import glob
import imp
import os
import random
import re
import stat

from jinja2 import Environment, FileSystemLoader
from pappyproxy import config
from pappyproxy.util import PappyException
from twisted.internet import defer

class Macro(object):
    """
    A class representing a macro that can perform a series of requests and add
    data to storage.
    """

    def __init__(self, filename=''):
        self.name = ''
        self.short_name = None
        self.file_name = '' # name from the file
        self.filename = filename or '' # filename we load from
        self.source = None

        if self.filename:
            self.load()

    def __repr__(self):
        s = self.name
        names = []
        if hasattr(self.source, 'SHORT_NAME'):
            if self.source.SHORT_NAME:
                names.append(self.source.SHORT_NAME)
        names.append(self.file_name)
        s += ' (%s)' % ('/'.join(names))
        return "<Macro %s>" % s
        
    def load(self):
        if self.filename:
            match = re.findall('.*macro_(.*).py$', self.filename)
            self.file_name = match[0]
            st = os.stat(self.filename)
            if (st.st_mode & stat.S_IWOTH):
                raise PappyException("Refusing to load world-writable macro: %s" % self.filename)
            module_name = os.path.basename(os.path.splitext(self.filename)[0])
            self.source = imp.load_source('%s'%module_name, self.filename)
            if not hasattr(self.source, 'MACRO_NAME'):
                raise PappyException('Macro in %s does not define MACRO_NAME' % self.filename)
            self.name = self.source.MACRO_NAME
            if self.name == '':
                raise PappyException('Macro in %s cannot have a blank name' % self.filename)
            if hasattr(self.source, 'SHORT_NAME'):
                self.short_name = self.source.SHORT_NAME
            else:
                self.short_name = None
        else:
            self.source = None

    def execute(self, args):
        # Execute the macro
        if self.source:
            self.source.run_macro(args)

class InterceptMacro(object):
    """
    A class representing a macro that modifies requests as they pass through the
    proxy
    """
    def __init__(self):
        self.name = ''
        self.short_name = None
        self.intercept_requests = False
        self.intercept_responses = False

        self.async_req = False
        self.async_rsp = False

    def __repr__(self):
        return "<InterceptingMacro (%s)>" % self.name

    def init(self, args):
        pass

    def mangle_request(self, request):
        return request

    def mangle_response(self, request):
        return request.response

    @defer.inlineCallbacks
    def async_mangle_request(self, request):
        defer.returnValue(request)

    @defer.inlineCallbacks
    def async_mangle_response(self, request):
        defer.returnValue(request.response)
            
class FileInterceptMacro(InterceptMacro):
    """
    An intercepting macro that loads a macro from a file.
    """
    def __init__(self, filename=''):
        InterceptMacro.__init__(self)
        self.file_name = '' # name from the file
        self.filename = filename or '' # filename we load from
        self.source = None

        if self.filename:
            self.load()

    def __repr__(self):
        s = self.name
        names = []
        if hasattr(self.source, 'SHORT_NAME'):
            if self.source.SHORT_NAME:
                names.append(self.source.SHORT_NAME)
        names.append(self.file_name)
        s += ' (%s)' % ('/'.join(names))
        return "<InterceptingMacro %s>" % s

    def load(self):
        if self.filename:
            match = re.findall('.*int_(.*).py$', self.filename)
            if len(match) > 0:
                self.file_name = match[0]
            else:
                self.file_name = self.filename
            st = os.stat(self.filename)
            if (st.st_mode & stat.S_IWOTH):
                raise PappyException("Refusing to load world-writable macro: %s" % self.filename)
            module_name = os.path.basename(os.path.splitext(self.filename)[0])
            self.source = imp.load_source('%s'%module_name, self.filename)
            self.name = self.source.MACRO_NAME
            if self.name == '':
                raise PappyException('Macro in %s cannot have a blank name' % self.filename)
            if hasattr(self.source, 'SHORT_NAME'):
                self.short_name = self.source.SHORT_NAME
            else:
                self.short_name = None

            if hasattr(self.source, 'mangle_request') and \
               hasattr(self.source, 'async_mangle_request'):
                raise PappyException('Intercepting macro in %s cannot define both mangle_request and async_mangle_request' % self.filename)
            if hasattr(self.source, 'mangle_response') and \
               hasattr(self.source, 'async_mangle_response'):
                raise PappyException('Intercepting macro in %s cannot define both mangle_response and async_mangle_response' % self.filename)
        else:
            self.source = None

        # Update what we can do
        if self.source and hasattr(self.source, 'mangle_request'):
           self.intercept_requests = True
           self.async_req = False
        elif self.source and hasattr(self.source, 'async_mangle_request'):
           self.intercept_requests = True
           self.async_req = True
        else:
           self.intercept_requests = True

        if self.source and hasattr(self.source, 'mangle_response'):
            self.intercept_responses = True
            self.async_rsp = False
        elif self.source and hasattr(self.source, 'async_mangle_response'):
            self.intercept_responses = True
            self.async_rsp = True
        else:
            self.intercept_responses = False

    def init(self, args):
        if hasattr(self.source, 'init'):
            self.source.init(args)

    def mangle_request(self, request):
        if hasattr(self.source, 'mangle_request'):
            req = self.source.mangle_request(request)
            return req
        return request

    def mangle_response(self, request):
        if hasattr(self.source, 'mangle_response'):
            rsp = self.source.mangle_response(request)
            return rsp
        return request.response

