/*
 * Akari Solver in Copris
 * by Naoyuki Tamura
 * http://bach.istc.kobe-u.ac.jp/copris/puzzles/akari/
 */
package akari

import jp.kobe_u.copris._
import jp.kobe_u.copris.dsl._
import puzzle._

case class Akari(m: Int, n: Int, board: Seq[Seq[String]]) extends BoardPuzzle {
  def isBlank(cell: Cell) = at(cell) == "-"
  def isBlack(cell: Cell) = at(cell) == "x"
  val lines = {
    def seq(cell: Cell, dij: Cell): Seq[Cell] =
      if (! isCell(cell) || ! isBlank(cell)) Seq.empty
      else cell +: seq(move(cell, dij), dij)
    val vLines = for ((i,j) <- cells; if ! isCell((i-1,j)) || ! isBlank((i-1,j)))
		 yield seq((i,j), (1,0)).toSet
    val hLines = for ((i,j) <- cells; if ! isCell((i,j-1)) || ! isBlank((i,j-1)))
		 yield seq((i,j), (0,1)).toSet
    vLines ++ hLines
  }
  def show(sol: Set[Cell]) {
    for (i <- 0 until m) {
      for (j <- 0 until n) {
	val cell = (i,j)
	if (sol.contains(cell)) print(" @")
        else print(" " + at(cell))
      }
      println
    }
  }
}

object Solver extends BoardPuzzleSolver[Akari] {
  val name = "akari.Solver"

  def puzzleFactory(m: Int, n: Int, board: Seq[Seq[String]]) =
    Akari(m, n, board)

  def define = {
    for (cell <- puzzle.cells; if puzzle.isBlank(cell))
      int('x(cell), 0, 1)
    for ((cell) <- puzzle.cells; if puzzle.isNumber(cell)) {
      val xs = puzzle.adjCells(cell, puzzle.isBlank).map('x(_))
      add(Add(xs) === puzzle.num(cell))
    }
    val lines = puzzle.lines
    for (k <- 0 until lines.size) {
      int('l(k), 0, 1)
      add('l(k) === Add(lines(k).map(cell => 'x(cell))))
    }
    for (cell <- puzzle.cells; if puzzle.isBlank(cell)) {
      val ks = (0 until lines.size).filter(k => lines(k).contains(cell))
      add(Or(ks.map(k => 'l(k) === 1)))
    }
  }

  def showSolution {
    // Set of light cell positions
    val sol =
      for (cell <- puzzle.cells.toSet; if puzzle.isBlank(cell) && solution('x(cell)) > 0)
      yield cell
    if (quiet == 0) {
      println("Solution = " + sol)
      println("Size = " + sol.size)
      puzzle.show(sol)
    }
  }
}