#!/usr/bin/env python
# -*- coding: UTF-8 -*-

"""Death by Captcha HTTP and socket API clients.

There are two types of Death by Captcha (DBC hereinafter) API: HTTP and
socket ones.  Both offer the same functionalily, with the socket API
sporting faster responses and using way less connections.

To access the socket API, use SocketClient class; for the HTTP API, use
HttpClient class.  Both are thread-safe.  SocketClient keeps a persistent
connection opened and serializes all API requests sent through it, thus
it is advised to keep a pool of them if you're script is heavily
multithreaded.

Both SocketClient and HttpClient give you the following methods:

get_user()
    Returns your DBC account details as a dict with the following keys:

    "user": your account numeric ID; if login fails, it will be the only
        item with the value of 0;
    "rate": your CAPTCHA rate, i.e. how much you will be charged for one
        solved CAPTCHA in US cents;
    "balance": your DBC account balance in US cents;
    "is_banned": flag indicating whether your account is suspended or not.

get_balance()
    Returns your DBC account balance in US cents.

get_captcha(cid)
    Returns an uploaded CAPTCHA details as a dict with the following keys:

    "captcha": the CAPTCHA numeric ID; if no such CAPTCHAs found, it will
        be the only item with the value of 0;
    "text": the CAPTCHA text, if solved, otherwise None;
    "is_correct": flag indicating whether the CAPTCHA was solved correctly
        (DBC can detect that in rare cases).

    The only argument `cid` is the CAPTCHA numeric ID.

get_text(cid)
    Returns an uploaded CAPTCHA text (None if not solved).  The only argument
    `cid` is the CAPTCHA numeric ID.

report(cid)
    Reports an incorrectly solved CAPTCHA.  The only argument `cid` is the
    CAPTCHA numeric ID.  Returns True on success, False otherwise.

upload(captcha)
    Uploads a CAPTCHA.  The only argument `captcha` can be either file-like
    object (any object with `read` method defined, actually, so StringIO
    will do), or CAPTCHA image file name.  On successul upload you'll get
    the CAPTCHA details dict (see get_captcha() method).

    NOTE: AT THIS POINT THE UPLOADED CAPTCHA IS NOT SOLVED YET!  You have
    to poll for its status periodically using get_captcha() or get_text()
    method until the CAPTCHA is solved and you get the text.

decode(captcha, timeout=DEFAULT_TIMEOUT)
    A convenient method that uploads a CAPTCHA and polls for its status
    periodically, but no longer than `timeout` (defaults to 60 seconds).
    If solved, you'll get the CAPTCHA details dict (see get_captcha()
    method for details).  See upload() method for details on `captcha`
    argument.

Visit http://www.deathbycaptcha.com/user/api for updates.

"""

import base64
import binascii
import errno
import imghdr
import random
import os
import select
import socket
import sys
import threading
import time
import urllib
try:
    from json import read as json_decode, write as json_encode
except ImportError:
    try:
        from json import loads as json_decode, dumps as json_encode
    except ImportError:
        from simplejson import loads as json_decode, dumps as json_encode


# API version and unique software ID
API_VERSION = 'DBC/Python v4.6'

# Default CAPTCHA timeout and decode() polling interval
DEFAULT_TIMEOUT = 60
DEFAULT_TOKEN_TIMEOUT = 120
POLLS_INTERVAL = [1, 1, 2, 3, 2, 2, 3, 2, 2]
DFLT_POLL_INTERVAL = 3

# Base HTTP API url
HTTP_BASE_URL = 'http://api.dbcapi.me/api'

# Preferred HTTP API server's response content type, do not change
HTTP_RESPONSE_TYPE = 'application/json'

# Socket API server's host & ports range
SOCKET_HOST = 'api.dbcapi.me'
SOCKET_PORTS = range(8123, 8131)


def _load_image(captcha):
    if hasattr(captcha, 'read'):
        img = captcha.read()
    elif type(captcha) == bytearray:
        img = captcha
    else:
        img = ''
        try:
            captcha_file = open(captcha, 'rb')
        except Exception:
            raise
        else:
            img = captcha_file.read()
            captcha_file.close()
    if not len(img):
        raise ValueError('CAPTCHA image is empty')
    elif imghdr.what(None, img) is None:
        raise TypeError('Unknown CAPTCHA image type')
    else:
        return img


class AccessDeniedException(Exception):
    pass


class Client(object):

