# standard imports
import logging

# external imports
from hexathon import valid as valid_hex

# local imports
from cic.output import StdoutWriter

logg = logging.getLogger(__name__)


class Extension:
    """Base class adapter to initialize, serialize and publish extension-specific token resources.

    :param chain_spec: Chain Spec that extension will operate for
    :type chain_spec: chainlib.chain.ChainSpec
    :param resources: Chain application resources to deploy or interface with
    :type resources: dict
    :param proof: Proof object to publish
    :type proof: cic.proof.Proof
    :param signer: Signer capable of generating signatures for chain aplication deployments
    :type signer: funga.signer.Signer
    :param rpc: RPC adapter capable of submitting and querying the chain network node
    :type rpc: chainlib.connection.RPCConnection
    :param writer: Writer interface receiving the output of the processor
    :type writer: cic.output.OutputWriter
    """
    def __init__(self, chain_spec, resources, proof, signer=None, rpc=None, outputs_writer=StdoutWriter()):
        self.resources = resources
        self.proof = proof
        self.chain_spec = chain_spec
        self.signer = signer
        self.rpc = rpc
        self.token_details = None
        self.token_address = None
        self.token_code = None
        self.outputs = []
        self.outputs_writer = outputs_writer


    # TODO: apply / prepare token can be factored out
    def apply_token(self, token):
        """Initialize extension with token data from settings.

        :param token: Token object
        :type token: cic.token.Token
        :rtype: dict
        :returns: Token data state of extension after load
        """
        return self.prepare_token(token.name, token.symbol, token.precision, token.code, token.supply)
         

    def prepare_token(self, name, symbol, precision, code, supply, extra=[], extra_types=[], positions=None):
        """Initialize extension token data.

        :param name: Token name
        :type name: str
        :param symbol: Token symbol
        :type symbol: str
        :param precision: Token value precision (number of decimals)
        :type precision: int
        :param code: Bytecode for token chain application
        :type code: str (hex)
        :param supply: Token supply (in smallest precision units)
        :type supply: int
        :param extra: Extra parameters to pass to token application constructor
        :type extra: list 
        :param extra_types: Type specifications for extra parameters
        :type extra_types: list
        :param positions: Sequence of parameter indices to pass to application constructor
        :type positions: list
        :rtype: dict
        :returns: Token data state of extension after load
        """
        self.token_details = {
            'name': name,
            'symbol': symbol,
            'precision': precision,
            'code': code,
            'supply': supply,
            'extra': extra,
            'extra_types': extra_types,
            'positions': positions,
            }
        return self.token_details


    def prepare_extension(self):
        """Prepare extension for publishing (noop)
        """
        pass


    def parse_code_as_file(self, v):
        """Helper method to load application bytecode from file into extensions token data state.

        Client code should call load_code instead.

        :param v: File path
        :type v: str
        """
        try:
            f = open(v, 'r')
            r = f.read()
            f.close()
            self.parse_code_as_hex(r)
        except FileNotFoundError:
            logg.debug('could not parse code as file: {}'.format(e))
            pass
        except IsADirectoryError:
            logg.debug('could not parse code as file: {}'.format(e))
            pass


    def parse_code_as_hex(self, v):
        """Helper method to load application bytecode from hex data into extension token data state.

        Client code should call load_code instead.

        :param v: Bytecode as hex
        :type v: str
        """
        try:  
            self.token_code = valid_hex(v)
        except ValueError as e:
            logg.debug('could not parse code as hex: {}'.format(e))
            pass


    def load_code(self, hint=None):
        """Attempt to load token application bytecode using token settings.

        :param hint: If "hex", will interpret code in settings as literal bytecode
        :type hint: str
        :rtype: str (hex)
        :return: Bytecode loaded into extension token data state
        """
        code = self.token_details['code']
        if hint == 'hex':
            self.token_code = valid_hex(code)
       
        for m in [
                self.parse_code_as_hex,
                self.parse_code_as_file,
                ]:
            m(code)
            if self.token_code != None:
                break
       
        if self.token_code == None:
            raise RuntimeError('could not successfully parse token code')

        return self.token_code


    def process(self, writer=None):
        """Adapter used by Processor to process the extensions implementing the Extension base class.

        Requires either token address or a valid token code reference to have been included in settings. If token address is not set, the token application code will be deployed.

        :param writer: Writer to use for publishing.
        :type writer: cic.output.OutputWriter
        :rtype: tuple
        :return: Token address, token symbol
        """
        if writer == None:
            writer = self.outputs_writer

        tasks = [] 
        self.token_address = self.resources['token']['reference']
       
        # TODO: get token details when token address is not none
        if self.token_address == None:
            if self.token_details['code'] == None:
                raise RuntimeError('neither token address nor token code has been set')
            self.load_code()
            tasks.append('token')

        for k in self.resources.keys():
            if k == 'token':
                continue
            if self.resources[k]['reference'] != None:
                tasks.append(k)
        
        self.prepare_extension()

        for task in tasks:
            logg.debug('extension adapter process {}'.format(task))
            r = getattr(self, 'process_' + task)(writer=writer)

        return (self.token_address, self.token_details.get('symbol'))