Scala-Play-Slick-Demo/modules/slick/src/main/scala/com/example/user/slick/dbios/SlickLibraryDbio.scala

package com.example.user.slick.dbios

import slick.jdbc.JdbcProfile
import com.example.models._
import io.scalaland.chimney.dsl._
import com.example.user.slick.Tables
import javax.inject.Singleton
// import slick.jdbc.H2Profile.api._
// import scala.concurrent.ExecutionContext

@Singleton
class SlickLibraryDbio extends Tables {

  override val profile: JdbcProfile = _root_.slick.jdbc.H2Profile

  import profile.api._

  def findBookById(id: Long): DBIO[Option[BooksRow]] =
    Query.bookById(id).result.headOption

  def findBookById2(id: Long): DBIO[Option[BookWithoutId]] =
    Query.test(id).result.headOption

  def findBooksWithAuthor: DBIO[Seq[(BooksRow, AuthorsRow)]] =
    Query.booksWithAuthor.result

  def insertBook(book: Book): DBIO[BooksRow] =
    Query.writeBooks += bookToRow(book)

  def insertBook2(book: NewBook): DBIO[Long] =
    Query.writeBooks3 += book
//
  def insertAuthor(author: Author): DBIO[AuthorsRow] =
    Query.writeAuthors += authorToRow(author)

  def insertAuthor2(author: NewAuthor): DBIO[Long] =
    Query.writeAuthors2 += author

  def getAuthorsForBook(bookId: Long): DBIO[Seq[(AuthorsRow, BooksRow)]] = {
    Query.authorOfBook(bookId).result
  }

  def authorToRow(author: Author) = author.transformInto[AuthorsRow]
  def bookToRow(book: Book) = book.transformInto[BooksRow]
  def authorsRowToAuthor(author: AuthorsRow) = author.transformInto[Author]
  def booksRowToBooks(book: BooksRow) = book.transformInto[Book]
  def booksRowToBooks2(book: BooksRow) = book.transformInto[BookWithoutId]
  // As mentioned under #2, we do encapsulate our queries
  object Query {

    // Return the book / author with it's auto incremented
    // id instead of an insert count
    lazy val writeBooks = Books returning Books
      .map(_.id) into ((book, id) => book.copy(id))
    lazy val writeBooks2 =
      Books.map(b => (b.title, b.authorId).mapTo[BookWithoutId])
    lazy val writeBooks3 = Books
      .map(b => (b.title, b.authorId).mapTo[NewBook])
      .returning(Books.map(_.id))

    lazy val writeAuthors = Authors returning Authors
      .map(_.id) into ((author, id) => author.copy(id))
    lazy val writeAuthors2 =
      Authors.map(a => (a.name).mapTo[NewAuthor]) returning Authors.map(_.id)

    lazy val test = (givenId: Long) =>
      Books
        .filter(_.id === givenId)
        .map(toBooksWithoutID)

    lazy val bookById = Books.findBy(_.id)

    lazy val toBooksWithoutID = (table: Books) =>
      (table.title, table.authorId).mapTo[BookWithoutId]

    lazy val booksWithAuthor = for {
      b <- Books
      a <- Authors if b.authorId === a.id
    } yield (b, a)

    lazy val authorOfBook = (bookId: Long) =>
      for {
        (author, book) <- Authors join
          Books on (_.id === _.authorId) filter {
          case (authors, books) => books.id === bookId
        }
      } yield (author, book)

    lazy val authorOfBook2 = (bookId: Long) =>
      for {
        (authorId, book) <- Books
          .filter(_.id === bookId)
          .take(1)
          .map(b => (b.authorId, b))
        author <- Authors filter (_.id === authorId)
      } yield (author, book)

    lazy val authorOfBook3 = (bookId: Long) =>
      for {
        (author, book) <- Authors join
          Books on (_.id === _.authorId) filter {
          case (authors, books) => books.id === bookId
        } map {
          case (authors, books) =>
            (authors.id, authors.name).mapTo[Author] -> (
              books.title,
              books.authorId,
              books.createdAt
            ).mapTo[BookDTO]
        }
      } yield (author, book)

      lazy val authorOfBook4 = (bookId: Long) =>
      for {
        book <- Books
        author <- book.authorsFk
      } yield (author, book)
    
  }
  case class BookWithoutId(title: String, authorId: Long)
  // def test() = {
  //   val maybeBook = findBookById(1)
  //   val x = maybeBook.map(_.map(_.title))

  //   db.run(x)
  // }
}