    """Death by Captcha API Client."""

    def __init__(self, username, password):
        self.is_verbose = False
        self.userpwd = {'username': username, 'password': password}

    def _log(self, cmd, msg=''):
        if self.is_verbose:
            print('%d %s %s' % (time.time(), cmd, msg.rstrip()))
        return self

    def close(self):
        pass

    def connect(self):
        pass

    def get_user(self):
        """Fetch user details -- ID, balance, rate and banned status."""
        raise NotImplementedError()

    def get_balance(self):
        """Fetch user balance (in US cents)."""
        return self.get_user().get('balance')

    def get_captcha(self, cid):
        """Fetch a CAPTCHA details -- ID, text and correctness flag."""
        raise NotImplementedError()

    def get_text(self, cid):
        """Fetch a CAPTCHA text."""
        return self.get_captcha(cid).get('text') or None

    def report(self, cid):
        """Report a CAPTCHA as incorrectly solved."""
        raise NotImplementedError()

    def upload(self, captcha):
        """Upload a CAPTCHA.

        Accepts file names and file-like objects.  Returns CAPTCHA details
        dict on success.

        """
        raise NotImplementedError()

    def decode(self, captcha=None, timeout=None, **kwargs):
        """
        Try to solve a CAPTCHA.

        See Client.upload() for arguments details.

        Uploads a CAPTCHA, polls for its status periodically with arbitrary
        timeout (in seconds), returns CAPTCHA details if (correctly) solved.
        """
        if not timeout:
            if not captcha:
                timeout = DEFAULT_TOKEN_TIMEOUT
            else:
                timeout = DEFAULT_TIMEOUT

        deadline = time.time() + (max(0, timeout) or DEFAULT_TIMEOUT)
        uploaded_captcha = self.upload(captcha, **kwargs)
        if uploaded_captcha:
            intvl_idx = 0  # POLL_INTERVAL index
            while deadline > time.time() and not uploaded_captcha.get('text'):
                intvl, intvl_idx = self._get_poll_interval(intvl_idx)
                time.sleep(intvl)
                pulled = self.get_captcha(uploaded_captcha['captcha'])
                if pulled['captcha'] == uploaded_captcha['captcha']:
                    uploaded_captcha = pulled
            if uploaded_captcha.get('text') and \
                    uploaded_captcha.get('is_correct'):
                return uploaded_captcha

    def _get_poll_interval(self, idx):
        """Returns poll interval and next index depending on index provided"""

        if len(POLLS_INTERVAL) > idx:
            intvl = POLLS_INTERVAL[idx]
        else:
            intvl = DFLT_POLL_INTERVAL
        idx += 1

        return intvl, idx


class HttpClient(Client):

    """Death by Captcha HTTP API client."""

    def __init__(self, *args):
        Client.__init__(self, *args)
        self.opener = urllib2.build_opener(urllib2.HTTPRedirectHandler())

    def _call(self, cmd, payload=None, headers=None):
        if headers is None:
            headers = {}
        headers['Accept'] = HTTP_RESPONSE_TYPE
        headers['User-Agent'] = API_VERSION
        if hasattr(payload, 'items'):
            payload = urllib.urlencode(payload)
            self._log('SEND', '%s %d %s' % (cmd, len(payload), payload))
        else:
            self._log('SEND', '%s' % cmd)
        if payload is not None:
            headers['Content-Length'] = len(payload)
        try:
            response = self.opener.open(urllib2.Request(
                HTTP_BASE_URL + '/' + cmd.strip('/'),
                data=payload,
                headers=headers
            )).read()
        except urllib2.HTTPError as err:
            if 403 == err.code:
                raise AccessDeniedException('Access denied, please check'
                                            ' your credentials and/or balance')
            elif 400 == err.code or 413 == err.code:
                raise ValueError("CAPTCHA was rejected by the service, check"
                                 " if it's a valid image")
            elif 503 == err.code:
                raise OverflowError("CAPTCHA was rejected due to service"
                                    " overload, try again later")
            else:
                raise err
        else:
            self._log('RECV', '%d %s' % (len(response), response))
            try:
                return json_decode(response)
            except Exception:
                raise RuntimeError('Invalid API response')
        return {}

