import os
import can
import re

from sphinx.util.osutil import getcwd

from scripts.base.base import Base


class SoftwareUpdateScript(Base):

    _DECODED_BYTES_KEY_NAME = 'decoded_bytes'
    _CUR_DATA_INDEX_KEY_NAME = 'cur_data_index'
    _CUR_INSERT_DATA_INDEX_KEY_NAME = 'cur_insert_index'
    _TOTAL_BYTES_TX_KEY_NAME = 'total_bytes_tx'
    _RESIDUAL_BYTES_KEY_NAME = 'residual_bytes'

    _DECODE_LIST_MAX_SIZE_BYTES = 2048
    _SHIFT_BITS_BY_8 = 8
    _DECODE_COPRIME_1 = 19
    _DECODE_COPRIME_2 = 23
    _DECODE_VALUE = 256
    _DECODE_ADD_VALUE = 211
    _XML_REPORT_END_TAG = "</root>"
    _XML_REPORT_HEADER_SIZE = 2

    _NUM_OF_BYTES_PER_CAN_FRAME = 8
    _CAN_INTERFACE = "can0"

    def __init__(self):

        super().__init__()
        self._signature_start_in_bytes = bytes(self.SIGNATURE_START, 'utf-8')
        self._signature_end_in_bytes = bytes(self.SIGNATURE_END, 'utf-8')
        self._decode_data_status = dict()
        self._xml_report_values = dict()

    def _reset_variables(self):

        # TODO #define for the dictionary keys
        self._decode_data_status['decode_values_found'] = False
        self._decode_data_status['end_tag_found'] = False
        self._decode_data_status['decode_found_index'] = 0
        self._decode_data_status['converted_xml'] = ''
        self._decode_data_status['is_first_line'] = False
        self._decode_data_status['num_of_bytes_sent'] = 0
        self._decode_data_status[self._RESIDUAL_BYTES_KEY_NAME] = list()
        self._decode_data_status[self._DECODED_BYTES_KEY_NAME] = list()
        self._decode_data_status[self._CUR_DATA_INDEX_KEY_NAME] = 0
        self._decode_data_status[self._CUR_INSERT_DATA_INDEX_KEY_NAME] = 0
        self._decode_data_status[self._TOTAL_BYTES_TX_KEY_NAME] = 0

        self._xml_report_values['name'] = ''
        self._xml_report_values['version'] = ''
        self._xml_report_values['filetype'] = ''
        self._xml_report_values['security'] = ''
        self._xml_report_values['version'] = ''
        self._xml_report_values['size'] = ''
        self._xml_report_values['raw'] = ''

    def _verify_signature(self, signature: bytes):
        # TODO fill up
        pass

    def _verify_key(self):
        pass

    def _get_decode_variables(self, line_bytes: bytes):

        if len(self._decode_data_status[self._RESIDUAL_BYTES_KEY_NAME]) != 0:
            line_bytes = self._decode_data_status[self._RESIDUAL_BYTES_KEY_NAME] + line_bytes

        if len(line_bytes) > 2:
            a = int(line_bytes[0])
            b = int(line_bytes[1])
            if a is not None and b is not None:
                code = (a << self._SHIFT_BITS_BY_8) + b
                for s in range(0, 0xFF):
                    convert = ((s % self._DECODE_COPRIME_1) << self._SHIFT_BITS_BY_8) + (s % self._DECODE_COPRIME_2)

                    if code == convert:
                        self._decode_data_status['decode_found_index'] = s
                        self._decode_data_status['decode_values_found'] = True
                        print("Breaking {} {} {} {} {}".format(code, convert, s, a, b))
                        break

    def _decode_line(self, line_bytes: bytes):

        start_index = 0

        if len(self._decode_data_status[self._RESIDUAL_BYTES_KEY_NAME]) != 0:
            line_bytes = self._decode_data_status[self._RESIDUAL_BYTES_KEY_NAME] + line_bytes
            self._decode_data_status[self._RESIDUAL_BYTES_KEY_NAME] = list()

        if self._decode_data_status['is_first_line'] is False:
            start_index = self._XML_REPORT_HEADER_SIZE
            self._decode_data_status['is_first_line'] = True

        for d in range(start_index, len(line_bytes)):

            if self._decode_data_status['end_tag_found'] is False:
                decoded_value_bytes = (line_bytes[d] - self._decode_data_status[
                    'decode_found_index']) % self._DECODE_VALUE
                self._decode_data_status['decode_found_index'] += self._DECODE_ADD_VALUE
                self._decode_data_status['converted_xml'] += ''.join(chr(decoded_value_bytes)).replace('\n', '')

                if self._XML_REPORT_END_TAG in self._decode_data_status['converted_xml']:

                    converted_xml = self._decode_data_status['converted_xml']
                    self._decode_data_status['end_tag_found'] = True
                    self._xml_report_values['filetype'] = re.search('<filetype>(.*)</filetype>', converted_xml).group(1)
                    self._xml_report_values['size'] = re.search('<size>(.*)</size>', converted_xml).group(1)
                    print(self._xml_report_values['filetype'], self._xml_report_values['size'],
                          len(converted_xml), converted_xml, self._decode_data_status['decode_found_index'], 'H')
            else:
                self._decode_data_status[self._DECODED_BYTES_KEY_NAME].append(hex(line_bytes[d]))
                self._decode_data_status[self._CUR_DATA_INDEX_KEY_NAME] += 1

    def _process_read_line(self, line: bytes):

        if self._signature_start_in_bytes in line:
            if self._signature_end_in_bytes:
                signature = line[len(self._signature_start_in_bytes):line.find(self._signature_end_in_bytes)]
                self._verify_signature(signature)
                end_of_signature_mark = line.find(self._signature_end_in_bytes) + len(self._signature_end_in_bytes)
                xml_report_start = line[end_of_signature_mark:]
                if (len(line) - end_of_signature_mark) > 2 and self._decode_data_status['decode_values_found'] is False:
                    self._get_decode_variables(xml_report_start)
                else:
                    print(xml_report_start, 'D')
                    self._decode_data_status[self._RESIDUAL_BYTES_KEY_NAME] = xml_report_start

                if self._decode_data_status['decode_values_found'] is True:
                    print(xml_report_start, len(xml_report_start), 'K')
                    self._decode_line(xml_report_start)
            else:
                # TODO fill up
                pass
        else:
            self._get_decode_variables(line) if self._decode_data_status['decode_values_found'] is False else None
            self._decode_line(line)

    def _send_update_data_to_bootloader(self):
        pass

    def update_software_packages(self, packages_dir: str, stack_to_update: str = None):
        # 1. Verify signature
        # 2. Verify key
        # 3. Read XML file for to find the packages to update
        # 4. Decrypt the content
        # 5. Send the data to bootloader
        # 6. Wait for the bootloader to ack/nack or timeout after 3000 ms
        # 7. Send the entire file
        # 8. Show progress

        for file in os.listdir(packages_dir):
            if file.endswith(".bin"):
                with open(os.path.join(packages_dir, file), 'rb') as f:
                    # Get ready for the next binary file
                    self._reset_variables()
                    for line in f:
                        self._process_read_line(line)
                        self._send_update_data_to_bootloader()
                f.close()

        print(self._decode_data_status[self._CUR_DATA_INDEX_KEY_NAME],
              self._decode_data_status[self._DECODED_BYTES_KEY_NAME][0],
              self._decode_data_status[self._DECODED_BYTES_KEY_NAME][-3],
              self._decode_data_status[self._DECODED_BYTES_KEY_NAME][-2],
              self._decode_data_status[self._DECODED_BYTES_KEY_NAME][-1])