import logging
import traceback

from aiohttp import ClientSession, ClientTimeout, TCPConnector
from aiohttp.client_exceptions import ClientConnectorError, ServerTimeoutError
from datetime import datetime
from cachetools import LRUCache
from json.decoder import JSONDecodeError
from urllib.parse import urlparse

from . import __version__
from .misc import (
	MIMETYPES,
	DotDict,
	Message,
	create_signature_header,
	generate_body_digest
)


HEADERS = {
	'Accept': f'{MIMETYPES["activity"]}, {MIMETYPES["json"]};q=0.9',
	'User-Agent': f'ActivityRelay/{__version__}'
}


class Cache(LRUCache):
	def set_maxsize(self, value):
		self.__maxsize = int(value)


class HttpClient:
	def __init__(self, limit=100, timeout=10, cache_size=1024):
		self.cache = Cache(cache_size)
		self.cfg = {'limit': limit, 'timeout': timeout}
		self._conn = None
		self._session = None


	@property
	def limit(self):
		return self.cfg['limit']


	@property
	def timeout(self):
		return self.cfg['timeout']


	def sign_headers(self, method, url, message=None):
		parsed = urlparse(url)
		headers = {
			'(request-target)': f'{method.lower()} {parsed.path}',
			'Date': datetime.utcnow().strftime('%a, %d %b %Y %H:%M:%S GMT'),
			'Host': parsed.netloc
		}

		if message:
			data = message.to_json()
			headers.update({
				'Digest': f'SHA-256={generate_body_digest(data)}',
				'Content-Length': str(len(data.encode('utf-8')))
			})

		headers['Signature'] = create_signature_header(headers)

		del headers['(request-target)']
		del headers['Host']

		return headers


	async def open(self):
		if self._session:
			return

		self._conn = TCPConnector(
			limit = self.limit,
			ttl_dns_cache = 300,
		)

		self._session = ClientSession(
			connector = self._conn,
			headers = HEADERS,
			connector_owner = True,
			timeout = ClientTimeout(total=self.timeout)
		)


	async def close(self):
		if not self._session:
			return

		await self._session.close()
		await self._conn.close()

		self._conn = None
		self._session = None


	async def get(self, url, sign_headers=False, loads=None, force=False):
		await self.open()

		try: url, _ = url.split('#', 1)
		except: pass

		if not force and url in self.cache:
			return self.cache[url]

		headers = {}

		if sign_headers:
			headers.update(self.sign_headers('GET', url))

		try:
			logging.verbose(f'Fetching resource: {url}')

			async with self._session.get(url, headers=headers) as resp:
				## Not expecting a response with 202s, so just return
				if resp.status == 202:
					return

				elif resp.status != 200:
					logging.verbose(f'Received error when requesting {url}: {resp.status}')
					logging.verbose(await resp.read()) # change this to debug
					return

				if loads:
					if issubclass(loads, DotDict):
						message = await resp.json(loads=loads.new_from_json)

					else:
						message = await resp.json(loads=loads)

				elif resp.content_type == MIMETYPES['activity']:
					message = await resp.json(loads=Message.new_from_json)

				elif resp.content_type == MIMETYPES['json']:
					message = await resp.json(loads=DotDict.new_from_json)

				else:
					# todo: raise TypeError or something
					logging.verbose(f'Invalid Content-Type for "{url}": {resp.content_type}')
					return logging.debug(f'Response: {resp.read()}')

				logging.debug(f'{url} >> resp {message.to_json(4)}')

				self.cache[url] = message
				return message

		except JSONDecodeError:
			logging.verbose(f'Failed to parse JSON')

		except (ClientConnectorError, ServerTimeoutError):
			logging.verbose(f'Failed to connect to {urlparse(url).netloc}')

		except Exception as e:
			traceback.print_exc()
			raise e


	async def post(self, url, message):
		await self.open()

		headers = {'Content-Type': 'application/activity+json'}
		headers.update(self.sign_headers('POST', url, message))

		try:
			logging.verbose(f'Sending "{message.type}" to {url}')

			async with self._session.post(url, headers=headers, data=message.to_json()) as resp:
				## Not expecting a response, so just return
				if resp.status in {200, 202}:
					return logging.verbose(f'Successfully sent "{message.type}" to {url}')

				logging.verbose(f'Received error when pushing to {url}: {resp.status}')
				return logging.verbose(await resp.read()) # change this to debug

		except (ClientConnectorError, ServerTimeoutError):
			logging.verbose(f'Failed to connect to {url.netloc}')

		## prevent workers from being brought down
		except Exception as e:
			traceback.print_exc()


	## Additional methods ##
	async def fetch_nodeinfo(domain):
		nodeinfo_url = None
		wk_nodeinfo = await self.get(f'https://{domain}/.well-known/nodeinfo', loads=WKNodeinfo)

		for version in ['20', '21']:
			try:
				nodeinfo_url = wk_nodeinfo.get_url(version)

			except KeyError:
				pass

		if not nodeinfo_url:
			logging.verbose(f'Failed to fetch nodeinfo url for domain: {domain}')
			return False

		return await request(nodeinfo_url, loads=Nodeinfo) or False