feat: Implements common database interactions as dependencies.

Sources/App/Controllers/DB/UserDB.swift

@@ -1,36 +1,56 @@
+import Dependencies
+import DependenciesMacros
 import Fluent
 import Vapor
 
-struct UserDB {
-
-  func create(_ model: User.Create, on db: any Database) async throws -> User.DTO {
-    guard model.password == model.confirmPassword else {
-      throw Abort(.badRequest, reason: "Passwords did not match.")
-    }
-    let user = try User(
-      username: model.username,
-      email: model.email,
-      passwordHash: Bcrypt.hash(model.password)
-    )
-    try await user.save(on: db)
-    return user.toDTO()
+extension DependencyValues {
+  var users: UserDB {
+    get { self[UserDB.self] }
+    set { self[UserDB.self] = newValue }
+  }
+}
+
+@DependencyClient
+struct UserDB: Sendable {
+  var create: @Sendable (User.Create) async throws -> User.DTO
+  var delete: @Sendable (User.IDValue) async throws -> Void
+  var fetchAll: @Sendable () async throws -> [User.DTO]
+  var login: @Sendable (User) async throws -> UserToken
+}
+
+extension UserDB: TestDependencyKey {
+  static let testValue: UserDB = Self()
+
+  static func live(database db: any Database) -> Self {
+    self.init(
+      create: { model in
+        guard model.password == model.confirmPassword else {
+          throw Abort(.badRequest, reason: "Passwords did not match.")
+        }
+        let user = try User(
+          username: model.username,
+          email: model.email,
+          passwordHash: Bcrypt.hash(model.password)
+        )
+        try await user.save(on: db)
+        return user.toDTO()
+
+      },
+      delete: { id in
+        guard let user = try await User.find(id, on: db) else {
+          throw Abort(.notFound)
+        }
+        try await user.delete(on: db)
+
+      },
+      fetchAll: {
+        try await User.query(on: db).all().map { $0.toDTO() }
+      },
+      login: { user in
+        let token = try user.generateToken()
+        try await token.save(on: db)
+        return token
+      }
+    )
   }
-
-  func login(user: User, on db: any Database) async throws -> UserToken {
-    let token = try user.generateToken()
-    try await token.save(on: db)
-    return token
-  }
-
-  func fetchAll(on db: any Database) async throws -> [User.DTO] {
-    try await User.query(on: db).all().map { $0.toDTO() }
-  }
-
-  func delete(id: User.IDValue, on db: any Database) async throws {
-    guard let user = try await User.find(id, on: db) else {
-      throw Abort(.notFound)
-    }
-    try await user.delete(on: db)
-  }
-
 }