    def get_user(self):
        return self._call('user', self.userpwd.copy()) or {'user': 0}

    def get_captcha(self, cid):
        return self._call('captcha/%d' % cid) or {'captcha': 0}

    def report(self, cid):
        return not self._call('captcha/%d/report' % cid,
                              self.userpwd.copy()).get('is_correct')

    def upload(self, captcha=None, **kwargs):
        boundary = binascii.hexlify(os.urandom(16))
        banner = kwargs.get('banner', '')
        if banner:
            kwargs['banner'] = 'base64:' + base64.b64encode(_load_image(banner))
        body = '\r\n'.join(('\r\n'.join((
            '--%s' % boundary,
            'Content-Disposition: form-data; name="%s"' % k,
            'Content-Type: text/plain',
            'Content-Length: %d' % len(str(v)),
            '',
            str(v)
        ))) for k, v in self.userpwd.items())

        body += '\r\n'.join(('\r\n'.join((
            '--%s' % boundary,
            'Content-Disposition: form-data; name="%s"' % k,
            'Content-Type: text/plain',
            'Content-Length: %d' % len(str(v)),
            '',
            str(v)
        ))) for k, v in kwargs.items())

        if captcha:
            img = _load_image(captcha)
            body += '\r\n'.join((
                '',
                '--%s' % boundary,
                'Content-Disposition: form-data; name="captchafile"; '
                    'filename="captcha"',
                'Content-Type: application/octet-stream',
                'Content-Length: %d' % len(img),
                '',
                img,
                '--%s--' % boundary,
                ''
            ))

        response = self._call('captcha', body, {
            'Content-Type': 'multipart/form-data; boundary="%s"' % boundary
        }) or {}
        if response.get('captcha'):
            return response


class SocketClient(Client):

    """Death by Captcha socket API client."""

    TERMINATOR = '\r\n'

    def __init__(self, *args):
        Client.__init__(self, *args)
        self.socket_lock = threading.Lock()
        self.socket = None

    def close(self):
        if self.socket:
            self._log('CLOSE')
            try:
                self.socket.shutdown(socket.SHUT_RDWR)
            except socket.error:
                pass
            finally:
                self.socket.close()
                self.socket = None

    def connect(self):
        if not self.socket:
            self._log('CONN')
            host = (socket.gethostbyname(SOCKET_HOST),
                    random.choice(SOCKET_PORTS))
            self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            self.socket.settimeout(0)
            try:
                self.socket.connect(host)
            except socket.error as err:
                if (err.args[0] not in
                        (errno.EAGAIN, errno.EWOULDBLOCK, errno.EINPROGRESS)):
                    self.close()
                    raise err
        return self.socket

    def __del__(self):
        self.close()

    def _sendrecv(self, sock, buf):
        self._log('SEND', buf)
        fds = [sock]
        buf += self.TERMINATOR
        response = ''
        intvl_idx = 0
        while True:
            intvl, intvl_idx = self._get_poll_interval(intvl_idx)
            rds, wrs, exs = select.select((not buf and fds) or [],
                                          (buf and fds) or [],
                                          fds,
                                          intvl)
            if exs:
                raise IOError('select() failed')
            try:
                if wrs:
                    while buf:
                        buf = buf[wrs[0].send(buf):]
                elif rds:
                    while True:
                        s = rds[0].recv(256)
                        if not s:
                            raise IOError('recv(): connection lost')
                        else:
                            response += s
            except socket.error as err:
                if (err.args[0] not in
                        (errno.EAGAIN, errno.EWOULDBLOCK, errno.EINPROGRESS)):
                    raise err
            if response.endswith(self.TERMINATOR):
                self._log('RECV', response)
                return response.rstrip(self.TERMINATOR)
        raise IOError('send/recv timed out')

