package jp.ymir.taskReporter.core
import scala.collection._
import scala.collection.immutable.StringLike
import scala.language.higherKinds
import scala.language.implicitConversions
import scala.language.reflectiveCalls
import scalaz._
import Scalaz._

abstract class TSVTypes {

  implicit val ParserFunctor = new Functor[Parser] {
    def map[A, B](m: Parser[A])(f: A => B) = new Parser[B] {
      def runParser[F[_], R](kf: Failure[F, R], ks: Success[B, F, R]): F[R] = {
        def ks_(a: A) = ks(f(a))
        return m.runParser(kf, ks_)
      }
    }
  }

  implicit val ParserApplicative = new Applicative[Parser] {
    def point[A](a: => A) = new Parser[A] {
      def runParser[F[_], R](kf: Failure[F, R], ks: Success[A, F, R]): F[R]
        = ks(a)
    }
    def ap[A, B](m: => Parser[A])(fm: => Parser[A => B]) = new Parser[B] {
      def runParser[F[_], R](kf: Failure[F, R], ks: Success[B, F, R]): F[R] = {
        def ks_(f: A => B): F[R] = {
          def ks__(a: A) = ks(f(a))
          return m.runParser(kf, ks__)
        }
        return fm.runParser(kf, ks_)
      }
    }
  }

  implicit val ParserMonad = new Monad[Parser] {
    def point[A](a: => A) = a.point[Parser]

    def bind[A, B](m: Parser[A])(f: A => Parser[B]) = new Parser[B] {
      def runParser[F[_], R](kf: Failure[F, R], ks: Success[B, F, R]): F[R] = {
        def ks_(a: A) = f(a).runParser(kf, ks)
        return m.runParser(kf, ks_)
      }
    }
  }

  implicit val ParserMonadError = new MonadError[({type λ[String, α] = Parser[α]})#λ, String] {
    def point[A](a: => A) = a.point[Parser]
    def bind[A, B](m: Parser[A])(f: A => Parser[B]) = m.flatMap(f)

    def handleError[A](m: Parser[A])(f: String => Parser[A]) = new Parser[A] {
      def runParser[F[_], R](kf: Failure[F, R], ks: Success[A, F, R]): F[R] = {
        def kf_(e: String) = f(e).runParser(kf, ks)
        return m.runParser(kf_, ks)
      }
    }

    def raiseError[A](e: String) = new Parser[A] {
      def runParser[F[_], R](kf: Failure[F, R], ks: Success[A, F, R]): F[R]
        = kf(e)
    }
  }

  implicit def ToMonadErrorOps[A](m: Parser[A]) = new {
    def handleError(f: String => Parser[A]): Parser[A]
      = implicitly[MonadError[({type λ[String, α] = Parser[α]})#λ, String]].handleError(m)(f)
  }

  implicit def ToMonadErrorIdOps(e: String) = new {
    def raiseError[A]: Parser[A]
      = implicitly[MonadError[({type λ[String, α] = Parser[α]})#λ, String]].raiseError(e)
  }

  type Header = Seq[Symbol]

  case class Field(value: String) {
    def parseField[A: FromField]
      = implicitly[FromField[A]].parseField(Field(value))
  }

  case class Record(value: Map[Symbol, Field]) {
    def parseRecord[A: FromRecord]
      = implicitly[FromRecord[A]].parseRecord(Record(value))

    def lookup[A: FromField](name: Symbol): Parser[A]
      = value.get(name).fold(("no field named " + name.name).raiseError[A])(_.parseField[A])

    def lookup[A: FromField](name: Symbol, default: String): Parser[A]
      = value.get(name).getOrElse(Field(default)).parseField[A]
  }

  type Failure[   F[_], R] = String => F[R]
  type Success[A, F[_], R] = A      => F[R]

  trait Parser[+A] {
    def runParser[F[_], R](kf: Failure[F, R], ks: Success[A, F, R]): F[R]
  }

  def runParser[A](p: Parser[A]): Either[String, A] = {
    type F[R] = Either[String, R]
    def left (e: String): F[A] = Left(e)
    def right(x: A     ): F[A] = Right(x)
    return p.runParser(left, right)
  }

  trait FromRecord[A] {
    def parseRecord(r: Record): Parser[A]
  }

  trait FromField[A] {
    def parseField(f: Field): Parser[A]
  }

  trait ToRecord[A] {
    def toRecord(a: A): Record
  }

  trait ToField[A] {
    def toField(a: A): Field
  }

  class DecodeFailedException private(e: RuntimeException) extends RuntimeException(e) {
    def this(msg: String) = this(new RuntimeException(msg))
    def this(msg: String, cause: Throwable) = this(new RuntimeException(msg, cause))
  }

  // Option[A]
  implicit def OptionFromField[A: FromField] = new FromField[Option[A]] {
    def parseField(f: Field): Parser[Option[A]] = {
      if (f.value.isEmpty) {
        return None.point[Parser]
      }
      else {
        f.parseField[A].map { Some(_) }
      }
    }
  }

  // String
  implicit val StringFromField = new FromField[String] {
    def parseField(f: Field): Parser[String] = f.value.point[Parser]
  }

  // Int
  implicit val IntFromField = new FromField[Int] {
    def parseField(f: Field): Parser[Int] = {
      try {
        f.value.toInt.point[Parser]
      }
      catch {
        case e: NumberFormatException =>
          e.getMessage().raiseError[Int]
      }
    }
  }
}

trait TSVFunctions extends TSVTypes {
  def decode[A: FromRecord](tsv: StringLike[_]): Seq[A] = {
    val lines   = tsv.split('\n').filter(!_.isEmpty)
    val header  = lines.head.split('\t').map(Symbol(_))
    val records = lines.tail.map(line => Record((header zip line.split('\t').map { Field(_) }).toMap))
    return records.map { r =>
      runParser(r.parseRecord[A]) match {
        case Right(a) => a
        case Left(e)  => throw new DecodeFailedException(e)
      }
    }
  }
}

object TSV extends TSVTypes with TSVFunctions