matching.py

import config
from typing import Dict
import models
import math

db = config.MAIN_DB
log = config.MAIN_APP.logger


def find_best_match(latitude: float, longitude: float, donating: str) -> Dict[str, str]:
    sql = "SELECT * FROM organizations INNER JOIN organization_needs ON organizations.id = organization_needs.org_id WHERE organization_needs.need = :donating"
    rows = db.session.execute(sql,  {'donating': donating})

    min_distance = float('inf')
    winner_id = -1
    for row in rows:
        org_lat = row.latitude
        org_lon = row.longitude

        try:
            dist = distance(
                float(latitude),
                float(longitude), float(org_lat), float(org_lon))
            if dist < min_distance:
                min_distance = dist
                winner_id = row.id
        except Exception as e:
            continue

    if winner_id != -1:
        winner = get_org_by_id(winner_id)
        return winner[0].serialize()

    return None


def find_closest(latitude: float, longitude: float) -> Dict[str, str]:
    sql = "SELECT * FROM organizations INNER JOIN organization_needs ON organizations.id = organization_needs.org_id"
    rows = db.session.execute(sql)
    min_distance = float('inf')
    winner_id = -1
    for row in rows:
        org_lat = row.latitude
        org_lon = row.longitude

        try:
            dist = distance(
                float(latitude),
                float(longitude), float(org_lat), float(org_lon))
            if dist < min_distance:
                min_distance = dist
                winner_id = row.id
        except Exception as e:
            continue

    winner = get_org_by_id(winner_id)
    return winner[0].serialize()


def distance(lat1: float, lon1: float, lat2: float, lon2: float) -> float:
    """
    Borrowed from https://gist.github.com/rochacbruno/2883505

    Function to calculate the distance between two longitudes and latitudes
    """

    radius = 6371  # km
    dlat = math.radians(lat2 - lat1)
    dlon = math.radians(lon2 - lon1)
    a = math.sin(dlat/2) * math.sin(dlat/2) + math.cos(math.radians(lat1)) \
        * math.cos(math.radians(lat2)) * math.sin(dlon/2) * math.sin(dlon/2)
    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a))
    d = radius * c

    return float(d)


def get_org_by_id(org_id: float) -> models.Organization:
    org = models.Organization.query.filter_by(id=org_id).all()
    return org


def get_org_by_name(org_name: str) -> models.Organization:
    org = models.Organization.query.filter_by(name=org_name).all()
    return org