    def _call(self, cmd, data=None):
        if data is None:
            data = {}
        data['cmd'] = cmd
        data['version'] = API_VERSION
        request = json_encode(data)

        response = None
        for _ in range(2):
            if not self.socket and cmd != 'login':
                self._call('login', self.userpwd.copy())
            self.socket_lock.acquire()
            try:
                sock = self.connect()
                response = self._sendrecv(sock, request)
            except IOError as err:
                sys.stderr.write(str(err) + "\n")
                self.close()
            except socket.error as err:
                sys.stderr.write(str(err) + "\n")
                self.close()
                raise IOError('Connection refused')
            else:
                break
            finally:
                self.socket_lock.release()

        if response is None:
            raise IOError('Connection lost or timed out during API request')

        try:
            response = json_decode(response)
        except Exception:
            raise RuntimeError('Invalid API response')

        if not response.get('error'):
            return response

        error = response['error']
        if error in ('not-logged-in', 'invalid-credentials'):
            raise AccessDeniedException('Access denied, check your credentials')
        elif 'banned' == error:
            raise AccessDeniedException('Access denied, account is suspended')
        elif 'insufficient-funds' == error:
            raise AccessDeniedException(
                'CAPTCHA was rejected due to low balance')
        elif 'invalid-captcha' == error:
            raise ValueError('CAPTCHA is not a valid image')
        elif 'service-overload' == error:
            raise OverflowError(
                'CAPTCHA was rejected due to service overload, try again later')
        else:
            self.socket_lock.acquire()
            self.close()
            self.socket_lock.release()
            raise RuntimeError('API server error occured: %s' % error)

    def get_user(self):
        return self._call('user') or {'user': 0}

    def get_captcha(self, cid):
        return self._call('captcha', {'captcha': cid}) or {'captcha': 0}

    def upload(self, captcha=None, **kwargs):
        data = {}
        if captcha:
            data['captcha'] = base64.b64encode(_load_image(captcha))
        if kwargs:
            banner = kwargs.get('banner', '')
            if banner:
                kwargs['banner'] = base64.b64encode(_load_image(banner))
            data.update(kwargs)
        response = self._call('upload', data)
        if response.get('captcha'):
            uploaded_captcha = dict(
                (k, response.get(k))
                for k in ('captcha', 'text', 'is_correct')
            )
            if not uploaded_captcha['text']:
                uploaded_captcha['text'] = None
            return uploaded_captcha

    def report(self, cid):
        return not self._call('report', {'captcha': cid}).get('is_correct')


if '__main__' == __name__:
    # Put your DBC username & password here:
    # client = HttpClient(sys.argv[1], sys.argv[2])
    client = SocketClient(sys.argv[1], sys.argv[2])
    client.is_verbose = True

    print('Your balance is %s US cents' % client.get_balance())

    for fn in sys.argv[3:]:
        try:
            # Put your CAPTCHA image file name or file-like object, and optional
            # solving timeout (in seconds) here:
            captcha = client.decode(fn, DEFAULT_TIMEOUT)
        except Exception as e:
            sys.stderr.write('Failed uploading CAPTCHA: %s\n' % (e, ))
            captcha = None

        if captcha:
            print('CAPTCHA %d solved: %s' % \
                  (captcha['captcha'], captcha['text']))

            # Report as incorrectly solved if needed.  Make sure the CAPTCHA was
            # in fact incorrectly solved!
            # try:
            #    client.report(captcha['captcha'])
            # except Exception, e:
            #    sys.stderr.write('Failed reporting CAPTCHA: %s\n' % (e, ))