from eventlet.api import trampoline, get_hub
from eventlet import util


BUFFER_SIZE = 4096

import errno
import os
import socket
from socket import socket as _original_socket
import time


from errno import EWOULDBLOCK, EAGAIN


__all__ = ['GreenSocket', 'GreenFile', 'GreenPipe']

def higher_order_recv(recv_func):
    def recv(self, buflen, flags=0):
        if self.act_non_blocking:
            return self.fd.recv(buflen, flags)
        buf = self.recvbuffer
        if buf:
            chunk, self.recvbuffer = buf[:buflen], buf[buflen:]
            return chunk
        fd = self.fd
        bytes = recv_func(fd, buflen, flags)
        if self.gettimeout():
            end = time.time()+self.gettimeout()
        else:
            end = None
        timeout = None
        while bytes is None:
            try:
                if end:
                    timeout = end - time.time()
                trampoline(fd, read=True, timeout=timeout, timeout_exc=socket.timeout)
            except socket.timeout:
                raise
            except socket.error, e:
                if e[0] == errno.EPIPE:
                    bytes = ''
                else:
                    raise
            else:
                bytes = recv_func(fd, buflen, flags)
        self.recvcount += len(bytes)
        return bytes
    return recv


def higher_order_send(send_func):
    def send(self, data, flags=0):
        if self.act_non_blocking:
            return self.fd.send(data, flags)
        count = send_func(self.fd, data, flags)
        if not count:
            return 0
        self.sendcount += count
        return count
    return send


CONNECT_ERR = (errno.EINPROGRESS, errno.EALREADY, errno.EWOULDBLOCK)
CONNECT_SUCCESS = (0, errno.EISCONN)
def socket_connect(descriptor, address):
    err = descriptor.connect_ex(address)
    if err in CONNECT_ERR:
        return None
    if err not in CONNECT_SUCCESS:
        raise socket.error(err, errno.errorcode[err])
    return descriptor


def socket_accept(descriptor):
    try:
        return descriptor.accept()
    except socket.error, e:
        if e[0] == errno.EWOULDBLOCK:
            return None
        raise
        

def socket_send(descriptor, data, flags=0):
    try:
        return descriptor.send(data, flags)
    except socket.error, e:
        if e[0] == errno.EWOULDBLOCK or e[0] == errno.ENOTCONN:
            return 0
        raise

# winsock sometimes throws ENOTCONN
SOCKET_CLOSED = (errno.ECONNRESET, errno.ENOTCONN, errno.ESHUTDOWN)
def socket_recv(descriptor, buflen, flags=0):
    try:
        return descriptor.recv(buflen, flags)
    except socket.error, e:
        if e[0] == errno.EWOULDBLOCK:
            return None
        if e[0] in SOCKET_CLOSED:
            return ''
        raise


def file_recv(fd, buflen, flags=0):
    try:
        return fd.read(buflen)
    except IOError, e:
        if e[0] == EAGAIN:
            return None
        return ''
    except socket.error, e:
        if e[0] == errno.EPIPE:
            return ''
        raise


def file_send(fd, data, flags=0):
    try:
        fd.write(data)
        fd.flush()
        return len(data)
    except IOError, e:
        if e[0] == EAGAIN:
            return 0
    except ValueError, e:
        written = 0
    except socket.error, e:
        if e[0] == errno.EPIPE:
            written = 0


def set_nonblocking(fd):
    try:
        setblocking = fd.setblocking
    except AttributeError:
        # This version of Python predates socket.setblocking()
        import fcntl
        fileno = fd.fileno()
        flags = fcntl.fcntl(fileno, fcntl.F_GETFL)
        fcntl.fcntl(fileno, fcntl.F_SETFL, flags | os.O_NONBLOCK)
    else:
        # socket supports setblocking()
        setblocking(0)


class GreenSocket(object):
    is_secure = False
    timeout = None
    def __init__(self, family_or_realsock=socket.AF_INET, *args, **kwargs):
        if isinstance(family_or_realsock, (int, long)):
            fd = _original_socket(family_or_realsock, *args, **kwargs)
        else:
            fd = family_or_realsock
            assert not args, args
            assert not kwargs, kwargs

        set_nonblocking(fd)
        self.fd = fd
        self._fileno = fd.fileno()
        self.sendcount = 0
        self.recvcount = 0
        self.recvbuffer = ''
        self.closed = False
        self.timeout = socket.getdefaulttimeout()

