Extract an if statement to a named method
if (distance.kilometers > 10 && !driver.hasLongRangeVehicle) { ... }
if (delivery.exceedsDriverRange(driver)) { ... }

// Name a boolean expression
const canAssign = driver.isAvailable && driver.isInZone(delivery.zone) && !driver.atCapacity
const canAssign = driver.canAccept(delivery)

// Rename to use domain language
const fee = customFee ?? standardFee
const fee = customFee ?? defaultDeliveryFee

// ❌ WRONG - no aggregate boundary, invariants violated
class Delivery {
  stops: DeliveryStop[]  // Exposed!
  totalDistance: Distance
}

// External code can break invariants
delivery.stops.push(new DeliveryStop(location))
// Oops - totalDistance is now wrong!

// ✅ RIGHT - aggregate protects invariants
class Delivery {
  private stops: DeliveryStop[] = []
  private _totalDistance: Distance = Distance.zero()

  addStop(location: Location): void {
    if (this.status !== DeliveryStatus.Planning) {
      throw new DeliveryNotModifiableError(this.id)
    }
    const previousStop = this.stops[this.stops.length - 1]
    const stop = new DeliveryStop(location)
    this.stops.push(stop)
    this._totalDistance = this._totalDistance.add(
      previousStop.distanceTo(location)  // Invariant maintained!
    )
  }

  removeStop(stopId: StopId): void {
    if (this.stops.length <= 2) {
      throw new MinimumStopsRequiredError(this.id)
    }
    // Recalculate total distance after removal
    this.stops = this.stops.filter(s => !s.id.equals(stopId))
    this._totalDistance = this.calculateTotalDistance()  // Invariant maintained!
  }

  get totalDistance(): Distance {
    return this._totalDistance
  }
}

// Entity with primitives that should be a value object
class Delivery {
  id: DeliveryId
  feeAmount: number
  feeCurrency: string
}

// Extract the value object
class Delivery {
  id: DeliveryId
  fee: Money
}

class Money {
  constructor(
    readonly amount: number,
    readonly currency: Currency
  ) {}

  add(other: Money): Money {
    if (this.currency !== other.currency) {
      throw new CurrencyMismatchError(this.currency, other.currency)
    }
    return new Money(this.amount + other.amount, this.currency)
  }

  equals(other: Money): boolean {
    return this.amount === other.amount && this.currency === other.currency
  }
}