import os
import time
from datetime import datetime
from typing import Awaitable, Callable, Optional

import inject
from starlette.background import BackgroundTasks
from starlette.requests import Request
from starlette.responses import Response

from .fluentbit_gateway import FluentbitGateway
from .gateway import Gateway

__all__ = ["FastAPIAccessLogger"]


class FastAPIAccessLogger:
    def __init__(self, hostname: str, gateway_override: Optional[Gateway] = None):
        self.origin = f"{hostname}-{os.getpid()}"
        self.gateway_override = gateway_override

    @property
    def gateway(self) -> Gateway:
        return self.gateway_override or inject.instance(FluentbitGateway)

    async def __call__(
        self, request: Request, call_next: Callable[[Request], Awaitable[Response]]
    ) -> Response:
        time_received = time.time()
        response = await call_next(request)
        request_time = time.time() - time_received

        # Instead of logging directly, set it as background task so that it is
        # executed after the response. See https://www.starlette.io/background/.
        if response.background is None:
            response.background = BackgroundTasks()
        response.background.add_task(
            log_access, self.gateway, request, response, time_received, request_time
        )
        return response


def fmt_timestamp(timestamp: float) -> str:
    return datetime.utcfromtimestamp(timestamp).isoformat() + "Z"


async def log_access(
    gateway: Gateway,
    request: Request,
    response: Response,
    time_received: float,
    request_time: float,
) -> None:
    """
    Create a dictionary with logging data.
    """
    try:
        content_length = int(response.headers.get("content-length"))
    except (TypeError, ValueError):
        content_length = None

    try:
        view_name = request.scope["route"].name
    except KeyError:
        view_name = None

    item = {
        "tag_suffix": "access_log",
        "remote_address": getattr(request.client, "host", None),
        "method": request.method,
        "path": request.url.path,
        "portal": request.url.netloc,
        "referer": request.headers.get("referer"),
        "user_agent": request.headers.get("user-agent"),
        "query_params": request.url.query,
        "view_name": view_name,
        "status": response.status_code,
        "content_type": response.headers.get("content-type"),
        "content_length": content_length,
        "time": fmt_timestamp(time_received),
        "request_time": request_time,
    }
    await gateway.add(item)