from Constants import ROWS, COLS
from Engine.Point import Point


class PathFinder:

    def __init__(self, board):
        self.board = board
        self.openList = []
        self.cameFrom = {}
        self.gScore = {}
        self.fScore = {}
        self.current = Point(0,0)


    def findPath(self,startPoint, endPoint):
        self.openList.append(startPoint)
        self.gScore[startPoint] = 0
        self.fScore[startPoint] = startPoint.distance(endPoint)

        while self.openList:
            self.current = self.minKey(self.fScore, self.openList)

            if self.current.__eq__(endPoint):
                return self.reconstructPath()

            self.openList.remove(self.current)

            for point in self.getNeighbour(self.current):
                tentativeGScore = self.gScore.get(self.current) + self.current.distance(point)
                if tentativeGScore < self.gScore.get(point, 10000):
                    self.cameFrom[point] = self.current
                    self.gScore[point] = tentativeGScore
                    self.fScore[point] = point.distance(startPoint)
                    if(point not in self.openList):
                        self.openList.append(point)
        return []

    def reconstructPath(self):
        totalPath = []
        totalPath.append(self.current)
        while self.current in self.cameFrom:
            self.current = self.cameFrom[self.current]
            totalPath.insert(0,self.current)
        return totalPath

    def getNeighbour(self, current):
        neighbourlist = []
        point1 = Point(current.getX() + 1, current.getY())
        point2 = Point(current.getX(), current.getY() + 1)
        point3 = Point(current.getX(), current.getY() - 1)
        point4 = Point(current.getX() - 1, current.getY())
        if self.checkField(current,current):
            neighbourlist.append(point1)
        if self.checkField(current, point2):
            neighbourlist.append(point2)
        if self.checkField(current,point3):
            neighbourlist.append(point3)
        if self.checkField(current,point4):
            neighbourlist.append(point4)
        return neighbourlist

    def checkField(self,current, point):
        if not (point.getX() < 0 or point.getX() > COLS - 1 or point.getY() < 0 or point.getY() > ROWS - 1 or point.__eq__(current)) and point not in self.board.stoneMap:
            return True
        return False

    def minKey(self, fscore, openlist):
        minkey = Point(0,0)
        minValue = float('inf')
        for point in openlist:
            value = fscore.get(point, 10000)
            if value < minValue:
                minValue = value
                minkey = point
        return minkey