from django.shortcuts import render
from django.http import HttpResponse
from django.views.decorators.csrf import csrf_exempt

import json
import math

# Create your views here.


def index(request):
    return HttpResponse('It lives!')


@csrf_exempt
def classify(request):
    return HttpResponse(json.load(request))


@csrf_exempt
def shortestPath(request):
    loaded_request = json.load(request)

    graph = loaded_request["graph"]
    graph = {int(k): v for k, v in graph.items()}
    for node in graph:
        graph[node] = {
            int(k): v for k, v in graph[node].items()}

    start_node = loaded_request["start_node"]
    dest_node = loaded_request["dest_node"]

    distance = {}
    predecessor = {}
    path = {}
    unseen_nodes = graph.copy()

    for node in graph:
        distance[node] = math.inf
    distance[start_node] = 0

    while unseen_nodes:
        min_node = None
        for node in unseen_nodes:
            if min_node is None:
                min_node = node
            elif distance[node] < distance[min_node]:
                min_node = node

        for childNode, weight in graph[min_node].items():
            if distance[min_node] + weight < distance[childNode]:
                distance[childNode] = distance[min_node] + weight
                predecessor[childNode] = min_node
        unseen_nodes.pop(min_node)

    for node in graph:
        current = node
        p = [current]
        while current != start_node:
            p.append(predecessor[current])
            current = predecessor[current]
        path[node] = p[::-1]

    return HttpResponse(path[dest_node][1:])