import json
import sys
from pprint import pformat

import requests
import requests.auth
from requests.defaults import defaults

from . import sessions
from . import __version__


FORM = 'application/x-www-form-urlencoded; charset=utf-8'
JSON = 'application/json; charset=utf-8'
DEFAULT_UA = 'HTTPie/%s' % __version__


def get_response(args):
    """Send the request and return a `request.Response`."""

    requests_kwargs = get_requests_kwargs(args)

    if args.debug:
        sys.stderr.write(
            '\n>>> requests.request(%s)\n\n' % pformat(requests_kwargs))

    if not args.session and not args.session_read:
        return requests.request(**requests_kwargs)
    else:
        return sessions.get_response(
            name=args.session or args.session_read,
            request_kwargs=requests_kwargs,
            read_only=bool(args.session_read),
        )


def get_requests_kwargs(args):
    """Translate our `args` into `requests.request` keyword arguments."""

    base_headers = defaults['base_headers'].copy()
    base_headers['User-Agent'] = DEFAULT_UA

    auto_json = args.data and not args.form
    if args.json or auto_json:
        base_headers['Accept'] = 'application/json'
        if args.data:
            base_headers['Content-Type'] = JSON

        if isinstance(args.data, dict):
            # If not empty, serialize the data `dict` parsed from arguments.
            # Otherwise set it to `None` avoid sending "{}".
            args.data = json.dumps(args.data) if args.data else None

    elif args.form and not args.files:
            # If sending files, `requests` will set
            # the `Content-Type` for us.
            base_headers['Content-Type'] = FORM

    credentials = None
    if args.auth:
        credentials = {
            'basic': requests.auth.HTTPBasicAuth,
            'digest': requests.auth.HTTPDigestAuth,
        }[args.auth_type](args.auth.key, args.auth.value)

    kwargs = {
        'prefetch': False,
        'method': args.method.lower(),
        'url': args.url,
        'headers': args.headers,
        'data': args.data,
        'verify': {
            'yes': True,
            'no': False
        }.get(args.verify, args.verify),
        'timeout': args.timeout,
        'auth': credentials,
        'proxies': dict((p.key, p.value) for p in args.proxy),
        'files': args.files,
        'allow_redirects': args.follow,
        'params': args.params,
        'config': {
            'base_headers': base_headers
        }
    }

    return kwargs