import sys
import os
import hashlib
import Queue
import random
import select
import time
import threading

import OpenSSL.crypto

from netlib import tcp, http, certutils, websockets

import language.http
import language.websockets
from . import utils, log


class PathocError(Exception):
    pass


class SSLInfo:
    def __init__(self, certchain, cipher):
        self.certchain, self.cipher = certchain, cipher

    def __str__(self):
        parts = [
            "Cipher: %s, %s bit, %s" % self.cipher,
            "SSL certificate chain:"
        ]
        for i in self.certchain:
            parts.append("\tSubject: ")
            for cn in i.get_subject().get_components():
                parts.append("\t\t%s=%s" % cn)
            parts.append("\tIssuer: ")
            for cn in i.get_issuer().get_components():
                parts.append("\t\t%s=%s" % cn)
            parts.extend(
                [
                    "\tVersion: %s" % i.get_version(),
                    "\tValidity: %s - %s" % (
                        i.get_notBefore(), i.get_notAfter()
                    ),
                    "\tSerial: %s" % i.get_serial_number(),
                    "\tAlgorithm: %s" % i.get_signature_algorithm()
                ]
            )
            pk = i.get_pubkey()
            types = {
                OpenSSL.crypto.TYPE_RSA: "RSA",
                OpenSSL.crypto.TYPE_DSA: "DSA"
            }
            t = types.get(pk.type(), "Uknown")
            parts.append("\tPubkey: %s bit %s" % (pk.bits(), t))
            s = certutils.SSLCert(i)
            if s.altnames:
                parts.append("\tSANs: %s" % " ".join(s.altnames))
            return "\n".join(parts)


class Response:
    def __init__(
        self,
        httpversion,
        status_code,
        msg,
        headers,
        content,
        sslinfo
    ):
        self.httpversion, self.status_code = httpversion, status_code
        self.msg = msg
        self.headers, self.content = headers, content
        self.sslinfo = sslinfo

    def __repr__(self):
        return "Response(%s - %s)" % (self.status_code, self.msg)


class WebsocketFrameReader(threading.Thread):
    def __init__(
            self,
            rfile,
            logfp,
            showresp,
            hexdump,
            callback,
            ws_read_limit):
        threading.Thread.__init__(self)
        self.ws_read_limit = ws_read_limit
        self.logfp = logfp
        self.showresp = showresp
        self.hexdump = hexdump
        self.rfile, self.callback = rfile, callback
        self.terminate = Queue.Queue()
        self.is_done = Queue.Queue()

    def log(self, rfile):
        return log.Log(
            self.logfp,
            self.hexdump,
            rfile if self.showresp else None,
            None
        )

    def run(self):
        while True:
            if self.ws_read_limit == 0:
                break
            r, _, _ = select.select([self.rfile], [], [], 0.05)
            try:
                self.terminate.get_nowait()
                break
            except Queue.Empty:
                pass
            for rfile in r:
                with self.log(rfile) as log:
                    try:
                        frm = websockets.Frame.from_file(self.rfile)
                    except tcp.NetLibError:
                        self.ws_read_limit = 0
                        break
                    log("<< %s" % frm.header.human_readable())
                    self.callback(frm)
                    if self.ws_read_limit is not None:
                        self.ws_read_limit -= 1
        self.is_done.put(None)


class Pathoc(tcp.TCPClient):
    def __init__(
            self,
            address,

            # SSL
            ssl=None,
            sni=None,
            sslversion=4,
            clientcert=None,
            ciphers=None,

            # Websockets
            ws_read_limit = None,

            # Output control
            showreq = False,
            showresp = False,
            explain = False,
            hexdump = False,
            ignorecodes = (),
            ignoretimeout = False,
            showsummary = False,
            fp = sys.stdout
    ):
        """
            spec: A request specification
            showreq: Print requests
            showresp: Print responses
            explain: Print request explanation
            showssl: Print info on SSL connection
            hexdump: When printing requests or responses, use hex dump output
            showsummary: Show a summary of requests
            ignorecodes: Sequence of return codes to ignore
        """
        tcp.TCPClient.__init__(self, address)
        self.settings = language.Settings(
            staticdir = os.getcwd(),
            unconstrained_file_access = True,
            request_host = self.address.host,
            is_client = True
        )
        self.ssl, self.sni = ssl, sni
        self.clientcert = clientcert
        self.sslversion = utils.SSLVERSIONS[sslversion]
        self.ciphers = ciphers
        self.sslinfo = None

        self.ws_read_limit = ws_read_limit

        self.showreq = showreq
        self.showresp = showresp
        self.explain = explain
        self.hexdump = hexdump
        self.ignorecodes = ignorecodes
        self.ignoretimeout = ignoretimeout
        self.showsummary = showsummary
        self.fp = fp

        self.ws_framereader = None

    def log(self):
        return log.Log(
            self.fp,
            self.hexdump,
            self.rfile if self.showresp else None,
            self.wfile if self.showreq else None,
        )

    def http_connect(self, connect_to):
        self.wfile.write(
            'CONNECT %s:%s HTTP/1.1\r\n' % tuple(connect_to) +
            '\r\n'
        )
        self.wfile.flush()
        l = self.rfile.readline()
        if not l:
            raise PathocError("Proxy CONNECT failed")
        parsed = http.parse_response_line(l)
        if not parsed[1] == 200:
            raise PathocError(
                "Proxy CONNECT failed: %s - %s" % (parsed[1], parsed[2])
            )
        http.read_headers(self.rfile)

