"""
# MicropyGPS - a GPS NMEA sentence parser for Micropython/Python 3.X
# Copyright (c) 2017 Michael Calvin McCoy (calvin.mccoy@protonmail.com)
# The MIT License (MIT) - see LICENSE file
#
# mini_micropyGPS.py is a is a reduced version of micropyGPS.py
# with the support for the main NMEA messages.
# Tested and working with ESP32 without the need of including it as a frozen module.
#
"""

# TODO:
# Time Since First Fix
# Distance/Time to Target
# More Helper Functions
# Dynamically limit sentences types to parse

from math import floor, modf

# Import utime or time for fix time handling
try:
    # Assume running on MicroPython
    import utime
except ImportError:
    # Otherwise default to time module for non-embedded implementations
    # Should still support millisecond resolution.
    import time


class MicropyGPS(object):
    """GPS NMEA Sentence Parser. Creates object that stores all relevant GPS data and statistics.
    Parses sentences one character at a time using update(). """

    # Max Number of Characters a valid sentence can be (based on GGA sentence)
    SENTENCE_LIMIT = 90
    __HEMISPHERES = ('N', 'S', 'E', 'W')
    __NO_FIX = 1
    __FIX_2D = 2
    __FIX_3D = 3
    __DIRECTIONS = ('N', 'NNE', 'NE', 'ENE', 'E', 'ESE', 'SE', 'SSE', 'S', 'SSW', 'SW', 'WSW', 'W',
                    'WNW', 'NW', 'NNW')
    __MONTHS = ('January', 'February', 'March', 'April', 'May',
                'June', 'July', 'August', 'September', 'October',
                'November', 'December')

    def __init__(self, local_offset=0, location_formatting='ddm'):
        """
        Setup GPS Object Status Flags, Internal Data Registers, etc
            local_offset (int): Timzone Difference to UTC
            location_formatting (str): Style For Presenting Longitude/Latitude:
                                       Decimal Degree Minute (ddm) - 40 26.7672 N
                                       Degrees Minutes Seconds (dms) - 40 262 463 N
                                       Decimal Degrees (dd) - 40.446 N
        """

        #####################
        # Object Status Flags
        self.sentence_active = False
        self.active_segment = 0
        self.process_crc = False
        self.gps_segments = []
        self.crc_xor = 0
        self.char_count = 0
        self.fix_time = 0

        #####################
        # Sentence Statistics
        self.crc_fails = 0
        self.clean_sentences = 0
        self.parsed_sentences = 0

        #####################
        # Logging Related
        self.log_handle = None
        self.log_en = False

        #####################
        # Data From Sentences
        # Time
        self.timestamp = [0, 0, 0.0]
        self.date = [0, 0, 0]
        self.local_offset = local_offset

        # Position/Motion
        self._latitude = [0, 0.0, 'N']
        self._longitude = [0, 0.0, 'W']
        self.coord_format = location_formatting
        self.speed = [0.0, 0.0, 0.0]
        self.course = 0.0
        self.altitude = 0.0
        self.geoid_height = 0.0

        # GPS Info
        self.satellites_in_view = 0
        self.satellites_in_use = 0
        self.satellites_used = []
        self.last_sv_sentence = 0
        self.total_sv_sentences = 0
        self.satellite_data = dict()
        self.hdop = 0.0
        self.pdop = 0.0
        self.vdop = 0.0
        self.valid = False
        self.fix_stat = 0
        self.fix_type = 1

    ########################################
    # Coordinates Translation Functions
    ########################################
    @property
    def latitude(self):
        """Format Latitude Data Correctly"""
        if self.coord_format == 'dd':
            decimal_degrees = self._latitude[0] + (self._latitude[1] / 60)
            return [decimal_degrees, self._latitude[2]]
        elif self.coord_format == 'dms':
            minute_parts = modf(self._latitude[1])
            seconds = round(minute_parts[0] * 60)
            return [self._latitude[0], int(minute_parts[1]), seconds, self._latitude[2]]
        else:
            return self._latitude

    @property
    def longitude(self):
        """Format Longitude Data Correctly"""
        if self.coord_format == 'dd':
            decimal_degrees = self._longitude[0] + (self._longitude[1] / 60)
            return [decimal_degrees, self._longitude[2]]
        elif self.coord_format == 'dms':
            minute_parts = modf(self._longitude[1])
            seconds = round(minute_parts[0] * 60)
            return [self._longitude[0], int(minute_parts[1]), seconds, self._longitude[2]]
        else:
            return self._longitude


    ########################################
    # Sentence Parsers
    ########################################
    def gprmc(self):
        """Parse Recommended Minimum Specific GPS/Transit data (RMC)Sentence.
        Updates UTC timestamp, latitude, longitude, Course, Speed, Date, and fix status
        """