        # when client calls setblocking(0) or settimeout(0) the socket must
        # act non-blocking
        self.act_non_blocking = False
        
    @property
    def _sock(self):
        return self

    @property
    def family(self):
        return self.fd.family

    @property
    def type(self):
        return self.fd.type

    @property
    def proto(self):
        return self.fd.proto

    def accept(self):
        if self.act_non_blocking:
            return self.fd.accept()
        fd = self.fd
        while True:
            res = socket_accept(fd)
            if res is not None:
                client, addr = res
                set_nonblocking(client)
                return type(self)(client), addr
            trampoline(fd, read=True, timeout=self.gettimeout(),
                           timeout_exc=socket.timeout)

    def bind(self, *args, **kw):
        fn = self.bind = self.fd.bind
        return fn(*args, **kw)

    def close(self, *args, **kw):
        if self.closed:
            return
        self.closed = True
        fileno = self.fileno()
        try:
            res = self.fd.close()
        finally:
            get_hub().closed(fileno)
        return res

    def connect(self, address):
        if self.act_non_blocking:
            return self.fd.connect(address)
        fd = self.fd
        if self.gettimeout() is None:
            while not socket_connect(fd, address):
                trampoline(fd, write=True, timeout_exc=socket.timeout)
        else:
            end = time.time() + self.gettimeout()
            while True:
                if socket_connect(fd, address):
                    return
                if time.time() >= end:
                    raise socket.timeout
                trampoline(fd, write=True, timeout=end-time.time(), timeout_exc=socket.timeout)

    def connect_ex(self, address):
        if self.act_non_blocking:
            return self.fd.connect_ex(address)
        fd = self.fd
        if self.gettimeout() is None:
            while not socket_connect(fd, address):
                try:
                    trampoline(fd, write=True, timeout_exc=socket.timeout)
                except socket.error, ex:
                    return ex[0]
        else:
            end = time.time() + self.gettimeout()
            while True:
                if socket_connect(fd, address):
                    return 0
                if time.time() >= end:
                    raise socket.timeout
                try:
                    trampoline(fd, write=True, timeout=end-time.time(), timeout_exc=socket.timeout)
                except socket.error, ex:
                    return ex[0]

    def dup(self, *args, **kw):
        sock = self.fd.dup(*args, **kw)
        set_nonblocking(sock)
        newsock = type(self)(sock)
        newsock.settimeout(self.timeout)
        return newsock

    def fileno(self, *args, **kw):
        fn = self.fileno = self.fd.fileno
        return fn(*args, **kw)

    def getpeername(self, *args, **kw):
        fn = self.getpeername = self.fd.getpeername
        return fn(*args, **kw)

    def getsockname(self, *args, **kw):
        fn = self.getsockname = self.fd.getsockname
        return fn(*args, **kw)

    def getsockopt(self, *args, **kw):
        fn = self.getsockopt = self.fd.getsockopt
        return fn(*args, **kw)

    def listen(self, *args, **kw):
        fn = self.listen = self.fd.listen
        return fn(*args, **kw)

    def makefile(self, mode='r', bufsize=-1):
        return socket._fileobject(self.dup(), mode, bufsize)

    def makeGreenFile(self, mode='r', bufsize=-1):
        return GreenFile(self.dup())

    recv = higher_order_recv(socket_recv)

    def recvfrom(self, *args):
        if not self.act_non_blocking:
            trampoline(self.fd, read=True, timeout=self.gettimeout(), timeout_exc=socket.timeout)
        return self.fd.recvfrom(*args)

    def recvfrom_into(self, *args):
        if not self.act_non_blocking:
            trampoline(self.fd, read=True, timeout=self.gettimeout(), timeout_exc=socket.timeout)
        return self.fd.recvfrom_into(*args)

    def recv_into(self, *args):
        if not self.act_non_blocking:
            trampoline(self.fd, read=True, timeout=self.gettimeout(), timeout_exc=socket.timeout)
        return self.fd.recv_into(*args)

    send = higher_order_send(socket_send)

    def sendall(self, data, flags=0):
        fd = self.fd
        tail = self.send(data, flags)
        while tail < len(data):
            trampoline(self.fd, write=True, timeout_exc=socket.timeout)
            tail += self.send(data[tail:], flags)

