certification.py

'''
Created on 2 déc. 2014

@author: inso
'''
import re
import base64
import logging

from . import Document


class SelfCertification(Document):
    '''
    A document discribing a self certification.
    '''

    re_inline = re.compile("([1-9A-Za-z][^OIl]{42,45}):([A-Za-z0-9+/]+(?:=|==)?):([0-9]+):([^\n]+)\n")
    re_uid = re.compile("UID:([^\n]+)\n")
    re_timestamp = re.compile("META:TS:([0-9]+)\n")

    def __init__(self, version, currency, pubkey, ts, uid, signature):
        if signature:
            super().__init__(version, currency, [signature])
        else:
            super().__init__(version, currency, [])
        self.pubkey = pubkey
        self.timestamp = ts
        self.uid = uid

    @classmethod
    def from_inline(cls, version, currency, inline):
        selfcert_data = SelfCertification.re_inline.match(inline)
        pubkey = selfcert_data.group(1)
        signature = selfcert_data.group(2)
        ts = int(selfcert_data.group(3))
        uid = selfcert_data.group(4)
        return cls(version, currency, pubkey, ts, uid, signature)

    def raw(self):
        return """UID:{0}
META:TS:{1}
""".format(self.uid, self.timestamp)

    def inline(self):
        return "{0}:{1}:{2}:{3}".format(self.pubkey, self.signatures[0],
                                    self.timestamp, self.uid)


class Certification(Document):
    '''
    A document describing a certification.
    '''

    re_inline = re.compile("([1-9A-Za-z][^OIl]{42,45}):\
([1-9A-Za-z][^OIl]{42,45}):([0-9]+):([A-Za-z0-9+/]+(?:=|==)?)\n")
    re_timestamp = re.compile("META:TS:([0-9]+)-([0-9a-fA-F]{5,40})\n")

    def __init__(self, version, currency, pubkey_from, pubkey_to,
                 blocknumber, blockhash, signature):
        '''
        Constructor
        '''
        super().__init__(version, currency, [signature])
        self.pubkey_from = pubkey_from
        self.pubkey_to = pubkey_to
        self.blockhash = blockhash
        self.blocknumber = blocknumber

    @classmethod
    def from_inline(cls, version, currency, blockhash, inline):
        cert_data = Certification.re_inline.match(inline)
        pubkey_from = cert_data.group(1)
        pubkey_to = cert_data.group(2)
        blocknumber = int(cert_data.group(3))
        if blocknumber == 0:
            blockhash = "DA39A3EE5E6B4B0D3255BFEF95601890AFD80709"
        signature = cert_data.group(4)
        return cls(version, currency, pubkey_from, pubkey_to,
                   blockhash, blocknumber, signature)

    def raw(self, selfcert):
        return """{0}META:TS:{1}-{2}
""".format(selfcert.signed_raw(), self.blocknumber, self.blockhash)


    def sign(self, selfcert, keys):
        '''
        Sign the current document.
        Warning : current signatures will be replaced with the new ones.
        '''
        self.signatures = []
        for key in keys:
            signing = base64.b64encode(key.signature(bytes(self.raw(selfcert), 'ascii')))
            logging.debug("Signature : \n{0}".format(signing.decode("ascii")))
            self.signatures.append(signing.decode("ascii"))

    def signed_raw(self, selfcert):
        raw = self.raw(selfcert)
        signed = "\n".join(self.signatures)
        signed_raw = raw + signed + "\n"
        return signed_raw

    def inline(self):
        return "{0}:{1}:{2}:{3}".format(self.pubkey_from, self.pubkey_to,
                                        self.blocknumber, self.signatures[0])