#  BSD 3-Clause License
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#  Copyright (c) 2019, Elasticsearch BV
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import asyncio

from starlette.datastructures import Headers
from starlette.requests import Request
from starlette.types import Message

from elasticapm.conf import Config, constants
from elasticapm.utils import get_url_dict


async def get_data_from_request(request: Request, config: Config, event_type: str) -> dict:
    """Loads data from incoming request for APM capturing.

    Args:
        request (Request)
        config (Config)
        event_type (str)

    Returns:
        dict
    """
    result = {
        "method": request.method,
        "socket": {"remote_address": _get_client_ip(request)},
        "cookies": request.cookies,
    }
    if config.capture_headers:
        result["headers"] = dict(request.headers)

    if request.method in constants.HTTP_WITH_BODY:
        if config.capture_body not in ("all", event_type):
            result["body"] = "[REDACTED]"
        else:
            body = None
            try:
                body = await get_body(request)
            except Exception:
                pass
            if body is not None:
                result["body"] = body

    result["url"] = get_url_dict(str(request.url))

    return result


async def get_data_from_response(message: dict, config: Config, event_type: str) -> dict:
    """Loads data from response for APM capturing.

    Args:
        message (dict)
        config (Config)
        event_type (str)

    Returns:
        dict
    """
    result = {}

    if "status" in message:
        result["status_code"] = message["status"]

    if config.capture_headers and "headers" in message:
        headers = Headers(raw=message["headers"])
        result["headers"] = {key: ";".join(headers.getlist(key)) for key in headers.keys()}

    return result


async def set_body(request: Request, body: bytes) -> None:
    """Overwrites body in Starlette.

    Args:
        request (Request)
        body (bytes)
    """

    async def receive() -> Message:
        await asyncio.sleep(0)
        return {"type": "http.request", "body": body}

    request._receive = receive


async def get_body(request: Request) -> str:
    """Gets body from the request.

    When we consume the body, we replace the streaming mechanism with
    a mocked version -- this workaround came from
    https://github.com/encode/starlette/issues/495#issuecomment-513138055

    Args:
        request (Request)

    Returns:
        str
    """
    body = await request.body()
    await set_body(request, body)

    request._stream_consumed = False

    return body.decode("utf-8", errors="replace")


async def query_params_to_dict(query_params: str) -> dict:
    """Transforms query params from URL to dictionary

    Args:
        query_params (str)

    Returns:
        dict

    Examples:
        >>> print(query_params_to_dict(b"key=val&key2=val2"))
        {"key": "val", "key2": "val2"}
    """
    query_params = query_params.split("&")
    res = {}
    for param in query_params:
        key, val = param.split("=")
        res[key] = val

    return res


def _get_client_ip(request: Request):
    x_forwarded_for = request.headers.get("HTTP_X_FORWARDED_FOR")
    if x_forwarded_for:
        ip = x_forwarded_for.split(",")[0]
    else:
        ip = request.headers.get("REMOTE_ADDR")
    return ip