package com.fullfacing.dsl

import com.mongodb.casbah.Imports._
import scala.util.parsing.combinator.syntactical.StandardTokenParsers

/**
 * Project: com.fullfacing.dsl
 * Created on 2015/05/19.
 * ryno aka lemonxah -
 * https://github.com/lemonxah
 * http://stackoverflow.com/users/2919672/lemon-xah
 */

sealed trait Statement
case class GreaterOrEqual(field: String, value: String) extends Statement
case class GreaterThan(field: String, value: String) extends Statement
case class LessOrEqual(field: String, value: String) extends Statement
case class LessThan(field: String, value: String) extends Statement
case class Equals(field: String, value: String) extends Statement
case class NotEquals(field: String, value: String) extends Statement

sealed trait Literal[A] { val v: A }
case class Field(v: String) extends Literal[String]
case class StringValue(v: String) extends Literal[String]
case class IntValue(v: Int) extends Literal[Int]
case class LongValue(v: Long) extends Literal[Long]
case class Operation(v: String) extends Literal[String]

object Interpreter extends StandardTokenParsers with App {
  def result(s: String) = phrase(program)(new lexical.Scanner(s.split("&&").reduceLeft(_ + '\n' + _)))
  def program = stmt+
  def stmt = field ~ op ~ value ^^ {
   case field ~ o ~ value => (o.v match {
     case "==" => Equals
     case "!=" => NotEquals
     case "<" => LessThan
     case ">" => GreaterThan
     case ">=" => GreaterOrEqual
     case "<=" => LessOrEqual
   })(field.v, value.v.toString)
  }
  def field = stringLit ^^ {case s => Field(s) }
  def value = stringLit ^^ {case s => StringValue(s)} | numericLit ^^ {case s => IntValue(s.toInt)}
  def op = stringLit ^^ { case s => Operation(s)}
  def getStatements(s: String): Option[List[Statement]] = result(s) match {
    case Success(tree, _) => Some(tree)
    case e: NoSuccess =>
      println(e)
      None
  }
  def statementss = getStatements("'name' '==' 'Zandre'\n'age' '>' 21\n'shoesize' '<' 12\n'showsize' '>=' 22")
  def q = getStatements("'name' '==' 'Zandre'\n'age' '>' 21\n'shoesize' '<' 12\n'showsize' '>=' 22") match {
    case Some(list) => Some(list.map {
      case Equals(f, v) => f $eq v
      case GreaterOrEqual(f, v) => f $gte v
      case GreaterThan(f, v) => f $gt v
      case LessOrEqual(f, v) => f $lte v
      case LessThan(f, v) => f $lt v
      case NotEquals(f, v) => f $ne v
    }.foldLeft(MongoDBObject())(_ ++ _))
    case None => None
  }

  println(statementss)
  println(q)

}