    def sendto(self, *args):
        trampoline(self.fd, write=True, timeout_exc=socket.timeout)
        return self.fd.sendto(*args)

    def setblocking(self, flag):
        if flag:
            self.act_non_blocking = False
            self.timeout = None
        else:
            self.act_non_blocking = True
            self.timeout = 0.0

    def setsockopt(self, *args, **kw):
        fn = self.setsockopt = self.fd.setsockopt
        return fn(*args, **kw)

    def shutdown(self, *args, **kw):
        fn = self.shutdown = self.fd.shutdown
        return fn(*args, **kw)

    def settimeout(self, howlong):
        if howlong is None:
            self.setblocking(True)
            return
        try:
            f = howlong.__float__
        except AttributeError:
            raise TypeError('a float is required')
        howlong = f()
        if howlong < 0.0:
            raise ValueError('Timeout value out of range')
        if howlong == 0.0:
            self.setblocking(howlong)
        else:
            self.timeout = howlong

    def gettimeout(self):
        return self.timeout



class GreenFile(object):
    newlines = '\r\n'
    mode = 'wb+'

    def __init__(self, fd):
        if isinstance(fd, GreenSocket):
            set_nonblocking(fd.fd)
        else:
            set_nonblocking(fd)
        self.sock = fd
        self.closed = False

    def close(self):
        self.sock.close()
        self.closed = True

    def fileno(self):
        return self.sock.fileno()

    # TODO next

    def flush(self):
        pass

    def write(self, data):
        return self.sock.sendall(data)

    def readuntil(self, terminator, size=None):
        buf, self.sock.recvbuffer = self.sock.recvbuffer, ''
        checked = 0
        if size is None:
            while True:
                found = buf.find(terminator, checked)
                if found != -1:
                    found += len(terminator)
                    chunk, self.sock.recvbuffer = buf[:found], buf[found:]
                    return chunk
                checked = max(0, len(buf) - (len(terminator) - 1))
                d = self.sock.recv(BUFFER_SIZE)
                if not d:
                    break
                buf += d
            return buf
        while len(buf) < size:
            found = buf.find(terminator, checked)
            if found != -1:
                found += len(terminator)
                chunk, self.sock.recvbuffer = buf[:found], buf[found:]
                return chunk
            checked = len(buf)
            d = self.sock.recv(BUFFER_SIZE)
            if not d:
                break
            buf += d
        chunk, self.sock.recvbuffer = buf[:size], buf[size:]
        return chunk

    def readline(self, size=None):
        return self.readuntil(self.newlines, size=size)

    def __iter__(self):
        return self.xreadlines()

    def readlines(self, size=None):
        return list(self.xreadlines(size=size))

    def xreadlines(self, size=None):
        if size is None:
            while True:
                line = self.readline()
                if not line:
                    break
                yield line
        else:
            while size > 0:
                line = self.readline(size)
                if not line:
                    break
                yield line
                size -= len(line)

    def writelines(self, lines):
        for line in lines:
            self.write(line)

    def read(self, size=None):
        if size is not None and not isinstance(size, (int, long)):
            raise TypeError('Expecting an int or long for size, got %s: %s' % (type(size), repr(size)))
        buf, self.sock.recvbuffer = self.sock.recvbuffer, ''
        lst = [buf]
        if size is None:
            while True:
                d = self.sock.recv(BUFFER_SIZE)
                if not d:
                    break
                lst.append(d)
        else:
            buflen = len(buf)
            while buflen < size:
                d = self.sock.recv(BUFFER_SIZE)
                if not d:
                    break
                buflen += len(d)
                lst.append(d)
            else:
                d = lst[-1]
                overbite = buflen - size
                if overbite:
                    lst[-1], self.sock.recvbuffer = d[:-overbite], d[-overbite:]
                else:
                    lst[-1], self.sock.recvbuffer = d, ''
        return ''.join(lst)



class GreenPipeSocket(GreenSocket):
    """ This is a weird class that looks like a socket but expects a file descriptor as an argument instead of a socket.
    """
    recv = higher_order_recv(file_recv)

    send = higher_order_send(file_send)


class GreenPipe(GreenFile):
    def __init__(self, fd):
        set_nonblocking(fd)
        self.fd = GreenPipeSocket(fd)
        super(GreenPipe, self).__init__(self.fd)