    @defer.inlineCallbacks
    def async_mangle_request(self, request):
        if hasattr(self.source, 'async_mangle_request'):
            req = yield self.source.async_mangle_request(request)
            defer.returnValue(req)
        defer.returnValue(request)

    @defer.inlineCallbacks
    def async_mangle_response(self, request):
        if hasattr(self.source, 'async_mangle_response'):
            rsp = yield self.source.async_mangle_response(request)
            defer.returnValue(rsp)
        defer.returnValue(request.response)

def load_macros(loc):
    """
    Loads the macros stored in the location and returns a list of Macro objects
    """
    macro_files = glob.glob(loc + "/macro_*.py")
    macro_objs = []
    for f in macro_files:
        try:
            macro_objs.append(Macro(f))
        except PappyException as e:
            print str(e)

    int_macro_files = glob.glob(loc + "/int_*.py")
    int_macro_objs = []
    for f in int_macro_files:
        try:
            int_macro_objs.append(FileInterceptMacro(f))
        except PappyException as e:
            print str(e)
    return (macro_objs, int_macro_objs)

def req_obj_def(req):
    lines = req.full_request.splitlines(True)
    esclines = [line.encode('string_escape') for line in lines]

    params = []
    if req.is_ssl:
        params.append('is_ssl=True')
        if req.port != 443:
            params.append('port=%d'%req.port)
    else:
        if req.port != 80:
            params.append('port=%d'%req.port)
    if 'host' in req.headers and req.host != req.headers['host']:
        params.append('host=%d'%req.host)
    if params:
        req_params = ', '+', '.join(params)
    else:
        req_params = ''

    ret = 'Request (('
    for line in esclines:
        ret += "'%s'\n" % line
    ret += ')'
    ret += req_params
    ret += ')'
    return ret

def macro_from_requests(reqs, short_name='', long_name=''):
    # Generates a macro that defines request objects for each of the requests
    # in reqs
    subs = {}
    if long_name:
        subs['macro_name'] = long_name
    else:
        random.seed()
        subs['macro_name'] = 'Macro %d' % random.randint(1,99999999)

    subs['short_name'] = short_name

    req_lines = []
    req_params = []
    for req in reqs:
        lines = req.full_request.splitlines(True)
        esclines = [line.encode('string_escape') for line in lines]
        req_lines.append(esclines)

        params = []
        if req.is_ssl:
            params.append('is_ssl=True')
            if req.port != 443:
                params.append('port=%d'%req.port)
        else:
            if req.port != 80:
                params.append('port=%d'%req.port)
        if params:
            req_params.append(', '+', '.join(params))
        else:
            req_params.append('')
    subs['req_lines'] = req_lines
    subs['req_params'] = req_params

    loader = FileSystemLoader(config.PAPPY_DIR+'/templates')
    env = Environment(loader=loader)
    template = env.get_template('macro.py.template')
    return template.render(zip=zip, **subs)

def gen_imacro(short_name='', long_name=''):
    subs = {}
    if long_name:
        subs['macro_name'] = long_name
    else:
        random.seed()
        subs['macro_name'] = 'Macro %d' % random.randint(1,99999999)

    subs['short_name'] = short_name

    loader = FileSystemLoader(config.PAPPY_DIR+'/templates')
    env = Environment(loader=loader)
    template = env.get_template('intmacro.py.template')
    return template.render(**subs)
    
@defer.inlineCallbacks
def mangle_request(request, intmacros):
    """
    Mangle a request with a list of intercepting macros.
    Returns a tuple that contains the resulting request (with its unmangled
    value set if needed) and a bool that states whether the request was modified
    Returns (None, True) if the request was dropped.
    
    :rtype: (Request, Bool)
    """
    # Mangle requests with list of intercepting macros
    if not intmacros:
        defer.returnValue((request, False))

    cur_req = request.copy()
    for k, macro in intmacros.iteritems():
        if macro.intercept_requests:
            if macro.async_req:
                cur_req = yield macro.async_mangle_request(cur_req.copy())
            else:
                cur_req = macro.mangle_request(cur_req.copy())

            if cur_req is None:
                defer.returnValue((None, True))

    mangled = False
    if not cur_req == request or \
       not cur_req.host == request.host or \
       not cur_req.port == request.port:
        # copy unique data to new request and clear it off old one
        cur_req.unmangled = request
        cur_req.unmangled.is_unmangled_version = True
        if request.response:
            cur_req.response = request.response
            request.response = None
        mangled = True
    else:
        # return the original request
        cur_req = request
    defer.returnValue((cur_req, mangled))

@defer.inlineCallbacks
def mangle_response(request, intmacros):
    """
    Mangle a request's response with a list of intercepting macros.
    Returns a bool stating whether the request's response was modified.
    Unmangled values will be updated as needed.
    
    :rtype: Bool
    """
    if not intmacros:
        defer.returnValue(False)

    old_rsp = request.response
    # We copy so that changes to request.response doesn't mangle the original response
    request.response = request.response.copy()
    for k, macro in intmacros.iteritems():
        if macro.intercept_responses:
            if macro.async_rsp:
                request.response = yield macro.async_mangle_response(request)
            else:
                request.response = macro.mangle_response(request)

            if request.response is None:
                defer.returnValue(True)

    mangled = False
    if not old_rsp == request.response:
        request.response.rspid = old_rsp
        old_rsp.rspid = None
        request.response.unmangled = old_rsp
        request.response.unmangled.is_unmangled_version = True
        mangled = True
    else:
        request.response = old_rsp
    defer.returnValue(mangled)