# Copyright 2016 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import json
import urllib2


# HWID info types to request.
HWID_INFO_LABEL = 'dutlabel'
HWID_INFO_BOM = 'bom'
HWID_INFO_SKU = 'sku'
HWID_INFO_TYPES = [HWID_INFO_BOM, HWID_INFO_SKU, HWID_INFO_LABEL]

# HWID url vars.
HWID_VERSION = 'v1'
HWID_BASE_URL = 'https://www.googleapis.com/chromeoshwid'
URL_FORMAT_STRING='%(base_url)s/%(version)s/%(info_type)s/%(hwid)s/?key=%(key)s'


class HwIdException(Exception):
    """Raised whenever anything fails in the hwid info request."""


def get_hwid_info(hwid, info_type, key_file):
    """Given a hwid and info type, return a dict of the requested info.

    @param hwid: hwid to use for the query.
    @param info_type: String of info type requested.
    @param key_file: Filename that holds the key for authentication.

    @return: A dict of the info.

    @raises HwIdException: If hwid/info_type/key_file is invalid or there's an
                           error anywhere related to getting the raw hwid info
                           or decoding it.
    """
    if not isinstance(hwid, str):
        raise ValueError('hwid is not a string.')

    if info_type not in HWID_INFO_TYPES:
        raise ValueError('invalid info type: "%s".' % info_type)

    key = None
    with open(key_file) as f:
        key = f.read().strip()

    url_format_dict = {'base_url': HWID_BASE_URL,
                       'version': HWID_VERSION,
                       'info_type': info_type,
                       'hwid': hwid,
                       'key': key}

    url_request = URL_FORMAT_STRING % url_format_dict
    try:
        page_contents = urllib2.urlopen(url_request)
    except (urllib2.URLError, urllib2.HTTPError) as e:
        # TODO(kevcheng): Might need to scrub out key from exception message.
        raise HwIdException('error retrieving raw hwid info: %s' % e)

    try:
        hwid_info_dict = json.load(page_contents)
    except ValueError as e:
        raise HwIdException('error decoding hwid info: %s - "%s"' %
                            (e, page_contents.getvalue()))
    finally:
        page_contents.close()

    return hwid_info_dict