import collections

import socket

import ssl

import logging as log

from datetime import datetime

import config as conf

import status

import stats

from util import Progress

from hashtree import HashTree,hashBlock

from netnode import BaseConnection,NetNode,FailedConnection,LockedException,IncompatibleException

class DeniedConnection(Exception): pass

class Connection(BaseConnection):

	def __init__(self,host,port):

		super().__init__()

		sock=socket.socket(socket.AF_INET, socket.SOCK_STREAM)

		sslContext=ssl.create_default_context(cafile=conf.peers)

		sslContext.check_hostname=False

		sslContext.load_cert_chain(conf.certfile,conf.keyfile)

		self._socket=sslContext.wrap_socket(sock)

		try:

			self._socket.connect((host,port))

		except (ConnectionRefusedError,OSError) as e:

			log.exception(e)

			print("Couldn't connect to {0}:{1}".format(host,port))

			raise FailedConnection()

		except ssl.SSLError as e:

			log.exception(e)

			print("Error creating SSL connection to {0}:{1}".format(host,port))

			raise FailedConnection()

		self.createNetworkers()

		print("Connected to {0}".format(host))

class Client(NetNode):

	def __init__(self,filename,treeFile=""):

		print(datetime.now(), "initializing...")

		super().__init__(filename,treeFile)

	def init(self,action):

		jsonData={"command":"init", "blockSize":self._tree.BLOCK_SIZE, "blockCount":self._tree.leafCount, "version":conf.version, "action":action}

		self._outcoming.writeMsg(jsonData)

		jsonData,binData=self._incoming.readMsg()

		if jsonData["command"]=="deny":

			if jsonData["status"]==status.incompatible.version:

				raise DeniedConnection("Incompatible client version. Consider upgrading it.")

			raise DeniedConnection()

		assert jsonData["command"]=="init"

		if jsonData["version"]<conf.lowestCompatible:

			raise IncompatibleException("Incompatible server version. Consider upgrading it.")

	## Asks server for node hashes to determine which are to be transferred.

	#

	# Uses a binary HashTree, where item at k is hash of items at 2k+1, 2k+2.

	#

	# Requests nodes in order of a batch DFS. Needs stack of size O(treeDepth*batchSize). Nodes in each tree level are accessed in order.

	def negotiate(self):

		localTree=self._tree

		blocksToTransfer=[]

		nodeStack=collections.deque([0]) # root

		# determine which blocks to send

		print(datetime.now(), "negotiating:")

		progress=Progress(localTree.leafCount)

		while len(nodeStack)>0:

			indices=[]

			for i in range(conf.batchSize):

				indices.append(nodeStack.pop())

				if len(nodeStack)==0: break

			self._outcoming.writeMsg({"command":"req", "index":indices, "dataType":"hash"})

			jsonData,binData=self._incoming.readMsg()

			assert jsonData["index"]==indices

			assert jsonData["dataType"]=="hash"

			stats.logExchangedNode(len(indices))

			frontier=[]

			for (j,i) in enumerate(indices):

				(j1,j2)=[HashTree.HASH_LEN*ji for ji in (j,j+1)]

				if localTree.store[i]!=binData[j1:j2]:

					# ie. 0-6 nodes, 7-14 leaves. 2*6+2<15

					if 2*i+2<len(localTree.store): # inner node

						frontier.append(2*i+1)

						frontier.append(2*i+2)

					else:

						blocksToTransfer.append(i-localTree.leafStart) # leaf

						progress.p(i-localTree.leafStart)

			nodeStack.extend(reversed(frontier))

		progress.done()

		size=stats.formatBytes(len(blocksToTransfer)*self._tree.BLOCK_SIZE)

		print(datetime.now(), "{0} to transfer".format(size))

		return blocksToTransfer

	def sendData(self,blocksToTransfer):

		log.info(blocksToTransfer)

		dataFile=open(self._filename, mode="rb")

		i1=-1

		print(datetime.now(), "sending data:")

		progress=Progress(len(blocksToTransfer))

		for k in range(0,len(blocksToTransfer),conf.batchSize):

			indices=[]

			blocks=[]

			for j in range(conf.batchSize):

				if k+j>=len(blocksToTransfer): break

				i2=blocksToTransfer[k+j]

				if i1+1!=i2:

					dataFile.seek(i2*HashTree.BLOCK_SIZE)

				block=dataFile.read(HashTree.BLOCK_SIZE)

				indices.append(i2)

				blocks.append(block)

				log.info("block #{0}: {1}...{2}".format(i2,block[:5],block[-5:]))

				i1=i2

				progress.p(k+j)

			if indices: self._sendData(indices,blocks)

		progress.done()

		self._outcoming.writeMsg({"command":"end","action":"push"})

		log.info("closing session...")