    def recv(self, *args, **kw):
        fn = self.recv = self.fd.recv
        return fn(*args, **kw)

    def send(self, *args, **kw):
        fn = self.send = self.fd.send
        return fn(*args, **kw)

    def flush(self):
        self.fd.fd.flush()


try:
    from OpenSSL import SSL
except ImportError:
    class SSL(object):
        class WantWriteError(object):
            pass

        class WantReadError(object):
            pass

        class ZeroReturnError(object):
            pass

        class SysCallError(object):
            pass

class GreenSSL(GreenSocket):
    """ Nonblocking wrapper for SSL.Connection objects.
    
    Note: not compatible with SSLObject 
    (http://www.python.org/doc/2.5.2/lib/ssl-objects.html) because it does not 
    implement server() or issuer(), and the read() method has a mandatory size.
    """
    def __init__(self, fd):
        super(GreenSSL, self).__init__(fd)
        assert isinstance(fd, (SSL.ConnectionType)), \
               "GreenSSL can only be constructed with an "\
               "OpenSSL Connection object"
        self.sock = self
        
    def close(self):
        # *NOTE: in older versions of eventlet, we called shutdown() on SSL sockets
        # before closing them. That wasn't right because correctly-written clients
        # would have already called shutdown, and calling shutdown a second time
        # triggers unwanted bidirectional communication.
        super(GreenSSL, self).close()
    
    def do_handshake(self):
        """ Perform an SSL handshake (usually called after renegotiate or one of 
        set_accept_state or set_accept_state). This can raise the same exceptions as 
        send and recv. """
        if self.act_non_blocking:
            return self.fd.do_handshake()
        while True:
            try:
                return self.fd.do_handshake()
            except SSL.WantReadError:
                trampoline(self.fd.fileno(), 
                           read=True, 
                           timeout=self.timeout, 
                           timeout_exc=socket.timeout)
            except SSL.WantWriteError:
                trampoline(self.fd.fileno(), 
                           write=True, 
                           timeout=self.timeout, 
                           timeout_exc=socket.timeout)
                           
    def dup(self):
        raise NotImplementedError("Dup not supported on SSL sockets")
        
    def get_app_data(self, *args, **kw):
        fn = self.get_app_data = self.fd.get_app_data
        return fn(*args, **kw)

    def set_app_data(self, *args, **kw):
        fn = self.set_app_data = self.fd.set_app_data
        return fn(*args, **kw)        
    
    def get_cipher_list(self, *args, **kw):
        fn = self.get_cipher_list = self.fd.get_cipher_list
        return fn(*args, **kw)
        
    def get_context(self, *args, **kw):
        fn = self.get_context = self.fd.get_context
        return fn(*args, **kw)
    
    def get_peer_certificate(self, *args, **kw):
        fn = self.get_peer_certificate = self.fd.get_peer_certificate
        return fn(*args, **kw)
        
    def makefile(self, mode='r', bufsize=-1):
        raise NotImplementedError("Makefile not supported on SSL sockets")  
        
    def pending(self, *args, **kw):
        fn = self.pending = self.fd.pending
        return fn(*args, **kw)      

    def read(self, size):
        """Works like a blocking call to SSL_read(), whose behavior is 
        described here:  http://www.openssl.org/docs/ssl/SSL_read.html"""
        if self.act_non_blocking:
            return self.fd.read(size)
        while True:
            try:
                return self.fd.read(size)
            except SSL.WantReadError:
                trampoline(self.fd.fileno(), 
                           read=True, 
                           timeout=self.timeout, 
                           timeout_exc=socket.timeout)
            except SSL.WantWriteError:
                trampoline(self.fd.fileno(), 
                           write=True, 
                           timeout=self.timeout, 
                           timeout_exc=socket.timeout)
            except SSL.SysCallError, e:
                if e[0] == -1 or e[0] > 0:
                    return ''
            
    recv = read
    
    def renegotiate(self, *args, **kw):
        fn = self.renegotiate = self.fd.renegotiate
        return fn(*args, **kw)  

