#!/usr/bin/env python
# This file is part of dnmapper, an AS--level mapping tool
# Licensed under GNU General Public License v3 or later
# Written by Sebastian Lohff (seba@someserver.de)
from __future__ import print_function

from collections import OrderedDict
import re
import socket

from backend.exceptions import RouterParserException


def err(msg):
    raise RouterParserException(msg)


def getBGPData(ip, asno):
    rawData = getDataFromHost(ip)
    if not rawData:
        err("Could not get data from host (empty response)")

    router = parseBGPData(rawData, asno)

    router["ip"] = ip

    return router


def getDataFromHost(ip):
    socket.setdefaulttimeout(5)
    x = socket.socket()
    x.connect((ip, 6556))
    f = x.makefile()
    data = f.read()
    x.close()

    return data

def parseBGPData(raw, asno):
    d = re.search(r"(?:^|\n)<<<(quagga|bird)>>>\n(.*?)(?:$|<<<[^\n]+>>>)", raw, re.DOTALL)

    if not d:
        err("Data not found in check mk output")

    # mkify
    raw = d.group(2).split("\n")
    arr = list(filter(lambda _z: _z, map(lambda _y: list(filter(lambda _x: _x, re.split(r"\s+", _y))), raw)))

    # parse for bird/quagga
    result = None

    if d.group(1) == "quagga":
        result = parseQuagga(arr, raw, asno)
    else:
        result = parseBird(arr, raw, asno)

    return result


def parseQuagga(data, raw, asno):
    status = _quaggaFindCommand(data, "show ip bgp sum")

    if status[0][0:3] == ['IPv4', 'Unicast', 'Summary:']:
        del(status[0])

    if status[0][0:3] != ['BGP', 'router', 'identifier']:
        print(status)
        err("Couldn't find router id in quagga output")

    peers = _quaggaFindNeighbors(data)
    if asno and int(asno) != int(status[0][7]):
        err("AS number (%s) does not match as number from quagga (%s)" % (asno, status[0][7]))

    routes = _quaggaFindRoutes(raw)

    return {"local_id": status[0][3].strip(","), "local_as": int(status[0][7]), "peers": peers, "routes": routes}

def parseBird(data, raw, asno):
    status = _birdFindTable(data, "show status")
    if status[2][0] != "1011-Router":
        err("Couldn't find router id in bird output")
    peers = list(filter(lambda _x: _x["type"] == "BGP", _birdMakeProtocols(data)))

    if asno == None:
        err("Host is bird")
        # FIXME

    routes = _birdFindRoutes(data)

    return {"local_id": status[2][3], "local_as": int(asno), "peers": peers, "routes": routes}

def _birdFindTable(info, command):
    """ find command output of a bird command, e.g. "show bgp neighbors" """
    command = ["bird>"] + command.split(" ")
    commandInfo = []
    editNextLine = False
    for line in info:
        if not commandInfo:
            if line == command:
                commandInfo.append(line)
                editNextLine = True
        else:
            if editNextLine:
                editNextLine = False
                commandInfo.append(line[1:])
            elif line[0] == "bird>":
                return commandInfo
            else:
                commandInfo.append(line)
    return []

def _birdFindProtocols(info):
    """ return a list of tuples (protoname, protoinfo) """
    protocolTable = _birdFindTable(info, "show protocols all")
    protocols = OrderedDict()
    currProto = None
    for line in protocolTable[2:]:
        if line[0][0:4] == "1002":
            currProto = line[0][5:]
            protocols[currProto] = [[currProto] + line[1:]]
        elif currProto == None:
            err("No proto selected, couldn't parse line:", line)
        else:
            protocols[currProto].append(line)

    return protocols

def _birdMakeProtocols(info):
    """ Parse birds show protocols all output """
    # proto: name, type, description, state (up/down?), up-since
    #        routes imported, exported, preferred
    #        also: routing stats (
    # bgp special stuff: state, neighbor (address, as, id) (id not available when down)
    #   state (established, active)
    #   if error, last error is avilable
    protocols = []
    for proto, data in _birdFindProtocols(info).items():
        protoInfo = {
            "name": proto,
            "type": data[0][1],
            "table": data[0][2],
            "state": data[0][3],
            "last_change": data[0][4],
            "info": " ".join(data[0][5:]),
            "description": " ".join(data[1][2:]),
            "routes": {
                "imported": data[5][1],
                "exported": data[5][3],
                "preferred": data[5][5],
            }
        }
        if protoInfo["type"] == "BGP":
            found = False
            for n, line in enumerate(data):
                if line[0:2] == ["BGP", "state:"]:
                    found = True
                    protoInfo["BGP"] = {
                        "state": data[n][2],
                        "online": data[n][2] == "Established",
                        "neighbor_address": data[n+1][2],
                        "neighbor_as": int(data[n+2][2]),
                        "neighbor_id": data[n+3][2] if len(data) > n+3 and data[n+3][0:2] == ["Neighbor", "ID:"] else None,
                        "last_error": " ".join(data[n+3][2:]) if len(data) > n+3 and data[n+3][0:2] == ["Last", "error:"] else None,
                    }

            if not found:
                protoInfo["BGP"] = None

        protocols.append(protoInfo)

    return protocols


def _birdFindRoutes(info):
    output = _birdFindTable(info, "show route all")
    if len(output) < 1:
        # no data found
        return None

