#!/usr/bin/env python3

def deadeasy(matrix):
    mx = len(matrix)
    my = len(matrix[0])
    change = True
    cache = [[9999999 for y in range(my+2)] for x in range(mx+2)]
    cache[1][1] = matrix[0][0]
    while change:
        change = False
        for x in range(1, mx+1):
            for y in range(1, my+1):
                new_val = matrix[x-1][y-1] + min(cache[x+1][y], cache[x][y+1], cache[x-1][y], cache[x][y-1])
                if new_val < cache[x][y]:
                    cache[x][y] = new_val
                    change = True
    return cache[mx][my]

class Matrix:
    def __init__(self, matrix):
        self.x = self.y = 0
        self.mx = len(matrix) - 1
        self.my = len(matrix[0]) - 1
        self.org = matrix
        self.overlay = [[None for y in x] for x in matrix]
        self.overlay[0][0] = self.org[0][0]
        self.change  = [[0 for y in x] for x in matrix]
    def add(self, xshft, yshft):
        x = self.x
        y = self.y
        xn = x + xshft
        yn = y + yshft
        chng_id = xshft + 2*yshft
        #if chng_id == -self.change[x][y]:
            #return False
        new_val = self.overlay[x][y] + self.org[xn][yn]
        if new_val < self.overlay[xn][yn] or self.overlay[xn][yn] == None:
            self.overlay[xn][yn] = new_val
            self.change[xn][yn]  = chng_id
            return True
        return False
    
    def right(self):
        return self.add(1, 0)
    def left(self):
        return self.add(-1, 0)
    def up(self):
        return self.add(0, -1)
    def down(self):
        return self.add(0, 1)

def up(matrix):
    matrix.y = matrix.my
    while matrix.y > 0:
        matrix.up()
        matrix.y -= 1

def down(matrix):
    matrix.y = 0
    while matrix.y < matrix.my:
        matrix.down()
        matrix.y += 1

def right(matrix):
    matrix.y = 0
    while matrix.y <= matrix.my:
        matrix.right()
        matrix.y += 1
    matrix.x += 1

def alter_right(matrix):
    matrix.x = 0
    while matrix.x < matrix.mx:
        matrix.y = 0
        while matrix.y <= matrix.my:
            matrix.right()
            matrix.y += 1
        up(matrix)
        down(matrix)
        matrix.x += 1

def alter_left(matrix):
    matrix.x = matrix.mx
    while matrix.x > 0:
        matrix.y = 0
        while matrix.y <= matrix.my:
            matrix.left()
            matrix.y += 1
        up(matrix)
        down(matrix)
        matrix.x -= 1

def left(matrix):
    cont = True
    matrix.x += 1
    while cont and matrix.x > 1:
        matrix.x -= 1
        up(matrix)
        down(matrix)
        matrix.y = 0
        cont = False
        while matrix.y <= matrix.my:
            cont = cont or matrix.left()
            matrix.y += 1

def get_matrix(path):
    with open(path) as f:
        matrix = [map(int, row.split(",")) for row in f.read().split("\n")[:-1]]
    return list(zip(*matrix))

def alter_main(matrix):
    down(matrix)
    prevm = False
    while prevm != matrix.overlay[matrix.mx][matrix.my]:
        prevm = matrix.overlay[matrix.mx][matrix.my]
        alter_right(matrix)
        alter_left(matrix)
    return matrix.overlay[matrix.mx][matrix.my]

def main(matrix):
    down(matrix)
    while matrix.x < matrix.mx:
        right(matrix)
        left(matrix)
    return matrix.overlay[matrix.mx][matrix.my]

if __name__ == "__main__":
    matrix = [[131, 201, 630, 537, 805],
              [673, 96,  803, 699, 732],
              [234, 342, 746, 497, 524],
              [103, 965, 422, 121, 37 ],
              [18,  150, 111, 956, 331]
              ]
    
    print(deadeasy(get_matrix("data/083_matrix.txt")))