    def connect(self, connect_to=None, showssl=False, fp=sys.stdout):
        """
            connect_to: A (host, port) tuple, which will be connected to with
            an HTTP CONNECT request.
        """
        tcp.TCPClient.connect(self)
        if connect_to:
            self.http_connect(connect_to)
        self.sslinfo = None
        if self.ssl:
            try:
                self.convert_to_ssl(
                    sni=self.sni,
                    cert=self.clientcert,
                    method=self.sslversion,
                    cipher_list = self.ciphers
                )
            except tcp.NetLibError as v:
                raise PathocError(str(v))
            self.sslinfo = SSLInfo(
                self.connection.get_peer_cert_chain(),
                self.get_current_cipher()
            )
            if showssl:
                print >> fp, str(self.sslinfo)

    def _resp_summary(self, resp):
        return "<< %s %s: %s bytes" % (
            resp.status_code, utils.xrepr(resp.msg), len(resp.content)
        )

    def stop(self):
        if self.ws_framereader:
            self.ws_framereader.terminate.put(None)

    def wait(self):
        if self.ws_framereader:
            while True:
                try:
                    self.ws_framereader.is_done.get(timeout=0.05)
                    self.ws_framereader.join()
                    return
                except Queue.Empty:
                    pass

    def websocket_get_frame(self, frame):
        """
            Called when a frame is received from the server.
        """
        pass

    def websocket_send_frame(self, r):
        """
            Sends a single websocket frame.
        """
        with self.log() as log:
            if isinstance(r, basestring):
                r = language.parse_requests(r)[0]
            log(">> %s" % r)
            try:
                language.serve(r, self.wfile, self.settings)
                self.wfile.flush()
            except tcp.NetLibTimeout:
                if self.ignoretimeout:
                    self.log("Timeout (ignored)")
                    return None
                raise

    def websocket_start(self, r, callback=None, limit=None):
        """
            Performs an HTTP request, and attempts to drop into websocket
            connection.

            callback: A callback called within the websocket thread for every
            server frame.
            limit: Disconnect after receiving N server frames.
        """
        resp = self.http(r)
        if resp.status_code == 101:
            self.ws_framereader = WebsocketFrameReader(
                self.rfile,
                self.fp,
                self.showresp,
                self.hexdump,
                callback,
                self.ws_read_limit
            )
            self.ws_framereader.start()
        return resp

    def http(self, r):
        """
            Performs a single request.

            r: A language.http.Request object, or a string representing one
            request.

            Returns Response if we have a non-ignored response.

            May raise http.HTTPError, tcp.NetLibError
        """
        with self.log() as log:
            if isinstance(r, basestring):
                r = language.parse_requests(r)[0]
            log(">> %s" % r)
            resp, req = None, None
            try:
                req = language.serve(r, self.wfile, self.settings)
                self.wfile.flush()
                resp = list(
                    http.read_response(
                        self.rfile,
                        req["method"],
                        None
                    )
                )
                resp.append(self.sslinfo)
                resp = Response(*resp)
            except tcp.NetLibTimeout:
                if self.ignoretimeout:
                    log("Timeout (ignored)")
                    return None
                raise
            finally:
                if resp:
                    log(self._resp_summary(resp))
                    if resp.status_code in self.ignorecodes:
                        log.suppress()
            return resp

    def request(self, r):
        """
            Performs a single request.

            r: A language.http.Request object, or a string representing one
            request.

            Returns Response if we have a non-ignored response.

            May raise http.HTTPError, tcp.NetLibError
        """
        if isinstance(r, basestring):
            r = language.parse_requests(r)[0]
        if isinstance(r, language.http.Request):
            if r.ws:
                return self.websocket_start(r, self.websocket_get_frame)
            else:
                return self.http(r)
        elif isinstance(r, language.websockets.WebsocketFrame):
            self.websocket_send_frame(r)


def main(args):  # pragma: nocover
    memo = set([])
    trycount = 0
    p = None
    try:
        cnt = 0
        while True:
            if cnt == args.repeat and args.repeat != 0:
                break
            if trycount > args.memolimit:
                print >> sys.stderr, "Memo limit exceeded..."
                return
            if args.wait and cnt != 0:
                time.sleep(args.wait)

            cnt += 1
            if args.random:
                playlist = [random.choice(args.requests)]
            else:
                playlist = args.requests
            p = Pathoc(
                (args.host, args.port),
                ssl = args.ssl,
                sni = args.sni,
                sslversion = args.sslversion,
                clientcert = args.clientcert,
                ciphers = args.ciphers,
                showreq = args.showreq,
                showresp = args.showresp,
                explain = args.explain,
                hexdump = args.hexdump,
                ignorecodes = args.ignorecodes,
                ignoretimeout = args.ignoretimeout,
                showsummary = True
            )
            if args.explain or args.memo:
                playlist = [
                    i.freeze(p.settings) for i in playlist
                ]
            if args.memo:
                newlist = []
                for spec in playlist:
                    h = hashlib.sha256(spec.spec()).digest()
                    if h not in memo:
                        memo.add(h)
                        newlist.append(spec)
                playlist = newlist
            if not playlist:
                trycount += 1
                continue

            trycount = 0
            try:
                p.connect(args.connect_to, args.showssl)
            except tcp.NetLibError as v:
                print >> sys.stderr, str(v)
                continue
            except PathocError as v:
                print >> sys.stderr, str(v)
                sys.exit(1)
            if args.timeout:
                p.settimeout(args.timeout)
            for spec in playlist:
                try:
                    ret = p.request(spec)
                    if ret and args.oneshot:
                        return
                except (http.HttpError, tcp.NetLibError) as v:
                    break
            p.wait()
    except KeyboardInterrupt:
        pass
    if p:
        p.stop()