from zope.interface import implements

from twisted.internet import defer, protocol
from twisted.protocols import basic, policies
from twisted.web2 import stream as stream_mod, http, http_headers, responsecode
from twisted.web2.channel import http as httpchan
from twisted.web2.channel.http import PERSIST_NO_PIPELINE, PERSIST_PIPELINE
from twisted.web2.client import interfaces

#from twisted.python.util import tracer

class ProtocolError(Exception):
    pass

class ClientRequest(object):
    """A class for describing an HTTP request to be sent to the server.
    """

    def __init__(self, method, uri, headers, stream):
        """
        @param method: The HTTP method to for this request, ex: 'GET', 'HEAD',
            'POST', etc.
        @type method: C{str}
        
        @param uri: The URI of the resource to request, this may be absolute or
            relative, however the interpretation of this URI is left up to the 
            remote server.
        @type uri: C{str}

        @param headers: Headers to be sent to the server.  It is important to 
            note that this object does not create any implicit headers.  So it 
            is up to the HTTP Client to add required headers such as 'Host'.
        @type headers: C{dict}, L{twisted.web2.http_headers.Headers}, or 
            C{None}
    
        @param stream: Content body to send to the remote HTTP server.
        @type stream: L{twisted.web2.stream.IByteStream}
        """

        self.method = method
        self.uri = uri
        if isinstance(headers, http_headers.Headers):
            self.headers = headers
        else:
            self.headers = http_headers.Headers(headers or {})
            
        if stream is not None:
            self.stream = stream_mod.IByteStream(stream)
        else:
            self.stream = None


class HTTPClientChannelRequest(httpchan.HTTPParser):
    parseCloseAsEnd = True
    outgoing_version = "HTTP/1.1"
    chunkedOut = False
    finished = False
    
    closeAfter = False
    
    def __init__(self, channel, request, closeAfter):
        httpchan.HTTPParser.__init__(self, channel)
        self.request = request
        self.closeAfter = closeAfter
        self.transport = self.channel.transport
        self.responseDefer = defer.Deferred()
        
    def submit(self):
        l = []
        request = self.request
        if request.method == "HEAD":
            # No incoming data will arrive.
            self.length = 0
        
        l.append('%s %s %s\r\n' % (request.method, request.uri,
                                   self.outgoing_version))
        if request.headers is not None:
            for name, valuelist in request.headers.getAllRawHeaders():
                for value in valuelist:
                    l.append("%s: %s\r\n" % (name, value))
        
        if request.stream is not None:
            if request.stream.length is not None:
                l.append("%s: %s\r\n" % ('Content-Length', request.stream.length))
            else:
                # Got a stream with no length. Send as chunked and hope, against
                # the odds, that the server actually supports chunked uploads.
                l.append("%s: %s\r\n" % ('Transfer-Encoding', 'chunked'))
                self.chunkedOut = True

        if self.closeAfter:
            l.append("%s: %s\r\n" % ('Connection', 'close'))
        else:
            l.append("%s: %s\r\n" % ('Connection', 'Keep-Alive'))
        
        l.append("\r\n")
        self.transport.writeSequence(l)
        
        d = stream_mod.StreamProducer(request.stream).beginProducing(self)
        d.addCallback(self._finish).addErrback(self._error)

    def registerProducer(self, producer, streaming):
        """Register a producer.
        """
        self.transport.registerProducer(producer, streaming)

    def unregisterProducer(self):
        self.transport.unregisterProducer()
        
    def write(self, data):
        if not data:
            return
        elif self.chunkedOut:
            self.transport.writeSequence(("%X\r\n" % len(data), data, "\r\n"))
        else:
            self.transport.write(data)

    def _finish(self, x):
        """We are finished writing data."""
        if self.chunkedOut:
            # write last chunk and closing CRLF
            self.transport.write("0\r\n\r\n")
        
        self.finished = True
        self.channel.requestWriteFinished(self)
        del self.transport

    def _error(self, err):
        self.abortParse()
        self.responseDefer.errback(err)

    def _abortWithError(self, errcode, text):
        self.abortParse()
        self.responseDefer.errback(ProtocolError(text))

    def connectionLost(self, reason):
        ### FIXME!
        pass
    
    def gotInitialLine(self, initialLine):
        parts = initialLine.split(' ', 2)
        
        # Parse the initial request line
        if len(parts) != 3:
            self._abortWithError(responsecode.BAD_REQUEST, 'Bad response line: %s' % initialLine)
            return

        strversion, self.code, message = parts
        
        try:
            protovers = http.parseVersion(strversion)
            if protovers[0] != 'http':
                raise ValueError()
        except ValueError:
            self._abortWithError(responsecode.BAD_REQUEST, "Unknown protocol: %s" % strversion)
            return
        
        self.version = protovers[1:3]

        # Ensure HTTP 0 or HTTP 1.
        if self.version[0] != 1:
            self._abortWithError(responsecode.HTTP_VERSION_NOT_SUPPORTED, 'Only HTTP 1.x is supported.')
            return

