from base64 import (
    b32encode,
    b64decode,
)
from collections.abc import Generator
from typing import (
    Any,
    Dict,
    List,
    Union,
)
from urllib.parse import (
    ParseResult,
    parse_qs,
    quote,
    urlencode,
    urlparse,
)

from .otpauth_enums import (
    Algorithm,
    DigitCount,
    OtpType,
)
from .otpauth_migration_pb2 import Payload


SCHEME = 'otpauth-migration'
HOSTNAME = 'offline'
PAYLOAD_MARK = 'data'
EXAMPLE_PAYLOAD = 'CjEKCkhlbGxvId6tvu8SGEV4YW1wbGU6YWxpY2VAZ29vZ2xlLmNvbRoHRXhhbXBsZTAC'
EXAMPLE_MIGRATION = f'{SCHEME}://{HOSTNAME}?{PAYLOAD_MARK}={EXAMPLE_PAYLOAD}'


def is_migration_incorrect(
        *,
        parsed_url: ParseResult,
        parsed_qs: Dict[str, Any],
) -> bool:
    return (
            parsed_url.scheme != SCHEME
            or parsed_url.hostname != HOSTNAME
            or PAYLOAD_MARK not in parsed_qs
            or not isinstance(parsed_qs[PAYLOAD_MARK], list)
    )


def decoded_data(data: List[str]) -> Generator:
    for data_item in data:
        yield b64decode(data_item)


def decode_secret(secret: bytes) -> str:
    return str(b32encode(secret), 'utf-8').replace('=', '')


def get_url_params(otp: Payload.OtpParameters) -> str:
    params: dict[str, Union[str, int]] = {}

    if otp.algorithm:
        params.update(algorithm=Algorithm.get(otp.algorithm, ''))
    if otp.digits:
        params.update(digits=DigitCount.get(otp.digits, ''))
    if otp.issuer:
        params.update(issuer=otp.issuer)
    if otp.secret:
        otp_secret = decode_secret(otp.secret)
        params.update(secret=otp_secret)

    return urlencode(params)


def get_otpauth_url(otp: Payload.OtpParameters) -> str:
    otp_type = OtpType.get(otp.type, '')
    otp_name = quote(otp.name)
    otp_params = get_url_params(otp)

    return f'otpauth://{otp_type}/{otp_name}?{otp_params}'


def validate_migration(migration: str) -> list:
    url: ParseResult = urlparse(migration)
    qs: Dict[str, Any] = parse_qs(url.query)


    return qs[PAYLOAD_MARK]


def decoder(migration_data: list) -> list:
    """Convert Google Authenticator data to plain otpauth links"""
    result = []

    for payload in decoded_data(data=migration_data):
        migration_payload = Payload()
        migration_payload.ParseFromString(payload)

        for otp_item in migration_payload.otp_parameters:
            result.append(get_otpauth_url(otp_item))
    
    return result

def start_decode_migration(migration_code: str) -> list:
    payload_list = validate_migration(migration_code)
    results = decoder(payload_list)
    return results
    
if __name__ == "__main__":
    start_decode_migration("otpauth-migration://offline?data=CkAKFFUlyp7lQLXJnL8Oc5%2BjVRVCEIMPEhpHb29nbGU6cHVha2Foa2luQGdtYWlsLmNvbRoGR29vZ2xlIAEoATACCj0KFEMSL8awHj%2BEFzX2cODi9rNgfvPFEhdHb29nbGU6a2Foa2luQGdtYWlsLmNvbRoGR29vZ2xlIAEoATACCi8KEBdHlsAmppdFyWD18FyPcQkSDXNhbXVlbEBhcG9sbG8aBmFwb2xsbyABKAEwAgouChQpi9Btg%2BHoQJj6tilYEsOef%2BSkiRIQc2FtdWVsQGFwaHJvZGl0ZSABKAEwAgo1ChDnUjGxj%2BJmsJJxdcrbBNpqEhBzYW11ZWxAc2FtdWVscHVhGglzYW11ZWxwdWEgASgBMAIKUAoUihAclMtkwYi3NfvbkHcHmgAi2yESJmdpdGxhYi5jb206Z2l0bGFiLmNvbV9rYWhraW5AZ21haWwuY29tGgpnaXRsYWIuY29tIAEoATACCioKCsaExzWrYHtcsLoSDkdpdEh1Yjp0ZWxib29uGgZHaXRIdWIgASgBMAIKbwooyfRfWMXsY%2B%2B%2FVvZKl9ypsl1VLAZrOPmyr3AsGxeCOuTHmGdGpt4OyBIoQW1hem9uIFdlYiBTZXJ2aWNlczp0ZWxib29uQDI2Nzk5NDAyOTgxMBoTQW1hem9uIFdlYiBTZXJ2aWNlcyABKAEwAgp%2FCiieutAtJJdKrtOMVznsVaMbvrpM%2FNvwURQSChMpPzgI2PlVshsoRk3QEjhBbWF6b24gV2ViIFNlcnZpY2VzOnJvb3QtYWNjb3VudC1tZmEtZGV2aWNlQDI2Nzk5NDAyOTgxMBoTQW1hem9uIFdlYiBTZXJ2aWNlcyABKAEwAgozCgr2b4%2BKdfJzdo%2ByEhRzYW11ZWxAd2F0Y2h0b3dyLmNvbRoJTWljcm9zb2Z0IAEoATACEAEYAiAAKKessZb6%2F%2F%2F%2F%2FwE%3D")