"""
    This module provides more sophisticated flow tracking. These match requests
    with their responses, and provide filtering and interception facilities.
"""
import json
import proxy, threading

class ReplayConnection:
    pass


class ReplayThread(threading.Thread):
    def __init__(self, flow, masterq):
        self.flow, self.masterq = flow, masterq
        threading.Thread.__init__(self)

    def run(self):
        try:
            server = proxy.ServerConnection(self.flow.request)
            response = server.read_response()
            response.send(self.masterq)
        except proxy.ProxyError, v:
            err = proxy.Error(self.flow.connection, v.msg)
            err.send(self.masterq)


class Flow:
    def __init__(self, connection):
        self.connection = connection
        self.request, self.response, self.error = None, None, None
        self.intercepting = False
        self._backup = None

    def get_state(self):
        return dict(
            request = self.request.get_state() if self.request else None,
            response = self.response.get_state() if self.response else None,
            error = self.error.get_state() if self.error else None,
        )

    @classmethod
    def from_state(klass, state):
        f = klass(None)
        if state["request"]:
            f.request = proxy.Request.from_state(state["request"])
        if state["response"]:
            f.response = proxy.Response.from_state(f.request, state["response"])
        if state["error"]:
            f.error = proxy.Error.from_state(state["error"])
        return f

    def __eq__(self, other):
        return self.get_state() == other.get_state()

    def backup(self):
        if not self._backup:
            self._backup = [
                self.connection.copy() if self.connection else None,
                self.request.copy() if self.request else None,
                self.response.copy() if self.response else None,
                self.error.copy() if self.error else None,
            ]

    def revert(self):
        if self._backup:
            restore = [i.copy() if i else None for i in self._backup]
            self.connection, self.request, self.response, self.error = restore

    def match(self, pattern):
        if pattern:
            if self.response:
                return pattern(self.response)
            elif self.request:
                return pattern(self.request)
        return False

    def is_replay(self):
        return isinstance(self.connection, ReplayConnection)

    def kill(self):
        if self.intercepting:
            if not self.request.acked:
                self.request.kill = True
                self.request.ack()
            elif self.response and not self.response.acked:
                self.response.kill = True
                self.response.ack()
            self.intercepting = False

    def intercept(self):
        self.intercepting = True

    def accept_intercept(self):
        if self.request:
            if not self.request.acked:
                self.request.ack()
            elif self.response and not self.response.acked:
                self.response.ack()
            self.intercepting = False


class State:
    def __init__(self):
        self.flow_map = {}
        self.flow_list = []
        # These are compiled filt expressions:
        self.limit = None
        self.intercept = None

    def add_browserconnect(self, f):
        """
            Start a browser connection.
        """
        self.flow_list.insert(0, f)
        self.flow_map[f.connection] = f

    def add_request(self, req):
        """
            Add a request to the state. Returns the matching flow.
        """
        f = self.flow_map.get(req.connection)
        if not f:
            return False
        f.request = req
        return f

    def add_response(self, resp):
        """
            Add a response to the state. Returns the matching flow.
        """
        f = self.flow_map.get(resp.request.connection)
        if not f:
            return False
        f.response = resp
        f.backup()
        return f

    def add_error(self, err):
        """
            Add an error response to the state. Returns the matching flow, or
            None if there isn't one.
        """
        f = self.flow_map.get(err.connection)
        if not f:
            return None
        f.error = err
        f.backup()
        return f

    def dump_flows(self):
        data = [i.get_state() for i in self.view]
        return json.dumps(data)

    def load_flows(self, js, klass):
        data = json.loads(js)
        data = [klass.from_state(i) for i in data]
        self.flow_list.extend(data)

    def set_limit(self, limit):
        """
            Limit is a compiled filter expression, or None.
        """
        self.limit = limit

    @property
    def view(self):
        if self.limit:
            return tuple([i for i in self.flow_list if i.match(self.limit)])
        else:
            return tuple(self.flow_list[:])

    def get_connection(self, itm):
        if isinstance(itm, (proxy.BrowserConnection, ReplayConnection)):
            return itm
        elif hasattr(itm, "connection"):
            return itm.connection
        elif hasattr(itm, "request"):
            return itm.request.connection

    def lookup(self, itm):
        """
            Checks for matching connection, using a Flow, Replay Connection,
            BrowserConnection, Request, Response or Error object. Returns None
            if not found.
        """
        connection = self.get_connection(itm)
        return self.flow_map.get(connection)

    def delete_flow(self, f):
        if not f.intercepting:
            c = self.get_connection(f)
            if c in self.flow_map:
                del self.flow_map[c]
            self.flow_list.remove(f)
            return True
        return False

    def clear(self):
        for i in self.flow_list[:]:
            self.delete_flow(i)

    def accept_all(self):
        for i in self.flow_list[:]:
            i.accept_intercept()

    def kill_flow(self, f):
        f.kill()
        self.delete_flow(f)

    def revert(self, f):
        """
            Replaces the matching connection object with a ReplayConnection object.
        """
        conn = self.get_connection(f)
        if conn in self.flow_map:
            del self.flow_map[conn]
        f.revert()
        self.flow_map[f.connection] = f

    def replay(self, f, masterq):
        """
            Replaces the matching connection object with a ReplayConnection object.

            Returns None if successful, or error message if not.
        """
        #begin nocover
        if f.intercepting:
            return "Can't replay while intercepting..."
        if f.request:
            f.backup()
            conn = self.get_connection(f)
            if conn in self.flow_map:
                del self.flow_map[conn]
            rp = ReplayConnection()
            f.connection = rp
            f.request.connection = rp
            if f.request.content:
                f.request.headers["content-length"] = [str(len(f.request.content))]
            f.response = None
            f.error = None
            self.flow_map[rp] = f
            rt = ReplayThread(f, masterq)
            rt.start()
        #end nocover