from flask import Flask, request, jsonify
from datetime import datetime, timedelta
import pint
import sqlite3
from pyproj import Geod
import timezonefinder, pytz
from datetime import timezone as dttz
app = Flask(__name__)

bear_correction = False

with sqlite3.connect('location.db', check_same_thread=False) as conn:
    cur = conn.cursor()

    cur.execute("""CREATE TABLE IF NOT EXISTS location_data (
            row_id INTEGER PRIMARY KEY,
            sender_id INTEGER,
            lat REAL,
            long REAL,
            gpsDateTime INTEGER,
            insertDateTime TEXT DEFAULT CURRENT_TIMESTAMP
    );"""
    )



ureg = pint.UnitRegistry()
geodesic = Geod(ellps='WGS84')




@app.route('/')
def hello():
    return 'Hello!'

@app.route('/updateGPS')
def getGpsDistance():

    current_datetime = datetime.now(dttz.utc)
    date_yesterday = current_datetime - timedelta(days=1)
    date_tomorrow = current_datetime +  timedelta(days=1)
    own_id = request.args.get('id')
    req_id = request.args.get('req_id')
    lat = request.args.get('lat').translate(str.maketrans('', '', ':'))
    long = request.args.get('long').translate(str.maketrans('', '', ':'))

    lat = dm(lat) if lat and len(lat) > 1 else 0.0
    long = dm(long) if long and len(long) > 1 else 0.0  

    valid_date = True

    print(request.args)
   
    try:
        gpsDateTime = datetime.strptime(request.args.get('gpsDateTime')[:11], '%d%m%y%H%M%S').replace(tzinfo=dttz.utc)
        if gpsDateTime > date_tomorrow or current_datetime < date_yesterday:
            gpsDateTime = datetime.now(dttz.utc)
            print(f'GPS datetime out of boundaries - replacing with system time: {gpsDateTime}')
    except ValueError:
        print("No gpsDateTime")
        gpsDateTime = datetime.now(dttz.utc)
        

        

    
    with sqlite3.connect('location.db', check_same_thread=False) as conn:
        timezone = None
        rTime = None
        cur = conn.cursor()
        try:

            res = cur.execute(f'SELECT lat, long, gpsDateTime, insertDateTime FROM location_data WHERE sender_id = {req_id} ORDER BY ROWID DESC LIMIT 1;')
            row = res.fetchone()

            if  row:
                req_lat, req_long, req_dateTime, insertDateTime = row
                rTime = datetime.fromisoformat(req_dateTime)
            else:
                req_lat = 0.0
                req_long = 0.0
                req_dateTime = datetime.now(dttz.utc)
                rTime = datetime.now(dttz.utc)

        except sqlite3.Error as error:
            print("Failed to read data from table, using default values", error)
            req_lat = 0.0
            req_long = 0.0
            req_dateTime = datetime.now(dttz.utc)
        
        if (((lat > 0.005 or lat < -0.005) and (long > 0.005 or long < - 0.005)) and valid_date):
            cur.execute(f'INSERT INTO location_data(sender_id, lat, long, gpsDateTime) VALUES({own_id}, {lat}, {long}, "{gpsDateTime.isoformat()}");')
            conn.commit()

            print(f'lat: {lat}, long: {long}, req_lat: {req_lat}, req_long: {req_long}, req_dateTime: {req_dateTime}')

            fwd_azimuth, back_azimuth, distance = geodesic.inv(long, lat, req_long, req_lat)

            distance = distance * ureg.meter
            prettyDistance = f"{distance:.1f~#P}" + '    (N)' if not bear_correction else ''
            print(f'fwd: {fwd_azimuth}, bwd: {back_azimuth}, dist: {prettyDistance}')
            tf = timezonefinder.TimezoneFinder()
            timezone_str = tf.certain_timezone_at(lat=lat, lng=long)
            if timezone_str is None:
                print("Could not determine the time zone")
            else:
                rTime = rTime.replace(tzinfo=dttz.utc).astimezone(pytz.timezone(timezone_str))
                print(f'GPS datetime of requested database entry: {rTime}')
        else:
            
            try:

                res = cur.execute(f'SELECT lat, long, gpsDateTime, insertDateTime FROM location_data WHERE sender_id = {own_id} ORDER BY ROWID DESC LIMIT 1;')
                row = res.fetchone()

                if  row:
                    lat, long, lastOwnDateTime, lastOwnInsertDateTime = row
                    print(f'lat: {lat}, long: {long}, req_lat: {req_lat}, req_long: {req_long}, req_dateTime: {req_dateTime}')
                    rTime = datetime.fromisoformat(req_dateTime)
                    if rTime < date_tomorrow and current_datetime > date_yesterday:        
                        fwd_azimuth, back_azimuth, distance = geodesic.inv(long, lat, req_long, req_lat)

                        distance = distance * ureg.meter
                        prettyDistance = f"{distance:.1f~#P}" + '    (N)' if not bear_correction else ''
                        print(f'fwd: {fwd_azimuth}, bwd: {back_azimuth}, dist: {prettyDistance}')
                        tf = timezonefinder.TimezoneFinder()
                        timezone_str = tf.certain_timezone_at(lat=lat, lng=long)
                        if timezone_str is None:
                            print("Could not determine the time zone")
                        else:
                            rTime = rTime.replace(tzinfo=dttz.utc).astimezone(pytz.timezone(timezone_str))
                    else:
                        prettyDistance = "Invalid GPS Signal"
                        fwd_azimuth = 0.0
                        rTime = datetime.utcnow()
                else:

                    prettyDistance = "Invalid GPS Signal"
                    fwd_azimuth = 0.0
                    rTime = datetime.utcnow()

            except sqlite3.Error as error:
                print("Failed to read data for last own entry from table -- ignore", error)
                prettyDistance = "Invalid GPS Signal"
                fwd_azimuth = 0.0
                rTime = datetime.now(dttz.utc)

    return jsonify({'distance': prettyDistance, 'azimuth': fwd_azimuth, 'lastUpdateTZ': rTime.strftime("%m/%d %H:%M:%S"), 'bear_correction': bear_correction})


def dm(ddmm: str):
    south = False
    
    south = 'S' in str(ddmm) or 'W' in str(ddmm)
        
    ddmm = float(str(ddmm)[:-1])

        
    degrees = int(ddmm) // 100
    minutes = ddmm - 100*degrees
    
    x = degrees + minutes/60
    if south:
        x = -x
    return x