    ## FIXME: Actually creates Response, function is badly named!
    def createRequest(self):
        self.stream = stream_mod.ProducerStream()
        self.response = http.Response(self.code, self.inHeaders, self.stream)
        self.stream.registerProducer(self, True)
        
        del self.inHeaders

    ## FIXME: Actually processes Response, function is badly named!
    def processRequest(self):
        self.responseDefer.callback(self.response)
        
    def handleContentChunk(self, data):
        self.stream.write(data)

    def handleContentComplete(self):
        self.stream.finish()


class EmptyHTTPClientManager(object):
    """A dummy HTTPClientManager.  It doesn't do any client management, and is 
    meant to be used only when creating an HTTPClientProtocol directly.
    """

    implements(interfaces.IHTTPClientManager)

    def clientBusy(self, proto):
        pass
    
    def clientIdle(self, proto):
        pass

    def clientPipelining(self, proto):
        pass
    
    def clientGone(self, proto):
        pass
    

class HTTPClientProtocol(basic.LineReceiver, policies.TimeoutMixin, object):
    """A HTTP 1.1 Client with request pipelining support."""
    
    chanRequest = None
    maxHeaderLength = 10240
    firstLine = 1
    readPersistent = PERSIST_NO_PIPELINE
    
    # inputTimeOut should be pending whenever a complete request has
    # been written but the complete response has not yet been
    # received, and be reset every time data is received.
    inputTimeOut = 60 * 4

    def __init__(self, manager=None):
        """
        @param manager: The object this client reports it state to.
        @type manager: L{interfaces.IHTTPClientManager}
        """

        self.outRequest = None
        self.inRequests = []
        if manager is None:
            manager = EmptyHTTPClientManager()
        self.manager = manager

    def lineReceived(self, line):
        if not self.inRequests:
            # server sending random unrequested data.
            self.transport.loseConnection()
            return

        # If not currently writing this request, set timeout
        if self.inRequests[0] is not self.outRequest:
            self.setTimeout(self.inputTimeOut)
            
        if self.firstLine:
            self.firstLine = 0
            self.inRequests[0].gotInitialLine(line)
        else:
            self.inRequests[0].lineReceived(line)

    def rawDataReceived(self, data):
        if not self.inRequests:
            print "Extra raw data!"
            # server sending random unrequested data.
            self.transport.loseConnection()
            return
        
        # If not currently writing this request, set timeout
        if self.inRequests[0] is not self.outRequest:
            self.setTimeout(self.inputTimeOut)
            
        self.inRequests[0].rawDataReceived(data)
        
    def submitRequest(self, request, closeAfter=True):
        """
        @param request: The request to send to a remote server.
        @type request: L{ClientRequest}

        @param closeAfter: If True the 'Connection: close' header will be sent,
            otherwise 'Connection: keep-alive'
        @type closeAfter: C{bool}

        @return: L{twisted.internet.defer.Deferred} 
        @callback: L{twisted.web2.http.Response} from the server.
        """

        # Assert we're in a valid state to submit more
        assert self.outRequest is None
        assert ((self.readPersistent is PERSIST_NO_PIPELINE and not self.inRequests)
                or self.readPersistent is PERSIST_PIPELINE)
        
        self.manager.clientBusy(self)
        if closeAfter:
            self.readPersistent = False
        
        self.outRequest = chanRequest = HTTPClientChannelRequest(self, request, closeAfter)
        self.inRequests.append(chanRequest)
        
        chanRequest.submit()
        return chanRequest.responseDefer

    def requestWriteFinished(self, request):
        assert request is self.outRequest
        
        self.outRequest = None
        # Tell the manager if more requests can be submitted.
        self.setTimeout(self.inputTimeOut)
        if self.readPersistent is PERSIST_PIPELINE:
            self.manager.clientPipelining(self)

    def requestReadFinished(self, request):
        assert self.inRequests[0] is request
        
        del self.inRequests[0]
        self.firstLine = True
        
        if not self.inRequests:
            if self.readPersistent:
                self.setTimeout(None)
                self.manager.clientIdle(self)
            else:
#                 print "No more requests, closing"
                self.transport.loseConnection()

    def setReadPersistent(self, persist):
        self.readPersistent = persist
        if not persist:
            # Tell all requests but first to abort.
            for request in self.inRequests[1:]:
                request.connectionLost(None)
            del self.inRequests[1:]
    
    def connectionLost(self, reason):
        self.readPersistent = False
        self.setTimeout(None)
        self.manager.clientGone(self)
        # Tell all requests to abort.
        for request in self.inRequests:
            if request is not None:
                request.connectionLost(reason)
    
    #isLastRequest = tracer(isLastRequest)
    #lineReceived = tracer(lineReceived)
    #rawDataReceived = tracer(rawDataReceived)
    #connectionLost = tracer(connectionLost)
    #requestReadFinished = tracer(requestReadFinished)
    #requestWriteFinished = tracer(requestWriteFinished)
    #submitRequest = tracer(submitRequest)
    

def testConn(host):
    from twisted.internet import reactor
    d = protocol.ClientCreator(reactor, HTTPClientProtocol).connectTCP(host, 80)
    def gotResp(resp, num):
        def print_(n):
            print "DATA %s: %r" % (num, n)
        def printdone(n):
            print "DONE %s" % num
        print "GOT RESPONSE %s: %s" % (num, resp)
        stream_mod.readStream(resp.stream, print_).addCallback(printdone)
    def sendReqs(proto):
        proto.submitRequest(ClientRequest("GET", "/", {'Host':host}, None)).addCallback(gotResp, 1)
        proto.submitRequest(ClientRequest("GET", "/foo", {'Host':host}, None)).addCallback(gotResp, 2)
    d.addCallback(sendReqs)
    del d
    reactor.run()