    def write(self, data):
        """Works like a blocking call to SSL_write(), whose behavior is 
        described here:  http://www.openssl.org/docs/ssl/SSL_write.html"""
        if not data:
            return 0 # calling SSL_write() with 0 bytes to be sent is undefined
        if self.act_non_blocking:
            return self.fd.write(data)
        while True:
            try:
                return self.fd.write(data)
            except SSL.WantReadError:
                trampoline(self.fd.fileno(), 
                           read=True, 
                           timeout=self.timeout, 
                           timeout_exc=socket.timeout)
            except SSL.WantWriteError:
                trampoline(self.fd.fileno(), 
                           write=True, 
                           timeout=self.timeout, 
                           timeout_exc=socket.timeout)
                           
    send = write
    
    def sendall(self, data):
        """Send "all" data on the connection. This calls send() repeatedly until
        all data is sent. If an error occurs, it's impossible to tell how much data
        has been sent.

        No return value."""
        tail = self.send(data)
        while tail < len(data):
            tail += self.send(data[tail:])
            
    def set_accept_state(self, *args, **kw):
        fn = self.set_accept_state = self.fd.set_accept_state
        return fn(*args, **kw)

    def set_connect_state(self, *args, **kw):
        fn = self.set_connect_state = self.fd.set_connect_state
        return fn(*args, **kw)
        
    def shutdown(self):
        if self.act_non_blocking:
            return self.fd.shutdown()
        while True:
            try:
                return self.fd.shutdown()
            except SSL.WantReadError:
                trampoline(self.fd.fileno(), 
                           read=True, 
                           timeout=self.timeout, 
                           timeout_exc=socket.timeout)
            except SSL.WantWriteError:
                trampoline(self.fd.fileno(), 
                           write=True, 
                           timeout=self.timeout, 
                           timeout_exc=socket.timeout)


    def get_shutdown(self, *args, **kw):
        fn = self.get_shutdown = self.fd.get_shutdown
        return fn(*args, **kw)
        
    def set_shutdown(self, *args, **kw):
        fn = self.set_shutdown = self.fd.set_shutdown
        return fn(*args, **kw)

    def sock_shutdown(self, *args, **kw):
        fn = self.sock_shutdown = self.fd.sock_shutdown
        return fn(*args, **kw)
        
    def state_string(self, *args, **kw):
        fn = self.state_string = self.fd.state_string
        return fn(*args, **kw)
    
    def want_read(self, *args, **kw):
        fn = self.want_read = self.fd.want_read
        return fn(*args, **kw)

    def want_write(self, *args, **kw):
        fn = self.want_write = self.fd.want_write
        return fn(*args, **kw)
        
        
def _convert_to_sslerror(ex):
    """ Transliterates SSL.SysCallErrors to socket.sslerrors"""
    return socket.sslerror((ex[0], ex[1]))
        
class GreenSSLObject(object):
    """ Wrapper object around the SSLObjects returned by socket.ssl, which have a 
    slightly different interface from SSL.Connection objects. """
    def __init__(self, green_ssl_obj):
        """ Should only be called by a 'green' socket.ssl """
        assert isinstance(green_ssl_obj, GreenSSL)
        self.connection = green_ssl_obj
        try:
            self.connection.do_handshake()
        except SSL.SysCallError, e:
            raise _convert_to_sslerror(e)
        
    def read(self, n=None):
        """If n is provided, read n bytes from the SSL connection, otherwise read
        until EOF. The return value is a string of the bytes read."""
        if n is None:
            # don't support this until someone needs it
            raise NotImplementedError("GreenSSLObject does not support "\
            " unlimited reads until we hear of someone needing to use them.")
        else:
            try:
                return self.connection.read(n)
            except SSL.ZeroReturnError:
                return ''
            except SSL.SysCallError, e:
                raise _convert_to_sslerror(e)
            
    def write(self, s):
        """Writes the string s to the on the object's SSL connection. 
        The return value is the number of bytes written. """
        try:
            return self.connection.write(s)
        except SSL.SysCallError, e:
            raise _convert_to_sslerror(e)

    def server(self):
        """ Returns a string describing the server's certificate. Useful for debugging
        purposes; do not parse the content of this string because its format can't be
        parsed unambiguously. """
        return str(self.connection.get_peer_certificate().get_subject())
        
    def issuer(self):
        """Returns a string describing the issuer of the server's certificate. Useful
        for debugging purposes; do not parse the content of this string because its 
        format can't be parsed unambiguously."""
        return str(self.connection.get_peer_certificate().get_issuer())