from webagg.utils import StreamIter, chunk_encode_iter, BUFF_SIZE
from webagg.inputrequest import DirectWSGIInputRequest

from pywb.utils.statusandheaders import StatusAndHeadersParser
from pywb.warc.recordloader import ArcWarcRecord
from pywb.warc.recordloader import ArcWarcRecordLoader

from recorder.filters import SkipRangeRequestFilter, CollectionFilter

from six.moves.urllib.parse import parse_qsl

import json
import tempfile

from requests.structures import CaseInsensitiveDict
import requests

import traceback

import gevent.queue
import gevent


#==============================================================================
class RecorderApp(object):
    def __init__(self, upstream_host, writer, skip_filters=None, **kwargs):
        self.upstream_host = upstream_host

        self.writer = writer
        self.parser = StatusAndHeadersParser([], verify=False)

        self.write_queue = gevent.queue.Queue()
        gevent.spawn(self._write_loop)

        if not skip_filters:
            skip_filters = self.create_default_filters(kwargs)

        self.skip_filters = skip_filters

    def create_default_filters(self, kwargs):
        skip_filters = [SkipRangeRequestFilter()]

        accept_colls = kwargs.get('accept_colls')
        if accept_colls:
            skip_filters.append(CollectionFilter(accept_colls))

        return skip_filters

    def _write_loop(self):
        while True:
            try:
                self._write_one()
            except:
                traceback.print_exc()

    def _write_one(self):
        req = None
        resp = None
        try:
            result = self.write_queue.get()

            req_head, req_pay, resp_head, resp_pay, params = result

            req = self._create_req_record(req_head, req_pay, 'request')
            resp = self._create_resp_record(resp_head, resp_pay, 'response')

            self.writer.write_req_resp(req, resp, params)

        finally:
            try:
                if req:
                    req.stream.close()

                if resp:
                    resp.stream.close()
            except Exception as e:
                traceback.print_exc()

    def _create_req_record(self, req_headers, payload, type_, ct=''):
        len_ = payload.tell()
        payload.seek(0)

        warc_headers = req_headers
        status_headers = self.parser.parse(payload)

        record = ArcWarcRecord('warc', type_, warc_headers, payload,
                                status_headers, ct, len_)
        return record

    def _create_resp_record(self, resp_headers, payload, type_, ct=''):
        len_ = payload.tell()
        payload.seek(0)

        warc_headers = self.parser.parse(payload)
        warc_headers = CaseInsensitiveDict(warc_headers.headers)

        status_headers = self.parser.parse(payload)

        record = ArcWarcRecord('warc', type_, warc_headers, payload,
                              status_headers, ct, len_)
        return record

    def send_error(self, exc, start_response):
        message = json.dumps({'error': repr(exc)})
        headers = [('Content-Type', 'application/json; charset=utf-8'),
                   ('Content-Length', str(len(message)))]

        start_response('400 Bad Request', headers)
        return [message.encode('utf-8')]

    def __call__(self, environ, start_response):
        input_req = DirectWSGIInputRequest(environ)
        headers = input_req.get_req_headers()
        method = input_req.get_req_method()
        request_uri = input_req.get_full_request_uri()

        input_buff = input_req.get_req_body()

        params = dict(parse_qsl(environ.get('QUERY_STRING')))

        skipping = any(x.skip_request(headers) for x in self.skip_filters)

        if not skipping:
            req_stream = ReqWrapper(input_buff, headers)
        else:
            req_stream = input_buff

        data = None
        if input_buff:
            data = req_stream

        try:
            res = requests.request(url=self.upstream_host + request_uri,
                                 method=method,
                                 data=data,
                                 headers=headers,
                                 allow_redirects=False,
                                 stream=True)
            res.raise_for_status()
        except Exception as e:
            #traceback.print_exc()
            return self.send_error(e, start_response)

        start_response('200 OK', list(res.headers.items()))

        if not skipping:
            resp_stream = RespWrapper(res.raw,
                                      res.headers,
                                      req_stream,
                                      params,
                                      self.write_queue,
                                      self.skip_filters)
        else:
            resp_stream = res.raw

        resp_iter = StreamIter(resp_stream)

        if res.headers.get('Transfer-Encoding') == 'chunked':
            resp_iter = chunk_encode_iter(resp_iter)

        return resp_iter


#==============================================================================
class Wrapper(object):
    def __init__(self, stream):
        self.stream = stream
        self.out = self._create_buffer()
        self.interrupted = False

    def _create_buffer(self):
        return tempfile.SpooledTemporaryFile(max_size=512*1024)

    def read(self, *args, **kwargs):
        try:
            buff = self.stream.read(*args, **kwargs)
        except Exception as e:
            print('INTERRUPT READ')
            self.interrupted = True
            raise

        self.out.write(buff)
        return buff

    def close(self):
        try:
            self.stream.close()
        except:
            traceback.print_exc()


#==============================================================================
class RespWrapper(Wrapper):
    def __init__(self, stream, headers, req,
                 params, queue, skip_filters):

        super(RespWrapper, self).__init__(stream)
        self.headers = headers
        self.req = req
        self.params = params
        self.queue = queue
        self.skip_filters = skip_filters

    def close(self):
        try:
            while True:
                if not self.read(BUFF_SIZE):
                    break

        except Exception as e:
            print(e)
            self.interrupted = True

        finally:
            try:
                self.stream.close()
            except Exception as e:
                traceback.print_exc()

            self._write_to_file()

    def _write_to_file(self):
        skipping = any(x.skip_response(self.req.headers, self.headers)
                        for x in self.skip_filters)

        if self.interrupted or skipping:
            self.out.close()
            self.req.out.close()
            self.req.close()
            return

        try:
            entry = (self.req.headers, self.req.out,
                     self.headers, self.out, self.params)
            self.queue.put(entry)
            self.req.close()
            self.req = None
        except:
            traceback.print_exc()


#==============================================================================
class ReqWrapper(Wrapper):
    def __init__(self, stream, req_headers):
        super(ReqWrapper, self).__init__(stream)
        self.headers = CaseInsensitiveDict(req_headers)
        for n in req_headers.keys():
            if not n.upper().startswith('WARC-'):
                del self.headers[n]