feat: Implements common database interactions as dependencies.

Sources/App/Controllers/DB/PurchaseOrderDB.swift

@@ -1,56 +1,72 @@
+import Dependencies
+import DependenciesMacros
 import Fluent
 import Vapor
 
-// An intermediate between our api and view controllers that interacts with the
-// database.
-struct PurchaseOrderDB {
+extension DependencyValues {
+  // An intermediate between our api and view controllers that interacts with the
+  // database.
+  var purchaseOrders: PurchaseOrdersDB {
+    get { self[PurchaseOrdersDB.self] }
+    set { self[PurchaseOrdersDB.self] = newValue }
+  }
+}
 
-  func create(
-    _ model: PurchaseOrder.Create,
-    createdById: User.IDValue,
-    on db: any Database
-  ) async throws -> PurchaseOrder.DTO {
-    guard let employee = try await Employee.find(model.createdForID, on: db) else {
-      throw Abort(.notFound, reason: "Employee not found.")
-    }
+@DependencyClient
+struct PurchaseOrdersDB: Sendable {
+  var create: @Sendable (PurchaseOrder.Create, User.IDValue) async throws -> PurchaseOrder.DTO
+  var fetchAll: @Sendable () async throws -> [PurchaseOrder.DTO]
+  var fetchPage: @Sendable (PageRequest) async throws -> Page<PurchaseOrder.DTO>
+  var get: @Sendable (PurchaseOrder.IDValue) async throws -> PurchaseOrder.DTO?
+  // var update: @Sendable (PurchaseOrder.IDValue, PurchaseOrder.Update) async throws -> PurchaseOrder.DTO
+  var delete: @Sendable (PurchaseOrder.IDValue) async throws -> Void
+}
 
-    guard employee.active else {
-      throw Abort(.badRequest, reason: "Employee is not active, unable to generate a PO for in-active employees")
-    }
+extension PurchaseOrdersDB: TestDependencyKey {
+  static let testValue: PurchaseOrdersDB = Self()
 
-    let purchaseOrder = model.toModel(createdByID: createdById)
-    try await purchaseOrder.save(on: db)
-    guard let loaded = try await get(id: purchaseOrder.requireID(), on: db) else {
-      return purchaseOrder.toDTO()
-    }
-    return loaded
+  static func live(database db: any Database) -> Self {
+    .init(
+      create: { model, createdById in
+        guard let employee = try await Employee.find(model.createdForID, on: db) else {
+          throw Abort(.notFound, reason: "Employee not found.")
+        }
+
+        guard employee.active else {
+          throw Abort(.badRequest, reason: "Employee is not active, unable to generate a PO for in-active employees")
+        }
+
+        let purchaseOrder = model.toModel(createdByID: createdById)
+        try await purchaseOrder.save(on: db)
+        guard let loaded = try await PurchaseOrder.get(purchaseOrder.requireID(), on: db) else {
+          return purchaseOrder.toDTO()
+        }
+        return loaded
+
+      },
+      fetchAll: {
+        try await PurchaseOrder.allQuery(on: db)
+          .sort(\.$id, .descending)
+          .all().map { $0.toDTO() }
+      },
+      fetchPage: { request in
+        try await PurchaseOrder.allQuery(on: db)
+          .sort(\.$id, .descending)
+          .paginate(request)
+          .map { $0.toDTO() }
+      },
+      get: { id in
+        try await PurchaseOrder.get(id, on: db)
+      },
+      delete: { id in
+        guard let purchaseOrder = try await PurchaseOrder.find(id, on: db) else {
+          throw Abort(.notFound)
+        }
+        try await purchaseOrder.delete(on: db)
+      }
+    )
   }
 
-  func fetchAll(on db: any Database) async throws -> [PurchaseOrder.DTO] {
-    try await PurchaseOrder.allQuery(on: db)
-      .sort(\.$id, .descending)
-      .all().map { $0.toDTO() }
-  }
-
-  func fetchPage(_ page: Int, limit: Int, on db: any Database) async throws -> Page<PurchaseOrder.DTO> {
-    try await PurchaseOrder.allQuery(on: db)
-      .sort(\.$id, .descending)
-      .paginate(PageRequest(page: page, per: limit))
-      .map { $0.toDTO() }
-  }
-
-  func get(id: PurchaseOrder.IDValue, on db: any Database) async throws -> PurchaseOrder.DTO? {
-    try await PurchaseOrder.allQuery(on: db)
-      .filter(\.$id == id)
-      .first()?.toDTO()
-  }
-
-  func delete(id: PurchaseOrder.IDValue, on db: any Database) async throws {
-    guard let purchaseOrder = try await PurchaseOrder.find(id, on: db) else {
-      throw Abort(.notFound)
-    }
-    try await purchaseOrder.delete(on: db)
-  }
 }
 
 private extension PurchaseOrder {
@@ -62,4 +78,10 @@ private extension PurchaseOrder {
         branch.with(\.$vendor)
       }
   }
+
+  static func get(_ id: PurchaseOrder.IDValue, on db: any Database) async throws -> PurchaseOrder.DTO? {
+    try await PurchaseOrder.allQuery(on: db)
+      .filter(\.$id == id)
+      .first()?.toDTO()
+  }
 }