Module pacai.core.distanceCalculator

class DistanceCalculator:
    def __init__(self, layout, distancer):
        self.layout = layout
        self.distancer = distancer
        self.cache = {}

    def run(self):
        if self.layout.walls not in self.cache:
            self.cache[self.layout.walls] = computeDistances(self.layout)

        self.distancer._distances = self.cache[self.layout.walls]

class Distancer(object):
    """
    A class for computing and caching the shortest path between any two points in a given maze.

    Example:
    ```
    distancer = Distancer(gameState.getInitialLayout())
    distancer.getDistance((1, 1), (10, 10))
    ```
    """

    def __init__(self, layout):
        self._distances = None
        self.dc = DistanceCalculator(layout, self)

    def getMazeDistances(self):
        self.dc.run()

    def getDistance(self, pos1, pos2):
        """
        The only function you will need after you create the object.
        """

        if (self._distances is None):
            return manhattan(pos1, pos2)

        if isInt(pos1) and isInt(pos2):
            return self.getDistanceOnGrid(pos1, pos2)

        pos1Grids = getGrids2D(pos1)
        pos2Grids = getGrids2D(pos2)
        bestDistance = DEFAULT_DISTANCE

        for pos1Snap, snap1Distance in pos1Grids:
            for pos2Snap, snap2Distance in pos2Grids:
                gridDistance = self.getDistanceOnGrid(pos1Snap, pos2Snap)
                distance = gridDistance + snap1Distance + snap2Distance
                if bestDistance > distance:
                    bestDistance = distance

        return bestDistance

    def getDistanceOnGrid(self, pos1, pos2):
        key = (pos1, pos2)
        if key in self._distances:
            return self._distances[key]

        raise Exception("Position not in grid: " + str(key))

    def isReadyForMazeDistance(self):
        return (self._distances is not None)