        # UTC Timestamp
        try:
            utc_string = self.gps_segments[1]

            if utc_string:  # Possible timestamp found
                hours = (int(utc_string[0:2]) + self.local_offset) % 24
                minutes = int(utc_string[2:4])
                seconds = float(utc_string[4:])
                self.timestamp = [hours, minutes, seconds]
            else:  # No Time stamp yet
                self.timestamp = [0, 0, 0.0]

        except ValueError:  # Bad Timestamp value present
            return False

        # Date stamp
        try:
            date_string = self.gps_segments[9]

            # Date string printer function assumes to be year >=2000,
            # date_string() must be supplied with the correct century argument to display correctly
            if date_string:  # Possible date stamp found
                day = int(date_string[0:2])
                month = int(date_string[2:4])
                year = int(date_string[4:6])
                self.date = (day, month, year)
            else:  # No Date stamp yet
                self.date = (0, 0, 0)

        except ValueError:  # Bad Date stamp value present
            return False

        # Check Receiver Data Valid Flag
        if self.gps_segments[2] == 'A':  # Data from Receiver is Valid/Has Fix

            # Longitude / Latitude
            try:
                # Latitude
                l_string = self.gps_segments[3]
                lat_degs = int(l_string[0:2])
                lat_mins = float(l_string[2:])
                lat_hemi = self.gps_segments[4]

                # Longitude
                l_string = self.gps_segments[5]
                lon_degs = int(l_string[0:3])
                lon_mins = float(l_string[3:])
                lon_hemi = self.gps_segments[6]
            except ValueError:
                return False

            if lat_hemi not in self.__HEMISPHERES:
                return False

            if lon_hemi not in self.__HEMISPHERES:
                return False

            # Speed
            try:
                spd_knt = float(self.gps_segments[7])
            except ValueError:
                return False

            # Course
            try:
                if self.gps_segments[8]:
                    course = float(self.gps_segments[8])
                else:
                    course = 0.0
            except ValueError:
                return False

            # TODO - Add Magnetic Variation

            # Update Object Data
            self._latitude = [lat_degs, lat_mins, lat_hemi]
            self._longitude = [lon_degs, lon_mins, lon_hemi]
            # Include mph and hm/h
            self.speed = [spd_knt, spd_knt * 1.151, spd_knt * 1.852]
            self.course = course
            self.valid = True

            # Update Last Fix Time
            self.new_fix_time()

        else:  # Clear Position Data if Sentence is 'Invalid'
            self._latitude = [0, 0.0, 'N']
            self._longitude = [0, 0.0, 'W']
            self.speed = [0.0, 0.0, 0.0]
            self.course = 0.0
            self.valid = False

        return True


    def gpvtg(self):
        """Parse Track Made Good and Ground Speed (VTG) Sentence. Updates speed and course"""
        try:
            course = float(self.gps_segments[1]) if self.gps_segments[1] else 0.0
            spd_knt = float(self.gps_segments[5]) if self.gps_segments[5] else 0.0
        except ValueError:
            return False

        # Include mph and km/h
        self.speed = (spd_knt, spd_knt * 1.151, spd_knt * 1.852)
        self.course = course
        return True

    def gpgga(self):
        """Parse Global Positioning System Fix Data (GGA) Sentence. Updates UTC timestamp, latitude, longitude,
        fix status, satellites in use, Horizontal Dilution of Precision (HDOP), altitude, geoid height and fix status"""

        try:
            # UTC Timestamp
            utc_string = self.gps_segments[1]

            # Skip timestamp if receiver doesn't have on yet
            if utc_string:
                hours = (int(utc_string[0:2]) + self.local_offset) % 24
                minutes = int(utc_string[2:4])
                seconds = float(utc_string[4:])
            else:
                hours = 0
                minutes = 0
                seconds = 0.0

            # Number of Satellites in Use
            satellites_in_use = int(self.gps_segments[7])

            # Get Fix Status
            fix_stat = int(self.gps_segments[6])

        except (ValueError, IndexError):
            return False

        try:
            # Horizontal Dilution of Precision
            hdop = float(self.gps_segments[8])
        except (ValueError, IndexError):
            hdop = 0.0

        # Process Location and Speed Data if Fix is GOOD
        if fix_stat:

            # Longitude / Latitude
            try:
                # Latitude
                l_string = self.gps_segments[2]
                lat_degs = int(l_string[0:2])
                lat_mins = float(l_string[2:])
                lat_hemi = self.gps_segments[3]

                # Longitude
                l_string = self.gps_segments[4]
                lon_degs = int(l_string[0:3])
                lon_mins = float(l_string[3:])
                lon_hemi = self.gps_segments[5]
            except ValueError:
                return False

            if lat_hemi not in self.__HEMISPHERES:
                return False

            if lon_hemi not in self.__HEMISPHERES:
                return False

            # Altitude / Height Above Geoid
            try:
                altitude = float(self.gps_segments[9])
                geoid_height = float(self.gps_segments[11])
            except ValueError:
                altitude = 0
                geoid_height = 0

