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
from datafile import DataFile


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.hash):
				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=DataFile.open(self._filename)

		print(datetime.now(), "sending data:")
		progress=Progress(len(blocksToTransfer))

		for k in range(0,len(blocksToTransfer),conf.batchSize.data):
			indices=[]
			blocks=[]
			for j in range(conf.batchSize.data):
				if k+j>=len(blocksToTransfer): break
				i=blocksToTransfer[k+j]
				block=dataFile.readFrom(i)

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

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

		print(datetime.now(), "receiving data:")
		progress=Progress(len(blocksToTransfer))

		for k in range(0,len(blocksToTransfer),conf.batchSize.data):
			indices=blocksToTransfer[k:k+conf.batchSize.data]
			self._outcoming.writeMsg({"command":"req", "index":indices, "dataType":"data"})
			jsonData,binData=self._incoming.readMsg()
			assert jsonData["command"]=="send" and jsonData["index"]==indices and jsonData["dataType"]=="data", jsonData
			for (j,i) in enumerate(indices):
				block=binData[j*HashTree.BLOCK_SIZE:(j+1)*HashTree.BLOCK_SIZE]
				dataFile.writeAt(i,block)

				if self._treeFile:
					self._newLeaves[i+self._tree.leafStart]=hashBlock(block)

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

				stats.logTransferredBlock()
				progress.p(k+j)
		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