# runtime.py
#
import os, sys, sarg, time

testing = sarg.Int("test",0)

class Environment :
    def __init__(self, board, fatal, interval=.1):
        self.board = board
        self.fatal = fatal             # the exit function
        self.karelPos = self.karelDir = None
        self.karelBeepers = 0           # beepers in Karel's bag
        self.beepers = {}               # squares with beepers
        self.interval   = interval      # the time between moves
        self.nrows = len(self.board)    # rows on the board
        self.ncols = len(self.board[0]) # all rows same width
        self.incr  = ((-1,0),(0,1),(1,0),(0,-1)) # for each dirc
        self.conditions = conditions    # boolean tests
        for row in range(self.nrows) :
            self.board[row] = list(self.board[row]) # nested lists
            for col in range(self.ncols) :
                pos = (row,col)
                c = self.board[row][col]
                kdir = "^>v<".find(c)    # set Karel's direction by symbol
                if kdir >= 0 :
                    self.karelPos = (row,col)
                    self.karelDir = kdir
                elif " 123456789".find(c) > 0 :
                    self.beepers[pos] = int(c) # set # of beepers for pos

    def getSquare(self, dirc) : # dirc relative to kdir
        incr  = ((-1,0),(0,1),(1,0),(0,-1)) # for each dirc
        kpos  = self.karelPos
        kdir  = self.karelDir
        ndir  = (kdir+dirc)%4
        return self.addPos(kpos,self.incr[ndir])

    def isBlocked(self,sqr) :
        occu = self.boardGet(sqr)
        return not (occu == '.' or self.beepers.get(sqr))

    def nbrBlocked(self, dirc) :
        sqr = self.getSquare(dirc)
        return self.isBlocked(sqr)

    def move(self) :
        kdir = self.karelDir
        kpos = self.karelPos
        dest = self.getSquare(0)  # one square ahead
        beeps= self.beepers.get(kpos)
        sym  = self.boardGet(kpos)
        if not self.isBlocked(dest) :
            self.boardPut(dest,sym)         # Place Karel here
            self.karelPos = dest
            if beeps : old = str(beeps)[0]  # just room for 1 digit
            else     : old = "."
            self.boardPut(kpos,old)         # replace prev content
        else : self.fatal("move is blocked")
        self.printBoard()

    def pickbeeper(self) :
        kpos = self.karelPos
        if not self.beepers.get(kpos) : self.fatal("No beeper to pick up")
        else :
            self.beepers[kpos] -= 1
            self.karelBeepers  += 1
        self.printBoard()
        
    def putbeeper(self) :
        kpos = self.karelPos
        if not self.karelBeepers : self.fatal("No beeper to put down")
        else :
            self.beepers[kpos] = self.beepers.get(kpos,0) + 1
            self.karelBeepers  -= 1
        self.printBoard()
            
    def turnleft(self) :
        self.karelDir = (self.karelDir-1) % 4  # 0-3 to the left
        row,col = self.karelPos   
        self.board[row][col] = "^>v<"[self.karelDir]
        self.printBoard()

    def addPos(self, pos, inc) :
        return (pos[0]+inc[0], pos[1]+inc[1])
    
    def boardGet(self, pos) :
        return self.board[pos[0]][pos[1]]

    def boardPut(self, pos, sym) :
        self.board[pos[0]][pos[1]] = sym

    def test(self, cond) :
        return conditions[cond](self)  # test the condition

    def printBoard(self) :
        if not testing :
            time.sleep(self.interval)
            os.system('clear')   # in windows change 'clear' to 'cls'
        for row in range(self.nrows) :
            print("".join(self.board[row]))  # make a string from list

conditions = { 
  "facing-north"     : lambda env: env.karelDir == 0,
  "not-facing-north" : lambda env: env.karelDir != 0,
  "facing-east"      : lambda env: env.karelDir == 1,
  "not-facing-east"  : lambda env: env.karelDir != 1,
  "facing-south"     : lambda env: env.karelDir == 2,
  "not-facing-south" : lambda env: env.karelDir != 2,
  "facing-west"      : lambda env: env.karelDir == 3,
  "not-facing-west"  : lambda env: env.karelDir != 3,
  "front-is-clear"   : lambda env: not env.nbrBlocked(0),
  "front-is-blocked" : lambda env:     env.nbrBlocked(0),
  "right-is-clear"   : lambda env: not env.nbrBlocked(1),
  "right-is-blocked" : lambda env:     env.nbrBlocked(1),
  "left-is-clear"    : lambda env: not env.nbrBlocked(3),
  "left-is-blocked"  : lambda env:     env.nbrBlocked(3),
  "next-to-a-beeper"     : lambda env: env.beepers.get(env.karelPos,0) > 0,
  "not-next-to-a-beeper" : lambda env: env.beepers.get(env.karelPos,0) < 1,
  "any-beepers-in-beeper-bag": lambda env: env.karelBeepers > 0,
  "no-beepers-in-beeper-bag" : lambda env: env.karelBeepers < 1,
}