            # Update Object Data
            self._latitude = [lat_degs, lat_mins, lat_hemi]
            self._longitude = [lon_degs, lon_mins, lon_hemi]
            self.altitude = altitude
            self.geoid_height = geoid_height

        # Update Object Data
        self.timestamp = [hours, minutes, seconds]
        self.satellites_in_use = satellites_in_use
        self.hdop = hdop
        self.fix_stat = fix_stat

        # If Fix is GOOD, update fix timestamp
        if fix_stat:
            self.new_fix_time()

        return True



    ##########################################
    # Data Stream Handler Functions
    ##########################################

    def new_sentence(self):
        """Adjust Object Flags in Preparation for a New Sentence"""
        self.gps_segments = ['']
        self.active_segment = 0
        self.crc_xor = 0
        self.sentence_active = True
        self.process_crc = True
        self.char_count = 0

    def update(self, new_char):
        """Process a new input char and updates GPS object if necessary based on special characters ('$', ',', '*')
        Function builds a list of received string that are validate by CRC prior to parsing by the  appropriate
        sentence function. Returns sentence type on successful parse, None otherwise"""

        valid_sentence = False

        # Validate new_char is a printable char
        ascii_char = ord(new_char)

        if 10 <= ascii_char <= 126:
            self.char_count += 1

            # Write Character to log file if enabled
            if self.log_en:
                self.write_log(new_char)

            # Check if a new string is starting ($)
            if new_char == '$':
                self.new_sentence()
                return None

            elif self.sentence_active:

                # Check if sentence is ending (*)
                if new_char == '*':
                    self.process_crc = False
                    self.active_segment += 1
                    self.gps_segments.append('')
                    return None

                # Check if a section is ended (,), Create a new substring to feed
                # characters to
                elif new_char == ',':
                    self.active_segment += 1
                    self.gps_segments.append('')

                # Store All Other printable character and check CRC when ready
                else:
                    self.gps_segments[self.active_segment] += new_char

                    # When CRC input is disabled, sentence is nearly complete
                    if not self.process_crc:

                        if len(self.gps_segments[self.active_segment]) == 2:
                            try:
                                final_crc = int(self.gps_segments[self.active_segment], 16)
                                if self.crc_xor == final_crc:
                                    valid_sentence = True
                                else:
                                    self.crc_fails += 1
                            except ValueError:
                                pass  # CRC Value was deformed and could not have been correct

                # Update CRC
                if self.process_crc:
                    self.crc_xor ^= ascii_char

                # If a Valid Sentence Was received and it's a supported sentence, then parse it!!
                if valid_sentence:
                    self.clean_sentences += 1  # Increment clean sentences received
                    self.sentence_active = False  # Clear Active Processing Flag

                    if self.gps_segments[0] in self.supported_sentences:

                        # parse the Sentence Based on the message type, return True if parse is clean
                        if self.supported_sentences[self.gps_segments[0]](self):

                            # Let host know that the GPS object was updated by returning parsed sentence type
                            self.parsed_sentences += 1
                            return self.gps_segments[0]

                # Check that the sentence buffer isn't filling up with Garage waiting for the sentence to complete
                if self.char_count > self.SENTENCE_LIMIT:
                    self.sentence_active = False

        # Tell Host no new sentence was parsed
        return None

    def new_fix_time(self):
        """Updates a high resolution counter with current time when fix is updated. Currently only triggered from
        GGA, GSA and RMC sentences"""
        try:
            self.fix_time = utime.ticks_ms()
        except NameError:
            self.fix_time = time.time()

    #########################################
    # User Helper Functions
    # These functions make working with the GPS object data easier
    #########################################

    def satellite_data_updated(self):
        """
        Checks if the all the GSV sentences in a group have been read, making satellite data complete
        :return: boolean
        """
        if self.total_sv_sentences > 0 and self.total_sv_sentences == self.last_sv_sentence:
            return True
        else:
            return False

    def unset_satellite_data_updated(self):
        """
        Mark GSV sentences as read indicating the data has been used and future updates are fresh
        """
        self.last_sv_sentence = 0

    def satellites_visible(self):
        """
        Returns a list of of the satellite PRNs currently visible to the receiver
        :return: list
        """
        return list(self.satellite_data.keys())

    def time_since_fix(self):
        """Returns number of millisecond since the last sentence with a valid fix was parsed. Returns 0 if
        no fix has been found"""

