##########################################################
## Battleship function                                   #
##                                                       #
## Janina Torbecke & Inga Schwabe                        #
## 5th TRUG meeting (Object oriented programming in R)   #
##                                                       #
## Input: Number of rows (nRow) and columns (nCol),      #
##        number of ships (nShips)                       #
##                                                       #
##########################################################

battleship <- function (nRow, nCol, nShips){
  
  #Create class "ship"
  setClass("Ship", representation(posX = "numeric",posY = "numeric",found = "logical"),
           prototype(found = FALSE))
  
  #Create board
  board <- matrix(0,nRow,nCol)    
 
  #For while loop, set to TRUE when all ships are found which will stop the game. 
  allFound <- FALSE               
  
  #Create empty list to store all ship objects
  ships <- list()
  
  #Create the first ship
  ships[1] <- new("Ship",posX = sample(1:nRow,1),posY = sample(1:nCol, 1))
  
  #Create remaining ships
  for(i in 2:nShips) {
    foundPos <- FALSE
    shipRow <- NA
    shipCol <- NA
    
    while(!foundPos){ #Loop continues until position of 1 ship is found
      shipRow <- sample(1:nRow,1) #Random row nr
      shipCol <- sample(1:nCol,1) #Random col nr
      
      #Check if position is available
      for(j in 1:length(ships)) {
        foundPos <- !(ships[[j]]@posX == shipRow && ships[[j]]@posY == shipCol)
        
        if(!foundPos) {
          break
        }
      }
    }
    
    #Create new ship on available position
    ships[i] <- new("Ship", posX = shipRow, posY = shipCol)
  } 
  
  
  #Plot output guess:
  
  #Plot grid/board
  par(mar = c(0, 0, 0, 0))
  plot(1, type = "n", asp = 1, xlab = "", ylab = "", 
       xlim = c(0.5, nCol + 0.5), ylim = c(0.5, nRow + 0.5), axes = FALSE)
  
  xGrid <- outer(1:nCol, 1:nRow, function(x, y) x)
  yGrid <- outer(1:nCol, 1:nRow, function(x, y) y)
  
  symbols(xGrid, yGrid, rectangles = matrix(1, length(xGrid), 2), inches = FALSE, 
          fg = "lightblue", bg = "white", add = TRUE)
  
  
  #Plot water
  plotWater <- function(shipCol, shipRow, color = "lightblue") {
    symbols(shipCol, shipRow, squares = rep(1, length(shipCol)), 
            inches = FALSE, fg = NULL, bg = color, add = TRUE)    
  }
  
  #Plot ship
  plotShip <- function(shipCol, shipRow) {    
    symbols(shipCol + 0.075, shipRow + 0.2, rectangles = matrix(rep(c(0.35, 0.2), rep(length(shipCol), 2)), ncol = 2), 
            inches = FALSE,fg = "red",bg = "red",add = TRUE)
    symbols(shipCol, shipRow - 0.25, rectangles = matrix(rep(c(0.8, 0.1), rep(length(shipCol), 2)), ncol = 2), 
            inches = FALSE, fg = "black", bg = "black", add = TRUE)
    segments(shipCol - 0.1, shipRow + 0.3, shipCol - 0.1, shipRow - 0.2)
  }
  
  
  #Play & Output
  while(!allFound){
    
    guess <- locator(1)
    guess$x <- min(nCol, max(1, round(guess$x)))
    guess$y <- min(nRow, max(1, round(guess$y)))
        
    allFound <- TRUE #Stop while loop!
    found <- FALSE
    
    plotWater(guess$x, guess$y)
    
    for(i in 1:nShips) {
      if (ships[[i]]@found || (guess$x == ships[[i]]@posX && guess$y == ships[[i]]@posY)){
        ships[[i]]@found <- TRUE
        plotWater(ships[[i]]@posX, ships[[i]]@posY)
        plotShip(ships[[i]]@posX, ships[[i]]@posY)
        
        #Good guess:
        if (guess$x == ships[[i]]@posX && guess$y == ships[[i]]@posY){
          found <- TRUE
        }
      }else if (!ships[[i]]@found) {
        allFound <- FALSE
      }
    }
    if (found) {
      print("Congratulations! You sank a battleship")
    }else{
      print("You missed the battleships")
    }
    
  }
}

win.graph() #Open 
#quartz() #for mac users

battleship(4,4,6) #Run the function with 4x4 board and 6 ships