from typing import List, Dict
from dataclasses import dataclass

from enum import Enum
from typing import List


class RecordType(Enum):
    UNKNOWN = -1
    DATA = 0
    EOF = 1
    SEGADDR = 2
    STARTADDR = 3
    EXTADDR = 4
    LINEARSTARTADDR = 5


@dataclass
class Record:
    type: RecordType
    address: int
    data: List[int]


def parse_line(line: str, file_extension: str) -> Record:
    if file_extension != ".hex":
        raise Exception("Unsupported file format: %s" % (file_extension))

    return parse_hex_line(line)


def parse_hex_line(line: str) -> Record:
    if line[0] != ':':
        raise Exception("Error: unexpected record mark on line %s, expect \':\', get \'%c\'" % (
            line, line[0]))

    datalen = int(line[1:3], base=16)               # Data field length
    addr = int(line[3:7], base=16)                  # Load offset field
    rectype = int(line[7:9], base=16)               # Record type field
    data_bytes_line = line[9:datalen*2 + 9]         # Data field
    crc = int(line[datalen*2 + 9:datalen*2 + 11], base=16)

    splitted_by_bytes: List[str] = []
    for i in range(datalen):
        splitted_by_bytes.append(data_bytes_line[i*2:i*2+2])
    
    data_bytes = list(map(lambda x: int(x, base=16), splitted_by_bytes))
    checksum = (datalen + int(line[3:5], base=16) + int(line[5:7], base=16) + rectype + sum(data_bytes)) % 256
    if (checksum + crc) % 256 != 0:
        raise Exception("Checksum mismatch in %s" % line)

    record = Record(RecordType.UNKNOWN, 0, [])

    if rectype == 0:  # Data Record
        record.type = RecordType.DATA
        record.address = addr
        record.data = data_bytes
    elif rectype == 1:  # End of File Record
        record.type = RecordType.EOF
    elif rectype == 2:  # Extended Segment Address Record
        record.type = RecordType.SEGADDR
        # record.address = addr
        # record.data = list(map(lambda x: int(x, base=16), splitted_by_bytes))
    elif rectype == 3:  # Start Segment Address Record
        record.type = RecordType.STARTADDR
        # record.address = addr
        # record.data = list(map(lambda x: int(x, base=16), splitted_by_bytes))
    elif rectype == 4:  # Extended Linear Address Record
        record.type = RecordType.EXTADDR
        record.address = data_bytes[1] * pow(256, 2) + data_bytes[0] * pow(256, 3)
    elif rectype == 5:  # Start Linear Address Record
        record.type = RecordType.LINEARSTARTADDR
        address = 0
        data_bytes.reverse()
        for i in range(4):
            address += data_bytes[i] * pow(256, i)
        record.address = address
    else:
        record_type = RecordType.UNKNOWN

    return record


def parse_hex(file: str) -> Dict:
    """
    TODO: Implement support for more record types
    """
    with open(file,
              "r", encoding='utf-8') as f:
        lines = f.readlines()

    memory_blocks = {}
    bytes = []
    block_offset = -1

    def add_memory_block():
        memory_blocks[block_offset] = bytes[:]

    is_error = False
    byte_len = 0

    next_line_offset = -1

    for i in range(lines.__len__()):
        line = lines[i]
        if line[0] != ':':
            print("Error: unexpected record mark on line %i, expect \':\', get \'%c\'" % (
                i+1, line[0]))
            is_error = True
            break

        reclen = int(line[1:3], base=16)        # Record length
        load_offset = int(line[3:7], base=16)   # Initial address of data byte
        rectype = int(line[7:9], base=16)       # Record type
        data_bytes: List[str] = []

        data_bytes_line = line[9:reclen*2 + 9]
        for i in range(reclen):
            data_bytes.append(data_bytes_line[i*2:i*2+2])
            byte_len += 1

        if rectype == 0:  # Data Record
            if next_line_offset == -1:
                next_line_offset = load_offset
                block_offset = load_offset

            if next_line_offset != load_offset:
                add_memory_block()
                bytes.clear()
                block_offset = load_offset
                next_line_offset = load_offset

            for i in range(reclen):
                byte = data_bytes[i]
                byte = int(f"0x{byte}", base=16)
                bytes.append(byte)

            next_line_offset += reclen

            # for i in range(data_len//4):
            #     data_bytes = word_bytes.reverse()
            # print("data words: ", data_words)
        elif rectype == 1:  # End of File Record
            # print("End of File")
            add_memory_block()
        elif rectype == 2:  # Extended Segment Address Record
            print("Record 2: Extended Segment Address Record")
            print("ERROR: unimplemented record type 2 on line %i" % (i+1))
            is_error = True
            break
        elif rectype == 3:  # Start Segment Address Record
            print("Start Segment Address Record")
            print("ERROR: unimplemented record type 3 on line %i" % (i+1))
            is_error = True
        elif rectype == 4:  # Extended Linear Address Record
            print("Extended Linear Address Record")
            print("ERROR: unimplemented record type 4 on line %i" % (i+1))
            # is_error = True
        elif rectype == 5:  # Start Linear Address Record
            print("Start Linear Address is 0x%s (line %i)" %
                  (data_bytes_line, (i+1)))
            print("MIK32 MCU does not support arbitrary start address")
        else:
            print("ERROR: unexpected record type %i on line %i" %
                  (rectype, i+1))
            is_error = True
            break
        # print("line %i data_bytes=%i line_addr=%i" % (i+1, data_bytes, line_addr))

    # for word in memory_blocks[0]:
    #     print(f"{word:#0x}")

    if is_error:
        print("ERROR: error while parsing")
        exit()

    return memory_blocks


def bytes2words(arr: List[int]) -> List[int]:
    bytes = []
    words = []
    for byte in arr:
        bytes.append(byte)
        if bytes.__len__() == 4:
            words.append(bytes[0]+2**8*bytes[1]+2**16*bytes[2]+2**24*bytes[3])
            bytes = []
    if bytes.__len__() != 0:
        print("WARNING: skipping not-word-aligned byte")
    return words