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# Copyright (c) 2017, 2021, Oracle and/or its affiliates. All rights reserved.
#

import json
import logging

import requests

from .patterns import COMMAND_PROPERTY
from .webutil import get_proxies

CONTENT_TYPE = 'Content-Type'
APPLICATION_JSON = 'application/json'   # default


def do_api_call(verb, uri, params=None, headers=None, data=None):
    """
    Perform an API call. Will raise an exception if the request fails.
    :param verb: string holding HTTP verb
    :param uri: URI string
    :param params: request parameters
    :param headers: HTTP headers dictionary
    :param data: data or None
    :return: the result of the handler call, can be None
    """
    logger = logging.getLogger(__name__)

    handler = getattr(requests, verb.lower())
    if handler is None or not callable(handler):
        raise Exception('Unknown HTTP verb: {}'.format(verb))

    logger.debug("{} API call: {} with data '{}' and headers: {}".
                 format(verb, uri, data, headers))
    r = handler(
        uri,
        data=data,
        params=params,
        headers=headers,
        proxies=get_proxies(uri)
    )

    if r is None:
        raise Exception("API call failed")

    r.raise_for_status()

    return r


def subst(src, substitutions):
    if substitutions:
        for pattern, value in substitutions.items():
            if value:
                src = src.replace(pattern, value)

    return src


def call_rest_api(command, substitutions=None, http_headers=None):
    """
    Make RESTful API call. Occurrence of the pattern in the URI
    (first part of the command) or data payload will be replaced by the name.

    Default content type is application/json.

    :param command: command (list of URI, HTTP verb, data payload,
                             HTTP header dictionary)
    :param substitutions: dictionary of pattern:value for command and/or
                          data substitution
    :param http_headers: optional dictionary of HTTP headers to be appended
    :return return value from given requests method
    """

    logger = logging.getLogger(__name__)

    if not isinstance(command, dict) or command.get(COMMAND_PROPERTY) is None:
        raise Exception("invalid command")

    command = command[COMMAND_PROPERTY]

    uri, verb, data, *_ = command
    try:
        headers = command[3]
        if headers and not isinstance(headers, dict):
            raise Exception("headers must be a dictionary")
    except IndexError:
        headers = {}

    if headers is None:
        headers = {}

    if http_headers:
        headers.update(http_headers)

    uri = subst(uri, substitutions)
    header_names = [x.lower() for x in headers.keys()]

    if data:
        if CONTENT_TYPE.lower() not in header_names:
            logger.debug("Adding header: {} = {}".
                         format(CONTENT_TYPE, APPLICATION_JSON))
            headers[CONTENT_TYPE] = APPLICATION_JSON

        for (k, v) in headers.items():
            if k.lower() == CONTENT_TYPE.lower():
                if headers[k].lower() == APPLICATION_JSON.lower():
                    logger.debug("Converting {} to JSON".format(data))
                    data = json.dumps(data)
                break

        data = subst(data, substitutions)
        logger.debug("entity data: {}".format(data))

    return do_api_call(verb, uri, headers=headers, data=data)