vapor-po/Sources/DatabaseClientLive/Users.swift

import DatabaseClient
import FluentKit
import Foundation
import HummingbirdBcrypt
import SharedModels

public extension DatabaseClient.Users {

  static func live(database: any Database) -> Self {
    .init { create in
      let model = try create.toModel()
      try await model.save(on: database)
      return model.toDTO()
    } delete: { id in
      guard let model = try await UserModel.find(id, on: database) else {
        throw NotFoundError()
      }
      try await model.delete(on: database)
    } fetchAll: {
      try await UserModel.query(on: database).all().map { $0.toDTO() }
    } get: { id in
      try await UserModel.find(id, on: database).map { $0.toDTO() }
    } login: { login in
      try login.validate()

      var query = UserModel.query(on: database)

      if let username = login.username {
        query = query.filter(\.$username == username)
      } else {
        query = query.filter(\.$email == login.email!)
      }

      guard let user = try await query.first() else {
        throw NotFoundError()
      }

      let token = try user.generateToken()

      try await token.save(on: database)

      return try User.Token(
        id: token.requireID(),
        userID: user.requireID(),
        value: token.value
      )

    } logout: { id in
      guard let token = try await UserTokenModel.find(id, on: database)
      else { return }
      try await token.delete(on: database)
    }
  }
}

extension User {
  struct Migrate: AsyncMigration {
    let name = "CreateUser"

    func prepare(on database: any Database) async throws {
      try await database.schema(UserModel.schema)
        .id()
        .field("username", .string, .required)
        .field("email", .string, .required)
        .field("password_hash", .string, .required)
        .field("created_at", .datetime)
        .field("updated_at", .datetime)
        .unique(on: "email", "username")
        .create()
    }

    func revert(on database: any Database) async throws {
      try await database.schema(UserModel.schema).delete()
    }
  }
}

extension User.Token {
  struct Migrate: AsyncMigration {
    let name = "CreateUserToken"

    func prepare(on database: any Database) async throws {
      try await database.schema(UserTokenModel.schema)
        .id()
        .field("value", .string, .required)
        .field("user_id", .uuid, .required, .references(UserModel.schema, "id"))
        .unique(on: "value")
        .create()
    }

    func revert(on database: any Database) async throws {
      try await database.schema(UserTokenModel.schema).delete()
    }
  }
}

extension User.Create {

  func toModel() throws -> UserModel {
    try validate()
    return .init(username: username, email: email, passwordHash: Bcrypt.hash(password, cost: 12))
  }

  func validate() throws {
    guard !username.isEmpty else {
      throw ValidationError(message: "Username should not be empty.")
    }
    guard !email.isEmpty else {
      throw ValidationError(message: "Email should not be empty")
    }
    guard password.count > 8 else {
      throw ValidationError(message: "Password should be more than 8 characters long.")
    }
    guard password == confirmPassword else {
      throw ValidationError(message: "Passwords do not match.")
    }
  }
}

extension User.Login {

  func validate() throws {
    guard username != nil || email != nil else {
      throw ValidationError(message: "Either username or email must be provided to login.")
    }
  }
}

/// The user database model.
///
/// A user is someone who is able to login and generate PO's for employees.  Generally a user should also
/// have an employee profile, but not all employees are users. Users are generally restricted to office workers
/// and administrators.
///
///
final class UserModel: Model, @unchecked Sendable {
  static let schema = "user"

  @ID(key: .id)
  var id: UUID?

  @Field(key: "username")
  var username: String

  @Field(key: "email")
  var email: String

  @Field(key: "password_hash")
  var passwordHash: String

  @Timestamp(key: "created_at", on: .create)
  var createdAt: Date?

  @Timestamp(key: "updated_at", on: .update)
  var updatedAt: Date?

  init() {}

  init(
    id: UUID? = nil,
    username: String,
    email: String,
    passwordHash: String
  ) {
    self.id = id
    self.username = username
    self.email = email
    self.passwordHash = passwordHash
  }

  func toDTO() -> User {
    .init(
      id: id,
      createdAt: createdAt,
      email: email,
      updatedAt: updatedAt,
      username: username
    )
  }

  func generateToken() throws -> UserTokenModel {
    try .init(
      value: [UInt8].random(count: 16).base64,
      userID: requireID()
    )
  }

}

final class UserTokenModel: Model, Codable, @unchecked Sendable {

  static let schema = "user_token"

  @ID(key: .id)
  var id: UUID?

  @Field(key: "value")
  var value: String

  @Parent(key: "user_id")
  var user: UserModel

  init() {}

  init(id: UUID? = nil, value: String, userID: UserModel.IDValue) {
    self.id = id
    self.value = value
    $user.id = userID
  }

}