		dataFile.close()

	def pullData(self,blocksToTransfer,ignoreLock=False):

		if not ignoreLock:

			try:

				self._lock()

			except LockedException:

				print("The file is locked. Either (a) there's another pull going on (then wait or kill it), or (b) a previous pull ended prematurely and the file is probably corrupt (then repeat pull with -f for force).")

				return

		log.info(blocksToTransfer)

		print(datetime.now(), "receiving data:")

		progress=Progress(len(blocksToTransfer))

		progress.done()

		self._outcoming.writeMsg({"command":"end"})

		log.info("closing session...")

		dataFile.close()

		self._unlock()

		if self._treeFile:

			self._updateTree()

	def _sendData(self,indices,blocks):

		jsonData={"command":"send", "index":indices, "dataType":"data"}

		binData=b"".join(blocks)

		self._outcoming.writeMsg(jsonData,binData)

		stats.logTransferredBlock(len(indices))

		jsonData,binData=self._incoming.readMsg()

		assert jsonData["command"]=="ack" and jsonData["index"]==indices, jsonData

	def setConnection(self,connection):

		(self._incoming,self._outcoming)=connection

import sys

import os.path

import logging as log

from argparse import ArgumentParser

from util import spawnDaemon, splitHost

import config as conf

import stats

from hashtree import HashTree

from server import Miniserver

def _checkFile(f):

	if not os.path.isfile(f):

		print("invalid file specified:",f,file=sys.stderr)

		sys.exit(1)

def buildTree(args):

	_checkFile(args.datafile)

	if os.path.isfile(args.treefile):

		treeMod=os.stat(args.treefile).st_mtime

		dataMod=os.stat(args.datafile).st_mtime

		if dataMod<treeMod and not args.force:

			print("tree file is up to date")

			return

	tree=HashTree.fromFile(args.datafile)

	tree.save(args.treefile)

def push(args):

	_checkFile(args.datafile)

	if args.tree:

		_checkFile(args.tree)

	if args.host: conf.hosts=[args.host]

	if args.port: conf.port=args.port

	c=Client(args.datafile,args.tree)

	for h in conf.hosts:

		host=splitHost(h,conf.port)

		stats.reset()

		try:

			with ClientConnection(*host) as con:

				c.setConnection(con)

				c.init("push")

				blocksToTransfer=c.negotiate()

				c.sendData(blocksToTransfer)

			print()

			print(stats.report())

			print()

		except FailedConnection: pass

		except DeniedConnection as e:

			print("Server {0}:{1} denied connection.".format(*host))

			print(e)

def pull(args):

	_checkFile(args.datafile)

	if args.tree:

		_checkFile(args.tree)

	if args.host: conf.hosts=[args.host]

	if args.port: conf.port=args.port

	c=Client(args.datafile,args.tree)

	host=splitHost(conf.hosts[0],conf.port)

	try:

		with ClientConnection(*host) as con:

			c.setConnection(con)

			c.init("pull")

			blocksToTransfer=c.negotiate()

			c.pullData(blocksToTransfer,args.force)

		print()

		print(stats.report())

	except FailedConnection: pass

	except DeniedConnection as e:

		print("Server {0}:{1} denied connection.".format(*host))

		print(e)

def serve(args):

	_checkFile(args.datafile)

	if args.tree:

		_checkFile(args.tree)

	if args.host: conf.hosts.insert(0,args.host)

	if args.port: conf.port=args.port

	s=Miniserver(args.datafile,args.tree)

	try:

		spawnDaemon(s.serve)

	except Exception as e:

		log.exception("exception: %s",e)

parser=ArgumentParser()

subparsers=parser.add_subparsers()

pBuild=subparsers.add_parser("build")

pBuild.add_argument("-f","--force",action="store_true",help="force tree rebuild")

pBuild.add_argument("treefile", help="stored hash tree location")

pBuild.add_argument("datafile")

pBuild.set_defaults(func=buildTree)

pUpdate=subparsers.add_parser("push")

pUpdate.add_argument("-p","--port",type=int)

pUpdate.add_argument("--host")

pUpdate.add_argument("-t","--tree",help="stored hash tree location")

pUpdate.add_argument("datafile")

pUpdate.set_defaults(func=push)

pUpdate=subparsers.add_parser("pull")

pUpdate.add_argument("-p","--port",type=int)

pUpdate.add_argument("--host")

