from __future__ import annotations

import json
import time

from django.views.decorators.csrf import csrf_exempt
from django.http import HttpResponse, StreamingHttpResponse
from rest_framework.decorators import api_view
from rest_framework.response import Response

from .services import gps_service, network_service, video_service


@api_view(["GET"])
def dashboard_snapshot(request):
    return Response(
        {
            "gps": gps_service.get_latest(),
            "network": network_service.get_latest(),
            "video": video_service.get_status(),
        }
    )


@api_view(["GET"])
def gps_latest(request):
    return Response(gps_service.get_latest())


@api_view(["GET"])
def network_latest(request):
    return Response(network_service.get_latest())


@api_view(["GET"])
def clock_calibration(request):
    server_received_unix_ns = time.time_ns()
    server_sent_unix_ns = time.time_ns()
    response = Response(
        {
            "server_received_unix_ms": round(server_received_unix_ns / 1_000_000.0, 3),
            "server_sent_unix_ms": round(server_sent_unix_ns / 1_000_000.0, 3),
        }
    )
    response["Cache-Control"] = "no-store, no-cache, must-revalidate, max-age=0"
    return response


@api_view(["GET"])
def video_status(request):
    return Response(video_service.get_status())


def video_frame(request):
    try:
        frame, headers = video_service.get_next_frame_with_headers()
    except (FileNotFoundError, RuntimeError) as error:
        status = video_service.get_status()
        return HttpResponse(
            status.get("source_detail") or str(error),
            status=503,
            content_type="text/plain; charset=utf-8",
        )

    response = HttpResponse(frame, content_type="image/jpeg")
    response["Cache-Control"] = "no-store, no-cache, must-revalidate, max-age=0"
    for key, value in headers.items():
        response[key] = value
    return response


def video_stream(request):
    status = video_service.get_status()
    if not status["available"]:
        return HttpResponse(
            status.get("source_detail") or f"JPEG frame directory not found: {status['frame_dir']}",
            status=503,
            content_type="text/plain; charset=utf-8",
        )

    try:
        fps = float(request.GET.get("fps", status["fps"]))
    except (TypeError, ValueError):
        fps = float(status["fps"])

    response = StreamingHttpResponse(
        video_service.iter_mjpeg(fps=fps),
        content_type="multipart/x-mixed-replace; boundary=frame",
    )
    response["Cache-Control"] = "no-store, no-cache, must-revalidate, max-age=0"
    return response


@csrf_exempt
@api_view(["POST"])
def video_display_probe(request):
    try:
        payload = json.loads(request.body.decode("utf-8"))
    except (UnicodeDecodeError, json.JSONDecodeError):
        return Response({"detail": "invalid json"}, status=400)

    if not isinstance(payload, dict):
        return Response({"detail": "expected json object"}, status=400)

    video_service.record_display_probe(payload)
    return Response({"ok": True})