        # Test if a Fix has been found
        if self.fix_time == 0:
            return -1

        # Try calculating fix time using utime; if not running MicroPython
        # time.time() returns a floating point value in secs
        try:
            current = utime.ticks_diff(utime.ticks_ms(), self.fix_time)
        except NameError:
            current = (time.time() - self.fix_time) * 1000  # ms

        return current

    def compass_direction(self):
        """
        Determine a cardinal or inter-cardinal direction based on current course.
        :return: string
        """
        # Calculate the offset for a rotated compass
        if self.course >= 348.75:
            offset_course = 360 - self.course
        else:
            offset_course = self.course + 11.25

        # Each compass point is separated by 22.5 degrees, divide to find lookup value
        dir_index = floor(offset_course / 22.5)

        final_dir = self.__DIRECTIONS[dir_index]

        return final_dir

    def latitude_string(self):
        """
        Create a readable string of the current latitude data
        :return: string
        """
        if self.coord_format == 'dd':
            formatted_latitude = self.latitude
            lat_string = str(formatted_latitude[0]) + ' ' + str(self._latitude[2])
        elif self.coord_format == 'dms':
            formatted_latitude = self.latitude
            lat_string = str(formatted_latitude[0]) + ' ' + str(formatted_latitude[1]) + "' " + str(formatted_latitude[2]) + '" ' + str(formatted_latitude[3])
        else:
            lat_string = str(self._latitude[0]) + ' ' + str(self._latitude[1]) + "' " + str(self._latitude[2])
        return lat_string

    def longitude_string(self):
        """
        Create a readable string of the current longitude data
        :return: string
        """
        if self.coord_format == 'dd':
            formatted_longitude = self.longitude
            lon_string = str(formatted_longitude[0]) + ' ' + str(self._longitude[2])
        elif self.coord_format == 'dms':
            formatted_longitude = self.longitude
            lon_string = str(formatted_longitude[0]) + ' ' + str(formatted_longitude[1]) + "' " + str(formatted_longitude[2]) + '" ' + str(formatted_longitude[3])
        else:
            lon_string = str(self._longitude[0]) + ' ' + str(self._longitude[1]) + "' " + str(self._longitude[2])
        return lon_string

    def speed_string(self, unit='kph'):
        """
        Creates a readable string of the current speed data in one of three units
        :param unit: string of 'kph','mph, or 'knot'
        :return:
        """
        if unit == 'mph':
            speed_string = str(self.speed[1]) + ' mph'

        elif unit == 'knot':
            if self.speed[0] == 1:
                unit_str = ' knot'
            else:
                unit_str = ' knots'
            speed_string = str(self.speed[0]) + unit_str

        else:
            speed_string = str(self.speed[2]) + ' km/h'

        return speed_string

    def date_string(self, formatting='s_mdy', century='20'):
        """
        Creates a readable string of the current date.
        Can select between long format: Januray 1st, 2014
        or two short formats:
        11/01/2014 (MM/DD/YYYY)
        01/11/2014 (DD/MM/YYYY)
        :param formatting: string 's_mdy', 's_dmy', or 'long'
        :param century: int delineating the century the GPS data is from (19 for 19XX, 20 for 20XX)
        :return: date_string  string with long or short format date
        """

        # Long Format Januray 1st, 2014
        if formatting == 'long':
            # Retrieve Month string from private set
            month = self.__MONTHS[self.date[1] - 1]

            # Determine Date Suffix
            if self.date[0] in (1, 21, 31):
                suffix = 'st'
            elif self.date[0] in (2, 22):
                suffix = 'nd'
            elif self.date[0] == (3, 23):
                suffix = 'rd'
            else:
                suffix = 'th'

            day = str(self.date[0]) + suffix  # Create Day String

            year = century + str(self.date[2])  # Create Year String

            date_string = month + ' ' + day + ', ' + year  # Put it all together

        else:
            # Add leading zeros to day string if necessary
            if self.date[0] < 10:
                day = '0' + str(self.date[0])
            else:
                day = str(self.date[0])

            # Add leading zeros to month string if necessary
            if self.date[1] < 10:
                month = '0' + str(self.date[1])
            else:
                month = str(self.date[1])

            # Add leading zeros to year string if necessary
            if self.date[2] < 10:
                year = '0' + str(self.date[2])
            else:
                year = str(self.date[2])

            # Build final string based on desired formatting
            if formatting == 's_dmy':
                date_string = day + '/' + month + '/' + year

            else:  # Default date format
                date_string = month + '/' + day + '/' + year

        return date_string

    # All the currently supported NMEA sentences
    supported_sentences = {'GPRMC': gprmc, 'GLRMC': gprmc,
                           'GPGGA': gpgga, 'GLGGA': gpgga,
                           'GPVTG': gpvtg, 'GLVTG': gpvtg,
                           'GNGGA': gpgga, 'GNRMC': gprmc,

                          }

if __name__ == "__main__":
    pass
