#!/usr/bin/python
# -*- coding: utf-8 -*-

# thumbor imaging service
# https://github.com/thumbor/thumbor/wiki

# Licensed under the MIT license:
# http://www.opensource.org/licenses/mit-license
# Copyright (c) 2011 globo.com thumbor@googlegroups.com

import datetime
import re
from functools import partial

import tornado.httpclient
from six.moves.urllib.parse import quote, unquote, urlparse

from thumbor.loaders import LoaderResult
from thumbor.utils import logger
from tornado.concurrent import return_future


def encode_url(url):
    if url == unquote(url):
        return quote(url.encode('utf-8'), safe='~@#$&()*!+=:;,.?/\'')
    else:
        return url


def quote_url(url):
    return encode_url(unquote(url).decode('utf-8'))


def _normalize_url(url):
    url = quote_url(url)
    return url if url.startswith('http') else 'http://%s' % url


def validate(context, url, normalize_url_func=_normalize_url):
    url = normalize_url_func(url)
    res = urlparse(url)

    if not res.hostname:
        return False

    if not context.config.ALLOWED_SOURCES:
        return True

    for pattern in context.config.ALLOWED_SOURCES:
        if isinstance(pattern, re._pattern_type):
            match = url
        else:
            pattern = '^%s$' % pattern
            match = res.hostname

        if re.match(pattern, match):
            return True

    return False


def return_contents(response, url, callback, context, req_start=None):
    if req_start:
        finish = datetime.datetime.now()
        res = urlparse(url)
        context.metrics.timing(
            'original_image.fetch.{0}.{1}'.format(response.code, res.netloc.replace('.', '_')),
            (finish - req_start).total_seconds() * 1000,
        )

    result = LoaderResult()
    context.metrics.incr('original_image.status.' + str(response.code))
    if response.error:
        result.successful = False
        if response.code == 599:
            # Return a Gateway Timeout status downstream if upstream times out
            result.error = LoaderResult.ERROR_TIMEOUT
        else:
            result.error = LoaderResult.ERROR_NOT_FOUND

        logger.warn(u"ERROR retrieving image {0}: {1}".format(
            url, str(response.error)))

    elif response.body is None or len(response.body) == 0:
        result.successful = False
        result.error = LoaderResult.ERROR_UPSTREAM

        logger.warn(u"ERROR retrieving image {0}: Empty response.".format(url))
    else:
        if response.time_info:
            for x in response.time_info:
                context.metrics.timing('original_image.time_info.' + x,
                                       response.time_info[x] * 1000)
            context.metrics.timing(
                'original_image.time_info.bytes_per_second',
                len(response.body) / response.time_info['total'])
        result.buffer = response.body
        result.metadata.update(response.headers)
        context.metrics.incr('original_image.response_bytes', len(
            response.body))

    callback(result)


@return_future
def load(context, url, callback, normalize_url_func=_normalize_url):
    load_sync(context, url, callback, normalize_url_func)


def load_sync(context, url, callback, normalize_url_func):
    using_proxy = context.config.HTTP_LOADER_PROXY_HOST and context.config.HTTP_LOADER_PROXY_PORT
    if using_proxy or context.config.HTTP_LOADER_CURL_ASYNC_HTTP_CLIENT:
        http_client_implementation = 'tornado.curl_httpclient.CurlAsyncHTTPClient'
        prepare_curl_callback = _get_prepare_curl_callback(context.config)
    else:
        http_client_implementation = None  # default
        prepare_curl_callback = None

    tornado.httpclient.AsyncHTTPClient.configure(
        http_client_implementation,
        max_clients=context.config.HTTP_LOADER_MAX_CLIENTS)
    client = tornado.httpclient.AsyncHTTPClient()

    user_agent = None
    headers = {
        'Accept': 'image/*;q=0.9,*/*;q=0.1'
    }
    if context.config.HTTP_LOADER_FORWARD_ALL_HEADERS:
        headers = context.request_handler.request.headers
    else:
        if context.config.HTTP_LOADER_FORWARD_USER_AGENT:
            if 'User-Agent' in context.request_handler.request.headers:
                user_agent = context.request_handler.request.headers[
                    'User-Agent']
        if context.config.HTTP_LOADER_FORWARD_HEADERS_WHITELIST:
            for header_key in context.config.HTTP_LOADER_FORWARD_HEADERS_WHITELIST:
                if header_key in context.request_handler.request.headers:
                    headers[
                        header_key] = context.request_handler.request.headers[
                            header_key]

    if user_agent is None and 'User-Agent' not in headers:
        user_agent = context.config.HTTP_LOADER_DEFAULT_USER_AGENT

    url = normalize_url_func(url)
    req = tornado.httpclient.HTTPRequest(
        url=url,
        headers=headers,
        connect_timeout=context.config.HTTP_LOADER_CONNECT_TIMEOUT,
        request_timeout=context.config.HTTP_LOADER_REQUEST_TIMEOUT,
        follow_redirects=context.config.HTTP_LOADER_FOLLOW_REDIRECTS,
        max_redirects=context.config.HTTP_LOADER_MAX_REDIRECTS,
        user_agent=user_agent,
        proxy_host=encode(context.config.HTTP_LOADER_PROXY_HOST),
        proxy_port=context.config.HTTP_LOADER_PROXY_PORT,
        proxy_username=encode(context.config.HTTP_LOADER_PROXY_USERNAME),
        proxy_password=encode(context.config.HTTP_LOADER_PROXY_PASSWORD),
        ca_certs=encode(context.config.HTTP_LOADER_CA_CERTS),
        client_key=encode(context.config.HTTP_LOADER_CLIENT_KEY),
        client_cert=encode(context.config.HTTP_LOADER_CLIENT_CERT),
        validate_cert=context.config.HTTP_LOADER_VALIDATE_CERTS,
        prepare_curl_callback=prepare_curl_callback)

    start = datetime.datetime.now()
    client.fetch(
        req,
        callback=partial(
            return_contents,
            url=url,
            callback=callback,
            context=context,
            req_start=start))


def encode(string):
    return None if string is None else string.encode('ascii')


def _get_prepare_curl_callback(config):
    if config.HTTP_LOADER_CURL_LOW_SPEED_TIME == 0 or config.HTTP_LOADER_CURL_LOW_SPEED_LIMIT == 0:
        return None

    class CurlOpts:
        def __init__(self, config):
            self.config = config

        def prepare_curl_callback(self, curl):
            curl.setopt(curl.LOW_SPEED_TIME,
                        self.config.HTTP_LOADER_CURL_LOW_SPEED_TIME)
            curl.setopt(curl.LOW_SPEED_LIMIT,
                        self.config.HTTP_LOADER_CURL_LOW_SPEED_LIMIT)

    return CurlOpts(config).prepare_curl_callback
