# The contents of this file are subject to the BitTorrent Open Source License
# Version 1.1 (the License).  You may not copy or use this file, in either
# source code or executable form, except in compliance with the License.  You
# may obtain a copy of the License at http://www.bittorrent.com/license/.
#
# Software distributed under the License is distributed on an AS IS basis,
# WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the License
# for the specific language governing rights and limitations under the
# License.

# Written by Bram Cohen

import datetime
from RawServer_twisted import Handler
from cStringIO import StringIO
from sys import stdout
import time
from gzip import GzipFile
from BTL.translation import _

DEBUG = False

class HTTPConnector(object):

    def __init__(self, handler, connection):
        self.handler = handler
        self.connection = connection
        self.buf = ''
        self.closed = False
        self.done = False
        self.donereading = False
        self.next_func = self.read_type

    def get_ip(self):
        return self.connection.ip

    def data_came_in(self, data):
        if self.donereading or self.next_func is None:
            return True
        self.buf += data
        while True:
            try:
                i = self.buf.index('\n')
            except ValueError:
                return True
            val = self.buf[:i]
            self.buf = self.buf[i+1:]
            self.next_func = self.next_func(val)
            if self.donereading:
                return True
            if self.next_func is None or self.closed:
                return False

    def read_type(self, data):
        self.header = data.strip()
        words = data.split()
        if len(words) == 3:
            self.command, self.path, garbage = words
            self.pre1 = False
        elif len(words) == 2:
            self.command, self.path = words
            self.pre1 = True
            if self.command != 'GET':
                return None
        else:
            return None
        if self.command not in ('HEAD', 'GET'):
            return None
        self.headers = {}
        return self.read_header

    def read_header(self, data):
        data = data.strip()
        if data == '':
            self.donereading = True
            # check for Accept-Encoding: header, pick a 
            if self.headers.has_key('accept-encoding'):
                ae = self.headers['accept-encoding']
                if DEBUG:
                    print "Got Accept-Encoding: " + ae + "\n"
            else:
                #identity assumed if no header
                ae = 'identity'
            # this eventually needs to support multple acceptable types
            # q-values and all that fancy HTTP crap
            # for now assume we're only communicating with our own client
            if ae.find('gzip') != -1:
                self.encoding = 'gzip'
            else:
                #default to identity. 
                self.encoding = 'identity'
            r = self.handler.getfunc(self, self.path, self.headers)
            if r is not None:
                self.answer(r)
            return None
        try:
            i = data.index(':')
        except ValueError:
            return None
        self.headers[data[:i].strip().lower()] = data[i+1:].strip()
        if DEBUG:
            print data[:i].strip() + ": " + data[i+1:].strip()
        return self.read_header

    def answer(self, (responsecode, responsestring, headers, data)):
        if self.closed:
            return
        if self.encoding == 'gzip':
            #transform data using gzip compression
            #this is nasty but i'm unsure of a better way at the moment
            compressed = StringIO()
            gz = GzipFile(fileobj = compressed, mode = 'wb', compresslevel = 9)
            gz.write(data)
            gz.close()
            compressed.seek(0,0) 
            cdata = compressed.read()
            compressed.close()
            if len(cdata) >= len(data):
                self.encoding = 'identity'
            else:
                if DEBUG:
                   print _("Compressed: %i  Uncompressed: %i\n") % (len(cdata),len(data))
                data = cdata
                headers['Content-Encoding'] = 'gzip'

        # i'm abusing the identd field here, but this should be ok
        if self.encoding == 'identity':
            ident = '-'
        else:
            ident = self.encoding
        username = '-'
        referer = self.headers.get('referer','-')
        useragent = self.headers.get('user-agent','-')
        timestamp = datetime.datetime.utcnow().isoformat()
        if DEBUG:
            print '%s %s %s [%s] "%s" %i %i "%s" "%s"' % (
                self.connection.ip, ident, username, timestamp, self.header,
                responsecode, len(data), referer, useragent)
        t = time.time()
        if t - self.handler.lastflush > self.handler.minflush:
            self.handler.lastflush = t
            stdout.flush()

        self.done = True
        r = StringIO()
        r.write('HTTP/1.0 ' + str(responsecode) + ' ' + 
            responsestring + '\r\n')
        if not self.pre1:
            headers['Content-Length'] = len(data)
            for key, value in headers.items():
                r.write(key + ': ' + str(value) + '\r\n')
            r.write('\r\n')
        if self.command != 'HEAD':
            r.write(data)
        self.connection.write(r.getvalue())
        if self.connection.is_flushed():
            self.connection.shutdown(1)


class HTTPHandler(Handler):

    def __init__(self, getfunc, minflush):
        self.connections = {}
        self.getfunc = getfunc
        self.minflush = minflush
        self.lastflush = time.time()

    def connection_made(self, connection):
        if DEBUG:
            print "HTTPHandler.connection_made"
        self.connections[connection] = HTTPConnector(self, connection)

    def connection_flushed(self, connection):
        if self.connections[connection].done:
            connection.shutdown(1)

    def connection_lost(self, connection):
        ec = self.connections[connection]
        ec.closed = True
        del ec.connection
        del ec.next_func
        del self.connections[connection]

    def data_came_in(self, connection, data):
        if DEBUG:
            print "HTTPHandler.data_came_in: '%s'" % data
        c = self.connections[connection]
        if not c.data_came_in(data) and not c.closed:
            c.connection.shutdown(1)