    def handleCandidate(routes, candidate):
        if candidate:
            # path, nexthop, network
            for key in ["path", "nexthop", "network", "iBGP"]:
                if key not in candidate:
                    return
            route = {"prefix": candidate["network"], "nexthop": candidate["nexthop"],
                     "path": list(map(int, candidate["path"])), "iBGP": candidate["iBGP"]}
            routes.append(route)

    routes = []
    candidate = None
    lastIP = None
    for line in output:
        if line[0].startswith("1007-"):
            # new route!
            handleCandidate(routes, candidate)
            if line[0] != "1007-":
                # line has a network, use it!
                lastIP = line[0][5:]
            candidate = {"network": lastIP, "iBGP": None}

        elif candidate is not None:
            # search bgp attributes
            if line[0] == "1012-":
                pass
                k, v = line[1], line[2:]
            else:
                k, v = line[0], line[1:]

            k = k.rstrip(":")
            if k == "BGP.next_hop":
                candidate["nexthop"] = v[0]
            elif k == "BGP.as_path":
                candidate["path"] = v


    handleCandidate(routes, candidate)

    return routes


def _quaggaFindCommand(info, cmd):
    # ['core-frunde#', 'show', 'ip', 'bgp', 'sum']
    # ['core-frunde#', 'show', 'ip', 'bgp', 'neighbors']
    output = []
    cmd = cmd.split(" ")
    prompt = None
    for line in info:
        if line[1:] == cmd:
            prompt = line[0]
        elif line[0] == prompt:
            # done
            return output
        elif prompt != None:
            output.append(line)

    err("Could not find command '%s' in output" % " ".join(cmd))

def _quaggaFindNeighbors(info):
    #['BGP', 'neighbor', 'is', '10.50.1.2,', 'remote', 'AS', '65001,', 'local', 'AS', '65001,', 'internal', 'link']
    output = _quaggaFindCommand(info, "show ip bgp neighbors")
    start = ["BGP", "neighbor", "is"]

    curr = None
    rawNeighbors = []
    for line in output:
        if line[0:3] == start:
            if curr:
                rawNeighbors.append(curr)
            curr = [line]
        elif curr:
            curr.append(line)
        else:
            err("Could not find start of neighbors")

    if curr:
        rawNeighbors.append(curr)
        curr = None

    neighbors = []
    neighborDict = OrderedDict()
    for raw in rawNeighbors:
        descrIdx = 1 if raw[1][0] == "Description:" else 0
        if raw[descrIdx + 1][0] == "Hostname:":
            descrIdx += 1

        peerdict = {
            "neighbor_address": raw[0][3].rstrip(","),
            "neighbor_as": int(raw[0][6].rstrip(",")),
            "local_as": int(raw[0][9].rstrip(",")),
            "description": " ".join(raw[1][1:]) if descrIdx else "No description",
            "neighbor_id": raw[1+descrIdx][6].strip(","),
            "state": raw[2+descrIdx][3].strip(","),
            "routes": {
                "imported": 0,
            },
            "BGP": {
                "state": raw[2+descrIdx][3].strip(","),
                "online": raw[2+descrIdx][3].strip(",") == "Established",
                "neighbor_id": raw[1+descrIdx][6].strip(","),
                "neighbor_address": raw[0][3].rstrip(","),
                "neighbor_as": int(raw[0][6].rstrip(",")),
                "state": raw[2+descrIdx][3].strip(","),
            },
        }

        for line in raw:
            if line[1:3] == ["accepted", "prefixes"]:
                # woooo
                peerdict["routes"]["imported"] = int(line[0])
                break

        neighbors.append(peerdict)
        neighborDict[peerdict["neighbor_address"]] = peerdict

    return neighbors

def _quaggaFindRoutes(raw):
    # from # show ip bgp to Total number of prefixes XX
    # BGP table version is 0, local router ID is 10.50.0.1
    # *> 10.3.14.0/27     10.75.0.22                             0 65002 65112 i
    cmdre = re.compile(r"^([^\s#]+#) show ip bgp$")
    routere = re.compile(r"^(?P<status>.)(?P<status2>.)(?P<origin>.)(?P<network>[0-9./]+)?\s+(?P<nexthop>[0-9./]+)[\s0-9i?]+$")

    # find output
    output = []
    prompt = None
    for line in raw:
        if not prompt:
            m = cmdre.match(line)
            if m:
                prompt = m.group(1) + " "
        else:
            if line.startswith(prompt):
                break
            else:
                output.append(line)

    if len(output) < 1:
        # no data found
        return None

    routes = []
    foundTable = False
    lastIP = None
    for line in output:
        if not foundTable:
            if line.endswith("Metric LocPrf Weight Path"):
                foundTable = True
        else:
            if line != '':
                if line.startswith("Total number of prefixes") or line.startswith("Displayed "):
                    break
                else:
                    # parse one route line
                    #print(line)
                    m = routere.match(line)
                    d = m.groupdict()
                    if d["network"]:
                        lastIP = d["network"]
                    else:
                        d["network"] = lastIP

                    # "parse" path (everything after 61 chars, but no i)
                    path = list(filter(lambda _x: _x not in ('', 'i'), line[61:].split(" ")))

                    # currently skip incomplete routes
                    if '?' not in path:
                        route = {"prefix": d["network"], "nexthop": d["nexthop"],
                                 "path": list(map(int, path)), "iBGP": d["origin"] == "i"}
                        routes.append(route)

    return routes