__filename__ = "pgp.py"
__author__ = "Bob Mottram"
__license__ = "AGPL3+"
__version__ = "1.2.0"
__maintainer__ = "Bob Mottram"
__email__ = "bob@freedombone.net"
__status__ = "Production"

import os
import subprocess
from pathlib import Path
from person import getActorJson


def getEmailAddress(actorJson: {}) -> str:
    """Returns the email address for the given actor
    """
    if not actorJson.get('attachment'):
        return ''
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue['name'].lower().startswith('email'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue.get('value'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        if '@' not in propertyValue['value']:
            continue
        if '.' not in propertyValue['value']:
            continue
        return propertyValue['value']
    return ''


def getPGPpubKey(actorJson: {}) -> str:
    """Returns PGP public key for the given actor
    """
    if not actorJson.get('attachment'):
        return ''
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue['name'].lower().startswith('pgp'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue.get('value'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        if not containsPGPPublicKey(propertyValue['value']):
            continue
        return propertyValue['value']
    return ''


def getPGPfingerprint(actorJson: {}) -> str:
    """Returns PGP fingerprint for the given actor
    """
    if not actorJson.get('attachment'):
        return ''
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue['name'].lower().startswith('openpgp'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue.get('value'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        if len(propertyValue['value']) < 10:
            continue
        return propertyValue['value']
    return ''


def setEmailAddress(actorJson: {}, emailAddress: str) -> None:
    """Sets the email address for the given actor
    """
    notEmailAddress = False
    if '@' not in emailAddress:
        notEmailAddress = True
    if '.' not in emailAddress:
        notEmailAddress = True
    if '<' in emailAddress:
        notEmailAddress = True
    if emailAddress.startswith('@'):
        notEmailAddress = True

    if not actorJson.get('attachment'):
        actorJson['attachment'] = []

    # remove any existing value
    propertyFound = None
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('email'):
            continue
        propertyFound = propertyValue
        break
    if propertyFound:
        actorJson['attachment'].remove(propertyFound)
    if notEmailAddress:
        return

    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('email'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        propertyValue['value'] = emailAddress
        return

    newEmailAddress = {
        "name": "Email",
        "type": "PropertyValue",
        "value": emailAddress
    }
    actorJson['attachment'].append(newEmailAddress)


def setPGPpubKey(actorJson: {}, PGPpubKey: str) -> None:
    """Sets a PGP public key for the given actor
    """
    removeKey = False
    if not PGPpubKey:
        removeKey = True
    else:
        if not containsPGPPublicKey(PGPpubKey):
            removeKey = True
        if '<' in PGPpubKey:
            removeKey = True

    if not actorJson.get('attachment'):
        actorJson['attachment'] = []

    # remove any existing value
    propertyFound = None
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('pgp'):
            continue
        propertyFound = propertyValue
        break
    if propertyFound:
        actorJson['attachment'].remove(propertyValue)
    if removeKey:
        return

    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('pgp'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        propertyValue['value'] = PGPpubKey
        return

    newPGPpubKey = {
        "name": "PGP",
        "type": "PropertyValue",
        "value": PGPpubKey
    }
    actorJson['attachment'].append(newPGPpubKey)


def setPGPfingerprint(actorJson: {}, fingerprint: str) -> None:
    """Sets a PGP fingerprint for the given actor
    """
    removeFingerprint = False
    if not fingerprint:
        removeFingerprint = True
    else:
        if len(fingerprint) < 10:
            removeFingerprint = True

    if not actorJson.get('attachment'):
        actorJson['attachment'] = []

    # remove any existing value
    propertyFound = None
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('openpgp'):
            continue
        propertyFound = propertyValue
        break
    if propertyFound:
        actorJson['attachment'].remove(propertyValue)
    if removeFingerprint:
        return

    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('openpgp'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        propertyValue['value'] = fingerprint.strip()
        return

    newPGPfingerprint = {
        "name": "OpenPGP",
        "type": "PropertyValue",
        "value": fingerprint
    }
    actorJson['attachment'].append(newPGPfingerprint)


def extractPGPPublicKey(content: str) -> str:
    """Returns the PGP key from the given text
    """
    startBlock = '--BEGIN PGP PUBLIC KEY BLOCK--'
    endBlock = '--END PGP PUBLIC KEY BLOCK--'
    if startBlock not in content:
        return None
    if endBlock not in content:
        return None
    if '\n' not in content:
        return None
    linesList = content.split('\n')
    extracting = False
    publicKey = ''
    for line in linesList:
        if not extracting:
            if startBlock in line:
                extracting = True
        else:
            if endBlock in line:
                publicKey += line
                break
        if extracting:
            publicKey += line + '\n'
    return publicKey


def _pgpImportPubKey(recipientPubKey: str) -> str:
    """ Import the given public key
    """
    # do a dry run
    cmdImportPubKey = \
        'echo "' + recipientPubKey + '" | gpg --dry-run --import 2> /dev/null'
    proc = subprocess.Popen([cmdImportPubKey],
                            stdout=subprocess.PIPE, shell=True)
    (importResult, err) = proc.communicate()
    if err:
        return None

