util.py

import settings
import math
import simplejson
import urllib

def coord_distance(lat1, lon1, lat2, lon2):
    """
    Finds the distance between two pairs of latitude and longitude.
    :param lat1: Point 1 latitude.
    :param lon1: Point 1 longitude.
    :param lat2: Point two latitude.
    :param lon2: Point two longitude.
    :return: Kilometer distance.
    """
    lon1, lat1, lon2, lat2 = map(math.radians, [lon1, lat1, lon2, lat2])
    dlon = lon2 - lon1
    dlat = lat2 - lat1
    a = math.sin(dlat/2)**2 + math.cos(lat1) * math.cos(lat2) * math.sin(dlon/2)**2
    c = 2 * math.asin(math.sqrt(a))
    km = 6367 * c
    return km

def google_transit_time(start, end, time):
    """
    Get the time to travel between start and stop
    :param start: List of lat and log for starting position
    :param end: List of lat and log for Ending position
    :param time:
    :return: transit time in minutes
    """
    url = "http://maps.googleapis.com/maps/api/distancematrix/json?origins={},{}&destinations={},{}&mode=driving&language=en-EN&sensor=false"\
        .format(start[0], start[1], end[0], end[1])
    result= simplejson.load(urllib.request.urlopen(url))

    try:
        driving_time = result['rows'][0]['elements'][0]['duration']['value']
    except KeyError:
        driving_time = 0
    except IndexError:
        driving_time = 0

    return driving_time / 60.0

def get_walkscore(lat, lon):
    url = "http://api.walkscore.com/score?format=json&lat={}&lon={}&wsapikey={}" \
        .format(lat, lon, settings.WS_API_KEY)

    result = simplejson.load(urllib.request.urlopen(url))

    try:
        score = result["walkscore"]
    except KeyError:
        score = 0
    except IndexError:
        score = 0

    return score

def in_box(coords, box):
    """
    Find if a coordinate tuple is inside a bounding box.
    :param coords: Tuple containing latitude and longitude.
    :param box: Two tuples, where first is the bottom left, and the second is the top right of the box.
    :return: Boolean indicating if the coordinates are in the box.
    """
    if box[0][0] < coords[0] < box[1][0] and box[0][1] < coords[1] < box[1][1]:
        return True
    return False

def post_listing_to_slack(sc, listing):
    """
    Posts the listing to slack.
    :param sc: A slack client.
    :param listing: A record of the listing.
    """
    desc = "*{}* - {} - {}\nTime to work: {:.2f}\n{}\n<{}>".format(listing["area"], listing["price"],
                                                                    listing["walkscore"], listing["driving_time"],
                                                                    listing["name"], listing["url"])
    sc.api_call(
        "chat.postMessage", channel=settings.SLACK_CHANNEL, text=desc,
        username='Apartment Finder', icon_emoji=':robot_face:'
    )

def find_points_of_interest(geotag, location):
    """
    Find points of interest, like transit, near a result.
    :param geotag: The geotag field of a Craigslist result.
    :param location: The where field of a Craigslist result.  Is a string containing a description of where
    the listing was posted.
    :return: A dictionary containing annotations.
    """
    area_found = False
    area = ""
    min_dist = None
    near_bart = False
    bart_dist = "N/A"
    bart = ""
    # Look to see if the listing is in any of the neighborhood boxes we defined.
    for a, coords in settings.BOXES.items():
        if in_box(geotag, coords):
            area = a
            area_found = True

    # Check to see if the listing is near any transit stations.
    for station, coords in settings.TRANSIT_STATIONS.items():
        dist = coord_distance(coords[0], coords[1], geotag[0], geotag[1])
        if (min_dist is None or dist < min_dist) and dist < settings.MAX_TRANSIT_DIST:
            bart = station
            near_bart = True

        if (min_dist is None or dist < min_dist):
            bart_dist = dist

    # If the listing isn't in any of the boxes we defined, check to see if the string description of the neighborhood
    # matches anything in our list of neighborhoods.
    if len(area) == 0:
        for hood in settings.NEIGHBORHOODS:
            if hood in location.lower():
                area = hood

    # Try and find travel time to work
    driving_time = google_transit_time(geotag, settings.WORK_LOCATION, settings.TIME_TO_WORK)

    # Try and get walkscore
    walkscore = get_walkscore(geotag[0], geotag[1])

    return {
        "area_found": area_found,
        "area": area,
        "near_bart": near_bart,
        "bart_dist": bart_dist,
        "bart": bart,
        "driving_time": driving_time,
        "walkscore": walkscore
    }