pUpdate.add_argument("-t","--tree",help="stored hash tree location")

pUpdate.add_argument("-f","--force",action="store_true",help="ignore lock file")

pUpdate.add_argument("datafile")

pUpdate.set_defaults(func=pull)

pServe=subparsers.add_parser("serve")

pServe.add_argument("-p","--port",type=int)

pServe.add_argument("--host")

pServe.add_argument("-t","--tree",help="stored hash tree location")

pServe.add_argument("datafile")

pServe.set_defaults(func=serve)

args=parser.parse_args()

args.func(args)

		self._ssl.load_cert_chain(conf.certfile,conf.keyfile)

		self._ss = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

		self._ss.bind(("", conf.port))

		self._ss.listen(1)

	def serve(self):

		p=None

		with self._ss:

			while True:

				connection=Connection(self._ss,self._ssl)

				if p and p.is_alive():

					with connection as c:

						c[0].readMsg()

						c[1].writeMsg({"command":"deny","status":status.locked})

					continue

				p=multiprocessing.Process(target=Server.run,args=(connection,self._filename,self._treeFile))

				p.start()

class Server(NetNode):

	def __init__(self,connection,filename,treeFile=""):

		super().__init__(filename,treeFile)

		(self._incoming,self._outcoming)=connection

		self.BLOCK_SIZE=self._tree.BLOCK_SIZE

		self._lastIndex=-1

		self._dataFileHandle=None

	@staticmethod

	def run(connection,*args):

		with connection as c:

			s=Server(c,*args)

			s.serve()

	@property

	def _dataFile(self):

		if not self._dataFileHandle:

			self._dataFileHandle=open(self._filename, mode="rb+")

		return self._dataFileHandle

	def serve(self):

		try:

			while self._serveOne(): pass

		except (AssertionError,ConnectionResetError) as e:

			log.warning(e)

	def _serveOne(self):

		jsonData,binData=self._incoming.readMsg()

		if jsonData["command"]=="init":

			if jsonData["blockSize"]!=self.BLOCK_SIZE or jsonData["blockCount"]!=self._tree.leafCount:

				self._outcoming.writeMsg({"command":"deny","status":status.incompatible.parameters})

			if jsonData["version"]<conf.lowestCompatible:

				self._outcoming.writeMsg({"command":"deny","status":status.incompatible.version})

			if jsonData["action"]=="pull" and self.isLocked():

				self._outcoming.writeMsg({"command":"deny","status":status.locked})

			if jsonData["action"]=="push" and not self.isLocked():

				self._lock()

			self._outcoming.writeMsg({"command":"init", "version":conf.version})

		elif jsonData["command"]=="req":

			if jsonData["dataType"]=="data":

				self._outcoming.writeMsg(*self._requestData(jsonData["index"]))

			else:

				self._outcoming.writeMsg(*self._requestHash(jsonData["index"]))

		elif jsonData["command"]=="send" and jsonData["dataType"]=="data":

			self._outcoming.writeMsg(*self._receiveData(jsonData,binData))

		elif jsonData["command"]=="end":

			self._finalize()

			if jsonData.get("action")=="push": self._unlock()

			return False

		else:

			assert False, jsonData["command"]

		return True

	def _requestHash(self,indices):

		log.info("received request for nodes #{0}".format(",".join(str(i) for i in indices)))

		assert all(i<len(self._tree.store) for i in indices)

		hashes=[self._tree.store[i] for i in indices]

		jsonResponse={"command":"send", "index":indices, "dataType":"hash"}

		binResponse=b"".join(hashes)

		return (jsonResponse,binResponse)

	def _requestData(self,index):

		log.info("received request for data block #{0}".format(index))

		jsonResponse={"command":"send", "index":index, "dataType":"data"}

	def _receiveData(self,jsonData,binData):

		if not self.isLocked(): self._lock()

		log.info("received data block #{0}: {1}...{2}".format(jsonData["index"],binData[:5],binData[-5:]))

		indices=jsonData["index"]

		for (i,k) in enumerate(indices):

			if self._lastIndex+1!=k:

				self._dataFile.seek(k*self.BLOCK_SIZE)

			self._dataFile.write(binData[i*self.BLOCK_SIZE:(i+1)*self.BLOCK_SIZE])

			self._lastIndex=k

			if self._treeFile:

				self._newLeaves[k+self._tree.leafStart]=hashBlock(binData)

		return ({"command": "ack", "index": indices},)

	def _finalize(self):

		log.info("closing session...")

		self._dataFile.close()

		self._dataFileHandle=None

		if self._treeFile:

			self._updateTree()

		log.info("done")