    # this time for real
    cmdImportPubKey = \
        'echo "' + recipientPubKey + '" | gpg --import 2> /dev/null'
    proc = subprocess.Popen([cmdImportPubKey],
                            stdout=subprocess.PIPE, shell=True)
    (importResult, err) = proc.communicate()
    if err:
        return None

    # get the key id
    cmdImportPubKey = \
        'echo "' + recipientPubKey + '" | gpg --show-keys'
    proc = subprocess.Popen([cmdImportPubKey],
                            stdout=subprocess.PIPE, shell=True)
    (importResult, err) = proc.communicate()
    if not importResult:
        return None
    importResult = importResult.decode('utf-8').split('\n')
    keyId = ''
    for line in importResult:
        if line.startswith('pub'):
            continue
        elif line.startswith('uid'):
            continue
        elif line.startswith('sub'):
            continue
        keyId = line.strip()
        break
    return keyId


def _pgpEncrypt(content: str, recipientPubKey: str) -> str:
    """ Encrypt using your default pgp key to the given recipient
    """
    keyId = _pgpImportPubKey(recipientPubKey)
    if not keyId:
        return None

    cmdEncrypt = \
        'echo "' + content + '" | gpg --encrypt --armor --recipient ' + \
        keyId + ' 2> /dev/null'
    proc = subprocess.Popen([cmdEncrypt],
                            stdout=subprocess.PIPE, shell=True)
    (encryptResult, err) = proc.communicate()
    if not encryptResult:
        return None
    encryptResult = encryptResult.decode('utf-8')
    if not isPGPEncrypted(encryptResult):
        return None
    return encryptResult


def _getPGPPublicKeyFromActor(handle: str, actorJson=None) -> str:
    """Searches tags on the actor to see if there is any PGP
    public key specified
    """
    if not actorJson:
        actorJson = getActorJson(handle, False, False, True)
    if not actorJson:
        return None
    if not actorJson.get('attachment'):
        return None
    if not isinstance(actorJson['attachment'], list):
        return None
    # search through the tags on the actor
    for tag in actorJson['attachment']:
        if not isinstance(tag, dict):
            continue
        if not tag.get('value'):
            continue
        if not isinstance(tag['value'], str):
            continue
        if containsPGPPublicKey(tag['value']):
            return tag['value']
    return None


def hasLocalPGPkey() -> bool:
    """Returns true if there is a local .gnupg directory
    """
    homeDir = str(Path.home())
    gpgDir = homeDir + '/.gnupg'
    if os.path.isdir(gpgDir):
        return True
    return False


def pgpEncryptToActor(content: str, toHandle: str) -> str:
    """PGP encrypt a message to the given actor or handle
    """
    # get the actor and extract the pgp public key from it
    recipientPubKey = _getPGPPublicKeyFromActor(toHandle)
    if not recipientPubKey:
        return None
    # encrypt using the recipient public key
    return _pgpEncrypt(content, recipientPubKey)


def isPGPEncrypted(content: str) -> bool:
    """Returns true if the given content is PGP encrypted
    """
    if '--BEGIN PGP MESSAGE--' in content:
        if '--END PGP MESSAGE--' in content:
            return True
    return False


def containsPGPPublicKey(content: str) -> bool:
    """Returns true if the given content contains a PGP public key
    """
    if '--BEGIN PGP PUBLIC KEY BLOCK--' in content:
        if '--END PGP PUBLIC KEY BLOCK--' in content:
            return True
    return False


def pgpDecrypt(content: str, fromHandle: str) -> str:
    """ Encrypt using your default pgp key to the given recipient
    fromHandle can be a handle or actor url
    """
    if not isPGPEncrypted(content):
        return content

    # if the public key is also included within the message then import it
    if containsPGPPublicKey(content):
        pubKey = extractPGPPublicKey(content)
    else:
        pubKey = _getPGPPublicKeyFromActor(content, fromHandle)
    if pubKey:
        _pgpImportPubKey(pubKey)

    cmdDecrypt = \
        'echo "' + content + '" | gpg --decrypt --armor 2> /dev/null'
    proc = subprocess.Popen([cmdDecrypt],
                            stdout=subprocess.PIPE, shell=True)
    (decryptResult, err) = proc.communicate()
    if not decryptResult:
        return content
    decryptResult = decryptResult.decode('utf-8').strip()
    return decryptResult